Code of practice for demolition - xa.yimg.comxa.yimg.com/.../name/BS_6187_Code_of_Practice_for_Demolition.pdf · Figure 14 — Example of designed exclusion zone showing practical

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BRITISH STANDARD BS 6187:2000

ICS 91.200

NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW

Code of practicefor demolition

This British Standard, havingbeen prepared under thedirection of the SectorCommittee for Building and CivilEngineering, was published underthe authority of the StandardsCommittee and comes into effecton 15 September 2000

BSI 09-2000

First published as CP 94 in 1971Second edition published asBS 6187 in 1982Third edition publishedSeptember 2000

The following BSI referencesrelate to the work on thisstandard:Committee reference B/513/9Draft for comment 97/106292 DC

ISBN 0 580 33206 3

BS 6187:2000

Amendments issued since publication

Amd. No. Date Comments

Committees responsible for thisBritish Standard

The preparation of this British Standard was entrusted by Technical CommitteeB/513, Construction equipment and plant, and site safety, to Subcommittee B/513/9,Demolition, upon which the following bodies were represented:

Construction Health and Safety Group

District Surveyors Association

Drilling and Sawing Association

Health and Safety Executive

Institute of Demolition Engineers

Institute of Explosives Engineers

Institution of Civil Engineers

Institution of Structural Engineers

National Federation of Demolition Contractors

National Joint Utilities Group

Royal Institute of British Architects

Royal Institution of Chartered Surveyors

BS 6187:2000

BSI 09-2000 i

Contents

PageCommittees responsible Inside front coverForeword ii

Introduction 11 Scope 42 Normative references 43 Terms and definitions 54 Legislative overview (see Figure 4) 105 Planning and managing projects (see Figure 5) 176 Tenders and contracts 227 Knowledge of the site (see Figure 6) 258 Decommissioning procedures (see Figure 7) 319 Structural hazards (see Figure 8) 34

10 Health hazards (see Figure 9) 3811 Protection of the environment (see Figure 10) 4212 Health and safety of persons on or off site (see Figure 11) 5013 Safe working spaces and exclusion zones (see Figure 12) 6014 Principles of structural demolition (see Figure 17) 6915 Avoidance of unplanned structural collapses (see Figure 19) 7216 Temporary structures for stability and access (see Figure 20) 7517 Demolition techniques (see Figure 21) 7918 Materials handling and processing 8919 Typical demolition methods for various types of structure (see Figure 22) 9320 Completion of the works 102

Annex A (informative) Training and competencies 103Annex B (informative) Useful contacts 104Annex C (normative) Hazards associated with prestressed materials 114

Bibliography 118

Figure 1 Ð Outline route map 2Figure 2 Ð Flowchart for the suggested use of structural stability clauses 3Figure 3 Ð Illustration of the definitions of base machine, equipment andattachments 8Figure 4 Ð Route map for clause 4 9Figure 5 Ð Route map for clause 5 16Figure 6 Ð Route map for clause 7 24Figure 7 Ð Route map for clause 8 30Figure 8 Ð Route map for clause 9 33Figure 9 Ð Route map for clause 10 37Figure 10 Ð Route map for clause 11 41Figure 11 Ð Route map for clause 12 49Figure 12 Ð Route map for clause 13 59Figure 13 Ð Terminology of designed exclusion zone and its constituent parts 62Figure 14 Ð Example of designed exclusion zone showing practical application 63Figure 15 Ð Example of designed exclusion zone showing phased and partialdemolition 64Figure 16 Ð Example of reduced exclusion zone by the use of containment 65Figure 17 Ð Example of safe working space within an exclusion zone 66Figure 18 Ð Route map for clause 14 68Figure 19 Ð Route map for clause 15 72Figure 20 Ð Route map for clause 16 75Figure 21 Ð Route map for clause 17 78Figure 22a Ð Route map for clause 19 (sheet 1) 91Figure 22b Ð Route map for clause 19 (sheet 2) 92

Table 1 Ð Items to be included in Health and Safety Plans (examples) 20Table 2 Ð Examples of key features for sampling 29Table 3 Ð Areas comprising an exclusion zone 61Table 4 Ð Examples of hazards related to the areas of an exclusion zone 61

ii BSI 09-2000

BS 6187:2000

Foreword

This Code of Practice has been prepared by Subcommittee B/513/9 which comprisespeople with a wide experience of demolition, from a variety of interestedorganizations. This document supersedes BS 6187:1982 which is withdrawn.

This revision of BS 6187 is a re-write of the 1982 version which takes into account theadvances in technology and equipment that are available to the demolition industry.The application of new techniques and the effects of new legislation that has beenintroduced, particularly health and safety, and environmental legislation, including theConstruction (Design and Management) Regulations 1994, the Construction (Health,Safety and Welfare) Regulations 1996, the Management (Health, Safety and Welfare)Regulations 1999 and the Environmental Protection Act 1990 have been taken intoaccount. The document is written for all involved in demolition (which includes partialdemolition) projects and gives emphasis to responsibilities from concept stage tocompletion. This code addresses the health and safety of those engaged in thedemolition process and also of those members of the public who may be affected bythe demolition activities.

This edition of BS 6187 has been expanded to cover, for example, project developmentand management, site assessments, risk assessments, decommissioning procedures,environmental requirements and faõade retention. Deconstruction techniques areconsidered, including activities for re-use and recycling. Principles relating to exclusionzones and safe working spaces, their design and application have also been added.

Clauses on recommendations for methods of, and techniques for, demolition, togetherwith considerations of specific types of structure have been retained. The text hasbeen significantly updated, however, to reflect current and developing best practices,allowing for innovative techniques and methods to be developed and introduced, bybeing less prescriptive.

As a Code of Practice, this British Standard takes the form of guidance andrecommendations. It should not be quoted as if it were a specification and particularcare should be taken to ensure that claims of compliance are not misleading.

A British Standard does not purport to include all the necessary provisions of acontract. Users of British Standards are responsible for their correct application. Thiscode of practice can, however, be included as part of a contractual relationship.

Annexes A and B are informative and annex C is normative.

Compliance with a British Standard does not of itself confer immunityfrom legal obligations.

Summary of pages

This document comprises a front cover, an inside front cover, pages i and ii, pages 1to 120, an inside back cover and a back cover.

The BSI copyright notice displayed in this document indicates when the document waslast issued.

BS 6187:2000

BSI 09-2000 1

IntroductionThis Code of Practice concerns the process of demolition from initial considerations, through planning, to theexecution stages, see Figure 1.

This Code has been written on the understanding that the execution of its provisions is entrusted toappropriately qualified and competent people.

Route maps have been included at the beginning of most clauses to guide the user through the information in thetext. This is particularly in respect of the hierarchy and interdependence of use of the clauses and sub-clauses,which may not always be obvious because of the complexity of the demolition process and the wide coverage inthis document. Part of the complexity arises because a demolition project from inception to completion is acomplex process that involves many activities, many of which are iterative (but at different levels) and whichrequire re-visiting. An example is, as the project moves through the tender process to contract acceptance andonto site operations by referring to planned methods of work which will be developed and augmented further ateach of these stages.

The maps are not intended to be process flowcharts, but indicative of the interdependence. One flow chart isincluded, however, which shows the processes in the document for dealing with structural stability (see Figure 2).

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BS 6187:2000

Scope1.0

Normativereferences2.0

Terms and definitions3.0

Legislativeoverview4.0

Bibliography

AnnexesA,B and C

Planning and managingprojects; Tenders and contracts5.0, 6.0

Knowledgeof the site;Structural hazards:Health hazards7.0, 9.0, 10.0

Decommissioningprocedures8.0

Protection of theenvironment11.0

Health and safetyof persons on or offsite12.0

Safe working spacesand exclusion zones13.0

Principles ofstructuraldemolition14.0

Start

Avoidance ofunplannedstructuralcollapses15.0

Temporary structures forstability and access16.0

Demolitiontechniques17.0

Materials handlingand processing18.0

Typical demolition methodsfor various types ofstructure19.0

Completion of the works20.0

Finish

Figure 1 Ð Outline route map

BS 6187:2000

BSI 09-2000 3

Clause 7Complete acquisition of

knowledge of site

Clause 9Determine the structural

hazards

Clause 17Select appropriate

demolition technique

Clause 19Check suitability of chosen

method for the structurebeing demolished

Clause 14Select type of demolition to

be used

Clause 12Check that health and safetyaspects are not compromised

by choice made

Clause 15Is unplanned collapse possible?

Clause 13Can safe working area and

exclusion zone beestablished?

Clause 16Will temporary support provide

solution?

Demolition can proceed

If not OK

If not OK

If OK

If OK

No

No

No

Yes

Yes

Yes

Figure 2 Ð Flowchart for the suggested use of structural stability clauses

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BS 6187:2000

1 ScopeThis Code recommends good practice methods for the demolition (both partial and whole), as well asdecommissioning, of sites including buildings and structures. It takes into account safety, health and issues whichaffect the protection of environment. Recommendations are included for:

a) the proper, and effective, management of the demolition process;

b) maintaining structural stability, through the provision of temporary structural support, where necessary;

c) managing deliberate structural collapse.

The Code gives recommendations for:

Ð identifying and establishing responsibilities during all phases of the demolition process;

Ð acquiring a knowledge of the site, including its former uses;

Ð appropriate environmental management;

Ð managing health and safety hazards;

Ð carrying out risk assessments, and planning the work accordingly;

Ð establishing and managing procedures effectively;

Ð determining and managing safe exclusion zones.

2 Normative referencesThe following normative documents contain provisions, which, through reference in this text, constituteprovisions of this Code of Practice. For dated references, subsequent amendments to, or revisions of, any ofthese publications do not apply. For undated references, the latest edition of the publication referred to applies.

BS 5228-1, Noise and vibration control on construction and open sites Ð Part 1: Code of practice for basicinformation and procedures for noise and vibration control.

BS 5228-2, Noise and vibration control on construction and open sites Ð Part 2: Guide to noise and vibrationcontrol legislation for construction and demolition, including road construction and maintenance.

BS 5228-4, Noise and vibration control on construction and open sites Ð Part 4: Code of practice for noise andvibration control applicable to piling operations.

BS 5607, Code of practice for safe use of explosives in the construction industry.

BS 5837, Guide for trees in relation to construction.

BS 5973, Code of practice for access and working scaffolds and special scaffold structures in steel.

BS 5974, Code of practice for temporary installed suspended scaffolds and access equipment (partiallysuperseded by BS EN 1808).

BS 5975, Code of practice for falsework.

BS 6100, Glossary of building and civil engineering terms.

BS 6164, Code of practice for safety in tunnelling in the construction industry.

BS 6399-2, Loading for buildings Ð Part 2: Code of practice for wind loads.

BS 6472, Guide to evaluation of human exposure to vibration in buildings (1 Hz to 80 Hz).

BS 6482, Guide to measurement and evaluation of human exposure to vibration transmitted to the hand.

BS 7121-1, Code of practice for safe use of cranes Ð Part 1: General.

BS 7121-2, Code of practice for safe use of cranes Ð Part 2: Inspection, testing and examination.

BS 7121-3, Code of practice for safe use of cranes Ð Part 3: Mobile cranes.

BS 7121-4, Code of practice for safe use of cranes Ð Part 4: Lorry loaders.

BS 7121-5, Code of practice for safe use of cranes Ð Part 5: Tower cranes.

BS EN 1808, Safety requirements on suspended access equipment Ð Design calculations, stability criteria,construction Ð Tests.

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BSI 09-2000 5

3 Terms and definitionsFor the purposes of this Code of Practice, the definitions in BS 6100, together with the following apply.

3.1

adjoining owners

freeholders, owners, lessees, tenants and/or occupiers of a property adjoining the site of demolition

3.2

attachment

assembly of components forming the working tool that can be mounted onto the base machine or (optional)equipment for specific use (see Figure 3)

3.3

base machine

machine without equipment and attachment, that includes the mountings necessary to secure equipment, asrequired, e.g. operator protective structures for demolition (see Figure 3)

3.4

building owner

person or organization having the right to demolish or partly demolish a building, including plant or otherstructure, by virtue of legal ownership or other legal authority

3.5

client

initiator of the demolition project (usually the building owner) or, e.g. a main contractor

NOTE 1 Client can also have a particular meaning in contractual relationships.

NOTE 2 Client has a specific meaning under the Construction (Design and Management) Regulations 1994 (CDM Regulations 1994) [1](see 4.2.9.4).

3.6

cold cutting

method of cutting with the generation of no incendiary sparks and little or no heat

3.7

competent person

person who has training and experience relevant to the matter being addressed, and has an understanding of therequirements of the particular task being approached (see annex A)

NOTE Such a person should understand the hazards and the methods to be implemented to eliminate or reduce the risks that mayarise. For example, when on site, such a person should recognize at all times whether it is safe to proceed.

3.8

complex structure

structure with unusual or complicated load paths or internal forces which, because they may not be obvious,makes the prediction of safe modes of failure during demolition difficult (and hence the need for the involvementof an appropriately competent person)

3.9

contaminated site

site which harbours residual health hazards resulting from the presence of biological or chemical entities

3.10

decommissioning

process whereby an area is brought from its fully operational status to one where all live or charged systems arerendered dead or inert and reduced to the lowest possible hazard level (see also 3.24)

NOTE Decommissioning includes decontamination where appropriate. Some industries, e.g. the nuclear industry, have specificmeanings for this term which include dismantling. In practice different hazard levels will apply. In this Code of Practicedecommissioning does not include demolition or dismantling.

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BS 6187:2000

3.11

deliberate collapse

controlled removal of key structural members causing complete collapse in a planned way of the whole or partof the building or structure being demolished

3.12

deliberate removal

controlled removal of selected components of the structure by dismantling or deconstruction

3.13

equipment

set of components mounted onto the base machine to fulfil the primary design function when an attachment isfitted (see Figure 3) (see also 3.25)

3.14

exclusion zone

designated three-dimensional space from which all persons, including the public, are excluded during demolitionactivitiesNOTE In certain circumstances key site personnel may remain within the zone for a specific task provided they are adequatelyprotected.

3.15

facade retention

method of maintaining the outer wall of a building or structure in its original position during and after demolitionby using appropriately designed temporary structures (see also 3.33)

3.16

fan

temporary platform at height, usually formed in scaffolding projecting from a building or structure at an inclinedangle, used solely to contain any debris accidentally dropped in the demolition process, preventing such debrisfrom being a danger to persons or property below (see also 3.17)NOTE Fans are not intended to be used for access or as working platforms.

3.17

gantry

temporary structure providing a covered way that protects people from unplanned falls of materials(see also 3.16)

3.18

hand-held equipment

powered portable equipment or manual tools for operation in the hand of one or two operatives

3.19

health and safety file

record of information as required by the CDM Regulations 1994 [1], for the client or for the end user, on the keyhealth and safety risks that will need to be addressed during subsequent work on the site, which can includeland development or, where appropriate, maintenance, repair and eventual demolition

3.20

health and safety plan

document which contains the arrangements for securing the health and safety of everyone carrying out thedemolition work and all others who may be affected by it, as required by the CDM Regulations 1994 [1](see clause 5, Table 1)

3.21

high-pressure water jetting

cutting, removal or cleaning of material by the use of high-pressure water

3.22

hot cutting

method of cutting where heat is applied, e.g. by flame, or is generated, and/or where there is potentialfor producing incendiary sparks

BS 6187:2000

BSI 09-2000 7

3.23

mobile demolition machine

self-propelled machine made for, or adapted for use on, demolition sites which comprises a base machine (3.3),equipment (3.13), optional equipment (3.25) and attachments (3.2), as appropriate (see Figure 3)

3.24

mothballing

process of decommissioning and then preserving buildings, plant or structures in such a way that they can bereadily brought back into service if required (see also 3.10)

3.25

optional equipment

optional items of equipment mounted onto the base machine to increase, e.g. capacity, flexibility, comfort and/orsafety (see Figure 3) (see also 3.13)

3.26

permit to work procedure

procedure which sets out the agreed work to be undertaken on identified equipment, or in an identified area, andthe precautions to be taken and managed as part of a safe system of work (see 12.7)

3.27

planning supervisor

person or organization that has responsibility for co-ordinating health and safety issues relating to designactivities, as required by the CDM Regulations 1994 [1]

3.28

prestressed element

structural element in which compressive stresses are built in to the parent material, for example, concrete orblockwork, by tensioning wires or bars to give strength prior to working loads being imposed

3.29

post-tensioned prestressed element

prestressed structural element in which the wires or bars are tensioned after the material to be compressed is inplace and has reached a suitable strength

3.30

pretensioned prestressed element

prestressed structural element in which the wires or bars are tensioned prior to the placing of the material to becompressed, e.g. before concrete is poured, and then released after the material has reached a suitable strength

3.31

pre-weakening

deliberate weakening of a structure as part of a more efficient controlled design collapse mechanism to beeffected a short time afterwards (see also 3.34)

3.32

progressive demolition

controlled in situ removal of parts of the structure whilst maintaining the stability of the remainder

3.33

shoring (including propping)

system of temporary supports which provide a load path to maintain stability (see also 3.15)

3.34

weakening

deliberate removal of parts of a structure that can reduce its ability to resist loadings, including imposed loadingsand its own self-weight

NOTE Weakening may be undertaken to create openings (for example, in walls and floors) for removal of materials, for example, butexcludes deliberate structural pre-weakening (see 3.31).

8 BSI 09-2000

BS 6187:2000

Protective cage overand in front of operativescabin (and to the sides ifappropriate)

Dipper arm Boom

Optional extension

Examples of optionalattachments

Equipment

Base machine

NOTE This is an example. The equipment and attachments can differ.

Figure 3 Ð Illustration of the definitions of base machine, equipment and attachments

BS 6187:2000

BSI 09-2000 9

Legislative overview4

Legislative framework4.1

National and localvariations

4.1.2

Statutory requirements4.2

General4.2.1

General4.1.1

Specialrequirements

4.2.1.1

Permissions4.2.2

Buildings4.2.3

Dangerousstructures

4.2.1.2

Occupationalhealth and safety

4.2.9

Environment4.2.8

Party walls4.2.4

Utilities4.2.6

Insurances4.2.7

Highways androad4.2.5

General4.2.5.1

General4.2.8.1

Rights of accessand avoidanceof congestion

4.2.5.2

Use of plant onor over highways

or roads4.2.5.3

Erection of temporarystructures on or

over highways or roads4.2.5.4

Waste4.2.8.2

Control of burningon site4.2.8.3

Others4.2.9.10

RIDDOR4.2.9.9

COSHHR4.2.9.8

LOLER4.2.9.7

PUWER4.2.9.6

CHSWR4.2.9.5

CDMR4.2.9.4

MHSWR4.2.9.3

HSW Act4.2.9.2

General4.2.9.1

Figure 4 Ð Route map for clause 4

10 BSI 09-2000

BS 6187:2000

4 Legislative overview (see Figure 4)

4.1 Legislative framework

4.1.1 General

All demolition work should be carried out in accordance with appropriate acts and their supplementaryregulations and the relevant British Standards. Equipment, materials and designs used in the work shouldconform to these regulations and British Standards.

Statutory requirements can alter during the currency of this standard and all such requirements should bechecked for accuracy at the time of use.

When the value of a contract is estimated to be above the European Union (EU) limit, it should be advertised inthe Official Journal of the European Community.

NOTE This is covered by British law in the Utilities Contracts Regulations 1996 [2].

4.1.2 National and local variations

Legislation can vary nationally, such as in Scotland, Wales, Northern Ireland or under local authorities, and therequirements of any particular site should be ascertained (see B.2 for contact points of government departments,agencies, authorities and enforcers).

NOTE 1 National and local statutory requirements are enforced by local and other authorities and agencies.

NOTE 2 Information and advice can be obtained from enforcing authorities such as the Health and Safety Executive, the EnvironmentAgency and local authorities (see B.2). Further advice can be sought, for example, from the relevant professional institutions andindustry associations.

4.2 Statutory requirements

NOTE This clause gives examples of relevant legislation but is not exhaustive.

4.2.1 General

4.2.1.1 Special requirements

Special requirements should be applied, where appropriate on some sites or parts of sites, for example, whichmay be or may have been subject to the Nuclear Installations (Dangerous Occurrences)Regulations 1965 (as amended) [3] or the Control of Major Accident Hazards Regulations 1999 (COMAHRegulations 1999) [4]. Early consultation between licensees and/or duty holders and all relevant regulatoryauthorities should be undertaken in such cases.

4.2.1.2 Dangerous structures

When a dangerous structure is dealt with by a local authority or equivalent regulatory authority under statute forexempt sites, the demolition or remedial works should be completed to the authority's satisfaction and mayinclude the provision of temporary supports or shoring. Discussions should be held with the authority to ensurethat an acceptable solution is implemented.

4.2.2 Permissions

As permissions are required under a variety of acts and regulations, the property owner/developer (client) shouldobtain approvals including any planning permission, as appropriate. Contractors should ensure that suchapprovals have been granted before work commences. Contractors should obtain all permissions for which theyare responsible, and comply with the conditions imposed by the local authority or any other appropriate body,particularly in relation to any licenses, deposits and indemnities required, e.g. for hoarding, fencing, lighting,barriers, platforms, ramps and handrails for public safety. In addition, the requirements of any regulatoryauthority for exempt sites should be taken into account.

Examples of primary acts are:

a) Town and Country Planning Act 1990 [5] (Tree Preservation and Conservation Areas Orders are covered inSection 197 et seq. of the Act);

b) Planning (Listed Buildings and Conservation Areas) Act 1990 [6];

c) Building Act (England and Wales) 1984 [7], see 4.2.3.1;

d) Building (Scotland) Acts 1959 [8] and 1970 [9], see 4.2.3.2;

e) Highways Act 1980 [10], see 4.2.5;

f) Roads (Scotland) Act 1984 [11], see 4.2.5;

g) New Roads and Street Works Act 1991 [12], see 4.2.5;

h) Party Wall etc. Act 1996 [13], see 4.2.4.

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BSI 09-2000 11

4.2.3 Buildings

4.2.3.1 England and Wales

Local authority control of demolition in England and Wales is covered by the Building Act (England and Wales)(1984) [7], with very few exceptions, e.g. some sections of this Act do not apply in inner London. Apart fromcertain exemptions listed in Section 80 of the Act, any person intending to carry out demolition works is requiredto give notice under Section 80 to the local authority. That authority then has six weeks in which to serve aªCounter Noticeº under Section 81 of the Act.

In the ªCounter Noticeº the local authority, or equivalent regulatory authority for exempt sites, has powers torequire that, for example:

a) any building adjacent to the building to which the notice relates be shored up;

b) any surfaces of an adjacent building that are exposed by the demolition be weatherproofed;

c) any damage to an adjacent building caused either by the demolition or by the negligent act or omission ofany person engaged upon it be repaired and be made good;

d) any material or rubbish resulting from the demolition and clearance of the site be removed;

e) any sewer or drain in or under the building be disconnected and sealed at such points that the authoritymay require;

f) any such sewer or drain be removed and any connecting sewer or drain, be sealed;

g) the surface of the ground disturbed by anything done under e) or f) above be made good to the satisfactionof the authority;

h) arrangements are made with the services providers for the disconnection of the supply of, for example, gas,electricity and water to the building;

i) arrangements be made for the burning of structures or materials on the site by the fire authority(but see also 4.2.8.3);

j) steps relating to the conditions subject to which the demolition is to be undertaken, and the condition inwhich the site is to be left on completion of the demolition, are taken, as may be considered reasonablynecessary for the protection of the public and the preservation of public amenity.

4.2.3.2 Scotland

Demolition is subject to the Building (Scotland) Acts 1959 [8] and 1970 (as subsequently amended) [9]. The Actsrequire that before any work can commence, a warrant be obtained from the local authority. The warrant will beissued only if the authority is satisfied that the work will be carried out in accordance with the BuildingOperations (Scotland) Regulations 1975 [14] and that it will be completed within the period of time specified inthe warrant. The Building Procedure (Scotland) Regulations 1981 [15] as amended by the Building Procedure(Scotland) Amendment Regulations 1991 [16] should be consulted for the procedures for obtaining the warrant.Section 1 of these regulations deals with demolition and includes:

(1) a statement showing by what manner the applicant proposes to demolish the building;

(2) a statement providing information on the construction of the building proposed to be demolished;

(3) a section drawing of the building proposed to be demolished.

NOTE Site protection and clearance are covered by, e.g. The Building Operations (Scotland) Regulations 1975 [14].

4.2.4 Party Walls

The Party Wall etc. Act 1996 [13] provides a framework designed to prevent and resolve disputes which frequentlyoccur between neighbouring owners when works are undertaken to party walls. It applies to commercial andresidential premises alike. The Act applies in England and Wales and the provisions are also recommended forapplication elsewhere.

The Act covers three main areas:

a) the construction of a new wall which straddles the boundary between adjoining properties in separateownership;

b) repairs and works to existing party walls;

c) excavation works within 3 m of any building on a neighbour's land.

The Act applies to existing walls that straddle the boundary line between adjoining properties. It thereforeapplies to an internal boundary wall dividing a semi-detached or terraced house, for example, and also toexternal boundary walls dividing gardens of the properties.

Prescriptive rights can exist in the building owner's structure. In such cases any rights of support acquired by theadjoining owner/occupier over a period should be maintained. The Party Wall etc. Act 1996 [13] procedures donot strictly apply to such circumstances but it is recommended that they be applied.

12 BSI 09-2000

BS 6187:2000

4.2.5 Highways and roads

4.2.5.1 General

Where the demolition works would be helped by a partial or total closure of public and/or private roads andhighways, the relevant roads or highway authorities (or other owner) should be approached at an early stage toobtain the necessary permissions. As periods of notice are involved, sufficient time should be allowed for theprocess to be completed within the requirements of each particular case.

NOTE Temporary closures will often only be granted at weekends or between evening and early morning. The Road Traffic (TemporaryRestrictions) Act 1991 [17] applies.

Consideration should be given to making arrangements for temporary diversions of both pedestrian and vehiculartraffic and discussions should take place at an early stage with, for example, the emergency services and busoperators.

The requirements of pedestrians and all statutory undertakers should be taken into account (see 4.2.6).

Where temporary traffic management is to be provided, chapter 8 of the Traffic Signs Manual [18] and theCode of Practice for Signing and Guarding at Road Works [19] should be consulted for guidance, even when theNew Roads and Streetworks Act 1991 [12] does not apply.

4.2.5.2 Rights of access and avoidance of congestion

The roads or highways authority and police should be consulted about site access, safety and matters oftransport to avoid or minimize congestion, particularly in densely populated areas.

Where access to a site is across a footway the demolition contractor should consult the roads or highwaysauthority or other owner to obtain all necessary permissions. Suitable access to adjacent and nearby propertiesshould be maintained. Access across such properties is a matter for the relevant owners; agreements should benegotiated and any indemnities confirmed. Footways, over which there are crossings, should be adequatelystrengthened to the authority's (or other owner's) satisfaction and at the contractor's expense.

All works affecting features outside the curtilage of the site, e.g. footway lights, vaults and other voids under thehighway, require the approval of the authority, which should be sought.

NOTE 1 The relevant roads or highways authority can require vaults and voids to be filled in accordance with their specification, undertheir supervision and to their satisfaction, at the contractor's expense.

Any proposals to use local streets as holding areas for site vehicles should be planned and should consider usersand residents.

NOTE 2 In some areas local streets would not be appropriate for use as holding areas for site vehicles.

4.2.5.3 Use of plant on or over highways or roads

For any form of plant or equipment using the public highway for support, or oversailing the public highway toany extent, the permission of the appropriate authority should be obtained and applications and consentsformally recorded.

NOTE In some cases permits or licences are required.

Where scaffolding or a crane jib will pass over adjoining property, a licence is required which should be soughtfrom the freeholder/lessee/tenant/occupier. Proposals should be discussed with the authority at an early stage,before starting work on site, in order to facilitate the operation, reduce the risk of delay and place relationshipswith the community on a sound footing.

4.2.5.4 Erection of temporary structures on or over highways or roads

Consent for the erection of all temporary structures (including scaffolds, fans, screens, hoardings and anysupports to the remaining structure) on or over highways and roads should be obtained. These structures shouldbe included as part of the contractor's ªtemporary structuresº and the consent should be for however long theyremain in place. Such structures, when completed, should conform to the requirements of the statutoryregulations and with any local authority requirements. Designs for support to remaining structures, e.g. faõades,or basement retaining walls, should be submitted to the local authority for approval. (See clause 16 for furtheradvice.)

NOTE 1 In some cases authorities will insist on such support being at the rear face of the structure.

NOTE 2 Copies of the appropriate planning permission, and where necessary approval of details, is required to accompany applicationsfor the approval of temporary structures.

4.2.6 Utilities

Utilities, when they are statutory undertakers, have specific rights particularly of permanent and continuousaccess to their equipment. Arrangements should be made to ensure that those rights are planned for. Utilities thatcan be affected should be identified and consulted (see also 4.2.5.1 and B.3).

NOTE Statutory undertakers are subject to the provision of the New Roads and Street Works Act 1991 [12].

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4.2.7 Insurances

Contractors should have public and employer's liability insurance and should abide by the terms of thatinsurance.

Clients should ensure that demolition contractors have appropriate and adequate insurance cover for the workbeing undertaken, paying particular attention to the insurance policy, contractor's business description, limits ofindemnity, policy exclusions and any hotwork conditions.

CAUTION Often only restrictive insurance protection is offered by underwriters for demolition and ancillaryworks.

4.2.8 Environment

4.2.8.1 General

NOTE The term ªenvironmentº covers many topics, including waste management and emissions from site such as fumes, fluids, noise,dust, smoke and vibration.

Clause 11 should be referred to for more detail and further legal issues, including polluting emissions.

4.2.8.2 Waste

Those concerned with controlled waste should comply with the waste management licensing system and with theduty of care, as provided for by Part II of the Environmental Protection Act 1990 [20]. Controlled waste should beconsidered to be household, commercial and industrial waste and any other such waste, including unwantedsurplus substances, building and demolition waste and anything that is disposed of as broken, worn out,contaminated or spoiled in some other way.

Account should be taken of the Special Waste Regulations 1996 as amended [49] in respect of the most hazardouswastes that are classified and subject to stricter controls. Account should also be taken of regulations on thetransport of such wastes. (See 11.4.)

4.2.8.3 Control of burning on site

The control of the burning of materials on site is generally subject to Section 80 (Nuisance provisions) of theEnvironmental Protection Act 1990 [20] and the Clean Air Act 1993 [21]. (See also clause 11.)

4.2.9 Occupational health and safety

4.2.9.1 General

Demolition and decommissioning processes are required to conform to occupational health and safety legislation.This should be taken into account in the procurement, management and execution of such work.

NOTE The reference numbers following the regulations give the full reference in the Bibliography to the regulation and also, whereappropriate, include the Approved Code of Practice (ACOP) and guidance associated with the regulations. The ACOP and guidanceprovide explanations for the application of the regulations.

4.2.9.2 Health and Safety at Work etc. Act 1974

The Health and Safety at Work etc. Act 1974 (HSW Act 1974) [22] is the primary legislation under which manyregulations have been made and apply, and should be read in conjunction with these regulations.

The HSW Act 1974 [22] sets out duties, in a general way, of employers, including directors and managers, as wellas employees, suppliers and manufacturers. The Act requires employers to provide and maintain systems of workthat are safe, so far as is reasonably practicable. This includes the provision and maintenance of all premises,plant and systems of work, of safe access ways and of the handling and transport of materials.

Those in control should reduce the risks to health and safety to the point at which the cost of further riskreduction greatly exceeds the benefits, but if the lives of operatives are placed at risk it is necessary to seek analternative method of carrying out the work. Employees and the self-employed should take care of their ownhealth and safety, as well as that of others, who can be affected by their work activity.

Those who should be considered for protection from harm due to work activities include:

a) employees;

b) the self-employed;

c) employees of other companies working on the job;

d) visitors;

e) members of the public in the vicinity, or outside the site.

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4.2.9.3 Management of Health and Safety at Work Regulations 1999

The Management of Health and Safety at Work Regulations 1999 (MHSW Regulations 1999) [23] set out moredetailed requirements for industry in general, and are aimed at effective management of health and safety byemployers and the self-employed following the concepts of risk assessment. They also require the appointment ofa person or persons to assist in health and safety management, appropriate health surveillance, emergencyprocedures, information to employees, co-operation and co-ordination, and training.

NOTE The principles of risk assessment are given in 5.2.2.2.

4.2.9.4 Construction (Design and Management) Regulations 1994

The Construction (Design and Management) Regulations 1994 (CDM Regulations 1994) [1] apply specifically toconstruction work, including demolition, decommissioning, alteration, renovation, dismantling, site clearance andground works, as well as most other construction industry activities including building, civil engineering andworks of engineering construction.

Duties are placed on clients (see 3.5) or clients' agents, designers, planning supervisors, principal contractors andother contractors (see also 5.3 and 7.3).

The CDM Regulations 1994 [1] apply to all demolition work irrespective of the duration of the work and thenumber of people working on site. They also require that any works expected to last more than 30 days, orinvolve more than 500 person days, be notified to the Health and Safety Executive (HSE) as soon as practicableafter the appointment of the planning supervisor and again as soon as practicable after the appointment of theprincipal contractor. In any event the HSE should be notified before the start of work on site.

These regulations require that the client ensures the preparation of a Health and Safety Plan before workcommences and that a Health and Safety File is completed at the end of the work. Examples of matters to beconsidered when preparing the Health and Safety Plan are given in Table 1.

If a Health and Safety File is already available for premises where demolition work is to be undertaken, the newinformation should be amalgamated into this file. Where a Health and Safety File does not exist one should beprepared.

There is no direct legal duty to pass on the Health and Safety File if the facility (or part thereof) is sold. If thefile is not passed on however, the original client retains the legal (criminal) duty to make the file available for anyinspection by any person who may need information from the file. It is therefore recommended that the fileshould be passed on when ownership changes.

4.2.9.5 Construction (Health, Safety and Welfare) Regulations 1996

The Construction (Health, Safety and Welfare) Regulations 1996 (CHSW Regulations 1996) [24] set out the health,safety and welfare requirements for specific activities within the construction industry (including demolition) andare aimed at protecting not only everyone who carries out construction work but also those who can be affectedby such work.

The main duty-holders under these regulations are employers, the self-employed and those who control the wayin which construction work is carried out.

4.2.9.6 Provision and Use of Work Equipment Regulations 1998

The Provision and Use of Work Equipment Regulations 1998 (PUWER 1998) [25] place duties on all employersproviding work equipment to ensure that it is suitable, properly maintained etc. The self-employed, and personsin control of non-domestic premises, are required to achieve the same goals with the equipment they use atwork. Principal contractors should co-ordinate the provision and use of items of plant and equipment which areshared by a number of contractors. All contractors are required to co-operate and exchange information toensure the safe use of shared equipment.

Every employer is required to ensure that work equipment is so constructed (or adapted) as to be suitable forthe purpose for which it is used or provided. When selecting work equipment, every employer should takeaccount of the working conditions and the risks posed to health and safe use of that equipment. Every employershould also ensure that work equipment is only used for operations and under conditions for which it is suitable.

4.2.9.7 Lifting Operations and Lifting Equipment Regulations 1998

The Lifting Operations and Lifting Equipment Regulations 1998 (LOLER 1998) [26] address, for example, therequirements for cranes, lifts and hoists, and components such as chains, ropes, slings, hooks, shackles andeyebolts.

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4.2.9.8 Control of Substances Hazardous to Health Regulations 1999

The Control of Substances Hazardous to Health Regulations 1999 (COSHH Regulations 1999) [27] place duties onemployers who are using substances hazardous to health.

The duty holders should ensure, for example, that work is not carried out which is liable to expose employees toany substance hazardous to health, unless a suitable and sufficient assessment of the risk created by that workhas been made and appropriate measures have been taken to remove the risk or control the effect of anyresidual risk.

NOTE These duties extend to employees and to any other person, whether at work or not, who can be affected by the work carriedout, including members of the public.

4.2.9.9 Reporting of Injuries, Diseases and Dangerous Occurrences Regulations 1995

The Reporting of Injuries, Diseases and Dangerous Occurrences Regulations 1995 (RIDDOR 1995) [28] require thatemployers, the self-employed or those in control of work premises report certain accidents, dangerousoccurrences and certain work related diseases.

Accidents that result in death, major injury or hospitalization of a member of the public should be notifiedimmediately to the HSE (or the local authority where appropriate) and followed up by a report on theappropriate HSE form. Disease and accidents resulting in absence from work for more than 3 days should bereported within ten days.

NOTE Dangerous occurrences include the unintended collapse or partial collapse of buildings or structures in excess of 5 tonnes, andof falsework or scaffolding over 5.0 m high.

4.2.9.10 Other regulations

Further health and safety regulations including, for example, the Confined Spaces Regulations 1997 [29] and thoserelating to asbestos which may need to be consulted, are included in the Bibliography and are also referred toelsewhere in this Code. For details of appropriate legislation in Northern Ireland, the HSE NI should be consulted(see B.2).

BS

6187:2

000

16

BS

I09-2

000

Planning andmanaging projects

5

Key considerations whenplanning demolition projects

5.1

Planning andmanaging for site work

5.2

Competencies andtraining

5.3

Management andplanning tools

5.4

Information technologyincluding knowledge

based systems5.4.2

Quality assurance (QA)5.4.1

General5.2.1

General5.1.1

Risk management5.2.2

Preparing methodstatements

5.2.3

Determining methodsand sequences of work

5.2.4

Supervision5.2.6

Avoidance of unplannedcollapse

5.2.5

Effective siteknowledge

5.1.2

Arrangements forprotecting the

public5.1.5

Occupationalsafety of theworkforce

5.1.8

Programmemanagement

5.1.4

Environmentalmanagement

5.1.7

General5.2.2.1

General5.2.3.1

Format5.2.3.2

Principles of riskassessments

5.2.2.2

Principles of riskcontrol5.2.2.3

Principles forHealth and SafetyPlan preparation

5.2.2.4

Predictedweather

conditions5.1.10

Arrangementsfor complying

with legalrequirements

5.1.3

Arrangementsfor structural

stability5.1.6

Occupationalhealth of the

workforce5.1.9


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5 Planning and managing projects (see Figure 5)

5.1 Key considerations when planning demolition projects

5.1.1 General

Demolition is undertaken on a very wide range of structures and site variations. The items to be addressedshould be identified as part of the planning process for the proposed works, as appropriate.

NOTE The key considerations listed below are relevant at many stages from scheme concept and development, through tenderdevelopment, tendering procedure and contract awarding procedures to contract management and work on site.

Clauses 5.1.2 to 5.1.10 give groupings of considerations that should be assessed, and included, whereappropriate, when planning demolition projects. The examples are broad and not exclusive, and should be readin conjunction with each other.

5.1.2 Effective site knowledge (see e.g. clauses 7 and 8)

Considerations should include:

a) extent of decommissioning;

b) details of the isolation or removal of services and details of temporary supplies;

c) knowledge of the structure;

d) isolation and protection of adjacent structures.

5.1.3 Arrangements for complying with legal requirements (see e.g. clauses 4 and 11)

Activities should include, where appropriate:

a) obtaining permissions from and for liaison with, for example, the police, roads and highways and localauthorities, utilities, rail and waterways companies and others as necessary;

b) prior agreement with the local environmental health departments in respect of environmental noise;

c) application to the local authorities for licensing of crusher or screening plant;

d) possible permission from the local authorities for site burning of waste materials;

e) prior consents or other agreements with the relevant enforcer in respect of the disposal of ground water orwaste water and other fluid discharges;

f) waste management including waste disposal in accordance with the Environmental Protection (Duty ofCare) Regulations 1991 [30] and Waste Management Ð The Duty of Care Ð A Code of Practice 1991 [31].

5.1.4 Programme management (see e.g. clause 6)


a) the sequence and method of proposed demolition;

b) details of the plant required, including the capacities and location of the cranes and the methods of placingand recovering plant to be used, including those within the structure;

c) a site traffic plan, detailing arrangements for, and the control of site traffic, see HS(G) 144 [32];

d) details of debris management including removal and temporary storage on-site and disposal (includingre-use and recycling) where appropriate;

e) contingency arrangements in case of, for example, partial collapses or misfires when explosives are used;

f) a detailed programme and timetable of events, as appropriate.

5.1.5 Arrangements for protecting the public (see e.g. clauses 12 and 13)


a) site security including the provision of, e.g. suitable fencing and/or barriers;

b) the control of spectators and/or site visitors;

c) exclusion zones outside the site boundaries during critical aspects of the work, when appropriate;

d) containment of demolition materials.

5.1.6 Arrangements for structural stability (see Figure 2 and also, e.g. clauses 9 and 14 to 16)


a) avoidance of unplanned, including premature, collapses and maintenance of residual structural integrity;

b) details of any pre-weakening and knowledge of the remaining structural stability, which should be designedby a competent engineer, including the sequence of the operation;

c) details of any temporary works to provide support, which should be designed by a competent engineer.

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5.1.7 Environmental management (see e.g. clause 11)


a) assessment and control of noise at the site boundaries;

b) control of dust emissions;

c) waste minimization including re-use and recycling;

d) minimization of materials haulage;

e) bunding arrangements for storage and dispensing of fuel oils;

f) wheel washing plant and road-cleaning arrangements, where required;

g) skip or truck sheeting arrangements;

h) arrangements for dealing with, e.g. flammable materials, gases, hazardous liquids and asbestos;

i) anticipated values of air over-pressure and ground vibration;

j) areas of conservation, including flora and fauna.

5.1.8 Occupational safety of the workforce (see e.g. clauses 12 and 16)


a) details of personnel access and working platforms, including the procedure for their maintenance andsubsequent removal as the structure is reduced;

b) establishing appropriate working spaces and exclusion zones;

c) arrangements for the protection of the workforce, including reference to any permit to work procedures;

d) effective communications including details of warning signs and signals.

5.1.9 Occupational health of the workforce (see e.g. clauses 10 and 12)


a) hazard recognition, risk assessments and control measures for substances potentially hazardous to healthe.g. from heavy metals or other toxic substances, including when working with materials which can be re-usedor recycled;

b) hazard recognition, risk assessments and control measures for exposures to harmful substances such asasbestos and radioactivity;

c) assessments and control measures for noise on sites;

d) identification of deleterious atmospheres such as oxygen deficiency in confined spaces;

e) hazard recognition and risk assessments for the need for, and the provision of, appropriate personalprotective equipment (PPE);

f) appropriate welfare arrangements, including for when the work involves exposure to contaminated materialsor dirty work.

5.1.10 Predicted weather conditions

Arrangements should be made where appropriate for liaison with, for example, the Meteorological Office toprovide forecasts with respect to sudden and severe weather changes, such as strong winds, lightning, snow andheavy rain, and how these can affect the planned works and programme.

5.2 Planning and managing for site work

5.2.1 General

Demolition work should be planned in such a way that it is undertaken using systems of work that take intoconsideration safety, health, environmental and efficiency issues.

All those involved from concept through tender to contract execution should ensure effective planning andcommunication and the provision of sufficient time to allow the execution of a successful and efficient project.

The time scales required for the acquisition of any licences or permits should be allowed for in the programmingof works.

After the contract has been awarded and before starting work, the contractor should determine the proposedsafe sequence of operations as a result of an assessment of the comparative risks, related specifically to the siteand conditions. This sequence should be used to assess and expand the Health and Safety Plan for the tenderand proposed programme of works (see 5.2.2.4). The expanded plan for the tender should form the basis of theHealth and Safety Plan for the demolition.

The methods of work should allow for completion of demolition and site clearance as stipulated by the contract,taking account of any constraints that the client will have identified to be complied with by thetenderer/contractor.

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5.2.2 Risk management

5.2.2.1 General

When planning methods of work, a suitable and sufficient risk assessment should be carried out and recorded.Methods, materials and equipment should be selected to remove or minimize risk from work.Tenderers/contractors who are selected should look for the hazards in the job, including how and where it couldbe done, and what equipment and materials should be used.

5.2.2.2 Principles of risk assessments

The principles of risk assessments listed below should be adhered to when determining methods and sequencesof work:

a) identification of the hazards involved with the proposed work;

b) assessment of the risk (likelihood and severity) of any harm arising;

c) removal of risks, possibly by changing the proposed methods or processes;

d) control of the remaining risks;

e) review and, if appropriate, update.

The risk assessments should address any constraints that the client has identified, but the tenderer/contractorshould be given the freedom to determine the proposed methods of demolition.

The result of risk assessments should identify the risks associated with the work and enable the contractor toselect appropriate demolition solutions that remove or reduce the risks before the work commences.

The contractor should then select the most suitable methods of demolition which include measures to properlycontrol any remaining risks (see 5.2.2.3).

5.2.2.3 Principles of risk control

The following principles should be applied to the control of risk:

a) if possible, avoid the risk completely by using alternative methods or materials;

b) combat risks at source, rather than by superficial measures that leave the risk in place;

c) wherever possible, adapt the work to the individual, particularly in the choice of work equipment andmethods of work. This will make the work less monotonous, improve the concentration and reduce thetemptation to improvise equipment and methods;

d) take advantage of technological progress, which often offers opportunities for safer and more efficientworking methods;

e) incorporate the protective and preventive measures into a coherent plan to reduce progressively those riskswhich cannot altogether be avoided and which takes into account working conditions, organizational factors,the working environment and social factors.

5.2.2.4 Principles for Health and Safety Plan preparation

A Health and Safety Plan should be prepared taking into account all available information supplied by the clientor his professional adviser, together with any surveys and investigations that are deemed necessary.

The Health and Safety Plan (see Table 1) should be prepared and applied on the basis that criteria such as thefollowing are in place:

a) principles of risk control;

b) employees and the self-employed should understand their responsibilities in, for example, training,instruction and communication of plans and risk assessments;

c) all the organizations involved in developing and executing any project should have an active safety culture.

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Table 1 Ð Items to be included in Health and Safety Plans (examples)

Tender stage1) Demolition stage2)

a) General description of the project g) Items developed from a) to f)

b) Time constraints of the project h) Arrangements for ensuring health and safety of allwho may be affected by the work

c) Details of risks remaining to people as a result ofwork activity

i) Arrangements for the management of the work andthe monitoring of compliance

d) Information reasonably required of the tenderer todemonstrate competency and adequacy of resources

j) Sufficient information, including arrangements forwelfare

e) Information for the purposes of preparing the Healthand Safety Plan for the demolition and provision ofwelfare facilities

k) Emergency procedures (see 12.6)

f) Any requirements for permits to work1) The planning supervisor should ensure that the Health and Safety Plan for the tender is prepared.2) The principal contractor should ensure that the Health and Safety Plan for the demolition, which is a development of the tenderHealth and Safety Plan, is prepared before commencing work.

On individual projects, the Health and Safety Plan should act as the focus for bringing together and co-ordinatingthe individual policies of everyone involved.

5.2.3 Preparing method statements

5.2.3.1 General

Method statements should address the particular needs of the site and should detail the planned sequences andmethods of demolition. The proposed working methods of demolition should be assessed to determine whether anumber of method statements are required, particularly where the operations are phased.

Method statements should be prepared in such a way that they enable supervisors and managers to ensure thatpersons on site are made aware of how the work should be carried out including the sequence of operations, theplant and types of equipment to be used and the precautions to be taken, as appropriate.

NOTE Methods such as ªtool boxº talks are recommended to help in disseminating the information, especially for those carrying outthe work.

Method statements should be regarded as live documents and should be modified as required to cater forplanned changes in systems of work. Any modifications should be made in accordance with 5.2.2 and 5.2.4.

5.2.3.2 Format

Each method statement should be succinct and should form a single document, including site plans, annotateddiagrams and a detailed programme for the work, to clearly communicate to those carrying out the work on sitewhat is required. A logical order should be followed. It should be easy to understand, agreed by and known to alllevels of management and supervision. Repetitive tasks may be covered by standard sheets but critical activitiesshould be specified in full.

The document should be clearly marked with the date of preparation and any revision number or letter, so thatthe latest edition can be readily identified.

5.2.4 Determining methods and sequences of work

The chosen methods of work should be determined in accordance with 5.2.1 and 5.2.2 and detailed in eachmethod statement (see 5.2.3).

When proposed methods of work need to be altered because of changed and/or unforeseen circumstances, thecycle of determining methods and sequences of work should be repeated commencing at 5.2.1.

New methods should not be applied on site unless agreed by all concerned. They should then be included in arevised method statement that should then be promulgated before implementation.

5.2.5 Avoidance of unplanned collapse

The chosen methods of work should not compromise structural integrity. Demolition should be carried out insuch a way that danger arising from the unplanned collapse of any part is avoided by maintaining the structuralintegrity of the remaining parts at all times.

NOTE Unplanned collapse can result from instability caused by, e.g. the interruption of load paths or from overloading individualelements.

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A detailed structural assessment should identify any weak elements, supports or connections and consider theoverall stability throughout demolition to avoid danger from unplanned collapse. The findings should be recordedwithin the risk assessment.

When methods of work require modification, a fresh assessment should be undertaken.

5.2.6 Supervision

Managers and supervisors should ensure that the planned method of work arising from any assessment ismonitored for its correct implementation during the demolition process, and that the actual conditions found onsite, e.g. concerning the type and strength of the structure, confirm the assumptions made in the structuralsurvey, risk assessment and planned method of work.

NOTE 1 The demolition contractor is required, by health and safety legislation (see 4.2.9) to employ a competent person to superviseand control the work on site.

Where two or more demolition contractors take part in work on the same site, each should appoint persons tosupervise the work. To ensure the safety of the whole works these persons should collaborate in the planningand execution of the work.

NOTE 2 This does not prevent the joint appointment of one person by two or more demolition contractors. It is in the interest of thebuilding owner to arrange for adequate supervision and co-ordination of the work on site.

The demolition contractor should maintain competent supervisory staff on site throughout the working day. Theextent of supervision and management should be appropriate to the complexity and size of the work to beundertaken. Supervisory staff should have direct access to higher management at all times.

5.3 Competencies and training

5.3.1 Competencies

All personnel should be competent for the tasks that they undertake. The CDM Regulations 1994 [1] placeresponsibilities on the client and other persons involved with demolition works to ensure that competent personsare employed on the project. The client should make reasonable enquiries to ensure that the person(s) appointedas planning supervisor and principal contractor is/are competent to undertake that role. No person shouldappoint a designer or contractor unless reasonably satisfied that the person is competent to undertake the role(see 4.2.9.4 and 7.3).

5.3.2 Training

Management should ensure that the necessary levels of competencies exist and are developed by appropriatetraining as required.

The objectives of industry recognized training schemes should be to make positive contributions to ensuring thatmanagers, supervisors and operatives in the demolition industry are competent at the level of experience thatthey claim and to ensure that they have received suitable training in e.g. health and safety.

NOTE Bodies providing industry recognized demolition training schemes are shown in B.6.

5.4 Management and planning tools

5.4.1 Quality assurance (QA)

As part of rigorous project management, consideration should be given to using QA systems to help compliancewith environmental, health, safety and legal requirements.

NOTE Users of this Code of Practice are advised to consider the desirability of quality system assessment and registration against theappropriate standard in the BS EN ISO 9000 and BS EN 14000 series by an accredited third-party certification body.

5.4.2 Information technology (IT) including knowledge based systems

Consideration should be given to the advantages of using computer based information technology (IT) inrecording, accessing, searching, updating and retrieving information pertinent to the demolition process, to aidefficiency.

The potential for the use of innovative IT systems should be explored, for example:

a) virtual reality;

b) knowledge based and expert systems;

c) robotics;

d) sensing and recording devices including lasers.

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BS 6187:2000

To enhance project management and project control some systems have been developed for the constructionindustry which can be applied to demolition and consideration should be given to using appropriate systems.

The internet should be considered for use as a source of information, e.g. the Department of the Environment,Transport and the Regions (DETR) Materials Information Exchange (MIE) database [33], hosted by the BuildingResearch Establishment (BRE), which offers advice and an exchange facility for construction and demolitionmaterials (see annex B for other useful website addresses).

NOTE The Data Protection Act 1998 [34] can apply.

6 Tenders and contracts

6.1 Professional advice

The initiator of the demolition project should be aware of any direct responsibilities for their duty of care andreceive professional advice as appropriate.

NOTE The initiator will usually be the building owner (but see 3.4 and 3.5).

A formal contract, in writing, should be entered into and signed by both the client (or their legal representatives)and the demolition contractor. The use of standard forms of contract are recommended and can be obtainedfrom, e.g., professional bodies and industry associations (see B.1 and B.4).

6.2 Tender and contract documents

Aspects and documents to be considered when preparing the tender and contract documents should include, asappropriate, the following.

a) The location and site of the works.

b) Plan or plans showing the ownership and nature of boundary walls, fences, hedges, trees and location ofbuildings, structures or subterranean features that are to be the subject of the works or that are to bepreserved.

c) Plans obtained from services providers showing the alignment, position and depth of all their cables, pipes,ducts, tunnels, apparatus and equipment, together with any special requirements that they have in order tosafeguard their installation and service. (Written confirmation should be obtained from each of the utilitiesproviding services on the site, e.g. gas, electricity, telecommunications, that they have disconnected their supplyoutside the site boundary.) The results of the survey carried out round the site perimeter, for example, toensure that there are no live power cables remaining, unknown to the electricity supply company, should betaken into account.

d) Roads and highways authorities and/or police requirements regarding the position of points of access to andegress from the site to the surrounding highways and to the periods of the day when such access/egress willbe permitted.

e) Local requirements relating to the provision of hoardings, gantries, walkways, fans, scaffolding, workingarrangements and notices prior to commencement of work by the demolition contractor.

f) Insurance provisions to indemnify the building owner and cover employer's, public and third party liabilitiesto a specified level and also to cover any specified risks arising as part of the works. (See also 4.2.7.)

g) The action to be taken by the demolition contractor to protect specified features of historical,archaeological, or geological importance during the works and, if unknown at the commencement of works,provisions as to the notification of such items and costs arising from the need to preserve them.

h) The appointment and duties of the person supervising the demolition for the building owner.

i) Provisions relating to bankruptcy and completion of the works by the building owner, should the contractorbe unable to complete his works at the required time.

j) Financial provisions, which should include management of retention monies; such monies are notappropriate where sites have been cleared. Provision for assessment of liquidated and ascertained damagesarising from delay in commencement or completion of the works should be included.

NOTE The Scheme for Construction Contracts (England and Wales) 1996 [35] affects procedures for demolition contracts. It willautomatically be applied to all contracts signed after the scheme that brings the Housing Grants Construction and RegenerationAct 1996 [36] into effect. See also similar schemes for Scotland and Northern Ireland.

k) The date, where known, for commencement of the works and the date, or time allowed, for the completionof the works.

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BSI 09-2000 23

l) Any party wall agreements and schedules of condition, including photographic materials, agreed between thebuilding owner and adjoining owners/occupiers which are to form the basis of any claims by them against thebuilding owner. This should include a list of adjoining owners' (see 3.1) names and addresses together withthose of their agents.

m) Indication of any known prescriptive rights of support or way which have been acquired, for example, byadjoining owners/occupiers by virtue of enjoyment over a long period.

NOTE Such rights can include rights of support provided by a part or parts of the building owner's building to an adjoining owner'sbuilding.

n) Assignment or underletting of the whole or part of the works should only be permitted with the priorwritten consent of the building owner. Where such consent is granted, the terms of the contract should be thesame as those between the building owner and demolition contractor.

o) The specification of the works which should be clear and unambiguous and provide the contractor with thebuilding owner's requirements. A list of all documents, plans, notices and information obtained by the buildingowner for incorporation in the contract should be included as an annex to the specification.

p) Specific constraints imposed on working methods.

q) The results of all relevant site surveys.

r) The decommissioning report for the site.

s) The Health and Safety Plan.

t) The Health and Safety File (for previous work when available).

6.3 Tender procedure and administration

Tendering for demolition work should generally follow the procedures used in good construction industrypractice. Professional advice should be sought to assist the building owner in the selection of tenderers and thepreparation of tender documentation. (See also 4.1.1 regarding estimated contract values.)

The tender procedure should include steps such as the following.

a) Pre-qualification of contractors. Professional advice should be sought to ensure that the contractor'scompetence and resources match the complexity and the size of the proposed project, thus complying, forexample, with the CDM Regulations 1994 [1].

b) Invitation. Arrangements should be made for each tenderer to inspect the site.

c) Information to tenderers. This should include compliance with the invitation requirements, specification,client statement, state of the site, history of use, legal and other requirements. Non-compliance with theinvitation should be assessed as this can invalidate the tender.

d) Tenderers bid preparation. Account should be taken of the considerations given in 5.1, with a proposedwork plan, an outline programme and a statement of sub-contracted elements.

e) Clarification. Any information for clarification should be given to all tenderers in writing.

f) Tender submissions. These should be received by a set date and all submissions should be opened at thesame time to ensure fair competition.

g) Examination of tenders. This should include clarification and removal of anomalies and qualifications insubmissions. Method statements should be assessed.

h) Acceptance. This should include agreement of start and completion dates and complete contract details.

i) Notification. All tenderers should be notified of the names of other tenderers and consideration should begiven to issuing a list of non-attributed tender figures upon award of contract.

j) Submission to all authorities and adjoining owners (see 3.1). This should state when work will commence,its duration, the name and address of the contractor and the site agent's name.

24 BSI 09-2000

BS 6187:2000

Knowledge of the site7

General7.1

Overview ofinformation needed

7.2

Responsibilities foracquiring and providing

information7.3

General7.3.1

Client7.3.2

Professionaladvisers

7.3.3

Contractors7.3.4

Desk study7.4

See also8.1.3

General7.4.1

Investigatingpast uses of

a site7.4.2

Informationsources and

types7.4.4

The site and itsenvironment

7.4.3

Outputs fromthe desk study

7.4.6

Out-of-servicedecommissioning

report7.4.5

Investigatingon site7.5.1

Surveymethodology

7.5.2

Industry processesand materials

7.2.1

Builtenvironment

7.2.2

Types of healthhazard7.2.3

Outputs from theon-site survey

7.5.3

On-sitesurvey

7.5

Seealso8.5

Condition ofadjoining premises

7.6

Disseminationof knowledge

7.7

See 8if more

required

Report

Report

Report

Report


BS 6187:2000

BSI 09-2000 25

7 Knowledge of the site (see Figure 6)

7.1 General

The site should be assessed and surveyed sufficiently such that all relevant information is established to providea clear understanding of the state and condition of the site.

NOTE 1 This understanding is fundamental to the completion of a successful project in respect of environment, efficiency and safetyand health, and will include physical and health hazards. The information will be needed initially for the tender stage.

The knowledge should be elicited by an initial desk study that should be followed by an on-site survey toaugment the desk study. Off-site features that can affect work on site should also be determined.

NOTE 2 In this context ªthe siteº includes everything above, at or below ground level, within the area under consideration.

The recommendations in clause 7 should be applied additionally when work starts on site, because howeverthorough the information gathering process was prior to the start of the contract, more information will berevealed as demolition proceeds. This can be regarded as the continuing and next phase of the survey andshould be recognized as such by all parties. Any additional information should be incorporated into the riskassessment process and reviewed to establish if the methods of work on site need amending.

The recommendations in 7.2 to 7.5, clause 9 and 10.1 should be followed through all stages of the project, fromconcept to completion of demolition on site.

7.2 Overview of information needed

7.2.1 Industry processes and materials

The information to be gathered should identify the industrial processes and associated materials, particularlyresidues that can form health and physical hazards, including:

a) materials forming, and within, the fabric of the buildings and structures;

b) raw materials;

c) end-products;

d) by-products or wastes;

e) ingress from neighbouring sites;

f) organic deposits.

7.2.2 Built environment

The information to be gathered should also relate to the built environment, where there can be potential forhealth and physical risks, including:

a) site physical features, either natural or built, such as buried tanks or waste materials;

b) form, type, elements and other features of the structures and buildings;

c) design philosophy, load paths, including stability features, of the structures and buildings;

d) construction materials and strengths of constituent materials;

e) any peculiarities plus any modifications of the structures and buildings;

f) other potential physical hazards, e.g. from plant, machinery and equipment;

g) claddings and coverings which can be a health risk, e.g. asbestos lagging or sheeting;

h) health risks from the building fabric, such as treated timber.

7.2.3 Types of health hazards

From the information gathered in 7.2.2 the types of health hazard associated with these materials which can betoxic, carcinogenic, pathogenic, sensitizing, corrosive or irritant should be identified, such as those listed below:

a) radioactive;

b) fibres which can be harmful, such as asbestos and man-made mineral fibres;

c) chemicals which can be harmful, such as polychlorinated biphenyls (PCBs).

7.3 Responsibilities for acquiring and providing information

7.3.1 General

The responsibilities for providing information are addressed by criminal law, civil law, common law andprofessional liabilities and those with such duties should be aware of their responsibilities, examples of whichare summarized in 7.3.2 to 7.3.4.

26 BSI 09-2000

BS 6187:2000

7.3.2 Client

The client should initiate the desk study and site survey. A detailed report should be produced which describesthe current state of the property and the steps that should be taken to complete any decommissioning prior todemolition, if this is required. As part of this, the client should provide drawings and sketches for informationthat should also take account of any alterations that may have taken place.

The client should have a decommissioning report (see 8.1.3) prepared which should, amongst other things,identify specific areas of concern relevant to future demolition work. The decommissioning report and results ofsurveys should be made available at the tender stage to assist in the provision of a tender that will cover the costof dealing properly with the identified issues.

The client should appoint a planning supervisor. It is also the client's responsibility to engage other professionaladvisers, where appropriate, to carry out, for example, structural surveys and contamination surveys to aid in thepreparation of the tender documentation.

When professional advisers are engaged, the client should make available all relevant information known to themand should ensure that the advisers make suitable and sufficient investigations to establish informationconcerning the site.

In cases where there is a possibility of the presence of toxic materials, including asbestos, a site survey detailingthe extent and identifying the type of the materials, should be carried out. The survey findings should then forma report, which could include an ªAsbestos Registerº (see 10.3.2.2).

NOTE The appointment of a professional adviser will not ultimately relieve clients of their responsibilities.

The client is responsible for the appointment of the principal contractor and should ensure that the principalcontractor has full and accurate information before work commences.

The client should be receptive to requests from the contractor for further information.

7.3.3 Professional advisers

Professional advisers such as consulting engineers and planning supervisors should be aware that they areresponsible for ensuring that surveys and assessments are made effectively, and that the client is informed of anyadditional information that may affect subsequent activities.

It should be noted that the planning supervisor's duties include ensuring that the required information concerningthe site and proposed work is collected in the Health and Safety Plan (see 5.2.2.4).

Professional advisers should be receptive to requests from the contractor for further information.

Adequate information should be provided by professional advisers to enable the demolition contractor to executethe planned work safely.

During the execution of the work, the planning supervisor should ensure that any additional relevant informationis collected and incorporated into the Health and Safety File which should be given to the client on completionof the project.

7.3.4 Contractors

Contractors should be satisfied that they have all the information necessary to undertake the work in a safe andefficient manner. Such information should include that provided by the client.

The contractor should confirm receipt of all such information provided by the client, and should request anyadditional information they require. The information received should be verified before use and is required forthe preparation of proposed methods of work and development of the Health and Safety Plan.

7.4 Desk study

7.4.1 General

The desk study should be used as the basis for determining more accurately, via the on-site survey, what existsand thus what has to be taken into account (for reasons of health, safety, environment and efficiency) whenplanning the demolition.

7.4.2 Investigating the past uses of a site

Past uses of a site, including its buildings, need to be known and should be investigated. This should beestablished through a comprehensive desk study in the first instance. All former uses of the site together withdetails of manufacturing processes and what materials were likely to have been present, as well as details ofphysical features should be included.

BS 6187:2000

BSI 09-2000 27

Any contamination is likely to be concentrated in particular areas of a site, and the desk study should showwhere on the site hazards are most likely to be encountered. The investigations can become complex when manychanges of use have occurred during the site's history of occupation, and arrangements should be implemented,as appropriate, to deal with this.

Where adequate information or detail cannot be obtained for a specific site, a more general review of processesand practices appropriate to the industry should be made to give a good indication of potential hazards.

NOTE For a given industry, the materials and processes are often similar regardless of geographical location.

A study of the past uses of the site should give a good indication of the likely presence of hazardous gases orchemical contaminants that may be present. The initial survey of the site should include the identification andscheduling of all locations where hazards from gas or chemicals may exist. The schedule should give apreliminary assessment of the nature of the hazard at each location and suggest suitable means of dealing with it.

7.4.3 The site and its environment

In addition to investigating the past uses of a site (including buildings) the following topics should beinvestigated at the desk study stage with respect to the past and current general site environment, in readinessfor the site survey:

a) access routes that are safe and convenient to use, and that have been established to and from the site,around the site, and to and from places of work;

b) topographical features such as trees and water courses which can require protection (see 11.6), orotherwise affect the planning of the work;

c) ground conditions, including the water table, the potential for flooding (see also 12.9), ground types, andthe presence of sink holes, mineshafts and shallow workings;

d) location and type of services, both above and below ground, as these can pose a hazard or requireprotection, isolation or diversion, including details of relevant contact(s);

e) extent of buried features such as basements, cellars, tanks and vaults with no structures on top should beestablished, including proximity to the boundaries of the site;

f) extent of above-ground structures, including those with basements, etc. and including those at or near theboundaries of the site;

g) presence of neighbours who require special consideration because their premises or equipment can besensitive to, for example, impact vibration, noise, dust or electronic transmissions;

h) presence of neighbours who can affect the contractor's activities, for example, by producing radiotransmissions that may affect the use of electric detonators when demolition by the use of explosives is beingconsidered.

7.4.4 Information sources and types

Archives can provide information concerning a site, however, archive material should not be totally relied uponas, e.g., the conditions can have changed since the archive was prepared, or original information may have beeninaccurate. Account should be taken of any modifications that have taken place on site since the creation of thearchive.

Types of information that should be considered include:

a) graphical, such as drawings and historical maps;

b) pictorial, such as photographs, engravings and paintings;

c) textual, such as trade directories and special interest books;

d) verbal, such as personal recollections.

Sources of information that should be considered include:

a) county and national record offices, local history societies, libraries, museums and industry based recordsoffices;

b) local government departments such as planning and building control, and central government basedorganizations including agencies such as the HSE, the Environment Agency (EA) and the Scottish EnvironmentProtection Agency (SEPA);

c) sources of information such as the Internet and data warehouses.

28 BSI 09-2000

BS 6187:2000

7.4.5 Out-of-service decommissioning report

The existence of a decommissioning report should be ascertained. This should usually be prepared when thefacility or site is taken out of service. The extent of decommissioning on the site should be known, e.g. it mightnot have included the whole site.

CAUTION The decommissioning and hence the report might not have been for demolition as there might havebeen plans to bring the facility back into service at a later date after being mothballed.

The status, including the date, of the decommissioning should be known, including whether it is:

a) out of service for re-fitting, repair or refurbishment;

b) out of service for mothballing;

c) out of service for some time prior to demolition which can lead to, e.g., health and safety hazards notpresent at the time of decommissioning;

d) immediately prior to demolition.

Such a report should be regarded as an essential part of the desk study; the extent of its value, however, willdepend on its age and accuracy.

See clause 8 for more on decommissioning procedures and reports.

7.4.6 Outputs from the desk study

The findings should be compiled into a report to give the most accurate picture of the site, to ensure that thebest possible information goes forward for confirmation and augmenting or development as appropriate byon-site investigation and survey.

7.5 On-site survey

7.5.1 Investigating on site

The investigation should be undertaken to augment the knowledge gained during the desk study to enable amore accurate understanding of:

a) indications of past features;

b) present features;

c) existing condition.

Existing information, including drawings, should be used when investigating the site. The information should beconfirmed as accurate or otherwise. The correct information should then be used as a basis for extendingknowledge, e.g. by taking account of any differences such as alterations or modifications that have taken place.Records should then be updated with the current knowledge and their status confirmed. Items that should beidentified in the survey and some of the more commonly found features, are described in clauses 9 and 10.

A survey of adjoining premises should be prepared when appropriate, to help resolve any dispute that arisesabout alleged property damage.

7.5.2 Survey methodology

When planning the survey the desk study should be taken only as an indication of what is present, as othersubstances and conditions can occur in practice.

Surveying should be undertaken in a planned, safe manner. Caution should be exercised and continual alertnessshould be maintained (clause 12 gives further advice on personal safety).

Methods of measuring and recording information can vary, but those used should be appropriate to thecircumstances to minimize the risk of harm to any individuals undertaking such measurements and recordings,e.g. for lone-working (see 12.12).

The survey methodology should be undertaken as a progressive, information gathering process, should not impairthe safety of the structure and should include, where and as appropriate:

a) observation;

b) close inspection;

c) dimensional measurement;

d) removal of, for example, panels and cladding, where appropriate, for the location of hazardous materials,including asbestos;

e) on-site identification of materials, e.g. residues;

f) sampling.

BS 6187:2000

BSI 09-2000 29

Key features that should be considered when organizing and planning sampling are included in Table 2.

Table 2 Ð Examples of key features for sampling

Key features Potential hazards

Atmospheres Breathable quality and explosive potential

Residues of chemicals Toxicity and detrimental vapours

Organic deposits and growths Pathogens

Water/moisture contents and residues Toxicity, pathogens and materials strengths

Ground water Assessment of migrated or deposited contaminants

Materials used in the construction Chemicals and fibres

Structural materials and connections Type, condition and thus residual strength

Materials changed during maintenance/refurbishment Potential entrapment of hazardous material/weakerconstruction

Insulating materials Chemicals and fibres

Paints and other preservatives Lead and other chemicals

7.5.3 Outputs from the on-site survey

The findings from the site survey should be produced in a report which details the current state of the site andbuildings, including true decommissioning status, and structural and health hazards (see clauses 9 and 10).

Full decommissioning should be achieved prior to the commencement of any demolition, however, where the siteis not fully decommissioned the measures needed to achieve full decommissioning should be included in asupplementary decommissioning action plan (see 8.1.2).

7.6 Condition of adjoining premises

The results of the condition surveys of adjoining premises should be compiled into a report [see 6.2l)].

7.7 Dissemination of knowledge

A site report should be prepared which combines the outputs of the decommissioning work, the desk study, thesite survey and the adjoining premises surveys. The site report should give the most accurate knowledge of thesite available. The report should be regarded as a ªliveº document that should be updated whenever moreinformation becomes available during the progress of the project. It should be used when developing projects,through the procurement process and into the works stage.

To ensure that all parties are aware of the current state of the site, the report should be made available to allappropriate parties as part of the dissemination of information for the site.

30 BSI 09-2000

BS 6187:2000

Management andsupervision

8.1

Decommissioningprocedures

8

Planning and preparation8.1.1

The decommissioningreport8.1.3

Decommissioningactivities

8.2

Industry-specificconsiderations

8.3

Time lag effects8.5

Mothballing8.4

Desk study7.4

Dissemination of thereport8.1.4

Decommissioning action plan8.1.2


BS 6187:2000

BSI 09-2000 31

8 Decommissioning procedures (see Figure 7)

8.1 Management and supervision

8.1.1 Planning and preparation

A planned decommissioning procedure should be carried out by the client or body responsible for the premises,before the demolition of any buildings, structures or industrial plant. The objective of this procedure should be tobring the area to be demolished from its fully-operational status to one where all ªliveº or charged systems arerendered ªdeadº or reduced to the lowest hazard level.

If there is a delay (see 8.5) between decommissioning for demolition and the demolition itself, or if there is achange of plan such that a mothballed facility is to be demolished rather than brought back into service, theadvice in 7.4.5 and 7.5.3 should be followed.

Planning and preparation should also include the elimination of any hazards specific to the process that has beencarried out prior to closure of the facility. All hazardous materials should be identified and recorded in the actionplan (see below).

Where hazards remain, for whatever reason, these should be made evident on site.

NOTE Further information can be found in Decommissioning, mothballing and revamping, published by the Institution of ChemicalEngineers [37].

8.1.2 Decommissioning action plan

A decommissioning action plan should be prepared by the client as an aid to the effective management ofdecommissioning. The plan should identify key target dates, including termination of services, and activities to beachieved for decommissioning.

8.1.3 The decommissioning report

The client should ensure that the decommissioning procedure is fully and accurately documented. Acomprehensive report should be produced showing exactly what has been carried out, based on the activitiesin 8.2, to reduce the inherent hazards. The decommissioning report should clearly state the extent ofdecommissioning and include details that can have health, safety or environmental implications during the courseof demolition.

The report should also provide a general description of the nature of the plant or building, its age, the variousprocesses that are likely to have been carried out, and details of any major changes like replanting or structuralalterations.

Comprehensive drawings and plans, particularly those showing underground services and underground chambersor plant rooms, should be included.

8.1.4 Dissemination of the report (see also 7.7)

On completion of the decommissioning report, the client or body responsible for the premises should arrange forthe report to be made available to those undertaking pre-contract site surveys and/or contaminated land/buildinginvestigations. The report should be made available to the planning supervisor for inclusion in the tender Healthand Safety Plan.

8.2 Decommissioning activities

Decommissioning should include a number of activities that should, where appropriate, take into account anyearlier decommissioning work which was not completed (for example, because of mothballing, see 8.4). Whererelevant, decommissioning activities should include identification and action in respect of, for example:

a) isolation, earthing, spiking and cutting of high voltage cables at points outside the demolition area;

b) isolation of low and medium voltage cables not rendered ªdeadº by the actions taken above;

c) disconnection of cables crossing the demolition area from buildings that are not to be demolished;

d) disconnection and separation of emergency/standby direct current (d.c.) battery systems;

e) removal of bulk process or other chemicals, including battery acids and oils;

f) draining and purging of all process chemicals from pipework and vessels such that the plant is chemicallyinert;

g) draining and purging of vessels and systems that have contained flammable or noxious gases; any suchsystems should be left vented to the atmosphere and ensuring that accumulation of fluids cannot occur;

h) draining of all substantial heads of water;

i) isolation of water and gas supplies at points outside the demolition area, or removal of a section of thepipework and the fitting of blanks or plugs;

32 BSI 09-2000

BS 6187:2000

j) controlled release of stored energy in strong springs or suspended counterweights;

k) removal or elimination of substances that can give rise to biological, chemical, explosive or radiologicalhazards;

l) giving consideration to the removal of all asbestos, however present, or if not removed, to the preparation ofan ªAsbestos Registerº.

8.3 Industry-specific considerations

Particular industrial hazards related to, for example, the industries listed below, should be taken into account:

a) chemical;

b) power;

c) offshore;

d) nuclear;

e) manufacturing industries;

f) mineral extraction;

g) food processing;

h) health care;

i) munitions.

8.4 Mothballing

Mothballing should be planned and executed in the same way as decommissioning, ensuring that every operationis undertaken with due regard for health, safety and environment, and is recorded.

In order to determine the method of mothballing, the following should be considered:

a) the probability of re-commissioning ever being required;

b) the extent of operation after re-commissioning;

c) the length of period of preservation;

d) the current state of the plant.

When planning the demolition of a previously mothballed facility, the decommissioning procedure should bere-activated and consideration should be given to the effect of the time lag.

8.5 Time lag effects

The effects of time lag between taking a facility or part of a facility out of service and its demolition should betaken into account (see 8.1). The extent of the effects can vary and the following aspects should be consideredand the length of time involved should be taken into account:

a) the environment in which the facility is located;

b) the extent of any earlier decommissioning (either full or partial);

c) whether mothballed or not;

d) the effects of weather;

e) variations in water table;

f) possible vandalism.

The effects to be considered should include:

a) deleterious atmospheres;

b) ingress and egress of fluids;

c) the chemical action of contained substances;

d) the deterioration of structures and containment vessels;

e) reduced stability, e.g. weakening of foundations;

f) impact damage;

g) reduced strength of any support intended to be temporary, e.g. scaffolding;

h) deliberate removal of parts of the facility for other uses elsewhere (cannibalizing).

BS 6187:2000

BSI 09-2000 33

Structural hazards9

Identifying structuralhazards

9.1

Identification ofstructural form and

features9.2

Stability sensitivestructures and elements

9.2.1

Structural forces whichmay cause instability

9.2.2

Structuralcondition

9.3

Assessment of condition9.3.1

Examination ofstructural condition

9.3.2

General9.3.2.1

Concrete9.3.2.2

Steel and iron work9.3.2.3

Timber9.3.2.4

Masonry9.3.2.5


34 BSI 09-2000

BS 6187:2000

9 Structural hazards (see Figure 8)

9.1 Identifying structural hazards

Structural form and features should be identified in order to reduce the risk of unplanned collapse of any partsof structures, whatever the size, during the demolition process. This information should be used to complementthe advice given in clause 15 on avoidance of unplanned collapses. To achieve this, however, the ways in whichloads are transmitted to the ground, i.e. the load paths, should be identified. The behaviour of the structure andits elements under the action of those loads will vary and should be understood. Structures that are designedwith load paths which might not be immediately obvious from an initial inspection should be identified, e.g. whenthey are covered by cladding or suspended ceilings, or structures which have been altered during their lifetime,e.g. for a change of use, extension of the premises or provision of additional services.

9.2 Identification of structural form and features

9.2.1 Stability sensitive structures and elements

Structural features should be identified which are stability sensitive, and/or where structural problems are knownto occur and can lead to particular problems in demolition. Consideration should be given to calling upon expertengineering advice to confirm the type of structure present. Problems that arise can be due to:

a) inherent form, elements and features including those that rely on interdependency for stability of structuresand buildings, including any modifications;

b) intrinsically weak features of structures and buildings, including any modifications;

c) stability features, including those that may be novel, of structures and buildings, as well as their effect onadjoining buildings and structures;

d) site physical features, either natural or built, including those that are buried and that can affect stability,e.g. ground anchors.

Stability sensitive structures and elements that should be identified include:

a) structures in which the floors are suspended by hangers, e.g. hanging bolts, from overhead cross beamssupported by a structural central core;

b) cable stayed roofs;

c) shell or membrane structures such as barrel roofs and domes;

d) space frame roofs;

e) high bay warehouses;

f) stressed-skin structures;

g) low and high rise panel buildings including proprietary ªsystem-buildingsº;

h) structures with unbalanced thrusts such as single and multiple arches, kilns, domes and single and multi-bayportal frames;

i) structures, roofs and floors that rely on tie bars for stability;

j) lift slab structures;

k) retained facades;

l) prestressed structures and components, e.g. in concrete;

m) cantilevered features, e.g. balconies, staircases or heavy cornices;

n) segmental, stayed and suspension bridges;

o) tanks and silos;

p) walls having been formerly restrained by roofs or floors;

q) structures retained by features such as ground anchors.

NOTE See 15.2 and clause 19 for factors to be taken into account, and for examples of demolition techniques appropriate, for suchstructures.

BS 6187:2000

BSI 09-2000 35

9.2.2 Structural forces which may cause instability

Consideration should be given to the causes of structural instability, which include the interruption of a loadpath, the effect of gravity and the inability of the rest of the structure to support any redistribution of remainingforces in load paths through other parts of the structure that remain.

Structural forces that can cause instability and that should be identified include:

a) unbalanced thrusts;

b) lateral components of forces e.g. from sway loads;

c) forces on basement walls from adjacent properties and thoroughfares;

d) effect of backfill loads on the stability of adjacent basement and other walls;

e) propping effect on vertical cantilever walls;

f) premature release of tensioned reinforcement in post-tensioned concrete beams;

g) non-vertical alignment of load-bearing walls, e.g. eccentric loadings.

9.3 Structural condition

9.3.1 Assessment of condition

The current condition as well as the reason for the condition (e.g. moisture ingress, overloading or fire, impactand blast damage) of the structure should be established.

Assessments should include, for example:

a) investigation of the form of construction and the condition of the building, including the extent andfrequency of any particular defects;

b) assessment of whether the building is inherently liable to disproportionate collapse through its design andconstruction and what could be the initiating event for such a collapse;

c) assessment of whether the rate of change in its condition needs to be monitored to enable furtherassessments of structural safety to be made;

d) assessment of the significance of any defects or deterioration, e.g. the potential for unplanned collapse,possibly disproportionate (see clause 15), whether such collapse is imminent and what would be the initiatingevent.

9.3.2 Examination of structural condition

9.3.2.1 General

The materials, their quality and the type of construction should be examined in order to identify any poorconstruction or deterioration that can affect the load-bearing capacity of the structure, and cause it to behave inan unpredictable way during demolition. The causes and rate of any deterioration should be identified wherepossible in order to determine their potential significance for the demolition process.

9.3.2.2 Concrete

Concrete should be examined, e.g. for:

a) deformation;

b) cracking and spalling;

c) corrosion of reinforcement;

d) chemical deterioration of the concrete, e.g. alkali-silica reaction (ASR), high alumina cement (HAC) problemsor attack by previous process chemicals;

e) effectiveness of grouting to tendons;

f) effectiveness of any concrete repairs.

If cores are to be taken in prestressed structures damage to tendons should be avoided.

9.3.2.3 Steel and iron work

Steel and iron work should be examined, e.g. for:

a) deformation;

b) corrosion, e.g. of gusset plates, boltheads, nuts and members;

c) rust jacking at connections;

d) integrity of tie rods, e.g. at jack arches;

e) springing of rivets;

f) effectiveness of any repairs, overplating, etc.

36 BSI 09-2000

BS 6187:2000

9.3.2.4 Timber

The support bearings and seatings of beams should be inspected with particular reference to the condition of oldor decayed joists, lintels and beams.

Timber should also be examined, e.g. for:

a) deformation;

b) splitting and cracking;

c) shakes;

d) knots;

e) integrity of fixings and bolthole elongation;

f) infestation (e.g. woodworm and toredo);

g) rotting (e.g. wet rot, dry rot).

9.3.2.5 Masonry

Load-bearing walls should be identified. Particular attention should be given to walls that are to remain, includingthe walls of any adjoining property, and their thickness should be noted, especially any reductions of thickness,for example, at fireplaces and cupboards.

Masonry should also be examined, e.g. for:

a) type of construction, including solid walls, cavity construction, ashlar construction or rubble filled cavities;

b) deformation;

c) cracking and spalling;

d) delamination;

e) corrosion of reinforcement and cavity wall ties;

f) effectiveness of any repairs;

g) verticality of walls;

h) security of bonding at the ends of cross-walls;

i) condition of mortar joints, including e.g. sulfate attack.

B

SI

09-2

000

37

BS

6187:2

000

Health hazards10

General10.1

Locations of healthhazards

10.2

Contaminated sites10.2.1

Plant, machinery andservices10.2.2

Sources of hazardousatmospheres

10.2.3

Identification and assessmentof health hazards

10.3

Assessments10.3.1

Dirty or contaminatedwater

10.3.2.1

Asbestos10.3.2.2

Chemicals and otherhazardous non-fibrous

materials10.3.2.3

Ionizing radiations10.3.2.4

Non-ionizingradiations10.3.2.5

Man-made mineralfibres

10.3.2.6

Pathogens10.3.2.7

Gases10.3.2.8

Recognition and disposalmethods for

hazardous materials10.3.2


38 BSI 09-2000

BS 6187:2000

10 Health hazards (see Figure 9)

10.1 General

Knowledge of the previous use of the site is important in determining health hazards and should always beobtained, as the main health hazards to demolition workers arise from substances likely to be inhaled or ingestedor likely to react with or to be adsorbed through the skin, such as:

a) gases, vapours, fumes and dusts which can be inhaled and which can be acutely or chronically toxic,allergenic, fibrogenic, carcinogenic and/or asphyxiant;

b) dusts, powders and liquids in contact with the skin which can be toxic or corrosive or give rise to, forexample, dermatitis or cancer;

c) inert dusts which in large quantities can cause, e.g. irritation.

Contaminants on sites should be identified and can include those present as a result of either previous use of thesite, or abandonment of materials such as containers, tanks, dust and debris including used syringes and organicdeposits, e.g. bird droppings.

HSE Guidance Note EH40 [38], which is updated regularly, should be consulted for the maximum exposurelimits (MEL) of these substances (see also 4.2.9.8).

Good hygiene should be encouraged, together with information, instruction and training, as important countermeasures for protection against these hazards.

NOTE Personal safety and methods of working safely are given in clause 12.

10.2 Locations of health hazards

10.2.1 Contaminated sites

Types of contaminated sites (including both ground and buildings) that can be contaminated as a result of theprocesses undertaken there at some time and that can harbour residual health hazards should be identified. Suchsites include:

a) waste disposal sites;

b) gasworks, coking plants and ancillary by-products works;

c) power stations;

d) sewage treatment works;

e) scrap yards;

f) railway land including sidings and depots;

g) coal-yards (contaminated by phenols);

h) oil refineries, distribution terminals, petrol stations and associated sites;

i) metal mines, smelters, electroplating works, refineries and foundries;

j) chemical works;

k) munitions production and testing sites;

l) asbestos works;

m) slaughter yards and abattoirs;

n) fish and meat markets;

o) tanneries;

p) paper and printing works;

q) wood preservative treatment sites;

r) hospitals, including isolation and quarantine premises;

s) dental surgeries, and medical and paramedical practitioners' clinics;

t) mortuaries and pathology laboratories;

u) cemeteries;

v) wool warehouses and works, and animal hair used as insulation in roofs (anthrax).

10.2.2 Plant, machinery and services

Fluids, sludges and solids that remain should be accurately identified as they can be hazardous. Whereappropriate, the contents of tanks and receptacles should be analysed. Residues should be handled and disposedof according to the results. Specialist advice should be applied to the handling and disposal of any hazardousmaterials, e.g. fluids contained in refrigeration plant and engine sumps, and a safe process for the workestablished (see also 11.4). Where appropriate, the enforcing body should be consulted, for example, the localpetroleum officer for licensed petroleum storage facilities.

BS 6187:2000

BSI 09-2000 39

When gas cylinders and chemical containers are not accepted for return by the manufacturers, the appropriateauthority should be contacted for advice on their disposal.

For advice on the disposal of liquefied petroleum gas (l.p.g.) cylinders and tanks the L.P. Gas Association shouldbe considered (see B.4).

10.2.3 Sources of hazardous atmospheres

Sources of hazardous atmospheres that should be identified include:

a) residues from former use or misuse in confined spaces;

b) leaking pipes in structures;

c) entry of contaminants to the structure through unsealed openings;

d) infiltration through ground;

e) decaying organic material, including sewage.

10.3 Identification and assessment of health hazards

10.3.1 Assessments

Where the pre-contract assessment indicates that the ground or building on the site is suspected of beingcontaminated, an investigation of the ground and/or building should be carried out. Investigations should becarried out by a competent person who understands the problems, hazards and risks associated with samplecollection, and who can take appropriate precautions, which should include an assessment of the hazardousmaterial found and whether the contaminants present are a risk due to inhalation, ingestion or skin contact. Theinitial site assessment should provide information on likely hazards.

Monitoring as demolition proceeds should be initiated and maintained, to ensure that workplaces are as planned.The workforce should be monitored as appropriate for indications of health problems however minor theyappear.

The site survey report (see 7.7) should be updated and disseminated as locations are tested for hazardousatmospheres. The occupational exposure limits (OEL) in HSE Guidance Note EH40 [38] should be applied. Thelatest edition of EH40 should be referred to for the current OELs.

10.3.2 Recognition and disposal methods for hazardous materials

10.3.2.1 Dirty or contaminated water

Accumulation of water from any source can become contaminated and should be treated and moved to alicensed waste tip where appropriate (see also 10.3.2.7 and 11.3.2.3).

10.3.2.2 Asbestos

Asbestos in a variety of forms has been extensively used in buildings, e.g. asbestos insulating board (AIB), laggingfor pipes and boilers, fire and sound insulation, cladding or roofing (asbestos cement), pipe-work and filters andcementitious and decorative coatings, and should be expected to be present unless established otherwise.

NOTE Regulations control the exposure to and removal of asbestos (see 11.4.2).

The ªAsbestos Registerº (see 7.3.2 and 8.2) should be prepared and reviewed prior to commencement of thedemolition, and its accuracy confirmed by sampling if appropriate. In the absence of an up-to-date ªAsbestosRegisterº a survey, which can require cautious removal of the fabric, should be carried out to identify the typeand quantity of asbestos present on site. Asbestos can also be found in the ground on redevelopment sites and asburied waste on other sites.

Asbestos removal should be carried out only after a survey, and before commencement of the main demolition.When planning the removal of asbestos all measures necessary should be included to prevent dust frombecoming airborne. (See HSG 189/1 [39], and for the removal of asbestos cement see HSG 189/2 [40].)

A safe system of work for asbestos handling and removal by a specialist contractor licensed by HSE should beestablished. Air-sampling before, during, and after the removal, as appropriate, should be carried out bytechnicians independent of the removal contractor.

Disposal of asbestos is controlled and it should be disposed of at a licensed tip.

10.3.2.3 Chemicals and other hazardous non-fibrous materials

If previous uses have left hazardous chemicals, e.g. radioactive luminous paint, lead paint, mercury, acids, alkalinesolutions, fumigation agents, water treatments, wood treatments or dusts, a survey should be undertaken by anappropriate specialist.

40 BSI 09-2000

BS 6187:2000

Chemical wastes should be analysed to ascertain whether they are hazardous, and if so, in which way and towhat extent. The analysis results should be used in the risk assessment to identify the risks, to determine thepreventative and protective measures required and to provide a recommendation for their treatment, safehandling and disposal.

10.3.2.4 Ionizing radiations

Prior to the commencement of demolition work, those in control should establish whether the presence ofradioactive material is possible. If the presence of ionizing radiations is known or expected, appropriate stepsshould be taken to obtain expert advice in compliance with the Ionizing Radiations Regulations 1985[IRR(85)] [41].

If radioactive materials are encountered unexpectedly, access to the area should be restricted and advice soughtfrom specialists in radiation protection who should carry out surveys and develop safe systems of work beforeany other action is taken.NOTE There are many sources of radiation likely to be found on site including naturally occurring radionuclides that can beconcentrated by human activity or manufactured radioactive materials and sources. Examples of sources are lightning conductors,smoke detectors, low specific activity materials such as some refractory sands and pipe scales, luminous paint and contaminants inland. Natural ionizing sources can be present, e.g. as radon gas in granite rock areas.

10.3.2.5 Non-ionizing radiations

Physical exposure to non-ionizing radiations (such as waves of frequencies that are either parts of theelectromagnetic spectrum, that is, ultraviolet and infra-red radiation, or radio waves used for communication) canbe harmful. Specialist advice should be obtained, including carrying out surveys and developing safe systems ofwork.

10.3.2.6 Man-made mineral fibres

When the presence of man-made mineral fibres such as mineral wool and glass fibre are found, the COSHHRegulations 1999 [27] apply and should be consulted as they require an assessment of exposure to potential riskand systems for preventing or controlling the risks.

10.3.2.7 Pathogens

As pathogens are organisms that cause diseases and can be derived from, for example, dead animals, birds orinsects, their wastes and fungal spores, consideration should be given to the possibility of pathogens occurring inthe structure and/or in the soil on sites, and particularly where organic materials have been processed orhandled. Where pathogenic materials are identified, appropriate working practices should be used, including forexample, the issue and use of appropriate personal protective equipment (PPE).

Where there is or has been rat infestation, or visitation, measures should be taken to prevent skin contact, and aban on eating, drinking or smoking in the workplace enforced, in order to protect the workforce from Weil'sdisease. The workforce should be made aware that Weil's disease or leptospirosis is spread through rats' urine,either directly in water, or from contact with the tail or paws. The virus survives in water, so appropriatemeasures should be introduced where there is water and rats. The presence of stagnant water should also beconsidered a hazard. Anyone who might come into contact with it should be aware of the advice given in theHSE Guidance Note on Leptospirosis [42] and appropriate action should be taken.

Where there are human remains, the appropriate authority, e.g. Home Office or police, should be consultedregarding their identity and re-internment.

Dead animal remains or animal products such as hides, fleeces, horns or hooves may support the anthraxbacillus, and should therefore be handled appropriately, following specialist advice.

CAUTION Anthrax spores can survive for many years in bricks, mortar, horse-hair roof insulation and plaster.

10.3.2.8 Gases

Dangerous atmospheres can be present for a number of reasons, such as migration or ingress from neighbouringpremises, and those that should be identified include:

a) carbon monoxide (fumes from combustion);

b) carbon dioxide (combustion, decaying organic material);

c) hydrogen sulfide (decaying organic material);

d) methane (public gas supply, landfill sites, coal mines and organic material);

e) petrol fumes;

f) liquefied petroleum gases (from leaky joints in equipment);

g) chemical fumes.

Where such migration is found, its source and extent should be determined.

The recommendations for recognizing and dealing with potentially hazardous gases given in BS 6164 should beconsulted for further guidance (see also 12.10).

B

SI

09-2

000

41

BS

6187:2

000

Protection of theenvironment

11

General11.1

Legislation11.2

General11.2.1

General11.2.3.1

Duty of care11.2.3.2

Noise andvibration11.2.3.4

Registrationof wastecarriers11.2.3.3

Radiation11.3.1.5

Vibration andimpact

11.3.2.1

Fluids11.3.2.3

Solids11.3.2.2

Noise11.3.1.1

Smoke11.3.1.4

Air over-pressure11.3.1.2

Dust11.3.1.3

Land11.3.2

Air11.3.1

Water courses11.3.3

Recovery andre-use of material

11.4.3

Controlledwaste11.4.1

Wastemanagement

licensing11.2.3

Some provisionsof the EnvironmentalProtection Act 1990

11.2.2

Protection ofproperty

11.6

Flora andfauna11.5

Wastemanagement

11.4

Planning11.1.1

Harmful wastematerials

11.1.2

Waste minimization,reuse andrecycling

11.1.3

Sources ofpollution

11.3

Specialwaste11.4.2


42 BSI 09-2000

BS 6187:2000

11 Protection of the environment (see Figure 10)

11.1 General

11.1.1 Planning

As demolition is considered to be a waste generating activity, those involved should plan to take account ofwaste control requirements, as well as other pollution control considerations that could result from demolitionoperations, e.g. spillage of chemicals, run-off of water, noise and dust generation.

Demolition should be planned, procured and undertaken in a manner that protects the environment and in a waythat, wherever possible, maximizes the opportunities for environmental improvement, including the re-use andrecycling of materials and components from demolition operations. All those involved in the demolition processshould understand their responsibility for the appropriate management of the arisings, including the properdisposal of waste.

Where it is planned to recover materials, the health and safety implications should be addressed, taking intoaccount, e.g. the potential risk from working close to and handling materials, and from working at height.

CAUTION It should be noted that if the activities on site require planning permission, a waste disposal licencewill not be issued until that permission has been granted.

When planning demolition, local enforcement authorities should be contacted for advice on what will be allowedfor the burning of materials, both by open fire or incineration, as these activities are subject to local and nationalrestrictions (see 4.2.8.3).

NOTE Subject to certain exemptions, all demolition companies have to register with their local authority or waste regulatory authorityfor a certificate of registration before they undertake the work (see 4.2.2).

11.1.2 Harmful waste materials

Wastes should be classified according to their composition and potential to harm the environment, and theirdisposal route reflects this classification. The demolition contractor should ensure segregation of materials tokeep disposal costs to a minimum, partly because the most potentially harmful materials will attract the highestdisposal costs.

If materials are mixed then the whole consignment should be classified according to the most potentially harmfulmaterial, e.g. a whole consignment of concrete and stone rubble would need to be classified as special waste if itis mixed with some asbestos waste. (See also 11.4.2.)

Where materials are to be transported off site a dangerous goods safety adviser should be appointed, as requiredby The Transport of Dangerous Goods (Safety Advisers) Regulations 1999 [43] and the advice given should betaken into account.

11.1.3 Waste minimization, re-use and recycling

To minimize contaminated waste and maximize the opportunity for re-use and recycling, the demolition processshould be designed for the optimal recovery of materials, but taking into account health and safety issues. Thesite survey should include an estimate of what type and quantity of wastes will be generated which will assist inplanning the storage and recovery options for the materials arising from the demolition. It should also help in theinitial stages of finding suitable outlets for re-useable or recyclable materials and components. (See also 11.4.)

In order to maximize the re-use and recycling of materials, different types of materials should be segregated toprevent cross-contamination, e.g. a small percentage of timber in with concrete can significantly reduce therecycling potential of crushed concrete.

Other types of materials which should be considered for segregation for re-use or recycling include topsoil, metaland architectural features.

NOTE Further information on waste management and the re-use and recycling of materials arising from demolition is given in theWaste Minimization in Construction Site Guide [44].

11.2 Legislation

11.2.1 General

The main items of environmental legislation that should be considered (see also 4.2.8) as being relevant todemolition and decommissioning processes include:

a) the Environmental Protection Act 1990 [20], which addresses many aspects of waste and other pollutioncontrol;

b) the Water Resources Act 1991 [45], which addresses water pollution;

c) the Wildlife and Countryside Act 1981 [46], which contains provisions for species protection and habitatprotection, including controls on the disturbance of flora and fauna (see 11.5);

d) the Control of Pollution Act 1974 [47], elements of which are still in force, covering noise from sites;

BS 6187:2000

BSI 09-2000 43

e) the Waste Management Licensing Regulations 1994 [48] (see 11.2.3);

f) the Special Waste Regulations 1996 [49] (see 11.4.2);

g) the Control of Asbestos at Work Regulations 1987 [50] and the Asbestos Licensing Regulations 1983 [51](see 11.4.2);

h) the Controlled Waste (Registration of Carriers and Seizure of Vehicles) Regulations 1991 [52] (see 11.4.1);

i) the Noise and Statutory Nuisance Act 1993 [53];

j) the Clean Air Act 1993 [21];

k) the Water Industry Act 1991 [54], which in part governs the substances that may be disposed of intosewerage systems.

Any local bylaws should be taken into account in addition to the nuisance provisions in the Public HealthAct 1961 [55] and EPA 90 [20].

For further guidance on the environmental legislative requirements, Part 3 of the CIRIA EnvironmentalHandbook [56] should be consulted.

11.2.2 Some provisions of the Environmental Protection Act 1990 (EPA 90)

The following explanations contained in the EPA 90 [20] are examples of those relevant to demolition anddecommissioning activities.

S.1(3) ªpollution of the environmentº means pollution of the environment due to the release from any process(into any environmental medium) of substances that are capable of causing harm to man or any other livingorganisms supported by the environment.

S.75(2) ªwasteº is taken to mean any substance or object in the categories set out in Part II of Schedule 4 of theWaste Management Licensing Regulations 1994 [48], which the producer or the person in possession of it discardsor intends or is required to discard, with the exception of anything excluded from the scope of the Directive byArticle 2.

NOTE Department of the Environment Circular 11/94 [57] (for Scotland, Scottish Office Environment Department Circular 10/94 [58])gives guidance on waste legislation including the EC Framework Directive on Waste, the definition of waste, waste managementlicensing and exemptions from licensing.

Annex 2 of the circular gives guidance on definitions of waste. Those definitions with particular relevance to demolition activitiesinclude:

a) any substance which constitutes a scrap material or an effluent or other unwanted surplus substance arising from the applicationof any process;

b) any substance or article that requires to be disposed of as being broken, worn out, contaminated or otherwise spoiled.

S.75(3) Any object or material that is discarded or otherwise dealt with as if it were waste shall be presumed tobe waste unless the contrary is proved.

S.79(1) ªstatutory nuisancesº include the following where they are prejudicial to health or a nuisance:

a) smoke;

b) fumes or gases;

c) dust, steam, smell or other effluvia;

d) any accumulation or deposit;

e) noise;

f) any other matter declared by any enactment.

11.2.3 Waste management licensing

11.2.3.1 General

The waste management licensing system is implemented by the Waste Management LicensingRegulations 1994 [48] and applications are assessed by the Environment Agency (EA) and SEPA. Under theEPA 90 [20] it is illegal to treat, keep or dispose of controlled waste without a waste management licence(or under an exemption in the Waste Management Licensing Regulations 1994 Schedule 3) [48], contrary to theconditions of a waste licence, or in a manner which causes pollution of the environment or harm to humanhealth. These activities are exempt from licensing only if the terms of the exemption are complied with.(See also 4.2.8.2.)

44 BSI 09-2000

BS 6187:2000

1) In accordance with the Waste Management Licensing Regulations 1994, Regulation 20 and Schedule 4, paragraph 12 [48].

Persons concerned with controlled waste are under a duty of care to ensure that it is kept safely, does not causepollution or harm to human health and is transferred to someone authorized to take it. A joint publication by theDepartment of the Environment, Transport and the Regions, Scottish and Welsh Offices [31] gives guidance onthis duty of care.

Applicants should ensure that the proposed activities do not cause:

a) pollution of the environment;

b) harm to human health;

c) serious detriment to the amenities of the locality.

NOTE 1 The granting of planning permission (see 11.1) satisfies condition c) above.

The holder of a waste management licence is required to be a ªfit and proper personº and when assessingwhether or not this is the case, the Environment Agency or SEPA should take into account:

a) whether the applicant, or other relevant person, has any convictions for pollution offences;

b) whether the applicant has taken steps to meet the possible cost of the obligations arising from the licence;

c) whether the site is run by someone who is technically competent.

NOTE 2 A person is considered to be technically competent if he or she holds a relevant certificate from the Waste ManagementIndustry Training and Advisory Board (WAMITAB) (see B.6).

11.2.3.2 Duty of care

Demolition contractors should understand their responsibility for the safe disposal of all materials leaving thesite, e.g. they can be held responsible if a disposal contractor fly tips a load of waste from the demolition site inorder to avoid gate fees at a disposal site.

Section 34 of the EPA 90 [20] imposes a duty of care upon all persons concerned with controlled waste and WasteManagement Ð The Duty of Care Ð A Code of Practice [31] should be consulted for practical guidance(see 11.2.3.1).

Those who produce, import, carry, keep, treat or dispose of controlled waste, or as a broker have control of suchwaste, should take all reasonable measures to ensure that the waste is managed properly and recovered ordisposed of safely. Waste should be stored safely and securely and be transferred to an authorized person(see NOTE below), who should be one, or possibly more, of the following:

a) a waste collection authority employee;

b) (in Scotland) a waste disposal authority employee;

c) a holder of a waste management licence;

d) a person carrying out an activity which is exempt from waste management licensing;

e) a registered waste carrier;

f) an exempt waste carrier;

g) a registered waste broker1);

h) an exempt waste broker1).

NOTE In legislation a ªpersonº can mean, for example, a corporate body, as well as an individual person.

The completion, signature and retention of a transfer note by the parties involved is necessary when waste istransferred and the note should include:

a) a description of the waste;

b) the quantity of waste;

c) how it is contained;

d) the time, date and site of the transfer;

e) the names and addresses of both people involved in the transfer and the category of authorized person towhich each belongs.

The description of the waste should provide enough information to enable subsequent holders to avoidmismanaging the waste.

Before waste is transferred, it should be contained in a manner that will prevent its escape.

BS 6187:2000

BSI 09-2000 45

11.2.3.3 Registration of waste carriers

Anyone who transports controlled waste is required to register with the Environment Agency or SEPA as a wastecarrier (or as a waste transporter exempt from waste carrier registration). The Controlled Waste (Registration ofCarriers and Seizure of Vehicles) Regulations 1991 [52] set out the rules on registration of waste carriers. The lawcovering the registration of waste brokers and registers of waste transporters is set out in the Waste ManagementLicensing Regulations 1994 [48].

The licence is subject to periodic renewal. It outlines the controls for storage and disposal of materials from thesite, along with all appropriate documentation required, as described above (see also 11.1.2 and 11.4).

11.2.3.4 Noise and vibration

Local authorities have powers for controlling noise and vibration from construction sites and other similar works.These powers can be exercised either before works start or after they have started.

Contractors, or persons arranging for works to be carried out, have the opportunity to take the initiative andshould ask local authorities to make their noise and vibration control requirements known. Because of anemphasis upon answering noise and vibration questions before work starts, the effects on the tender andcontract procedures should be taken into account (see 6.3).

11.3 Sources of pollution

11.3.1 Air

11.3.1.1 Noise

Machinery and methods of operation should be selected on the basis of the quietest available within theconstraints of reasonable cost. The noise assessment should contain measures to control noise at source. Whenthe noise cannot be adequately controlled at source by the appropriate selection of plant, equipment and workmethods, the use of enclosures and barriers should be considered. BS 5228-1 and BS 5228-2, which address noisecontrol on construction (including demolition) sites, should be followed (see also 12.14).

NOTE The noise from any plant, machine, or equipment can be subject to control/approval (see 11.2.3.4).

Agreement about the use of particular methods of work should be reached by consultation with the appropriateauthority (normally the local authority environmental health department).

To minimize noise emission, the following should be considered:

a) the condition of the machinery to be used, e.g. efficient engines, silencers and covers and compliance withmanufacturer's maintenance requirements;

b) the siting of machinery, e.g. the use of available shielding such as walls or buildings, the judicial placing ofmaterial stores and distance from noise sensitive premises;

c) the method of operation, e.g. the use of operational time restraints to avoid disturbance;

d) substitution of machinery, e.g. the use of valve compressors in place of reciprocating compressors, electricpower in place of internal combustion power;

e) substitution of methodology, e.g. pressured bursting (see 17.13) instead of percussion methods and the useof an enclosed chute to lower materials instead of throwing or dropping;

f) reduction of boundary noise levels by appropriate positioning of preformed shielding.

11.3.1.2 Air over-pressure

In demolition, air over-pressure, which can be considered as high intensity sound waves and can includefrequencies below the audible range, should be taken into account when planning the method of work.

Air over-pressure, which can occur when, e.g. significant amounts of material strike the ground and/or whenexplosives are used, should be minimized by appropriately designed systems of work.

Expert advice should be obtained where necessary to estimate the anticipated values of air over-pressure and theevent should be monitored if neighbours are likely to be affected.

The anticipated values of air over-pressure should be considered when establishing the exclusion zone(see clause 13) and when determining the risk of damage to property, e.g. windows, which should usually beregarded as the weakest part of the structure, depending on conditions.

46 BSI 09-2000

BS 6187:2000

11.3.1.3 Dust

Provision should be made for the reasonable prevention of dust generation, and where this is not possibleadequate dust suppression management should be applied.

Dust suppression by water should use a dispersal point close to the position of dust generation in order to bemore effective in both dust suppression and minimizing the volume of water used, and thus run-off. The WasteRegulation Authority should be notified as appropriate.

Where dust is likely to occur, e.g. during deliberate collapse, means of removing the dust that arises should beplanned and provided, such as water hoses, road sweepers and window cleaners, as appropriate.

11.3.1.4 Smoke

Provision should be made for the control of smoke through the effective control of burning of materials on site,when permitted (see 4.2.8.3 and 5.1).

11.3.1.5 Radiation

Suitable arrangements should be made for dealing with arisings from demolition activities that are contaminatedby radioactivity from either natural or manufactured sources (see 10.3.2.4 for more detail).

11.3.2 Land

11.3.2.1 Vibration and impact

Generation of excess vibration, caused, e.g. by the impact with the ground of felled structures or by the use ofexplosives, should be avoided. Consideration should be given to the potential detrimental effects of, for example:

a) cosmetic and structural damage of adjacent premises;

b) disturbance of sensitive equipment such as hospital equipment and computers;

c) buried services including gas pipes;

d) public perception of risk.

Expert advice should be obtained where necessary to estimate the anticipated values of vibration including,where appropriate, the effects of short duration ground vibration due to impact or detonation of explosivecharges which can impose very high peak particle velocity (ppv) levels.

The relevant provisions of BS 6472 should be taken into account. Vibration should be monitored in sensitivelocations, e.g. if neighbours and other facilities are likely to be affected both before (to establish existingvibration from, e.g. railways and roads) and during the works.

Consideration should be given to the provision of layers of fine graded material along the line of the fall(see also 12.14), if necessary, to reduce vibration caused by ground impact.

The vibration due to impact cannot necessarily be treated in the same way as steady state vibration. BS 5228-4,which considers vibration due to piling, should be consulted.

11.3.2.2 Solids

Solid materials should be handled in accordance with instructions devised following identification at the surveystage (see 7.5.2) and, where appropriate, disposed of at an approved site. Only inert materials should be used asfill material within the demolition site.

Materials of unknown source, for example, as a result of fly tipping, should not be present on site if adequatesecurity, including site boundary fencing is provided and maintained at all times (see 12.4). However, if suchmaterials are found they should be identified before handling and disposal.

Materials should not be inadvertently taken off-site on the wheels of vehicles and consideration should be givento providing wheel washing facilities (see also 11.3.2.3).

11.3.2.3 Fluids

The most common cause of pollution to land arises from the draining of containers such as tanks, sumps andtransformers. All liquids from such vessels should either be retained within their original containers ortransferred to other containers for safe transportation, and disposal or treatment, unless analysed and shown tobe acceptable for disposal on site, e.g. via the sewers, in which case the local water company or sewerageundertaker should be contacted.

Sumps that may contain contaminated water should be emptied into tankers for transport to a suitable disposalsite (this also applies to wash waters of any kind, e.g. when washing out a tank or washing wheels, seealso 11.3.3).

BS 6187:2000

BSI 09-2000 47

11.3.3 Water courses

No liquid or solid materials (see also 11.3.2.2 and 11.3.2.3) should be discharged to any water course other thanunder a discharge consent or agreement issued by the appropriate authority, e.g. the Environment Agency or inScotland, SEPA.

11.4 Waste management

11.4.1 Controlled waste

Controlled waste includes household, commercial and industrial wastes. This should include unwanted surplussubstances, building and demolition waste and anything which is disposed of due to being broken, worn out,contaminated or spoiled in some other way (see 11.3 and [44]).

11.4.2 Special waste

The most dangerous controlled wastes are classified as special wastes under the Special Waste Regulations 1996(as amended) [49] and should be tracked until they reach a waste management facility, by way of consignmentnote system, as required.

In some cases the Environment Agency (or for Scotland, SEPA) should be notified prior to the movement ofsuch waste (a fee is also payable for the majority of movements of these wastes).

Asbestos, and other hazardous waste, should be disposed of at a licensed toxic waste tip (see also 11.1.2).

NOTE Demolition works involving asbestos are controlled by the Control of Asbestos at Work Regulations 1987 [50]. When workingwith asbestos in a form such that its removal is notifiable under the Asbestos Licensing Regulations 1983 [51], 14 days notice is requiredto be made to the HSE. Asbestos wastes are also covered by the Special Waste Regulations 1996 (as amended) [49].

11.4.3 Recovery and re-use of materials

The recovery of materials should be managed within the established hierarchy (EPA [20]) which gives a broadindication of the environmental benefits and drawbacks of the different waste management options; the order ofpreference is:

a) reduction of waste by producing less waste in manufacture and by producing longer lasting products withlower polluting potential;

b) re-use, e.g. timber joists, dressed masonry;

c) recovery incorporating:

1) recycling waste to produce a usable product;

2) composting waste to produce growing media and soil conditioners;

3) recovering energy from waste, for example, by burning it;

d) disposal of waste by incineration without energy recovery or landfill.

However, the choice of waste management option for a particular waste stream should be guided by the principleof using the best practicable environmental option (BPEO).

NOTE 1 The BPEO procedure establishes, for a given set of objectives, the option that provides the most benefits or least damage tothe environment as a whole, at acceptable cost, in the long term as well as the short term.

NOTE 2 Materials arising from demolition may be re-used or recycled for use in a variety of applications, both on and off site.Information on the potential applications for a full range of materials is given in CIRIA handbooks [44], [56]. (See also MIE in 5.4.2.)

11.5 Flora and fauna

The Wildlife and Countryside Act 1981 [46] covers the protection of flora and fauna and contains schedules ofprotected species, the provisions of which should be taken into account. The effect of the Act is the possibledisruption of the demolition programme, as the Act makes it an offence to disturb a nesting bird, and soconsideration should be given to the timing of demolition operations to avoid such potential for disturbance.

Consideration should be given to contacting, e.g. the following organizations for advice on flora and fauna(see B.7):

a) English Nature;

b) Scottish Natural Heritage;

c) The Countryside Council for Wales.

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Areas of conservation should be known by the client, described in the tender and contract documents andshown on a drawing.

Sensitive areas, habitats and/or species that are to be protected should be protected from damage by usingfeatures such as suitable fencing, including vegetation that is to be retained.

Where fires are permitted (see 11.1) they should be lit a sufficient distance away from the furthest spread offoliage to prevent harm (e.g. at least 3 m depending on circumstances). No flammable materials should be used orstored within this area.

Reference should be made to BS 5837 for comprehensive guidance on precautions to be taken when working inproximity to trees. Trees to be retained should not be used to assist demolition operations. Heavy vehicles shouldbe kept sufficiently clear of trees to avoid damage to branches and also to roots by compaction of the soil. Ifexcavation has to be carried out within the spread of foliage, damage to roots should be avoided.

The controls on disposal of materials containing invasive plant species as defined by the Environment Agency,e.g. Japanese Knotweed, Himalayan Balsam and Giant Hogweed, should be taken into account.

Consideration should be given to obtaining advice from an ecologist to ensure that there is appropriate advice toenable the work to be undertaken in accordance with good environmental practice and the relevant legislativerequirements as appropriate.

11.6 Protection of property

The requirements for the protection of adjacent property, particularly structures, should be planned at an earlystage and detailed in the method statement (see 5.2.3). Where permanent or temporary support is required therecommendations in clauses 14, 15 and 16 should be followed. In addition to structural matters, appropriateprotection from the weather, debris, dust and liquids should be provided. The possible dislodgement of materialssuch as soot, which can block flues in adjacent properties should also be considered. The effects of airover-pressure and vibration should also be considered (see 11.3.1.2 and 11.3.2.1).

See also 5.1 for advice on planning for, and monitoring of, the property for damage.

Working methods should ensure that the support of remaining foundations, structures or land is not disturbedduring the excavation of existing foundations or basement floors.

Soakaways should be provided after basements and cellars have been cleared.

NOTE Precautions may be required to prevent water penetration to adjoining buildings.

Where watertight basements remain in ground having a high water table, consideration should be given topreventing flotation. Precautions should be taken to prevent accidental access to basements that are filled withwater.

B

SI

09-2

000

49

BS

6187:2

000

General12.1

Health and safety ofpersons on or off site

12

Emergencyprocedures

12.6

Site security12.4

Consultation12.3

Personal protectiveequipment on site

12.5

Risk-basedapproach

12.2

Permit to workprocedures

12.7

Planning12.7.1

Content12.7.2

Work over, ornext to, public

areas12.15

Falling andprojectedmaterials

12.16

Access andwork places

12.17

Hazards fromservices and combustible materials

12.8

Flooding12.9

Confined spaces,including hazardous

atmospheres12.10

General12.8.1

Sensitivity ofburied services

12.8.2

Loneworking12.12

General12.12.1

Lone workingcriteria12.12.3

Decisioncriteria12.12.2

Welfare andfirst aid12.13

Noise andvibration

12.14

Welfareprovision12.13.1

First aid12.13.2

Noise12.14.1

Vibration12.14.2

Materialshandling

12.11

Planning for fallsof materials

12.16.1

Prevention ofunplanned falls

of materials12.16.2

Protectiveenclosures

12.16.3

Projectedmaterials12.16.5

Catchment ofunplanned falls of

materials12.16.4

Electrical hazardsfrom overhead cables

12.8.3

Fire or explosion risks12.8.4

General12.10.1

Methods of work12.10.3

Emergencyarrangements

12.10.4

Hazardousatmospheres

12.10.2

Containment


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12 Health and safety of persons on or off site (see Figure 11)

12.1 General

The health and safety of persons on or off site should be addressed from an early stage and can involve, forexample:

a) those involved before demolition commences, e.g. those undertaking surveys;

b) those directly involved with the demolition process;

c) those who could be affected but are not directly involved in a) or b), e.g. members of the public, includingthose in neighbouring properties.

12.2 Risk-based approach

Demolition is recognized as a potentially hazardous operation and, at all times, the methods, materials, accessand equipment used should accord with the need to minimize the risk arising from the work.

The contractor is responsible for managing the health and safety risks on site. It is essential that risks to healthand safety are identified by an appropriate risk assessment before the work commences, and that the measuresintroduced to reduce and control the risks are maintained during the work (see 5.2.2). Where risks are identifiedthe principles of prevention and protection should always be applied by adopting measures either to prevent therisk or to protect from those risks that have not been eliminated.

In addition to general precautionary measures, there are various specific precautions that should be consideredin association with the particular method or methods of demolition being employed, and the structure orstructural element being demolished.

Where high-risk situations remain, a permit to work procedure should be considered and can be required(see 12.7).

The Health and Safety Plan should act as the focus for co-ordinating the proposals of all involved.

12.3 Consultation

Prior to carrying out the works, and at relevant stages throughout the works, the following should be contacted,as appropriate, in order to discuss the effects of the proposed demolition works (or its progress) and also theworking spaces or exclusion zones where they are planned to extend beyond the site boundary, including:

a) local authorities, including housing, environment and building control departments;

b) statutory undertakers;

c) highways and roads authorities;

d) local residents and housing bodies;

e) other interested or affected parties, for example, schools, hospitals and neighbouring businesses.

Consideration should also be given to contacting other organizations, as appropriate, such as the police,Environment Agency and the Health and Safety Executive (see also annex B).

12.4 Site security

High standards of site security should be established and maintained at all times because the public, and childrenin particular, are likely to be curious about the work and can be ignorant of the potential hazards which canexist. HSE booklet HS(G) 151 [59] should be consulted for guidance on site security.

Although spectators should be discouraged and unnecessary publicity avoided, it is important to make priorconsultation with all those members of the public who will be affected by the demolition (see 12.3).

The demolition site should be segregated from the public by an effective barrier. The types and extent of barriersshould be selected following risk assessments. Types of barriers to be considered include fencing, hoarding orpossibly existing structures that are independent and remote from the demolition activities.

Any fence should be not less than 2 m high and maintained to be effective at all times. It should not be capableof being climbed and should not have a gap at the base which is capable of being breached. Access gates shouldbe secured outside working hours. If the fencing causes an obstruction it should be adequately illuminated atnight to the satisfaction of the relevant authority.

At sites where it is not reasonably practicable to erect a perimeter fence, smaller secure compounds should beestablished to protect individual hazardous areas.

The following actions should be taken, as appropriate:

a) fence excavations;

b) immobilize vehicles and plant;

c) isolate electricity and gas supplies, or enclose them in locked compounds;

d) outside working hours, remove ladders which provide access from the ground to the first landing place andstore them in a secure area;

e) secure potential access points to buildings, including windows.

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The number of entrances to the site should be kept to the minimum required for the safe and efficient operationof the site. In order to prevent public access to the site and to control, for safety purposes, the movement ofvisitors on and off site it is recommended that the entrances should have adequate security controls. In addition,consideration should be given, where appropriate to employing 24-hour security patrols to deter trespass,vandalism and arson.

Warning signs should be used to communicate the presence of hazards to site personnel and third parties.

12.5 Personal protective equipment on site

The method of work chosen should ensure that the exposure to risk is minimized to such an extent that PPE isrequired to protect only against those risks that cannot be avoided by any other planned approach to the work.See also HSE guidance L25 on Personal Protective Equipment at Work Regulations 1992 [81].

As a result of the known risks to health and safety that are present during demolition work, all persons shouldwear, in addition to safety helmets, suitable basic protective clothing such as footwear, gloves and high visibilityclothing as appropriate. The use of additional PPE, e.g. eye protection, fall arrest systems (including full bodyharnesses), hearing protection, respiratory protection equipment (RPE) and ori-nasal masks should be consideredwhen alternative methods of work which do not require reliance on additional protective equipment have beenassessed and found not suitable (see also 17.14.3 when hot cutting).

The suitable protective equipment should be provided with appropriate training in its use when needed. Suchequipment should be suitably maintained and stored to ensure continued levels of its required performance.

Examples of hazards which should be catered for through the provision of planned control measures includechemicals which have been stored or used, arisings from lead paint, asbestos, dust, fumes or substances whichcan prejudice the health and safety of persons using the site, whether they have immediate (acute) or longterm (chronic) effects.

12.6 Emergency procedures

Contractors should establish emergency procedures to be followed in the event of premature collapse, fire orexplosion. Suitable and sufficient emergency procedures should be prepared in an emergency plan for identifiedscenarios, in association, as appropriate, with the emergency services, public and private bodies such as localauthorities, transport operators, housing managers, waterways operators, health, safety and environmentenforcers. The plan should set out appropriate actions (including limits of actions) and identify with whom theresponsibilities are placed. The emergency plan should be incorporated into the Health and Safety Plan.

All persons on site should be instructed in the emergency procedures. All those who may come on to site shouldalso be made aware of the procedures. A means of contacting the emergency services should always be availablewhilst work is in progress even on small jobs.

The arrangements should be tested by carrying out exercises at suitable intervals to familiarize site personnelwith the procedures, to test their effectiveness and, where necessary, to ensure effective liaison with theemergency services, and others as appropriate.

Where there is a risk of fire, suitable fire precautions should be established (see 12.8.4). These should includethe provision of adequate escape routes, as appropriate, identification and illumination of those routes, exits thatare readily usable, means of raising the alarm and the provision of fire fighting equipment and emergency plans.HS (G) 168 [60] should be consulted for further guidance.

12.7 Permit to work procedures

12.7.1 Planning

The aim of a permit to work procedure should be to provide a managed, safe, restricted working area. Thepermit to work procedure including the issue of a permit, should be regarded as an integrated part of a ªSafeSystem of Workº, but does not by itself make the job safe. The permit to work procedure should support thatsafe system and provide a record of activities, authorizations and timings for the protection of those undertakingthe activities, and sometimes others. (See also HSE Guidance INDG 98 [61] and HSC (OIAC) Guidance on permitto work systems in the petroleum industry [62].)

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The procedure should be implemented where there is a reasonably foreseeable risk of serious injury, e.g. wherethere is:

a) electrical work;

b) entry to or work in, e.g. confined spaces;

c) moving machinery;

d) hot work.

NOTE 1 Permits to work may be required either by the client or by a contractor's proposed method of work, based on the riskassessment.

NOTE 2 Special conditions can apply when working, e.g. on or near railways or waterways.

A permit to work procedure should be used:

a) to ensure that people working in the restricted area are aware of the hazards involved, the identity, natureand extent of the work to be done;

b) to ensure that a formal check is undertaken to confirm elements of a safe system of work are in place,before people are allowed to enter or work in the restricted area;

c) where there is a need to exclude or co-ordinate other people or their activities which could affect work orconditions in the restricted area;

d) if the work requires the authorization of more than one person, or there is a time limit on entry.

HS (G) 141 [63], HS (G) 168 [60], IND (G) 98 [61], IND (G) 314 [64] and HSE ACOP L101 [65] should be consultedfor appropriate advice.

12.7.2 Content

Where permit to work procedures are predetermined, the client should clearly state in the tender Health andSafety Plan the site rules and procedures regarding the permit to work procedure on his site. In every case thepermit to work should be issued to a competent person.

A typical permit to work procedure should include:

a) the task or work to be done;

b) risk assessment and method statement;

c) the minimum level required of PPE, including respiratory protective equipment (RPE) if appropriate;

d) any specific precautions to be taken;

e) details of electrical, piping, mechanical and underground service isolations;

f) a hazard check list;

g) timescales, as appropriate.

12.8 Hazards from services and combustible materials

12.8.1 General

Before commencing demolition work, the locations of any underground and overhead services, including gaspipes, water supplies, and electric, telephone and other cable communications systems should be identified andtheir status as operational, abandoned or decommissioned should be confirmed (see 6.2c) and clause 8). Work inproximity to operational services should be carried out following consultation with the owners and operators.

12.8.2 Sensitivity of buried services

If demolition works are likely to disturb pipes and cables outside the site boundary, prior contact should bemade with the services providers to determine the extent, if any, of the protective measures to be taken.

Arrangements should be made to ensure that those pipes and cables are identified which could be disturbedthrough ground movement or pressure as a result of, for example:

a) movement of heavy plant such as when crossing public footways;

b) work which alters the degree of support on retaining or basement walls, which might give rise to groundmovement;

c) ground-transmitted vibration from the operation of plant or from falling debris.

NOTE Under the New Roads and Street Works Act 1991 [12], only persons with a statutory power or a licence from the roads orhighways authority may undertake any excavation in the public street.

HS (G) 47 [66] should be consulted for further guidance.

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12.8.3 Electrical hazards from overhead cables

When mechanical plant, especially cranes, pusher arms or scaffold tubes are used in the course of demolition, nopart of such equipment should be handled or operated in the vicinity of exposed electrical sources such asoverhead cables. Where such a possibility exists, the local electricity supplier (or operators of overhead or thirdrail railway conductors) should be consulted and precautionary measures adopted, including the placement ofphysical barriers, disconnection, and removal or diversion of the affected wires or cables, in order to ensure safeworking.

GS 6 [67] should be consulted for further guidance on work in the proximity of electricity lines.

12.8.4 Fire or explosion risks

Precautions should be taken to prevent the risk of fire or explosion caused by the presence of combustiblematerials. As part of the site general fire precautions (GFP), consideration should be given to maintaining andutilizing existing GFPs such as means of escape and fire doors during the demolition process, as appropriate.

NOTE Combustible materials can be as gas, liquid, vapour or solids including dusts or powders.

Any activity involving potentially flammable materials should be the subject of a risk assessment. Whereappropriate, the operation should be managed through a permit to work procedure. When work activity can giverise to a risk of fire, the activity should not commence until suitable fire fighting equipment is available togetherwith a person who is trained in the use of that equipment.

Steps should be taken to prevent oxygen enrichment and the attendant risk of explosion or ignition of flammablevapour when gas cutting methods are used.

Containers of oxygen, acetylene or liquid petroleum gas should be used, handled and stored appropriately.

CAUTION Cutting tools, such as oxy-fuel gas torches and disc grinders can set fire to normally difficult to ignitematerials, e.g. timber.

Where combustible materials cannot be removed and a decision is taken to proceed with hot work, operatorsshould ensure that, prior to work commencing, those materials are suitably covered or wetted for the duration ofthe work, taking into account that the hot sparks/slag from these activities can fall considerable distances andstill have the potential to cause a fire (see 17.14).

Adequate precautions should also be taken to prevent hot sparks/slag from entering hidden voids. In the case ofhot work on, or in the vicinity of vessels which contain, or have contained combustible materials, particularprecautions should be taken to either remove the materials or render them inert (see 19.7).

Some materials can constitute both a fire risk and a health risk due to toxic combustion products, thereforemethods of demolition likely to cause ignition should be avoided. Examples of materials that should beconsidered include polyurethane foam plastics and similar materials, e.g. as insulation within cavity walls.

Timbers treated with copper/chrome/arsenate preservatives, when burnt, give off poisonous fumes, and thereforethey should be disposed of in a safe manner as site waste in accordance with the Special Waste DisposalRegulations 1996 [68] (see also clause 11).

12.9 Flooding

The contractor should assess the risk of flooding of all proposed work areas, with particular attention being paidto deep basements, underground tunnels, cooling water culverts and plant rooms and excavations. Accountshould be taken of weather predictions and the effect that these can have on the work area with regard topossible flooding problems. Flooding can arise from sources such as:

a) lack of natural drainage;

b) ingress of ground water, either from natural sources or a leaking water main or sewer (the local watersupply company may assist in determining the source of the water);

c) catastrophic flooding, especially if the demolition site is adjacent to a large body of water such as a lake,river, canal, sea, lagoon or reservoir.

Any ingress of ground water or water from a leaking water main or sewer should be assessed in the light of theproposed work and consequent potential for catastrophic flooding. Adequate temporary pumping arrangementsshould be installed to control ground water seepage. Consideration should be given to the possible need for theinstallation of temporary arrangements such as containment structures, or de-watering techniques to excludeground water.

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If the processes formerly carried out in the premises abstracted significant quantities of water from a large bodyof water, the contractor should be aware that water penstocks, valves, fire-fighting valves and associatedpipework might be holding back a differential head of water (see also clause 8). The contractor should also beaware of walls, dams, bulkheads, bunds and embankments which lie in the demolition area and which can be apart of the normal flood defence system. Account should be taken of any predicted water levels, including tidalvariation, which take place adjacent to the work area, and of the effect that these may have on support walls andstructures (see 7.5).

Water being used in the demolition process or an accumulation of rainwater can be a nuisance before it becomesa serious safety hazard; this should be dealt with by improving the drainage and/or installing temporary pumpingarrangements at an early stage.

12.10 Confined spaces, including hazardous atmospheres

12.10.1 General

Some spaces which should be treated as confined spaces can be obvious, for example, manholes, sewers,culverts, shafts, pressure vessels, storage tanks and silos. Others can be less obvious, but nevertheless can be ashazardous, e.g. by enabling dangerous concentrations of heavier or lighter than air gases to accumulate in layers,in places such as poorly ventilated basements, at the bottom of open-topped vats and tanks, tunnels or in roofspaces. (See also 19.7.)

Before entry for work in such spaces is planned, it should be established that it is not reasonably practicable toachieve the purpose without entry (see the Confined Spaces Regulations 1997 [29]). An assessment of whether apermit to work procedure is required should be undertaken (see 12.7) and where appropriate the space shouldbe clearly marked by warning notices.

Supervisors and operatives who will be required to work in confined spaces should be suitably equipped andtrained in the appropriate safe working practices (see also [29]).

12.10.2 Hazardous atmospheres

Before decommissioning or demolition begins, all potentially hazardous spaces should be clearly marked bywarning notices.

Any confined space should be regarded as a possible harbour for a hazardous atmosphere, with a higher risk ifthe structure has been unoccupied or inadequately ventilated for a long period.

The types of hazardous atmospheres should be identified and they could be one or more of the following:

a) asphyxiants, including oxygen deficiency;

b) toxic;

c) explosive/flammable;

d) oxygen rich.

CAUTION Hazardous atmospheres can be created as the consequence of demolition operations such as:

a) the use of flame-cutting equipment, e.g. generating lead fumes;

b) leaks from gas, including oxygen, cylinders;

c) exhaust fumes from internal combustion engines;

d) fumes from explosives;

e) the release of trapped pockets of gas, e.g. from beneath the demolition site.

NOTE See also 10.3.2.8.

12.10.3 Methods of work

Prior to and during entry into confined spaces, steps should be taken to establish and maintain an atmosphere fitfor respiration. Precautions should be taken when surveying, both initially and once work starts.

Standby personnel trained in the use of rescue equipment should be present during such operations.

The identification of potentially hazardous situations and the testing of the atmosphere for gases should alwaysbe undertaken by appropriately trained personnel.

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The method for the demolition work should take account of the results of surveys (the pre-start decommissionedstate) and the precautions to be taken. The precautions should include:

a) taking steps to remove the ªconfined spaceº status from the location by improving natural ventilation, ifnecessary by partial demolition (this is usually successful only with above-ground spaces);

b) avoiding entry into space if possible.

Where entry cannot be avoided the following measures should be implemented as appropriate:

a) testing for gas before entry;

b) removing the source of potential gases;

c) providing forced ventilation to dilute the gas;

d) test during the work and before re-entry after breaks;

e) the use of breathing apparatus, if necessary;

f) provision of an effective communication system.

12.10.4 Emergency arrangements

Emergency arrangements should be in place before entering a confined space in accordance with The ConfinedSpaces Regulations 1997 [29]. Consideration should be given to the provision of, for example:

a) rescue and resuscitation equipment;

b) raising the alarm and rescue;

c) safeguarding the rescuers;

d) fire safety;

e) control of plant;

f) first aid;

g) public emergency services;

h) training;

i) effective communications.

12.11 Materials handling

The risks inherent in materials handling should be assessed and planned as part of the demolition process (seealso clause 18). Unnecessary handling should be avoided, e.g. operations should be planned to avoid multiplehandling of materials.

Operations that involve lifting heavy or awkward loads, or repetitive lifting should be identified to enable safemethods to be planned. Where appropriate, mechanical lifting aids should be provided to avoid manual handlinginjuries. All equipment used for lifting should be in good condition (see 4.2.9.7). Workers should be trained inthe correct lifting techniques and in the safe handling of loads.

Reference should be made to the Manual Handling Operations Regulations 1992 [69].

12.12 Lone working

12.12.1 General

The good working practice of providing a minimum of two people to work together should be considered first.Where lone working is considered, the risks should be assessed including, for example, initial activities such assurveying for tender purposes. Appropriate precautions should be implemented if it is to be permitted.

12.12.2 Decision criteria

When considering permitting lone working for partial or total demolition (which can be for surveys, examinationsand inspections of buildings etc.) all appropriate hazards should be considered, including:

a) areas where levels of safety for access are reduced;

b) preliminary removal work, possibly by others and either planned or unplanned;

c) open shafts and voids;

d) deterioration of the structure;

e) reduced stability;

f) health hazards;

g) the presence of contamination, including from the site's previous use;

h) ineffective, incomplete or no decommissioning;

i) poor air quality;

j) lack of light.

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12.12.3 Lone working criteria

When lone working is considered appropriate, it should only be allowed provided that, for example:

a) the employer is satisfied that the lone worker is competent to work safely;

b) before an owner or client allows a lone worker into any site, they are assured that the lone worker iscompetent to work safely;

c) unsafe areas have been identified in recent previous inspections and this information has been passed on toany lone worker so that the unsafe areas can be avoided;

d) the lone worker has the expertise to appreciate structural hazards;

e) adequate light is available [see also g) below];

f) lone workers are not expected to risk their safety by clambering over or climbing through structures;

g) all personnel are furnished with relevant and appropriate safety equipment, including clothing and a torchwith spare batteries;

h) a method of communication with others is available at all times, e.g. a mobile or radio telephone;

i) the location, timing (including expected return time) and exact purpose of the visit are known and recordedat a base location;

j) a procedure is in place prescribing actions to be taken, and by whom, if any lone worker has not reportedby the expected return time.

IND (G) 73 [70] should be consulted for further guidance.

12.13 Welfare and first aid

12.13.1 Welfare provision

Welfare facilities should be provided and maintained at readily accessible places, for the duration of the works.Facilities should be suitable and sufficient and include toilet and washing facilities (including hot water, soap andtowels), drinking water, and showers if required by the nature of the work for health reasons. (See 4.2.9.)

Accommodation should be provided in the immediate vicinity, or should be conveniently accessible for the placeof work, for shelter, drying wet clothing and storing clothing not worn during working hours.

12.13.2 First aid

The demolition contractor should ensure that adequate first aid provision is made available. Those on site shouldbe informed of the first aid provisions that have been made for them.

The HSE publication ªFirst Aid at Work, Approved Code of Practiceº [71] should be consulted to establish thelevel of first aid that should be provided, and where appropriate, be determined initially by risk assessmentscarried out prior to the work commencing. The COSHH Regulations 1994 [27] should be taken into account,where appropriate.

12.14 Noise and vibration

12.14.1 Noise

The provisions of the Noise at Work Regulations 1989 [72] should be taken into account during all phases ofdemolition activity. The regulations require employers and the self-employed to ensure that the risk to hearing iskept to the lowest reasonably practical level. To comply with this a noise assessment should be made and anyappropriate action taken.

NOTE Guidance on lowering noise levels is given in 11.3.1.1.

12.14.2 Vibration

Exposure to whole body or hand-arm vibration resulting from the use and/or operation of tools, plant andmachinery is known to be a significant health risk and the method of work adopted should minimize exposure tovibration by, for example:

a) use of low vibration tools;

b) limiting the duration of exposure.

NOTE Guidance is available in BS 6842.

12.15 Work over, or next to, public areas

Lifting loads over areas of public access should be avoided where possible. Where it cannot be avoided,temporary closure of the highway and the provision of safe alternative pedestrian routes can be required(see 4.2.5.2). (See also clause 18 for guidance on the safe use of cranes.)

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Protective gantries, fans, crash decks and/or coverings should be erected to protect areas of public access wherefalling loads or equipment are foreseeable (see also 12.16.4).

The stability and safety of any bridging structure being demolished and of any associated temporary structures,such as falsework and access scaffolds, should be maintained and the structure should be assessed by acompetent person. A detailed plan of operation should be developed through liaison with the organizationsresponsible for controlling access beneath the bridging structure. Assessments should be made to determinewhether it is necessary to restrict or prohibit access beneath the work at times when safety cannot otherwise beassured.

Occupants should not remain in a building undergoing major demolition work. Where demolition work is carriedout to a building a part of which is to remain, and it is required to permit persons to stay in the remaining part, arisk assessment should be carried out as a basis for a safe system of work. The assessment should includeprovision for the occupied part requiring evacuation and for effecting such an evacuation safely.

12.16 Falling and projected materials

12.16.1 Planning for falls of materials

People should be kept away from where demolition is being undertaken by the effective application of exclusionzones (clause 13 outlines the procedure for developing such zones). Exclusion zones should be applied to allsizes of operation where there is work which includes deliberate dropping, or potential for dropping of materials.Such zones should also be established as part of a contingency plan where material may fall (see 5.2.5), not asplanned, but where the risk assessment identifies possible events, such as inadvertent falls of dislodged material.

12.16.2 Prevention of unplanned falls of materials

Precautions against uncontrolled collapse, including premature collapse, should include seeking expertengineering advice, especially for complex buildings or structures. Before demolition begins, it is necessary todetermine where temporary support will be needed and this should be clearly stated in the method statement fordemolition. No part of the structure should be so overloaded that any part of it becomes unstable duringdemolition work. (See also clause 15.)

CAUTION The removal of certain parts of the building or structure during demolition can result in other partsbecoming unsafe for persons in, on or nearby the building being demolished.

12.16.3 Protective enclosures

Consideration should be given to the need for protective, environmental and debris enclosures, for example,reinforced plastic sheeting or netting added to scaffolding or other temporary structures. Such structures shouldbe designed to take account of the loads (including wind loads) imposed when sheeting and/or netting materialsare used (see BS 5973). All aspects of design should be supported by drawings and calculations that are clearlyunderstood by site personnel (see 16.2).

CAUTION Fire safety arrangements should not be compromised. For example, fire exit routes should not beobstructed and consideration should be given to the use of fire retardant sheeting and netting.

Where appropriate, windows should be boarded up to prevent materials falling or being ejected from theapertures.

12.16.4 Catchment of unplanned falls of materials

Protective fans, crash decks and gantries are temporary structures that should be of adequate strength to safelysupport unplanned falls of material. They should be designed to withstand and contain the anticipated loadingsresulting from accidental falls of tools and materials. If necessary they should be waterproofed to protect personsbelow from drips. They should not be used for storage or for access.

Access ways and working places should not be used as catchment areas.

12.16.5 Projected materials

Where material can still be projected from apertures or can fall onto waterlogged ground or anyenergy-absorbing, hard-core impact mat the exclusion zone boundary assessment should take account of theresidual possibility of projectiles travelling a greater distance than in dry conditions (see also clause 13).

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12.17 Access and work places

Before and during demolition operations site managers should ensure that all site personnel have a safe place ofwork and a safe access to their place of work. This should include both provision and maintenance, and shouldbe regularly updated as the work progresses. Work and access areas should be managed so that they are kept ina safe condition and in good order at all times.

Permanent access stairs or catwalks should be maintained in a safe condition for use by demolition personnel,for as long as possible. Means of access to be considered should include access by roads, gangways,passageways, passenger hoists, staircases, ladders and scaffolds (see also 17.2.3).

The planning, provision and maintenance of access routes and working places should include the following:

a) freedom from obstructions, including tripping hazards such as debris, materials and tools and alsoprojecting nails from timbers (which should be removed or hammered flat);

b) that walkways and working platforms are not overloaded;

c) pedestrian routes that are segregated from routes used by vehicles and plant;

d) erection of adequate barriers or other edge protection, to prevent falls from the open edges of, e.g. roofs,buildings, gangways, staircases and lift shafts;

e) holes and openings that are securely fenced off or provided with adequate, fixed, clearly marked andproperly secured covers;

f) adequate artificial lighting should be provided when work is carried out in the absence of sufficient naturallight.

When the risk assessment shows that the only reasonable method is to work at an open edge, e.g. not usingremote machine methods, a safe, independent working platform should be used. Where these methods are notappropriate, suitably anchored fall restraint or fall arrest equipment should be used (see 12.5).

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General13.1

Safe working spacesand exclusion zones

13

Safe working spaces andexclusion zones as part

of the safety regime13.3

Purpose of safe workingspaces and exclusion

zones13.2

Application of safeworking spaces and

exclusion zones13.5

Exclusion zonesaround site vehicles

and plant13.4

Designing safeworking spaces and

exclusion zones13.6

Constituent areas13.6.2

Assessment and design13.6.1

Hazards to be consideredin the design of the size

of an exclusion zone13.6.3

Reducing the extent ofan exclusion zone

13.6.4

By partial demolition13.6.4.1

By containment13.6.4.2


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13 Safe working spaces and exclusion zones (see Figure 12)

13.1 General

All demolition work should be provided with an exclusion zone (see 3.14). Where personnel directly involved inthe execution of demolition work need to be within the exclusion zone however, they should be located in aposition of safety which relates to the stage of demolition, and which should be assessed within an overallplanned and monitored safe system of work. These personnel should not be permitted nearer the work thanwithin the designated buffer area. Such work should only be permitted when it is inappropriate to work fromoutside the exclusion zone.

The extent of the exclusion zone should be considered to be variable dependent on the demolition activity andrate of progress, and it can cover part of the site or even extend beyond the site boundary. In the latter case theconsent of the adjoining owner(s) should be obtained. On sites which are restricted by space, e.g. city centrelocations, the extent of the designed exclusion zones should be reassessed if there is a need to reduce the size,but only if adequate containment is provided (see 13.6.4).

13.2 Purpose of safe working spaces and exclusion zones

Exclusion zones should be provided to ensure that persons outside the zone are not harmed as a result of anydemolition activity including any processing of materials. The harms that should be considered include physical,chemical or biological hazards and the effects of noise, vibration and dust.

NOTE An example of a position of safety or a safe working space is a machine driver operating within the buffer area and providedwith a suitable protective cab structure.

13.3 Safe working spaces and exclusion zones as part of the safety regime

Exclusion zones should be part of an overall managed health and safety regime and should be included in themethod statements. The location of the boundaries of the exclusion zones should be determined after assessing anumber of parameters (see 13.4, 13.5 and the examples given in Figures 13 to 17).

13.4 Exclusion zones around site vehicles and plant

The work activity on site should be designed so that pedestrians and machines on site can move around withoutrisk of collision. All machines should be provided with safe operating spaces. The use of plant and machinerysuch as excavators and cranes should be planned so that their operation does not present a risk to those nearby.

In addition, the extent and location of the exclusion zone around the machine should take account of, e.g. acrushing hazard between part of the machine and stationary objects or structures, or inadvertent movement ofthe machinery.

Pedestrian and machine movements on site should be controlled by designed and clearly delineated traffic routesthat segregate their movements.

13.5 Application of safe working spaces and exclusion zones

An appropriate exclusion zone should be instigated when any person can be at risk from, or as a result of, anydemolition activity. Exclusion zones should be assessed and established for all types of collapse, irrespective ofthe method of demolition and size of the planned collapse. Each demolition activity should be individuallyassessed and new assessments should be made and used for different demolition activities and differing types ofsituation (see 13.6.3). Exclusion zones should be applied when a whole or part structure is being demolishedand should include areas where demolition machines are operating, and where arisings from the demolition canbe deposited or otherwise handled, including controlled areas for soft strip materials (see 19.2.2).

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Table 3 Ð Areas comprising an exclusion zone

Areaa Description

Plan area The area of the structure or part of the structure that is to be demolished and is thesubject of the assessment

Designed drop area The immediate hazard area, where the principal mass of the collapsing structure isdesigned to drop. Also included in this area is the plan area

Predicted debris area The perimeter of this second hazard area is the predicted limit or extent to which anydebris from, or secondary material resulting from, the structure being demolished willtravel and come to rest

Buffer area A hazard area that is planned to allow for any unpredictable events. People should besafe from the effects of the demolition activity beyond the external perimeter of thisarea, which will also become the theoretical boundary of the exclusion zone (see 13.3)

Exclusion zone This is the combined area of:Ð plan area;Ð designed drop area;Ð predicted debris area;Ð buffer area.

NOTE 1 In the above table, the term structure also means part of a structure, where applicable.

a Examples of these areas are shown in Figures 13 to 17.

Table 4 Ð Examples of hazards related to the areas of an exclusion zone

Source of material Area affecteda Cause of hazards Examples

1. Structure Designed drop area Gravity Material from the structure dropping to groundor surface with little further movement

2. Structure Designed drop areaplus predicteddebris area andpossibly the bufferarea

Gravity Dropped material from the structure withonward movement including possible upwardstrajectories; e.g. chimney rings, fire brick linings,other structure parts

3. Structure Designed drop areaplus predicteddebris area andpossibly the bufferarea

Forced propulsion,e.g. by explosives,structural distortion,fluids underpressure

Fragments of structure such as pieces ofsteelwork, cast iron, rivet heads, concretefragments of varying size, masonry, blastmaterial, blast protection debris which ejectfrom the blast area

4. Non-structure Designed drop areaplus predicteddebris area andpossibly the bufferarea

ªSlap effectº due toimpact on landingarea such as ground,hard-core cushion,fill area

Clods of earth, pieces of hard-core cushion,water surge; fragments of structures, such aspieces of steelwork, cast iron, rivet heads,concrete lumps, masonry ejected from thelanding area

5. Non-structure Designed drop areabut preferably notpredicted debrisarea and buffer area

Work on siteinitiating noise, airover-pressure,ground vibration

Indirect effects such as distraction, shock,damage to critical services, dust

6. Non-structure Designed drop areaplus predicteddebris area butpreferably not thebuffer area

Mechanical work onsite releasinghazardoussubstances

Chemicals or biological agents from aninadequately decommissioned plant andassociated structures (see clause 8)

NOTE 1 In general, there is no need to mark individual area boundaries, except for the perimeter of the exclusion zone and possiblythe outer boundary of the predicted debris area (see 13.1).NOTE 2 Account should be taken of activities where other trades may be involved or may need entry to vulnerable areas.

a See Figures 13 to 17 and Table 3.

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Limit of predicted debris area

Limit of designeddrop area

Structure to be demolished

Buffer area

Exclusion zoneboundary

Exclusion zone

Plan area

Direction of designedcollapse of part orwhole of structure

Structure,all or partof whichto bedemolished

Buffer area Predicted debris areaPredicted debris area

Plan

Elevation

Designed drop area

Some debris canfall in thisdirection also

Buffer area

NOTE Some boundaries may be co-located (merged) by suitable containment measures, and where appropriate methods ofwork are used (see Figure 16).

Figure 13 Ð Terminology of designed exclusion zone and its constituent parts

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Site boundary

Site boundary

Example of exclusion zone boundaryestablished beyond site boundaryfor particular operations

Buffer area

Limit ofpredicted debrisarea

Centre line of designed collapse

Limit of designeddrop area

Structure tobe demolished

Angle to be assessedbut unlikely to be lessthan 20º

θ

Designed drop area

Predicted debris area

Applied exclusion zone

Site

bou

ndar

y

Site

bou

ndar

y

Designedbufferarea

Designedbufferarea

Example of extensionof designed bufferarea to suitablephysical structureto give a largerapplied exclusion zone

Example of exclusionzone boundaryestablished outsidesite boundary forparticularoperations

Structure tobe demolished(in total or part)

Example ofdesigneddirectionof collapse

Plan

Elevation

Designed exclusion zone

1)

2)

Designed exclusionzone boundary 1),but extended 2)to apply tosuitable physicalfeatures, such assite boundary

Figure 14 Ð Example of designed exclusion zone showing practical application

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Site boundary

Limit of designeddrop area boundary

Angle to beassessed butunlikely to beless than 20º

Angle to beassessed butunlikely to beless than 20º

θ

θ

Designed temporary exclusionzone boundary for particularoperations, applied beyondsite boundary

Buffer area

Structure to bedemolished showingpossible stages

Designed exclusionzone boundary 1),but extended 2)to apply tosuitable physicalfeatures, such assite boundary

Limit of predicteddebris area

1)

2)

C B A

Plan

NOTE The location of the designed exclusion zone boundary and its constituent parts can vary as different phases of thework are undertaken Ð boundaries for stage A are shown.

Figure 15 Ð Example of designed exclusion zone showing phased and partial demolition

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1

2

Stable and secure continuous barrierat all times, including as thedemolition progresses

Outer wall of thestructure beingdemolished

Temporary designedexclusion zone boundary duringerection anddismantling of thesecure barrier

B

B

A

Plan

Elevation

Example of securecontinuous barrieron stable supports

Designed floorproppingif required

Example ofprogressivedemolition

Example of progressivedemolition

Materials to be removedonly when no demolitionwork is in progressabove

A - designed (and reduced) buffer area when demolition is in progressB - vertical exclusion zone which excludes any work on the floors below the demolition activities

Designed exclusionzone boundaryduring demolitionworks

NOTE The extent of reduction and strength and type of containment will be dependent upon the selected work methodsthat are used.

Figure 16 Ð Example of reduced exclusion zone by the use of containment

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Exclusion zoneboundary

Buffer area

Structure being demolished

Demolition machine Safe working space for operatorin protected cabLimit of designed drop area

Limit of predicted debris area

NOTE The safe working space is in a protected area within the buffer area and is therefore beyond the limit ofpredictable debris. (but see 13.1)

Figure 17 Ð Example of safe working space within an exclusion zone

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13.6 Designing safe working spaces and exclusion zones

13.6.1 Assessment and design

The assessment and design for the safe working spaces and exclusion zones should be determined by peoplecompetent to do so. The exclusion zones should be designed by building up the overall size by assessing eachconstituent area (see 13.6.2) and summing each to formulate the result. A more detailed assessment should berequired for some methods of demolition, e.g. when explosives are used BS 5607 should be consulted.

Consideration should include the following:

a) the site, including its topography;

b) the structure (including its height) and construction materials;

c) the surrounding environment (where applicable);

d) the proposed methods of demolition or partial demolition, (including the machines to be used);

e) the type of ground;

f) the landscape features;

g) visual distraction for those not on site (e.g. to drivers on adjacent roads).

13.6.2 Constituent areas

The exclusion zone should be considered as comprising a number of areas as shown and described in Table 3and Figures 13 to 17 inclusive.

13.6.3 Hazards to be considered in the design of the size of an exclusion zone

Examples of hazards related to the areas of exclusion zones can be seen in Table 4 and should be used duringthe design process. The exclusion zone should be designed to include machines, giving them sufficient space tomanoeuvre and operate safely (see 13.4).

When a method of deliberate collapse is used, there should be space for a fall that should be assessed, with thespace extending at least 208 either side of the designed line of collapse (see Figures 14 and 15).

The extents of the designed drop areas and the predicted debris areas, the alignment of the line of fall and theallowed deviation from that line for structures, including chimneys, should be determined by taking into accountfactors that include:

a) the height to be felled;

b) any variation in cross-section, e.g. shape and wall thicknesses, through its height;

c) any apertures, e.g. flue entries at the base or in the height to be felled, including those that have been filledin (including the effectiveness of the infill);

d) the extent of any deterioration of the materials;

e) the predicted break-up and fragmentation pattern of the structure as it falls;

f) materials that can become loose, such as roof top structures, or metal rings that can roll or be projected afurther distance after the structure hits the ground;

g) break-up of the structure on impact, including potential for ªflyº of material;

h) the surrounding environment.

13.6.4 Reducing the extent of an exclusion zone

13.6.4.1 By partial demolition

Where a reduction in the extent of an exclusion zone is desired or required, consideration should be given to theremoval during the initial stages of, e.g. parts of the structure [see 13.6.3f) and g)] that can become detachedduring the main demolition process such as deliberate collapse (see also 17.2.4).

13.6.4.2 By containment

Physical features, either those that already exist or those which have been deliberately constructed, should beconsidered to enable the extent of the safe working area or exclusion zone to be reduced. Such features can,e.g. prevent separated elements from rolling along the ground and those features that are scheduled fordemolition should therefore be retained until they have been used for this purpose. In addition, the constructionof physical barriers specifically for the demolition activity to enable the predicted debris area size to be reducedshould be considered (see Figure 16).

Examples of barriers, which should be considered, include:

a) a specially designed bund to retain elements which would otherwise roll along the ground;

b) on constricted sites containment measures, such as the use of appropriately sheeted scaffolding, where thereduction in the extent of the exclusion zone should be by the co-location of appropriate constituent areaboundaries (see Table 4, 12.16.3 and Figure 16).

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Types of structuraldemolition

14.2

Load-bearingstructural elements

14.3

Progressivedemolition

14.2.1

Deliberatecollapse

mechanisms14.2.2

Deliberateremoval ofelements

14.2.3

Structuralmaterials

14.4

Prestressedmaterials

14.4.1

Cast iron andwrought ironcolumns and

beams14.4.2

Steel14.4.3

Concrete andtimber14.4.4

General14.1

Principles ofstructural demolition

14

Roof trusses14.3.1

Cantilevers14.3.2.1

Columns14.3.2.2

Cantileversand columns

14.3.2

Walls14.3.6Composite

structures(slabs and

beams)14.3.7

Portal frames14.3.4

Arches14.3.5

Floors, slabs,beams and

roofs14.3.3

General14.4.1.1

Pretensionedmembers14.4.1.2

Post-tensionedmembers14.4.1.3

Reinforced concreteslabs

14.3.3.1

Beams14.3.3.2 Jack arches

14.3.3.3


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14 Principles of structural demolition (see Figure 17)

14.1 General

When selecting the most suitable method, the knowledge of the site (see clause 7) should be applied and theinterdependency of elements and the nature of the structure should be taken into account. Each of the basicprinciples of structural demolition, i.e. progressive, deliberate collapse or deliberate removal should beconsidered.

The strategic use of inherent forces should be considered as an aid to efficient demolition.

These same principles should be applied whether there is full or partial demolition, or where structuralalterations are to be carried out.

14.2 Types of structural demolition

14.2.1 Progressive demolition

Progressive demolition should be considered to be the controlled removal of sections of the structure, whilstretaining the stability of the remainder and avoiding collapse of the whole or part of the building to bedemolished. Where progressive demolition is adopted, it is essential that the key structural members on whichthe integrity of the structure relies should, together with their sequence of removal, be clearly indicated in themethod statement and also on site.

Progressive demolition should be considered for the majority of sites and is particularly useful in confined andrestricted areas.

14.2.2 Deliberate collapse mechanisms

Demolition by deliberate collapse should be considered to be the removal of key structural members to causecomplete collapse of the whole or part of the building or structure. Where deliberate collapse demolition isadopted, the key structural members to be removed should be clearly indicated, together with the sequence ofremoval, in the method statement (see also clause 15) and also on site.

This method should be employed only on detached, isolated, reasonably level sites where the whole structure isto be demolished. There should be sufficient space to enable equipment and personnel to be removed to a safedistance.

Where parts of a structure are to be demolished by deliberate collapse in separate operations, there should be nopotential instability of the remaining structure to cause a hazard to personnel on the site and to other peoplenear the structure being demolished.

14.2.3 Deliberate removal of elements

The deliberate removal of elements should be considered to be the removal of selected parts of the structure bydismantling or deconstruction. This method can be used, for example in the lead up to deliberate collapse or aspart of renovation or modification work. The elements to be removed should be identified and the effects ofremoval on the remaining structure fully understood and included in the method statement, with the elements tobe removed marked on site.

Sections of the structure should not be removed if instability of any of the remainder could result in a possiblerisk to personnel on the site and to other people nearby. Expert advice should be sought.

14.3 Load-bearing structural elements

14.3.1 Roof trusses

Where a pitched roof is to be removed progressively, the roof structure should be removed to wall plate or padlevel. Enough purlins and bracing should be retained to ensure stability of the remaining roof trusses while eachindividual truss is removed progressively.

Temporary bracing should be added where necessary to maintain stability. The end frame opposite to the endwhere dismantling is commenced, or a convenient intermediate frame, should be independently and securelyguyed in both directions before work starts. Generally, the bottom ties of trusses should not be cut in situ.

14.3.2 Cantilevers and columns

14.3.2.1 Cantilevers

Cantilevers such as cantilevered retaining walls, propped cantilevers, balanced bridge construction, canopies,cornices, staircases and balconies rely on superimposed loads or balancing restraining loads for their stability.They should be either demolished or supported before the counterbalancing, tailing-down or balancing loads areremoved.

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14.3.2.2 ColumnsThe engineered removal of columns can aid efficient demolition but the degree and type of fixity of theconnections at the top and bottom should be determined as these can be crucial to the predictability of collapsepatterns and thus the safety of the demolition.

14.3.3 Floors, slabs, beams and roofs

14.3.3.1 Reinforced concrete slabsBefore demolition is commenced the load bearing characteristics of the slab should be confirmed by firstestablishing the reinforcement details including the direction of the main reinforcement by, e.g. electronic sensingor by making small trial holes. The strength and quality of the concrete should also be determined. The methodof demolition should take into account the pattern of reinforcement, e.g. whether it is one-way or two-wayspanning.

Additionally, account should be taken of any stress reversal, which can occur in slabs or beams propped at,e.g. mid span, because the main steel reinforcement will not be situated in the appropriate position to form partof a continuous structure.

14.3.3.2 BeamsWhen removing beams by cutting or dismantling, the method adopted should ensure that, for example:

a) any weakening of the structure by, e.g. increasing the effective length of columns, should be taken intoaccount;

b) before lifting and lowering, temporary support should be provided if required. If dropping is plannedhowever, the dynamic effects should be taken into account;

c) effects of stress reversal if continuous beams are to be reduced to shorter lengths, are taken into account.

14.3.3.3 Jack archesWhere tie rods are present, they should not be cut until the horizontal thrusts have been removed by,e.g. removal of the arch or series of arches in the floor. The floor should be demolished in strips parallel to thespan of the arch rings (i.e. at right angles to the beams supporting the arches).

14.3.4 Portal framesA single portal frame should be considered a combination of two columns and a beam (which can be continuousor pin-jointed) forming a frame in a vertical plane, where the joint between each column and beam is designed tobe moment-resisting.

The type of rigidity at the base can differ as can the rigidity of the connection where the lengths of beam arejoined and should therefore be established.

14.3.5 ArchesAs arches carry load by exerting horizontal thrusts outwards at their spring points over the length of theconstruction, to ensure that the stability of the arch, which can include e.g. kiln structures, is maintained, thehorizontal thrusts should be resisted.

Methods to maintain stability during demolition in the vicinity of arches and of the arches themselves shouldensure the balance of the forces by, for example:

a) shoring to transmit horizontal thrusts to the ground;

b) building in temporary tie bars;

c) reducing vertical imposed loads;

d) demolition of the arch in whole strips;

e) some combination of a) to d).

CAUTION Failures in arches can occur both because the horizontal resistance has been removed or reduced, orbecause horizontal forces have increased as a result of increased downward loads. Ultimately resistance to theseloads may be at some distance from the arch being considered, such as at the end arch, where there are multiplearches.

14.3.6 WallsThe verticality of walls should be ascertained, load-bearing walls identified and the security of bonding at theends of cross walls should be established. The type of construction should be identified, including solid walls,cavity construction, ashlar construction or rubble filled cavities. The structural condition of walls which are toremain, including the walls of any adjoining property, should be established. This should also be applied wherewalls have been cracked or fractured, e.g. by settlement or heave or by adjacent piling work. The possible effecton the remaining structure of the removal of buttressing walls should also be considered with particular regardto wind loading.

The method decided upon for demolishing cantilevered retaining walls should take account of their dependencyon loading from above, or the propping action from floors or other structural members which can affect theirstability (see 14.3.2 and 19.8).

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14.3.7 Composite structures (slabs and beams)

Some basic structural elements have little inherent strength and rely for their stiffness upon the composite natureof the complementary members. The nature of any dependency can be broken by early demolition activities andthis should be identified as it might be necessary for temporary supports to be used.

Any demolition sequence involving composite structures should take account of the following factors, forexample:

a) prior to achieving composite action, steel beams will probably have been checked for their ability tosupport, unpropped, the loads on them during the construction phase; this should not be relied upon andfurther assessments should be carried out;

b) lateral restraints to the compression flange provided possibly by the slab (whether in situ concrete orprecast units) or by temporary bracing during the construction phase;

c) restraint, or composite action, can rely upon e.g. friction between the slab and the top flange.

Steel beams in which the lower flange is prestressed by encasement in high grade concrete, should usually beremoved intact from their working position before being processed. When lifting the overlying slabs prior toremoving the beams there can be movement of the beams, which should be taken account of in the proposedmethod of work (see 14.4.1).

The method of dealing with flitched beams should take account of the presence of the vertical metal plate placedbetween the timbers forming the beam.

14.4 Structural materials

14.4.1 Prestressed materials

14.4.1.1 General

The nature of prestressing is such that effective measures should be taken during the demolition of any structureor elements containing prestressed materials to ensure the control of inherent stored energy. Summaries of themethods for recognizing different forms of prestressed materials and the safety aspects to be considered duringdemolition are contained in annex C and should be read in conjunction with this clause.

In selecting a demolition technique, the potential consequences of sudden release of stress within the immediateworking area (and also beyond) should be considered (see clause 13).

14.4.1.2 Pretensioned members

Consideration should be given to demolition by lifting down elements after the removal of any coveringmaterials, for breaking up away from the structure. Cut strands should re-anchor a short distance from any cutpoints because the strands or wires should be fully bonded to the concrete. The cut pieces should remainprestressed.

Where in situ demolition is deemed appropriate, consideration should be given to the use of temporary supportsystems.

14.4.1.3 Post-tensioned members

Post-tensioned members should be considered for removal and broken up under the instructions of an engineerexperienced in this type of design.

CAUTION This is a hazardous operation. Post-tensioned tendons contain significant stored energy which canmake demolition hazardous. This is particularly the case when the tendons are unbonded or partly bonded, sinceit is the bond between the grout and tendons and duct walls which prevents the release of energy, thus stoppinganchorages being ejected from the ends of the members.

14.4.2 Cast iron and wrought iron columns and beams

The type of iron should be identified because sudden collapse can occur, e.g. due to brittle failure, in cast iron.

Explosives generally should not be employed in the demolition of this type of construction unless it is proposedto demolish the building as a whole (see 17.12).

CAUTION Historically, metals used in columns can differ from those used in beams. Cast iron columns usuallyoccur with either cast iron or wrought iron beams and load bearing brickwork. The strength of columns canvary, e.g. because of variable casting quality giving unequal wall thickness. Beams usually support either jack archconstruction or timber floors. Filler joists and jack arch beams are particularly susceptible to corrosion.

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14.4.3 Steel

Steel behaves in a ductile way under load, and will deflect before failure occurs in a member, however, careshould be taken to avoid catastrophic failure which can occur at the connections without warning.

14.4.4 Concrete and timber

Concrete can be subject to instantaneous failure and collapse. Both timber and concrete can be weaker thanmight be assessed from external inspection because of, e.g. internal deterioration, and the potential for thisshould be assessed and taken into account.

15 Avoidance of unplanned structural collapses (see Figure 19)

General15.1

Avoidance of unplannedstructural collapes

15

Achieving residual structuralstability as demolition progresses

15.2

Planned partial demolition ensuringstability of the remaining structure

15.5

Designed safe deliberate collapsemechanisms, including

pre-weakening15.3

Temporary structuralsupport for stability

15.4

Weather15.6

Residual structuralintegrity15.5.1

The use of facaderetention and shoring

15.5.2

Local instability15.5.3

Remote instability15.5.4

Principles of designedcollapse mechanisms

15.3.1

Pre-weakeningstructures

15.3.2

Pre-strengtheningstructures

15.3.3


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15.1 General

The potential for structural collapses should be foreseeable and avoided by planning suitable methods andsequences of demolition. These should be incorporated into the method statement and managed competently onsite.

Unplanned collapse, which includes the collapse of an entire structure or, more likely, parts of a structure orbuilding, generally occur:

a) prematurely (i.e. unintentional at that time) because of inadequate residual structural integrity,e.g. when pre-weakened; and/or

b) unintentionally (i.e. not intended for demolition) because of inadequate stability resulting in part of thestructure or building to collapse or fall.

CAUTION 1 The size of the collapse can be disproportionate to the initiating event.

Methods of managing the avoidance of unplanned collapses should be based on a sound knowledge of thestructure (see clause 9) and the way it acts to transmit the loads to the ground.

To predict the possibility of premature and unintentional collapse and to understand why such an event mightoccur, an assessment of the structure should be undertaken and the effects on the structure of the proposedmethods and sequences of work determined before work commences.

Floors should not be overloaded with machinery and/or debris resulting from the demolition process.

CAUTION 2 Some floor slabs are weaker in one direction and are therefore sensitive to the orientation ofloading from machines and thus more susceptible to the potential for unplanned premature collapse(see 14.3.3.1).

15.2 Achieving residual structural stability as demolition progresses

The ways loads are transmitted to the ground (i.e. the load paths) should be assessed prior to the work methodsbeing established. The proposed method of work should take account of the assessment of residual structuralintegrity at all locations, both in whole and in part, and at all times once work has commenced. Duringdemolition, the behaviour of the structure and its elements will vary; this behaviour should be understood. As theimposed loads need to be resisted, the load paths and resulting stability should be predicted by engineeringprinciples for the continually changing state of the structure.

Assessments should take into account both the structure and the materials of structural features that areuncovered as demolition proceeds, which were not obvious during the survey described in clause 7. Assessmentsshould include checks on the residual strength of the materials, the effects of any deterioration, and the effects ofany additional loading caused by debris and plant.

At any stage before and during demolition:

a) the residual structural integrity should be known;

b) the specific weaknesses and their positions should be identified;

c) the effects of a) and b) should be taken into acount.

When assessing the potential causes of structural instability, the significance of features such as unbalancedthrusts and critical bracing elements, the retaining action of the basement walls on adjacent properties andbackfill on the stability of adjacent basement walls should be determined (see clauses 9 and 19).

Where the interruption of a load path has been identified, the inability of the rest of the structure to support theredistribution of remaining forces in other load paths should be addressed by the provision of, e.g. temporarysupports and/or bracings (see 15.3.2 and clauses 16 and 19).

15.3 Designing safe deliberate collapse mechanisms, including pre-weakening

15.3.1 Principles of designed collapse mechanisms

As creating instability in a structure to initiate collapse or partial collapse is a fundamental principle ofdemolition, deliberate pre-weakening or pre-strengthening should be competently designed following assessmentof the risks, including structural assessment (see 15.2). The conditions encountered on site should be checked toensure that they conform to the designer's initial proposals for pre-weakening.

CAUTION This activity is potentially hazardous and effective control and monitoring systems should beimplemented to ensure that the designed requirements happen.

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15.3.2 Pre-weakening structures

As certain types of structure are inherently strong and can require weakening to ensure that they collapsesuccessfully, consideration should be given to the removal of load-bearing members or walls, as necessary, toensure a successful full or partial demolition. Any operation that requires the disturbance or removal of keyelements should be fully assessed, with calculations carried out by a competent engineer to obviate the danger ofunexpected or premature collapse. It is essential to provide, in advance, calculations which confirm stability afterthe section is removed. The dimensions of the section to be removed should be clearly marked on site to avoidoverbreaking and removal of incorrect elements.

Steel sections may be cut to assist the collapse mechanism, but this type of work should only be carried out byoperatives who are experienced and familiar with the technique. Where flame cutting is used to weaken astructural member, shims should be placed into the resulting void to prevent movement, distortion andreconnection.

Concrete shear walls may need to be kept in place until immediately prior to the demolition, when they shouldbe removed by remote means, e.g. by explosives.

15.3.3 Pre-strengthening structures

Consideration should be given to carrying out structural strengthening before demolition work begins, in order toenhance temporary stability. Such temporary works should be designed by a competent engineer experienced inthis type of work and can include, e.g. localized strengthening to steel columns.

15.4 Temporary structural support for stability

One method which should be considered for avoiding premature collapse is the provision of temporary structuralsupport which can be required to resist forces in any direction. If so, those responsible should ensure that thereis residual integrity during and after the installation.

Such support, including that to floors, should be secured to prevent movement during demolition operations, sothat it continues to be effective.

Checks should be made to ensure that reverse loads are not induced into the structure, or if they are, that theeffects are taken into account. The effects on the temporary structural supports should be assessed to ensurethat they remain adequate with any changing load patterns, including any induced reversal of stresses in thestructure as demolition progresses.

All temporary structural supports should be planned, designed, constructed and installed in accordance withclause 16.

15.5 Planned partial demolition ensuring stability of the remaining structure

15.5.1 Residual structural integrity

When partial demolition of a structure takes place, the structural integrity of the remaining parts of the structureand any adjacent structures should be maintained. A detailed assessment of all imposed loads acting on theremaining part of the structure should be made. Environmental loadings, e.g. wind and snow, should be assessed.Vibration and impact from traffic or adjacent demolition activities should also be considered. Foundation detailsof load-bearing and retaining walls should be established.

15.5.2 The use of facËade retention and shoring

The need for faõade retention and shoring should be considered when partial and, e.g. phased demolition takesplace in order to maintain the stability of:

a) the remaining parts of the structure;

b) any adjoining structures.

Faõade retention and temporary shoring should be designed, built and maintained, including any modificationsrequired due to the progress of the work and site conditions in accordance with clause 16. Any modificationsshould be evaluated against the original design.

15.5.3 Local instability

Partial demolition can create unplanned local instability in structures by the removal of load-bearing parts of thestructures, which can be taking loads in compression, tension, shear and torsion or in some combination ofthose. The effects of removing any load-bearing part can be to initiate premature collapse of any size. Thus toensure continuing stability, a thorough assessment of the effects should be undertaken prior to thecommencement of demolition work.

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15.5.4 Remote instability

To avoid the creation of unplanned instability in structures and particularly parts of structures remote from thelocation of the work in progress (e.g. by the transfer of load and movement through intact elements of thestructure) assessments should be undertaken and appropriate safe systems implemented, including monitoring.

The demolition method should avoid adversely affecting adjoining buildings and structures that can becomeunstable where common elements such as party walls (see 4.2.4), combined foundations, continuous beams andbasements are affected.

15.6 Weather

When the structure is weakened in the demolition process (e.g. by the removal of internal bracing members) andwork cannot be completed during the working day, the structure should be left in a condition capable ofwithstanding appropriate wind loads, such as a once in two year maximum gust (see BS 6399-2) or greater iflocal conditions dictate.

16 Temporary structures for stability and access (see Figure 20)

Types of temporarystructural support

16.1

Temporary structuresfor stability and access

16

See also Figure 2

General16.4.1

Scaffolding16.2

Facade retention16.4

Shoring andpropping

16.3

Survey andmonitoring

16.4.2

Temporary fixingto the facade

16.4.3


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16.1 Types of temporary structural support

Types of temporary structural support for shoring, propping and faõade retention include:

a) tube and fittings scaffolding;

b) system scaffolding;

c) screw jack propping;

d) shoring systems;

e) faõade retention systems.

Temporary structural supports should be used in accordance with the appropriate standards and should besufficient and suitable for the work required.

NOTE See BS 5973, BS 5974 and BS 5975 for further information on falsework design for temporary structures.

Proprietary systems should be designed and constructed in accordance with the manufacturer'srecommendations.

Temporary structural supports should be in position prior to the disturbance or removal of the existing supportswhich are taking structural loads, including vertical and/or horizontal loads. They should be suitably robust andfounded on secure and effective footings, be adequately laced and braced and, if appropriate, capable of resistingdynamic loadings. They should be checked both prior to and during demolition for effectiveness, including forthe effects of vibration.

16.2 Scaffolding

Any scaffolding required should be designed and erected in accordance with BS 5973 and BS 5974. Wherescaffolding is required it should normally be an independent tied scaffold. When completed, scaffolds should beleft in a condition suitable to perform the duty for which they were intended, and should conform to therequirements of the statutory regulations and with any local authority requirements.

A competent person only should inspect scaffolds, for example:

a) before being taken into use for the first time;

b) after substantial addition, dismantling or any other alteration;

c) after any event likely to have affected its strength or stability;

d) at regular intervals not exceeding 7 days since the last inspection.

After each inspection a report should be prepared for site management.

To ensure that the scaffold remains stable at all times:

a) there should be no unplanned removal of scaffold ties;

b) any debris collecting on a scaffold should be minimal and should not exceed the calculated loading for thedesign of the scaffold or obstruct access ways or working areas;

c) measures should be taken to prevent debris from being accidentally dislodged onto or from the scaffold(see also 12.16);

d) arrangements should be made for the scaffold to be adjusted as necessary and removed in a progressiveand planned manner as the work proceeds, to ensure its continued stability.

16.3 Shoring and propping

Shoring should be designed and erected in accordance with BS 5975. It should be adequate for its purpose,placed in position at the appropriate time and should be designed not to interfere with subsequent construction.

The shoring should be checked for effectiveness as the demolition proceeds and should never be loaded inexcess of the design limits.

16.4 FacËade retention

16.4.1 General

As demolition proceeds in the vicinity of facËades that are to be retained, methods of support such as temporarystructures, should be installed to ensure that stability is always maintained. Structural engineering advice shouldbe obtained for the design of temporary faõade supports, with account being taken of the stability of the faõadeand of the shorings as the demolition proceeds.

The effects of, e.g. hoardings, site cabins, signs and limited stored materials that are to be incorporated into thefaõade support should be considered in the design, together with the possible need for prevention of accidentalvehicle impact.

Prior to carrying out work that affects the footway or road the location of all services should be ascertained,adequately protected and access to them maintained.

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16.4.2 Survey and monitoring

To monitor any potential movement of a faõade an initial survey should be carried out, such as spatialco-ordinates of a series of points lying on a grid on its surface. Surveys should then be repeated at regularintervals throughout the contract, and all results from the monitoring should be used for assessment of theintegrity of the faõade and the retention system, and made available to all parties concerned.

16.4.3 Temporary fixing to the facËade

The method of fixing the temporary support system to the faõade should ensure that no damage is caused to thefaõade. Account should be taken of movement of the faõade that could occur before, during or after demolitionoperations.

All fixings should be regularly checked throughout the period of the contract.

Demolition work should be carried out so as not to damage the faõade. All elements which are built into thefaõade structure should be carefully cut away.

The temporary support system should not be weakened by removal of components until the faõade in thatlocation is fully supported either by the new structure or by an alternative, temporary structure.

BS

6187:2

000

78

BS

I09-2

000

Order ofwork

17.2.2

Workingplatforms

17.2.3

Partialdemolition

17.2.4

Pusherarm

17.8.2

Shears17.8.4

Grapple17.8.7

Pole17.8.6

Balling17.9.1

Pulverizer17.8.5

Impacthammer17.8.3

Multi-purposeattachments

17.8.8

Hydraulicattachments

17.8

Wire ropepulling17.9.2

Gasexpansionbursters17.13.2

Hydraulicbursters17.13.3

Expandingdemolition

agents17.13.4

General17.8.1

General17.3.1

General17.1

Contingencyplanning17.12.5Monitoring

17.12.8

Method statements

17.12.2

Consultation17.12.3

Exclusionzones

17.12.4

Blasting17.12.7

Explosivessystems, storage,use and security

17.12.6

Personal protectiveequipment

17.14.3

Flame cutting withcompressed gases

17.14.4

Cutting by drillingand sawing

17.10

General17.10.1

General17.12.1

General17.2.1

General17.13.1

General17.14.1

Drilling andsawing methods

17.10.2

Compact machines:use and access by

lifting17.5

Mechanical(non-hydraulic)

attachments17.9

Demolition byexplosives

17.12

Bursting17.13

Hot cutting17.14

High pressurewater jetting

17.15

Demolition bychemical agents

17.11

Demoliton byhand17.2

Fumehazards17.14.2

Handling andstoring

cylinders17.14.4.1

Flame cuttingequipment17.14.4.2

Thermiclancing

17.14.4.3

Demolition bymachine

17.3

Remotely controlledmachines and robotic

devices 17.4

Safe workingspaces17.3.2

Conditionsof use17.3.3

Operatinglimits17.3.4

Accumulationof debris17.3.5

High reachmachines

17.6

Tower and otherhigh-reach cranes

17.7

Demolitiontechniques

17


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17 Demolition techniques (see Figure 21)

17.1 General

There are a number of demolition techniques available, each of which requires specific precautionary measuresthat should be taken to enable the operators to execute safe demolition. Several methods of demolition can beused in combination or at different parts of the demolition site. The methods of work should be established aftercompletion of risk assessments (see clause 5).

Safe working spaces and exclusion zones should be established and maintained in accordance with clause 13.

Safety precautions relevant to the method of work should be clearly shown in the method statement for thework. All personnel on site should be fully aware of the requirements of the method statement.

In general, the choice of technique should enable the re-use and/or the recycling of materials arising from thedemolition (but see 11.4).

Irrespective of which demolition method is adopted, its choice should be based on minimizing the risk topersonnel. All personnel should be familiar with, and appropriately trained in, the use of plant and machinerywhich they will be required to operate for appropriate demolition techniques (see 5.3 and annex A).

CAUTION The method of collapsing structures by the deliberate burning of timber props acting as temporarysupports during pre-weakening can have unpredictable results and is not recommended.

17.2 Demolition by hand

17.2.1 General

Progressively demolished structures or elements of structures can be demolished by operatives using hand-heldtools, however, risk assessments will usually demonstrate that using remote demolition techniques, e.g. bymachine should be more appropriate. Mechanical assistance should be considered to assist with any handdemolition, such as lifting appliances for the lifting and lowering of elements once they have been released(see also 12.11 and 18.4) and the outcome of risk assessments should indicate the extent to which suchassistance should be utilized.

17.2.2 Order of work

Structures should generally be demolished in the reverse order to that of their construction. The order ofdemolition for buildings should be progressive, storey by storey, having regard to the type of construction, andshould be clearly shown in the method statement.

CAUTION Any scaffolding erected to facilitate the demolition, including ties, should only be removed inaccordance with the method statement (see 16.2).

17.2.3 Working platforms

Where it is necessary to work at height and it cannot be done safely from part of a building or structure, asecure and safe working platform should be provided.

The type of platform to be provided should be appropriate to the nature and duration of the work beingundertaken and can include, for example:

a) independent scaffolding;

b) suitably designed special scaffolds;

c) specially designed working platforms;

d) mobile elevating work platforms;

e) a man riding skip suspended from a crane.

Consideration should be given to the wearing of a securely anchored harness when working from platformsother than, e.g. rigid ones such as scaffolds.

Ladders are not recommended for use as a place from which to undertake demolition work (see clause 12).

17.2.4 Partial demolition

When only a portion of a structure is to be demolished, the stability of the part to remain should be monitoredregularly during demolition, and for a suitable time afterwards (see also 15.3).

17.3 Demolition by machine

17.3.1 General

Structures and elements of structures should preferably be demolished using a demolition machine operatedeither from a protected cab or remotely using, e.g. umbilical cable control or robotic devices (see 17.4).

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Any plant and equipment used should be, for example:

a) of an appropriate type and condition having regard to the location and type of work involved;

b) in the control of a competent operator, who should hold a valid certificate of training achievement whereappropriate;

c) maintained in good working condition at all times.

Any attachments should be properly fitted to machines of adequate power and stability for the intended use.

Where plant is being operated, the surface should be strong enough to support it. Where necessary, soft groundshould be excavated and replaced, e.g. by compacted hard-core, to provide a suitable base. Where appropriate,consideration should be given to providing adequate support for cranes and other machines where there arebasements and other below-ground voids, ducts, etc. by e.g. breaking into them and backfilling with hard-core.

An assessment of the strength of floors including suspended slabs should be made, taking into account that themachine and a quantity of debris could eventually be supported on part of the floor before being transferred tothe floor below. An assessment of their strength should be made prior to such use to confirm the bearingcapacity of the floor. Account should be taken of the weakening effects on the structure by the progressiveremoval of elements (see also clause 15). The extra loading caused by any temporary access ramps should betaken into consideration.

Possible solutions that should be considered include:

a) adequately designed and correctly installed and maintained back-propping;

b) methods of spreading the load of vehicles, e.g. by the use of designed temporary roadways;

c) a combination of a) and b).

(See also clause 18 for guidance on the safe use of cranes.)

17.3.2 Safe working spaces

Exclusion zones should be applied in accordance with clause 13.

Where it is necessary for demolition machines (including their operators) and any other personnel directlyinvolved in the operation, e.g. lookouts, to be located within the exclusion zone, they should be in a safe placelocated:

a) outside the limit of predicted debris (see also 13.3);

b) away from the deleterious effects of potential machinery or equipment failure, e.g. wire rope pullingsee 17.9.2;

c) outside the operating space of the machine and the effects of its operations.

17.3.3 Conditions of use

All machinery, equipment and attachments should be used, inspected and maintained in accordance with themanufacturer's recommendations. The machine should not be overloaded. The attachment's weight and payloadshould remain within the lift capacity of the machine.

Before use for demolition, lifting appliances should be thoroughly examined in accordance with the requirementsof LOLER [26] and again before being put back into use for traditional lifting duties.

Any crane driver undertaking demolition should be trained and competent, including having prior practicalexperience of the same type of crane in similar applications. The operator should ensure that the working radiusof the machine is not exceeded, as this can cause instability and the machine to overturn. Erratic and/or suddenmovements of the machine should be avoided during the cutting, handling, removing and processing of itemssuch as steel, concrete and plant.

Where the demolition machine is a modified excavator or loader, it should be modified to ensure the protectionof the operator, and of the machine itself, from falling debris (see Figure 3).

When using attachments to weaken and remove elements, the method of work should ensure that neither theattachment nor the machine are overloaded in any way, such as heavy side loading on to the attachment whichcan overcome the rotating facility if fitted. This can occur, e.g. when loads are trapped, when they are notcompletely freed from the jaws or when they are lifted eccentrically.

The operator should be aware at all times of the movement and of the operation of the attachment and of theprogress of the demolition. This should be achieved by the most appropriate means, e.g. by:

a) direct vision;

b) the use of a CCTV system;

c) information provided by a signaller;

d) a combination of any of these.

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17.3.4 Operating limits

The machine, and the attachment it is planned to use, should suit the height of the structure to be demolished.Consideration should be given at the planning stage either to building up the ground levels (see also 17.3.1) or toreducing the structure height by other means to achieve the required safe working height, if necessary.

For the demolition of attached buildings, the structure to be demolished should first be detached as appropriate,ensuring at all times the stability and safety of the remaining property (see clause 15). A clear space should beprovided which is wide enough to ensure that the retained buildings are not damaged by the demolition process,including the transmission of vibration.

The plant should not be worked from or over a roadway without permission as there can be restrictions on use(see 4.2.5.3).

An exclusion zone should be applied in accordance with clause 13.

17.3.5 Accumulation of debris

Debris should not be allowed to accumulate to such an extent that it imposes loads on the structure in excess ofthat which it has been calculated to carry safely (see 17.3.1).

17.4 Remotely controlled machines and robotic devices

Consideration should be given to the use of remotely controlled machines and robotic devices, particularly whenhazardous or potentially dangerous situations arise, thus isolating the operator from the work area and positionof risk. (See also 17.3.1.)

17.5 Compact machines: use and access by lifting

When compact machines (e.g. mini-excavators and skid-steer loaders) are used for demolition on the upper floorsof buildings, an assessment of the strength of the floor should be made, taking into account the possibility thatthe machine and a quantity of debris could eventually be supported on part of the floor before being removed,e.g. to the floor below (see 17.3.1). Appropriate methods of lifting the machine for use should be employed.

Compact machines should be fitted with appropriate capacity hydraulic attachments which can be used, e.g. forbreaking out and cutting, handling, processing and soft stripping.

Precautions should be taken to prevent machines used for this method of demolition from falling down holes infloors, or falling from the edges of buildings, through operator awareness by detailed instruction, and by theprovision of adequate:

a) edge protection;

b) restraint systems.

17.6 High reach machines

Operators of high reach machines should be provided with specialist training beyond that covered by theCertificate of Training Achievement (CTA) for low reach machines. This additional training should provide thenecessary information, instruction and operation on:

a) increased weight of the machine;

b) increased ground bearing pressure;

c) stability characteristics different from other demolition machines;

d) fitting, safe use and removal of attachments;

e) use of variable width tracks (where fitted).

It is important that the correct position of the machine relative to the work face should be maintained and thatthe angle of the boom be limited in accordance with the manufacturer's instructions to ensure the safe operationand stability of the machine.

Appropriate machines fitted with suitable booms and arms should be considered to mechanize the dismantling ofhigh rise buildings, including the use of concrete pulverizers and combination attachments.

17.7 Tower and other high-reach cranes

The installation, operation and dismantling of tower and of other high-reach cranes requires specialized skills andshould be planned and managed in accordance with BS 7121. (See also clause 18.)

The use of such cranes for deconstructing high rise structures should be considered for the removal of structuralelements and of debris by skip as an alternative to dropping of materials. Reference should also be made to theNational Federation of Demolition Contractors (NFDC) Guide on deconstructing tower blocks [73].

Tower cranes are designed for the lifting of freely suspended loads and should not be used for balling operations.

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17.8 Hydraulic attachments

17.8.1 General

Hydraulic attachments which cut steel and crush or pulverize concrete should be considered for the progressivedemolition of reinforced concrete or steel structures.

NOTE Hydraulic attachments can be mounted either directly on the boom or on the dipper arm in place of a backhoe bucket.

Account should be taken of the hazards when such attachments are fitted such as from falling debris or cutsections, or machine instability whatever the height of use.

Although the operator's CTA may be sufficient to cover the general operation of these attachments, they shouldbe provided with additional training as appropriate on the specific attachments, to ensure their safe fitting, useand removal.

When a hydraulic attachment is used to lift or handle material, the load should be held securely within theattachment under hydraulic power, whilst ensuring that the total weight and balance of the load and attachmentremain within the capacity of the machine (see 18.4).

17.8.2 Demolition by pusher arm

NOTE Demolition by pusher arm involves the progressive demolition of a structure using a machine fitted with a pusher arm exertinga horizontal thrust.

The pusher arm should be purpose made and fitted with a deflector plate. The height of the structure should bereduced progressively by pushing over small sections. The point where the pusher arm is applied to the wallbeing demolished should be at an appropriate distance below the top of the wall.

17.8.3 Demolition by impact hammer

NOTE Demolition by impact hammer involves the progressive demolition of masonry and concrete structures by applying heavy blowsto a point in contact with the material, and may be pneumatically or hydraulically operated.

When impact hammers are working on upper floors, regular inspections of the supporting floors, the areasaround these and any temporary works should be made from places of safety to ensure that there is nodeterioration in stability, e.g. due to vibration from its operation (see 15.4). Access to floors beneath, other thanfor those inspections, should be prohibited during these activities.

If it is necessary to cut steel reinforcement, remote means should be considered. The reinforcement should becut so that it does not spring and injure operatives during the operation.

Impact hammers should not be used to demolish tall vertical features such as walls or columns from the side,where there is the possibility of debris falling onto the machine or the operatives.

17.8.4 Demolition by hydraulic shears

17.8.4.1 General

NOTE Cold cutting of metal and reinforced concrete sections can be achieved by cutting and severing material using shear jaws.Shears attachments can be rigidly mounted to the machine or be able to rotate to provide increased working versatility for cutting.

Machines fitted with hydraulic shears should be considered for use where a wide range of materials, includingmetal sections and reinforced concrete are to be removed by cold cutting methods, and where materials are tobe cut in situ.

This method should also be considered for the processing of materials at ground level (see clause 13).

17.8.4.2 Tank and plate cutting

NOTE Rotating hydraulic shears can be used as a cold cutting technique for the dismantling of, e.g. redundant oil and chemical storagetanks (see 19.7).

Cutting of tanks should be carried out in such a way that any risk of fire or explosion through trapped gases orresidual substances is avoided. All tanks and pipe runs should be fully purged prior to any work beingundertaken by the contractor, and confirmation of purging should be obtained in writing. Caution should beexercised when dismantling tanks adjacent to occupied premises where personnel could be present, and anyadjacent tanks and services that could still be operational.

17.8.5 Demolition by pulverizer

NOTE Mechanical demolition by a machine mounted pulverizer is the progressive demolition of reinforced concrete or brick structuresby crushing the material with a powerful jaw action by closing the moving jaw(s) against the material.

The pulverizer attachment should be considered for crushing beams, columns, floor slabs and panels either insitu or as a subsequent processing operation, when reinforcing bars can also be separated.

It should also be considered as an option for the lifting and loading of steel and concrete beams and other solidmaterials.

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17.8.6 Demolition by demolition pole

NOTE A telescopic or rigid demolition pole, to which attachments such as a claw or ripper hooks can be fixed, can be used to achievea greater working height and distance from the base machine during the progressive dismantling of, e.g. roofs, walls, lintels of brick builtstructures. The working radius of the machine is increased by the fitting of an extended pole which is mounted on the dipper arm(see Figure 3).

Positioning and use of the attachment should be achieved by movement of the boom and/or pole rather than bymovement of the base machine. The position of the machine and the angle of the pole should be in accordancewith the manufacturer's instructions.

17.8.7 Demolition by grapple

NOTE A grapple is designed for use in primary demolition and rehandling applications for, e.g. steel and concrete beams, columns,walls and floor sections, and roof joists progressively to ground level. The jaws interlock to enable partial loads to be safely secured.The parallel-jaw closing action ensures that material is drawn into alignment during the dismantling, lifting and loading cycle asappropriate.

When the grapple is used for dismantling, account should be taken of the effects on both the structure locally,and also, where appropriate, the effects remote from where the load is being applied. Effective management andoperation should be applied in accordance with clause 18.

17.8.8 Demolition using hydraulic multi-purpose attachments

NOTE Multi-purpose attachments can be used to progressively demolish reinforced concrete or steel structures including chemical andoil storage tanks by the use of interchangeable jaws for steel cutting, concrete crushing, concrete pulverizing or plate/tank cutting.Multi-purpose attachments can be mounted either directly to the boom or to the dipper arm.

Account should be taken of the hazards when such attachments are fitted to long reach equipment in view of theheight of operation and the danger from falling debris or cut sections (see 17.3.1).

17.9 Mechanical (non-hydraulic) attachments

17.9.1 Demolition by demolition ball

17.9.1.1 General

NOTE Demolition by ball involves the progressive demolition of a building by the use of a weight that is suspended from a liftingappliance and then released to impact the structure, repeatedly, in the same or different locations.

One of two techniques should be used:

a) hoist the ball and release it to drop vertically;

b) winch the ball towards the machine and release it to swing in line with the jib.

The maximum ball weight should not exceed 50 % of the safe working load (SWL) of the machine, at the workingradius.

Cranes with telescopic jibs, tower cranes and other high reach machines should not be used for demolitionballing operations. Reference should be made to BS 7121. (See also clause 18.)

17.9.1.2 Machine restrictions

For all uses, reference should be made to the machine manufacturer's guidance regarding the limitation of use.

The use of a swinging motion to effect demolition by a ball weight should be restricted to machines designed forarduous or heavy duty.

The ball should not be swung by slewing or by jib derricking.

The supporting ropes should be of such length, or be so restrained, that it is not possible for the ball to swingagainst any structure other than that being demolished.

A rope from the second drum of the crane should also be attached to the ball to prevent an inadvertent increasein radius, which could cause an overload.

Swinging of the ball should be carried out by methods that do not overstress the jib or compromise the stabilityof the machine.

Swinging the ball in line with the jib should not be used where the angle of the jib exceeds 608 to the horizontal.

An anti-spin device should always be used on the hoist rope. The hoist rope, anti-spin device and all theattachments of the demolition ball to the hoist rope should be by appropriate means and should be inspected atleast twice daily by a competent person (see also 4.2.9.7).

As the demolition proceeds the length of the jib should be progressively reduced, but leaving sufficient length forthe jib head to have sufficient distance from the building being demolished (often not less than 3 m) to ensuresafe operation.

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Methods of work should ensure that the ball is not trapped when drop-balling arches, floor slabs or similarelements because a sudden collapse can result in the machine being overloaded. Where the ball becomestrapped, e.g. by reinforcing bar, the use of a second machine with a suitable attachment should be considered forthe release of the trapped ball.

CAUTION A trapped ball can cause overloading of the crane when trying to release it by dragging or lifting.

17.9.2 Demolition by wire rope pulling

NOTE This method of mechanical demolition involves attaching wire ropes to a structure, usually of steel, and pulling thepre-weakened structure to the ground by winch or tracked plant.

The results of risk assessments and the availability of many other demolition methods should demonstratewhether wire rope pulling is appropriate. However, wire rope pulling should not be used on brick or masonrystructures.

When undertaking the risk assessment, the following considerations should be included:

a) wire rope pulling should only be used on structures where it is possible to safely attach the ropes;

b) the provision of a second (stand-by) rope, in case the first rope breaks or becomes detached;

c) ropes should be attached prior to any pre-weakening;

d) only steel wire ropes should be used, and these should be inspected to ensure they are fit for the purpose;

e) the provision of restraining ropes to prevent premature collapse before the pull commences, from beforepre-weakening until it has been completed;

f) the designed exclusion zone should take into account the possibility of the failure of the ropes oranchorages (see clause 13);

g) the use of a pulley system so that the pulling machine and operator(s) are removed, and offset, from thedirect line of fall of the structure;

h) protection of the pulling machine operator against failure of the rope system, as well as projecteddemolition material by suitable positioning, possibly within an enclosure.

If attempts to cause collapse are unsuccessful, an alternative remote method of demolition should be selectedand used, following an assessment of the then current state of stability of the structure.

CAUTION It could be dangerous for anyone to approach the structure.

17.10 Cutting by drilling and sawing

17.10.1 General

NOTE Drilling and sawing methods are used to weaken and/or remove parts of (or complete) structures, particularly where work is inconfined spaces, in locations where a high degree of accuracy is needed, or where the noise, dust, smoke and vibration resulting fromother methods would be unacceptable or inappropriate.

When water coolant is used, an appropriate method of disposal should be established. Drilling and sawing workshould be planned following consideration of the guidance in the Drilling and Sawing Association Code of SafeWorking Practice [74].

Although commonly referred to as ªcold-cuttingº methods, these can generate heat and the general guidancein 17.14.1 should be taken into account where appropriate.

17.10.2 Drilling and sawing methods

The following are examples of drilling or sawing methods that should be considered.

a) Diamond core drilling. A quiet vibration-free method of drilling that produces clean holes without spallingin reinforced concrete and other solid materials. A series of diamond-drilled holes are made to form slots usingªstitchº drilling methods.

b) Diamond floor sawing. Self-propelled saws using diamond blades capable of cutting trenches, expansionjoints, removal of slabs, including e.g. motorway repairs and airport works.

c) Rock sawing. Large ªride-onº rock saws used for cutting out large areas of concrete rapidly. The machineemploys large tungsten-tipped wheels capable of cutting to depths in excess of 2 000 mm.

d) Tracked diamond sawing. Used in a large range of demolition methods, particularly for cutting throughreinforced concrete floor slabs and walls e.g. for new doorways, windows, stairwells, lift shafts, servicechutes etc.

e) Hand-held ring and chain sawing. Used to cut through brick and blockwork to form e.g. doorways,windows, expansion joints etc.

f) Diamond wire sawing. Used for cutting particularly thick walls or floors, e.g. in nuclear power stations.

g) Tungsten and dry cutting methods. A range of tungsten-tipped, hand-held drills for drilling holes ine.g. plain concrete, brick and block, also dry cutting diamond blades in hand-held cutting machines for forminge.g. cuts/holes where dust is not a hazard.

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17.11 Demolition by chemical agents

The selection and use of chemical agents such as explosives (17.12), bursting agents (17.13) and combustiblegases (17.14) should be undertaken only by, or under the supervision of, appropriately trained personnel as theyare highly specialized activities.

17.12 Demolition by explosives

17.12.1 General

When explosives are used in demolition, specific consideration should be given to, e.g. the suitability of thestructure for demolition by explosives, techniques appropriate to the structure and location, and associatedexclusion zones. Where explosives are being used, the whole operation should be under the close control of acompetent explosives engineer. Recommendations on the use of explosives are given in BS 5607 and these shouldbe applied in conjunction with this Code. Only explosives engineers who can demonstrate that they have thenecessary qualifications, experience and training in accordance with BS 5607 should be employed on such work.

Examples of the main purposes for which explosives should be considered in demolition, including partialdemolition, are:

a) deliberate collapse of concrete and masonry structures;

b) deliberate collapse of steel structures;

c) deliberate collapse of structures which contain combinations of steel, concrete and masonry;

d) breaking or shattering of objects such as concrete blocks and foundations;

e) full or partial removal of structural elements.

The use of explosives should be considered in order to achieve the effects of cutting, kicking and shattering onstructures and their members.

Each blast should be designed taking into account a number of factors, including:

a) the effect to be achieved;

b) the appropriate explosives types and system;

c) the number and weights of charges;

d) the method(s) of installation;

e) the locations of charges including the heights of placement;

f) the mass, types and strengths of materials to be displaced;

g) the sequential nature and effects of collapse initiation on other parts of the charged structure;

h) the probability, amount and extent to which debris will be projected;

i) types and extent of blast protection (see 17.12.7).

The design should be optimized for the most efficient use of explosives, e.g. by structural pre-weakening(see 15.3.2). The design should also be engineered to minimize fly of material, rather than relying solely on blastprotection. Test blasts should be made to increase knowledge of the materials to be blasted, thus allowing theblast design to be confirmed or modified as required. The extent of the exclusion zones (see clause 13) should bedetermined taking into account the factors such as those described above.

Consideration should be given to placing charges in, or on, the internal members of the structure to enable theperimeter of the structure to contribute to an efficient blast protection design, e.g. in multi-storey buildings withinternal columns.

17.12.2 Method statements

Before any work commences on site, a method statement based on the blast design and associated riskassessments should be prepared (see 5.2). Particular consideration should be given to the following for inclusionin the method statement, unless risk assessments indicate otherwise:

a) collapse mechanisms;

b) pre-weakening;

c) drilling;

d) charging and delay sequences;

e) ªat sourceº and remote protection (see below);

f) exclusion zones (see 17.12.4);

g) evacuation procedures on site or off;

h) crowd control and personnel control;

i) road closures;

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j) defined internal access ways;

k) sequence of events;

l) misfire procedures;

m) contingency plans;

n) arrangements for monitoring (see 17.12.8).

Details of ªat-sourceº protection and any remote protection, including that applied to, e.g. underground servicesand nearby properties should be included. The predictions of air over-pressure and ground vibration measured indecibels and peak particle velocity (ppv) respectively should be used to determine the protection measures to beapplied.

17.12.3 Consultation

Prior to carrying out the works, the explosives engineer should contact appropriate bodies/people, e.g. thoselisted in 12.3, to discuss the proposed system of work and whether the exclusion zones are planned to extendbeyond the site boundary.

17.12.4 Exclusion zones

The dimensions of exclusion zones should be determined by the person directly in charge of the explosivesoperation, usually the explosives engineer, after taking account of all existing conditions and the plannedmethods of work. All site personnel and the public should be excluded during demolition activities, except incertain circumstances when key operational personnel are required to remain within the zone provided they arein a position of safety (see clause 13).

The distance from the blasts to the exclusion zone boundary should be established following a risk assessment.In all circumstances the zone should be established after taking account of the risk of flying debris as a result ofthe detonation of the explosives, and material projected as a result of the structure breaking up. Details ofat-source protection and remote protection to surrounding properties should be taken into account.

Account should also be taken of the ground onto which the structure is to be dropped. This area should be clearof debris, mud or any other material that can be projected by the impacting structure.

Weather conditions prevailing at the time should be taken into account and if necessary, the size of the exclusionzone should be increased to give a new boundary (see 17.12.5).

17.12.5 Contingency planning

A contingency plan should be established and included in the method statement (see 17.12.2). The plan shouldaddress the possibility of the ªblowdownº not proceeding as intended. The plan should be agreed by all thosewho may have authority to instruct or direct. A clear statement that indicates who will take control and whatequipment and procedures will be available for use should be contained in the plan. Such a plan should alwaysprovide for an initial cooling off period after the firing, or an attempted firing, when the planned results were notachieved. During this period, nobody should be permitted to approach the structure. The implications of thefailure should be considered and a revised strategy including time-scales should be developed, agreed andimplemented. This should follow reassessment and consultation based on the site conditions at that time.

17.12.6 Explosives systems, storage, use and security

Explosives should be stored in accordance with BS 5607.

During placing of explosives and detonators a log should be kept showing the quantity of materials used, whichshould be balanced against the quantities of materials remaining. This log should be the responsibility of thesenior explosives engineer who should complete and sign it on a daily basis. The log should be available at alltimes for scrutiny. Any discrepancy should be investigated immediately and resolved. The senior site managershould be informed without delay of the incident and then of the outcome of the investigation as, for instance,more explosives could have been placed than was planned, with resulting safety implications.

Security needs to be effective when explosives are on site, including when they are in position in the structure,and provision should be made for:

a) an adequate number of security guards to be on duty;

b) a system of communications to be available to provide contact with the police or security control centre;

c) floodlights to be used to light the areas, as appropriate.

Arrangements should be made to ensure that explosives cannot be prematurely detonated, including anyunintentional initiation, e.g. when positioning floodlights or using mobile telephones and radios. Where electricaldetonating systems are being used they should be split and shunted to prevent unintentional initiation. Contactwith moisture should be avoided.

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17.12.7 Blasting

17.12.7.1 Design of blast and blast protection

The blast design and the design for blast protection should be assessed with the design for the exclusion zoneboundary to ensure that ejecta is contained within the predicted debris area, in accordance with clause 13(see also 17.12.1).

Blast protection should be provided to prevent fly of materials, e.g. by the use of steel drums filled with sand,covered with sand-bags and conveyor belting. (See 17.12.1.)

NOTE The use of sand-bags alone is unlikely to provide sufficient protection.

Any limitation of the containment ability of blast protection, e.g. for charges set at height (dependent on riskassessments), should be taken into account in the exclusion zone design to ensure that the exclusion zoneboundary extends far enough to receive any ejecta.

Consideration should be given to placing charges in, or on, internal members of structures to enable the externalwalls to contribute to efficient blast design and protection, e.g. in concrete or on steel columns or walls.

The blast design should take account of the possible need to strengthen members to ensure that the force of theexplosive is delivered as planned, resulting in the designed displacement being achieved without the memberfracturing first.

The design of the detonation sequence and delay periods should ensure that, for example:

a) mechanical disruption of undetonated charges does not occur;

b) the structure is not weakened in the vicinity of undetonated charges, and

c) the robustness of the blast protection is not compromised, especially in places where charges are still to bedetonated.

The use of delayed detonation sequences to initiate the charges should, however, be considered as part of themeasures to reduce potential high levels of air over-pressure.

17.12.7.2 Steel members

The objective when using kicking charges should be to displace members, thus removing structural support andwithout unplanned fragmentation. The objective of shaped cutting charges should be to remotely cut steelmembers.

Shaped cutting charges and kicking charges should be adequately secured to the surfaces to be blasted to ensurethat they act as planned.

All ancillary fittings such as cleats and parts of disconnected bracing should be cleared from the vicinity of thekicking charge to avoid their being sheared off by the blast and forming projectiles.

17.12.7.3 Concrete and masonry

The objective when using shattering charges should be to fragment the material. The charges should be placed indrilled holes inside the material and sealed in by adequate stemming.

17.12.8 Monitoring

Arrangements should be made to monitor the effects of the demolition, to include, e.g. air over-pressure, groundvibration and debris scatter. The results obtained should be compared with the predicted effects in order to learnfrom the design assumptions.

17.13 Bursting

17.13.1 General

Bursting techniques can be used for the demolition of concrete, masonry and rock, and should be considered,e.g. where environmental constraints such as reduction of noise, dust and/or vibration need to be taken intoaccount.

An estimate of when failure will occur should be made even though it can be difficult to predict the exact timingof structural failure because of the slow build-up of internal forces. Work should be planned so that when thestructure or mass does fail, it does so in a manner that does not create a risk.

17.13.2 Gas expansion bursters

NOTE The effect of the burster is obtained by inserting it into a prepared cavity in the mass to be demolished. Upon being energizedthe resultant increase in pressure of the gas ruptures a diaphragm, releasing the gas into crevices in the surrounding structure which isthen fractured.

A gas expansion burster should be effectively restrained within the prepared cavity in order to prevent it frombecoming projected in an uncontrolled manner.

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17.13.3 Hydraulic bursters

NOTE Hydraulic bursters work on the same principles as gas expansion bursters in that they use an expanding device to force apart amass, but the process is not as rapid as in a gas expansion burster. Pistons or wedges are placed in a prepared cavity and are graduallyjacked out under pressure, the resulting increase in size of the device fractures the surrounding material.

Work should be planned and controlled to ensure that dislodgement of the hydraulic bursting equipment is not arisk, e.g. when failure of the structure occurs.

17.13.4 Expanding demolition agents

NOTE This method of bursting employs the use of expanding chemicals that are mixed, e.g. with water to form a liquid or paste. Themixture is poured into pre-drilled holes in the material that is to be demolished, and expands to cause a fracture.

The handling, mixing, pouring and use of the chemicals should be undertaken in accordance with themanufacturer's instructions. An assessment of the products being used should form the basis for the selectionand use of appropriate, safe methods of work, including the provision of PPE.

17.14 Hot cutting

17.14.1 General

Hot cutting techniques should be considered to include any method that can potentially generate sufficient heat,e.g. in the form of incendive friction, sparks or flame, to cause a fire. Such techniques commonly use oxy-fuelgases and disc grinders. As a general principle, to reduce the risk of fire and/or explosion, methods other thanhot cutting should be considered in preference (see 17.8).

Hot cutting should be selected only where the work system chosen avoids the risk of fire or explosion. Hotcutting should not generally be used in the proximity of flammable materials, gases and vapours (see also 19.7).In particular, work methods should prevent localized oxygen enrichment because of the attendant risk ofexplosion. Combustible and flammable material should be removed from the area where flame cutting operationsare being carried out (see also 12.8.4).

Flame cutting techniques should commence only after the structure to be cut and the surrounding area havebeen made safe from the risk of fire or explosion (see also 12.7, 12.8.4 and 19.7 for further advice).

The manufacturer's guidance and recommendations should be followed, e.g. for lighting up procedures. Work onsite using flame cutting equipment and compressed gas cylinders should be undertaken with the necessaryprecautions, and by people with the appropriate training and experience. Reference should be made toIND(G) 297 [75] and HS(G) 139 [76].

Suitable fire-fighting equipment and trained personnel should be provided (see [60]).

The use of permit to work procedures should be considered, and may be required for hot cutting work(see 12.7).

17.14.2 Fume hazards

Work methods should be planned such that adequate precautions are in place to take account of fume hazardscaused by flame cutting, from, for example:

a) nitrous fumes which can build up very quickly in poorly ventilated areas, e.g. excavations, pits, smallbasements, tanks and metal containers;

b) lead poisoning when cutting steel that is coated in lead-based paint or from tanks that have been used forthe storage of lead-based products, including petrol; (the Control of Lead at Work Regulations 1998 [77] apply);

c) plated metal fumes such as from cadmium.

Risk reduction using the following control techniques (see also 12.10 for working in confined spaces) should beconsidered:

a) remote cutting methods;

b) forced ventilation in poorly ventilated areas;

c) appropriate approved respirator equipment.

17.14.3 Personal protective equipment

Operatives who carry out cutting operations should wear appropriate PPE, including suitable eye protection andprotective clothing. Suitable footwear should be worn, to protect from the possibility of falling molten metalburning legs or feet. Wellington boots should not be worn (see 12.5).

17.14.4 Flame cutting with compressed gases

17.14.4.1 Handling and storing cylinders

Oxygen cylinders should not be stored with fuel gas cylinders. Cylinders on site should be stored in secureadequately ventilated facilities, to prevent dangerous levels of fuel gas or oxygen building up. Cylinders shouldalways be secured in an upright position during both storage and use.

Cylinders should not be rolled along the ground or handled roughly as this may cause damage to the cylindervalve, resulting in a leak of fuel gas or oxygen. Cylinder trolleys should be used.

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17.14.4.2 Flame cutting equipment

Connection of the equipment, safety checks on it and any repairs should be carried out by a competent personwith the necessary training and experience.

Fuel gas and oxygen hoses should be checked daily at the commencement of work and as necessary during theday for signs of damage and badly connected sections of hose.

Hose length should be kept as short as possible, 20 m maximum for flame cutting. The routing of ªtrailingº hosesshould be arranged to reduce the risk of mechanical damage, or of damage by the hot work itself. If lengths ofhose have to be joined, e.g. after removal of damaged sections, proper hose couplers should be used to effectreliable repairs.

NOTE It is preferable to replace damaged hoses.

Non-return valves should be fitted to each hose on the burning guns and flashback arresters should be fitted tothe gauges to help reduce the risk of flashback. The correct fuel gas regulator should be connected for the fuelgas being used and a correct coupler used to connect the hose to the cylinder regulator.

A naked flame should never be used to check cylinders and hose connections for leaks, soapy water should beused instead.

CAUTION A build-up of oxygen caused by leaking cylinders and hoses, or by deliberately releasing oxygen,e.g. to clear fumes from the air, is potentially dangerous as a spark may cause a sudden and fierce fire.

Oil and grease should be kept away from all parts of equipment used for oxygen service, including cylinders,regulators, gauges, hoses and cutting nozzles. Hands, gloves, work clothes and tools for use on the equipmentshould be kept sufficiently clean to prevent oil or grease being inadvertently transferred onto the equipment.

When purging hoses the area should be well ventilated to reduce the risk of flashback.

17.14.4.3 Thermic lancing

NOTE Thermic lancing is used to cut through materials including concrete. The tip of the lance is preheated to start an oxygen/ionreaction which produces an intense heat source that is then applied to the material to be cut. Once started it is self-supporting.

During thermic lancing, combustion typically produces molten material and thick smoke, therefore suitableprecautions should be taken, particularly where there is limited ventilation.

17.15 High pressure water jetting

NOTE The term ªhigh pressure water jettingº covers all water jetting processes including those using additives and abrasives wherethere is an energy input to increase the pressure of water. In demolition the process is used, e.g. for cutting out concrete from aroundsteel reinforcing bars where the latter are to remain.

The process is highly specialized and should be carried out by suitably competent people in accordance with theWater Jetting Association's Code of Practice [78].

18 Materials handling and processing

18.1 General

The handling and processing of materials on site should be considered as part of the demolition process.Assessments should take account of, for example:

a) cutting and lifting (as one operation);

b) separating materials for re-use and recycling (see clause 11);

c) lifting and transporting;

d) creating a stable stock pile;

e) removing from a stock pile;

f) personal health and safety (see clause 12).

Attachments including grapples, electromagnets, buckets, chains and slings should be in a suitable condition foruse (see 4.2.9.7). The balance and security of loads should be safe for movement including transportation.

18.2 Transport arrangements

The management of traffic movements for the site should be carried out in accordance with the sitearrangements (see 5.1.4c) and [32]).

18.3 Safe use of cranes

When a crane is used, the recommendations given in the relevant part(s) of BS 7121 should be followed.

CIRIA publication 131 [79] should be consulted for further advice on crane stability.

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18.4 Lifting and lowering

Before any lifting and lowering, the weight and position of the centre of gravity of the load should be determinedto ensure that:

a) an appropriate method of lifting is used;

b) a crane or lifting equipment of adequate capacity is used.

When lifting and lowering, the demolished elements should be of a size appropriate to the methods used.

Where necessary, cranes and/or lifting equipment should be used to support beams and columns whilst they arebeing cut and lowered to the ground. In framed structures, similar support should be given to members whilejoints are being severed. The load should be taken up before the final cuts are made. Precautions should betaken to prevent the load swinging out of the calculated radius. Any ground, base or anchorage on which thecrane or lifting equipment relies, should be stable and have sufficient strength to prevent instability and possibleoverturning.

As demolition proceeds, lifting equipment of adequate capacity should be considered for the support of anyunrestrained members remaining, in order to control their movement and prevent unplanned falls.

A factor of safety corresponding with normal lifting practice should be applied when selecting the liftingaccessories (e.g. slings, shackles or lifting beams) that are to be used. The lifting accessories should be inspectedby the user prior to lifting (see also 17.3.3).

CAUTION Deformed, damaged or worn slings, chains and wire ropes should not be used.

Slinging of loads should only be undertaken by a person trained in safe lifting. Only one nominated personshould give directions to the crane driver and the system of signals to be used should be agreed on site beforethe lifting begins.

18.5 Free fall of demolition materials

A safe route for removal of debris from the structure should be determined and implemented.

Debris should only be allowed to fall freely to the ground, internally or externally, when an adequate exclusionzone (see clause 13) can be provided and managed. Account should be taken of the effects of wind on fallingdebris, and also bouncing onwards after the initial impact. Whenever possible material should be droppedthrough chutes, e.g. proprietary interlocking sections or purpose designed chutes, which terminate above skips.

CAUTION As soon as openings are created, e.g. to dispose of debris, they should be protected by edge barrierssuch as guard-rails and toe boards to prevent inadvertent falls of people or materials.

Precautions should be taken to contain flying or falling debris by sealing off all openings in walls, includingglazed areas, adjacent to the area of fall. Where debris above first floor level is to be dropped to the ground orbasement level within a building, sufficient openings should be formed in the floors to enable the debris to fallwithout accumulating on intermediate floors. The stability of the surrounding structure or any working platformshould not be compromised (see clause 15) e.g. if one or more joists (or beams) are to be removed to allow thefree passage of debris.

To prevent excessive lateral pressure, fallen debris should be removed at planned intervals to prevent build-upagainst walls and, e.g. in confined spaces such as lift wells and tall chimneys.

When material is being dropped, personnel should be used to ensure the integrity of the exclusion zone whichcan be, e.g. by the use of secure fencing. An effective system of communication should be established betweenthe look-out(s) and persons dropping material, to ensure that the exclusion zone is clear of personnel whendropping takes place.

As materials can become lodged on protrusions, an assessment should be undertaken before the area isconfirmed as safe for the temporary removal of the exclusion zone, to enable materials to be cleared.

B

SI

09-2

000

91

BS

6187:2

000

To sheet 2

Material types

Buildings19.2

General19.2.1

Bridges19.3

General19.1

Typical demolition methods forvarious types of structure

19

General19.3.1

Masonry andbrick arches

19.4

Independentchimneys

19.5

Dead load19.4.2

Single-spanarch

19.4.3

Multi-spanarch

19.4.4

Use ofexplosives

19.4.5

General19.5.1.1

Methods19.5.1

Structuralcondition19.5.1.2

Wire ropepulling

19.5.1.3.3

Explosives19.5.1.3.2

Steelchimneys

19.5.3

Reinforcedconcrete chimneys

(in situ, precastand

prestressed)19.5.4

Progressivedemolition

by machine19.5.1.4

Masonry andbrick chimneys

19.5.2

Plastics-reinforcedchimneys

19.5.5

Progressivedemolitionby hand19.5.1.5

Deliberatecollapse19.5.1.3

General19.5.1.3.1

Engineeringadvice19.3.2

Engineeringadvice19.4.1

Continuousstructures

19.3.6

Deliberatecollapse19.3.4

Temporaryworks19.3.3

Counter -balancing

19.3.5

Soft stripping19.2.2

Concreteindustrialized

systems19.2.3

Post-tensionedstructures

19.2.4

Monolithicstructures19.2.4.3

Progressivelypost-tensioned

structures19.2.4.2

Independentprecast units

19.2.4.1

Timber19.2.5

Glassreinforced

plastics19.2.6

Figure 22a Ð Route map for clause 19 (sheet 1)

BS

6187:2

000

92

BS

I09-2

000

Open basements,cellars, vaults

and other voids19.8.2

From sheet 1

Typical demolition methods forvarious types of structure

19

Lattice towersand masts

19.6

General19.6.1

Vessels thatcontained flammable

materials19.7

General19.7.1

General19.8.1

Basements andretaining walls

19.8

Spires19.9

Structuralcondition

19.6.2

Vessel cleaningand making safe

19.7.2

Vessel structures19.7.4

Vessels aboveor belowground19.7.3

Roofs19.7.4.1

Vessels belowground19.7.3.1

Vessels aboveground19.7.3.2

Floors19.7.4.3

Walls-single shells

19.7.4.2

Demolitionmethods19.6.4

Access and safeplaces of work

19.6.3

Filled basements,cellars, vaults

and other voids19.8.3

Figure 22b Ð Route map for clause 19 (sheet 2)

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19 Typical demolition methods for various types of structure (see Figure 22)

19.1 General

The demolition process should commence only when the relevant recommendations made in earlier clauses ofthis standard have been implemented.

The principle of the design and method of construction combined with the current knowledge of the site, such asthe relevance of any decommissioning, and including the state of services and presence of asbestos should beknown. Risk assessments should have been made, method statements should have been produced and exclusionzones should have been designed and implemented before demolition work starts (see clause 5).

Additionally the sequence of demolition should have been arranged to ensure that any remaining structure isstable, and where necessary, temporary bracing should be added.

Where appropriate, demolition materials should generally be segregated and consideration should be given to thepotential for their re-use and recycling (see clause 11).

19.2 Buildings

19.2.1 General

The demolition of buildings should commence with the removal of hazardous materials, e.g. asbestos (see 10.3).

This should be followed by the removal of non-structural items (commonly known as soft stripping), e.g. fixturesand fittings, doors, windows, frames, suspended ceilings, studding and partitions, but ensuring that safe accessesand working places are available before work on the structure itself commences.

19.2.2 Soft stripping

The stripping should be carried out using compact machines, hand tools or by hand, as appropriate. Materialsshould be separated using machines, where appropriate (see 18.1).

Soft stripping work methods should take account of potential hazards from, for example:

a) working at height, including the recovery of materials (see clause 12);

b) ineffective protection of voids;

c) falling debris (see 18.5);

d) ªbooby trapsº such as used syringes taped under banisters, on top of kitchen units and doors, etc.maliciously left to injure site personnel;

e) restricted workspace;

f) manual handling;

g) fire, if combustible debris is allowed to accumulate.

19.2.3 Concrete industrialized systems

Where a building has been constructed with an industrialized system, full information on the method of designand construction (including ªas-designedº, ªas-builtº and any retrospective strengthening or other modifications)should be obtained before the planning of the demolition works. Attention should be paid to the principles of thestructural design to determine which parts of the structure depend on each other to maintain overall stability,e.g. in some cases the building may rely on the panel walls for stability.

CAUTION Temporary supports to individual elements of the structure may be necessary in order to maintaininterim stability.

19.2.4 Post-tensioned structures

19.2.4.1 Independent precast units

Units should generally be removed from structures before being broken up (see annex C). Demolition ofindividual units can take place in situ, although this should be in a predetermined manner and with restraintprovided to movement as appropriate (see also annex C).

Separation of units, which can themselves be prestressed together, should be carried out using the mostappropriate methods selected from, for example: diamond sawing, water jetting, thermic lancing or mini-blastingtechniques, or a combination of hand or machine-mounted breaker and hot cutting. Transverse stability andstrength can be affected and should be taken into account and appropriate lateral support should be provided, ifrequired.

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Structures containing separately stressed precast units should be broken up using, e.g. impact hammers, hydraulicshears or explosives. The release of stress can be uncertain and sufficient investigation work such as determiningthe extent and effectiveness of grouting in ducts for bonded tendons, should have been undertaken to ensurethat ªfly-outº will not occur. However, measures should be taken to ensure that any potential anchorage ejectionis properly contained to prevent ªfly-outº.

19.2.4.2 Progressively post-tensioned structures

As the loading and reaction effects on these types of buildings are highly specialized, appropriate specialistengineering advice should be obtained and the demolition carried out in strict accordance with that advice.

CAUTION In some instances the inherent properties of the stressed section can delay failure for some time andthe presence of the large prestressing forces can cause sudden and complete collapse with little or no warning.

19.2.4.3 Monolithic structures

Engineering advice should be obtained before any attempt is made to expose the tendons or anchorages ofstructures in which two or more members have been stressed together.

Exposure of tendons or anchorages and any destressing of tendons should be undertaken in accordance with astrictly controlled procedure.

CAUTION It may be necessary for temporary supports to be provided before tendons or anchorages areworked on, including e.g. diaphragm (transverse) beams.

19.2.5 Timber

Normally a timber building should be demolished by deliberate collapse methods or by deconstruction. Attentionshould be paid to the possibilities of serious decay and/or infestation of timber that may greatly weakenmembers.

19.2.6 Glass reinforced plastics

Glass reinforced plastics (GRP) sections, which can be mounted on timber support frames, can have asbestoscement/board linings that may contain asbestos. In such cases, removal should be in accordance with 10.3.2.2.

19.3 Bridges

19.3.1 General

Bridges should be demolished either by deliberate collapse methods or in the reverse order of constructionusing, e.g. cutting and lifting (or removing the entire deck as one unit), (see also annex C). After removal ordeliberate collapse, those parts of the structure should generally be broken up before removal from site, ifrequired. Precautions should be taken to ensure that the collapsed structure does not present a hazard whenbeing cut into smaller pieces.

Any relevant additional temporary supports to help carry the dead load of the structure and demolition loadings,including plant and equipment, should be in place before work commences, together with any support to aidlateral and longitudinal stability.

Where any part of a bridge is post-tensioned, the recommendations of 19.2.4 should be applied.

19.3.2 Engineering advice

Engineering advice should be obtained for all stages of the demolition of bridges to ensure that the stability ofthe structure is maintained. The demolition should be closely supervised by persons fully experienced in, andconversant with, the type of work being undertaken.

Work should be programmed in consultation with, and to the satisfaction of, the authorities responsible for thebridge and for the land below it.

19.3.3 Temporary works

Temporary works should be designed to carry the required loads and temporary bracing should be incorporatedinto the bridge structure, where necessary, in order to maintain stability under the severest conditions. Beforetransverse members are removed, temporary supports or guys should be fixed to the main beams or girders, ifappropriate.

Where the horizontal thrusts from the abutments are designed to be taken by the deck, these should be dealtwith by, e.g. inserting temporary struts prior to removal of the deck.

Where temporary support is required as part of the demolition method, e.g. in the case of skew bridges, it shouldbe in place before the stability of the bridge is compromised.

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19.3.4 Deliberate collapse

Deliberate collapse methods should be designed such that appropriate initial preparation work is carried out toaid efficient demolition. Explosives or mechanical methods of pre-weakening should be considered as ways ofinitiating the collapse of the structure.

19.3.5 Counterbalancing

Where bridges have been constructed using a counterbalanced cantilever design, the demolition technique needsto ensure stability by taking into account considerations such as out of balance loadings and lack of fixity atsupports by using, e.g. temporary supports.

Where counterbalancing is used, the balancing materials should be securely and safely fixed. The bridge orelements of it should be transversely braced, if necessary.

19.3.6 Continuous structures

Where a bridge is continuous over one or more supports, consideration should be given to either cutting thedeck above the piers to form a simply supported structure, or cutting the deck at midspan to form staticallydeterminate cantilevers, but taking into account the ability of the structure to maintain stability in these forms.

19.4 Masonry and brick arches

19.4.1 Engineering advice

Engineering advice should be obtained for all stages of the demolition of arches, to ensure that the stability ofthe structure is maintained. The demolition should be closely supervised by persons fully experienced in, andconversant with, the type of work being undertaken. (See also 19.3.)

19.4.2 Dead load

Dead load may be removed provided that the stability of the main arch rings is not compromised, but it shouldbe noted that the load-carrying capacity of many old arches relies on the filling between the spandrels. On noaccount should the restraining influence of the abutments be removed before the dead load of the spandrel fill,the spandrels and the arch rings is removed.

19.4.3 Single-span arch

A single-span arch should be demolished by cutting strips progressively from each springing, parallel to the spanof the arch, until the width of each arch has been reduced to a minimum which can then be collapsed.

Where deliberate collapse methods are adopted the crown should be broken out either by remote mechanicalmethods or by explosives, unless temporary supports are provided before work commences.

CAUTION Breaking out the crown of the arch will lead to instability and collapse.

19.4.4 Multi-span arch

In multi-span arches, before individual spans are removed, lateral restraint should be provided at the springinglevel to prevent instability of adjacent spans including any supporting piers. Demolition should then proceed asfor a single span, ensuring that the spandrels are demolished as the work proceeds.

19.4.5 Use of explosives

The use of explosives should be considered where it is preferable to ensure the collapse of the whole structurein one operation, so as to avoid the potential for unstable portions remaining.

19.5 Independent chimneys

19.5.1 Methods

19.5.1.1 General

In general, remote demolition techniques should be used in preference to hand demolition. Any internal liningshould be demolished progressively with the rest of the structure or removed prior to collapse, if appropriate. Asmaterial will generally be dropped inside the chimney, debris should be cleared to a planned method and in acontrolled sequence in order to prevent a build-up of internal pressure in the chimney.

Openings should be large enough for the safe removal of debris and should be designed to ensure continuingstability until collapse initiation, if appropriate.

NOTE For more advice on material types see 19.5.2 to 19.5.5.

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19.5.1.2 Structural condition

The fabric of the chimney should be examined to determine its condition and whether there has been anydeterioration in the strength of the materials. When surveying chimneys account should be taken of the structuralmaterials that can be obscured by e.g. cladding. Measurements should be taken to determine whether thechimney is out of alignment, including deviation from the vertical in any direction.

Where radial separation between annular courses of brickwork is suspected, an investigation should be carriedout to establish the possibility of any gap between the stack and the refractory lining.

19.5.1.3 Deliberate collapse

19.5.1.3.1 General

Consideration should be given to the effects of high levels of vibration that can be generated when the structureimpacts the ground (see 11.2.3.4) and any potential for the ejection of materials. Prior to commencement on sitea fully detailed method statement giving predictions for vibration, air blast and possible ejecta should beprovided, showing the designed exclusion zones (see 13) and the reasoning used to determine their dimensions(see 17.12.4).

Sufficient support should remain to provide a sound fulcrum to allow the structure to overturn as planned.Where openings exist in the part to remain, these should be supported by propping or rebuilding, as appropriate.

19.5.1.3.2 Explosives

When explosives are used, the demolition method should be supervised to ensure that the designed method andoverall procedures are strictly adhered to (see clauses 12 and 17).

19.5.1.3.3 Wire rope pulling

If the chimney is guyed, two steel wire ropes with a suitable diverging angle should be attached before felling toensure control of the line of fall. The ropes should be made taut and the guys on the side opposite to the line offall should be systematically severed at an appropriate time in the felling operation, to prevent prematurecollapse (see 17.9.2).

19.5.1.4 Progressive demolition by machine

Consideration should be given to progressively lowering the structure from the top using machines. Machinesthat should be considered will depend upon the particular circumstances and can include independent machineson the chimney top, that may or may not be suspended during operation. The security of the machine on thechimney should be ensured at all times. Consideration should also be given to the use of machine mountedattachments (see clause 17). The method by which the debris is allowed to fall and is subsequently collected,including any means of access, should be planned.

19.5.1.5 Progressive demolition by hand

Hand demolition should be carried out from a safe place, such as a working platform.

NOTE This may be provided either internally or externally.

A careful inspection and survey should be made to determine whether existing ladders, climbing irons and bandsare safe if it is proposed to use them for access. No reliance should be placed on existing features without a fullassessment.

Work methods should ensure that any cornice or similar projecting feature is adequately supported or taileddown before the weight of the structure above is removed.

19.5.2 Masonry and brick chimneys

Where progressive demolition by hand is used, the chimney should be demolished course by course. The debrismay be allowed to fall to the ground internally but should be cleared in a planned way as the work proceeds inaccordance with 19.5.1.1. Where the masonry, brickwork or mortar is of poor quality this should be taken intoaccount, e.g. by not enlarging existing openings. Where adequate access cannot be provided, debris should belowered in suitable containers outside the chimney rather than dropped internally.

19.5.3 Steel chimneys

Where progressive demolition techniques are used, the chimney should be taken down from the top, and theplate should be cut into manageable sizes and lowered to the ground. If the lining is concrete, difficulty may beexperienced in burning the plate with it in position and the lining should be removed first. Guys, if any, should becut systematically as the shaft is lowered, temporary guys having first been fixed at other points, wherenecessary (see 19.5.1.3).

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19.5.4 Reinforced concrete chimneys (in situ, precast and prestressed)

The type of concrete construction should have been established (see clause 7) to determine, e.g. whether they areprestressed. If they are post-tensioned, work should be carried out in accordance with specialist engineeringadvice.

Where it would be appropriate to use progressive demolition techniques, the chimney should either be takendown in sections from the top in panels of manageable size which should be lowered to the ground, or should bebroken up in situ.

Debris should be cleared in accordance with 19.5.1.1.

When chimneys are progressively removed in cut panels, the concrete should be broken out locally to expose thereinforcement at the edges of each panel. Each section should be supported, if required, prior to thereinforcement being cut.

Remaining panels at the top of the chimney should not be left in an unstable condition. At the end of workperiods, e.g. at the end of the working shift, the top should be left level with no unstable parts.

19.5.5 Plastics-reinforced chimneys

Normally plastics-reinforced chimneys are constructed inside a framework and should be demolished in a similarmanner to that employed for masts or towers.

19.6 Lattice towers and masts

19.6.1 General

Lattice towers and masts should be out of service and appropriately decommissioned, however, the structureshould be adequately earthed during the demolition process. As stability is often provided by tensioned guyropes, the amount of tension and thus the overall balance of forces in the guys, which is critical to the stabilityof the mast, should be known from the survey and should be taken into account. Independent (tubular)structures that are secured only at the base should be considered to act as cantilevers.

No work should be undertaken at height in poor weather conditions, e.g. during strong or gusty winds, in icyconditions or if lightning is seen or predicted.

19.6.2 Structural condition

Although all prime members of the structure should be visible for inspection, a check for corrosion should beundertaken particularly at plated joints, and especially if the joint is a moisture trap.

Assessments of wire ropes should also be made, taking account of the difficulty of inspection because corrodedor broken strands can be hidden inside, or covered by grease.

19.6.3 Access and safe places of work

Work on parts of the structure away from ladders and working platforms (which should be checked for safetybefore any use) should be carried out by specialist riggers who are trained to work on masts and towers. Allpersonnel should be attached at all times to a suitable fall arrest device.

19.6.4 Demolition methods

The selected methods of demolition should minimize the need for work at heights, e.g. felling should beconsidered if sufficient space is available.

For progressive dismantling, the operations should be carried out in a predetermined order, based on a structuralanalysis of all stages to determine the degree of residual stability.

The use of explosive cutting charges should be considered to pre-weaken the structures prior to felling and alsoto cut members for progressive dismantling.

CAUTION Removal of bolts by hand can be difficult because of, e.g. the loads on them from the structure.

For the demolition of lattice towers or pylons, progressive demolition techniques should be considered, so thatassemblies of manageable size can be safely lowered to the ground by crane or attached derrick.

For guyed structures, the removal of guys should be carried out in a controlled sequence to ensure continuedstability during demolition.

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19.7 Vessels that contained flammable materials

19.7.1 General

CAUTION The preparation and cleaning of plant that has contained flammable or combustible materials forinternal inspection, hot work and demolition is a specialized activity. There is always the possibility that vesselscan contain hazardous atmospheres (see 12.10). Unsafe work practices can result in fires or explosions, not onlyfrom such obvious sources as hot work, but also, e.g. from friction sparks, an increase in temperature, orbuild-up of electrostatic charge.

Consideration should be given to ensuring that during any of the activities discussed in this section, the externalenvironment of the tank(s) is similarly free from potential hazards. (See also 17.14 and, as an alternative to hotcutting, 17.8.)

Those engaged for such work should be able to demonstrate their competence, including the earlier planning ofthe work, and making adequate provision for health and safety (see clause 12 and in particular 12.7).

The requirement to inform and/or consult the local authority petroleum officer, fire officer or other responsibleperson should be considered at the planning stage (see clause 5).

The information given in the decommissioning report (see 8.1.3) should include confirmation of the nature of thecontaminants present (if any), specification of appropriate decontamination procedures and precautions for thesafe disposal of waste (including any vent and/or purge gases), standards to be adopted and namedresponsibilities for the work etc. Any specific structural features of tanks or vessels where gases, liquids orresidues can be trapped, e.g. between the lining and the shell, tubular roof supports or floating roof crevices,should also be identified and taken into account when defining decontamination procedures.

Prior to commencing any work the operator/contractor should confirm the procedures to be carried out and beissued with the appropriate authority to work by the competent person controlling the activities (see clause 8and 12.7).

19.7.2 Vessel cleaning and making safe

Where a vessel is to be prepared for removal and/or demolition, and in order to eliminate the risk of fire andexplosion, it should be emptied and thoroughly cleaned (see 19.7.1) by such procedures as:

a) steaming;

b) water or solvent washing/jetting;

c) other manual means;

d) and finally ªgas-freedº by forced ventilation or another suitable method, with a ªgas-freeº certificate issuedas appropriate.

CAUTION 1 If vessels have contained even a small amount of flammable or combustible gas, liquid, sludge orsolid, including dust or powder, and have not been cleaned effectively, an explosion can occur on application ofthe flame cutting blow torch.

Alternatively, in cases where gas-freeing and cleaning cannot be readily carried out, e.g. if the vessel isunderground, the equipment can be rendered temporarily safer after removal of as much of the contents aspossible, by ªinertingº. Depending on the type of work planned however, consideration should be given to laterthorough cleaning. ªInertingº is the process of completely filling vessels with materials such as one of thefollowing to replace previous gaseous contents:

a) water;

b) inert gas (nitrogen or possibly ªcombustionº gas);

c) carbon dioxide (from dry ice);

d) nitrogen foam (there are limitations to the use of air foam);

e) hydrophobic foam.

CAUTION 2 If vessels have contained water, the atmosphere inside the vessel can be depleted of oxygen andcontain flammable hydrogen due to corrosion.

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Similar preparation/decontamination procedures should be applied to associated pipework and equipment, priorto its dismantling and/or entry, though by nature of its construction, it can invariably be dismantled by ªcoldcuttingº methods.

The cleaning/inerting techniques are employed to realize a specific purpose. Unless specified, it should not beassumed that the vessel is either suitable for entry and/or hot work.

When using gas inerting and purging techniques, it should be ensured that efficient dispersion/mixing of theinerting/purging gas occurs throughout the entire vessel and that there are no dead spaces. This should beconfirmed by frequent atmosphere checks, as appropriate, and where possible in different parts of the vessel(using remote sampling).

Methods of cleaning and/or inerting should be chosen to be compatible with vessel characteristics and nature ofcontaminants etc. and potential hazards considered and taking into account that some flammable materials willfloat.

In all these operations the process should be managed to ensure that no flammable liquid, vapour or gas isallowed to enter any drainage or water course and that flammable vapours purged to atmosphere do not createan explosion or health hazard.

Certificates confirming that a vessel is, e.g. ªGas-freeº, ªSafe for Entryº or ªSafe for Hot workº, should only beissued by a competent person, who should state for how long the certificate is valid and the nature of workpermitted.

If the vessel is to be subsequently dismantled on site it should be ensured that it remains in a safe state in theinterim period, and will be safe at the time of dismantling. Those making safe the tank and/or certifying thisshould be consulted before work proceeds.

HSE guidance note CS15 [80] should be consulted for further guidance. Further information can be obtained fromthe Institute of Petroleum (see B.1).

19.7.3 Vessels above or below ground

19.7.3.1 Vessels below ground

Prior to excavation, vessels should be cleaned or made safe using the methods outlined in 19.7.2. If a methodinvolving water filling is used, then water should be emptied from the vessel prior to lifting out of the excavationand subsequently refilled if necessary (see below).

Where a vessel surround is being excavated there should be an assessment to determine whether material in thesurrounding area has been contaminated, either by leakage from the vessel or by spillage. If contamination hasoccurred, precautions including the following should be taken:

a) appropriate barriers should be placed around the work and hazard notices displayed;

b) no smoking, naked lights or other potential ignition sources should be permitted in the vicinity. Equipmentshould either be suitable for use in a potentially flammable area (e.g. flame proof and non-sparking hand tools),or be located in a safe area (e.g. for plant such as compressors);

c) a plentiful supply of water should be used to lessen the risk from sparking.

The sides of excavations formed to enable removal of underground vessels should be made stable, e.g. by slopingback to a safe angle or by providing adequate support.

After excavation and prior to removing the vessel(s) consideration should be given to providing the wordsªFLAMMABLE HAZARDº in clear conspicuous letters at each end or on opposite sides of the vessel.

Where further cleaning (see 19.7.2) is appropriate for subsequent activities, this should be carried out when thevessel has been removed from the ground to a more suitable and safe location.

19.7.3.2 Vessels above ground

Before commencing removal and/or demolition the vessel should have been prepared using an appropriatemethod as outlined in 19.7.2 and certification provided as appropriate.

Only cold cutting techniques should be used unless the vessel has been cleaned and ªgas freedº or the risk of fireand explosion has been otherwise eliminated. (see 17.14)

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19.7.4 Vessel structures

19.7.4.1 Roofs

Cold cutting by remote means should generally be considered the preferred method.

Depending on the size, weight and type of construction of the vessel, consideration should be given to cuttingand then removing the roof in one piece by crane. If this is not appropriate, provision of temporary roof supportsshould be considered to ensure the stability of the roof during the demolition.

CAUTION The need to install any temporary supports should be determined prior to cutting.

On all vessels, when the roof or roof plating is being removed an edge ring beam should be left, sufficient toretain the rigidity of the tank walls. Occasionally consideration may need to be given to adding such a ring beamto provide temporary stability during the demolition.

On vessels where fixed roofs are supported by steelwork rafters or trusses, the removal of roof plating should beconsistent with retaining residual structural integrity in and by the steelwork supports. Consideration should begiven to leaving centre plates in place, e.g. as it may enhance structural stability.

The structure should generally be demolished in a sequence that removes diametrically opposite pieces.

Floating roofs should not be dismantled until they have been fully stabilized, such as by being landed on thefloor of the vessel. No start should be made to demolish roofs whilst they are still supported on maintenancelegs.

19.7.4.2 Walls Ð Single shells

On vessels with fixed roofs, no start should be made to remove the shell of the vessel, apart from accessmanholes, before the roof has been removed. On vessels with floating roofs, the roof should be fully landedbefore the shell is removed.

The shell of the vessel should generally be dismantled course by course horizontally around its perimeter, witheach piece supported and removed by a suitable crane. Methods using single, long vertical cuts in the walls canproduce unstable walls with results that are difficult to predict and should be considered only if remote,machine-based cutting techniques are employed together with suitably designed exclusion zones based on theassessed behaviour of the structure.

CAUTION Temporary support should be considered to maintain structural integrity as partially demolishedtanks are susceptible to collapse, e.g. due to wind loading.

19.7.4.3 Floors

The underside of the floors of vessels should be investigated for leakage and/or trapped vapour in any voidsbeneath the base plates which can give rise to a risk of fire and explosion. Preferably, where possible, theyshould be lifted prior to cold cutting into manageable sized pieces.

Where prior removal of the floor is not adopted and where decontamination or preparation suitable for hot workis necessary (but see 17.14), measures such as cold cutting and/or drilling into the base, followed by inert gaspurging or water flooding, or other suitable techniques, may need to be considered.

19.8 Basements and retaining walls

19.8.1 General

Before commencing the demolition of a structure with basements or retaining walls, the contractor shouldestablish whether any intermediate walls or floors are supporting the retaining or perimeter wall, so that suitablesupport may be provided if necessary. Any previous structural assessments should be referred to for additionalinformation.

The local highways or roads authority should have been consulted before any wall supporting a road or highwayis to be removed (see 4.2.5). Consideration should be given to leaving perimeter walls in place, whether or notthe void is to be filled.

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Water should either be allowed to drain from, or conversely be allowed in to the structure, to counter upwardpressure, depending on the water table in the area concerned. Methods to be considered should include holesbroken through the floors of basements, voids etc. provided that structural integrity is not compromised.

Appropriate precautions should be taken to prevent water penetration to adjoining buildings, including theprovision of appropriate damp proofing systems. Precautions should also be taken to prevent accidental accessto basements that are filled with water.

19.8.2 Open basements, cellars, vaults and other voids

Where basements, cellars, vaults or voids need to be left open, adequate buttressing walls should be left tosupport the retaining walls to ground level. Where there are insufficient buttressing walls the provision of shoringor ramping should be considered. In all cases where they are to be left open they should be securely fenced.

19.8.3 Filled basements, cellars, vaults and other voids

Where basements, cellars, vaults or voids need to be back-filled, all organic matter should first be removed.

Where the basements, cellars, vaults or voids adjoin any other property, any party or adjoining cellar walls shouldbe inspected as these may not be of adequate strength to withstand the resultant ground pressure imposed onthem by the fill. If the party or adjoining walls are inadequate, specialist engineering advice should be taken todetermine the method of strengthening of such walls prior to back-filling. Provision should be made for adequatedamp-proofing.

Wherever basements, cellars, vaults or voids extend beneath footpaths or roads, and they are not opened up,they should be filled to the approval and satisfaction of the local highway or roads authority (see 4.2.5).

19.9 Spires

The fabric of the spire should have been examined to determine its condition and whether there has been anydeterioration in the strength of the materials. The surveying of spires should include structural materials that areobscured by cladding. Measurements should be taken to determine whether the spire has deviated from theperpendicular. Examination of the structure should be carried out to ensure that vibration caused bypre-weakening and drilling does not cause any of the structure, such as masonry or brickwork to be dislodged. Ifnecessary specialist engineering advice should be obtained with respect to any pre-weakening that may benecessary. Reference should be made to any relevant information.

The same demolition principles should be applied to spires as for chimneys, when both deliberate collapse andprogressive demolition should be considered, particularly using remote machine techniques. Demolition bydeliberate collapse should be considered, only on sites that are detached and reasonably level, where the wholestructure is being demolished and where there is sufficient space all around the spire for an adequate exclusionzone to be provided (see clause 13).

When progressive demolition is being used, the heavy solid stonework at the peak of a masonry spire, which cannormally be removed only after releasing the central tie rod, should be reduced to a suitable size if manuallyhandled before being lowered to the ground.

Other considerations should include, as appropriate:

a) any hand demolition should be carried out from a safe working platform, such as by scaffolding encirclingthe spire (see 12.17);

b) flame-cutting tools should not be used to remove metal fittings or clamps from timber components in aspire, because of the risk of fire (see 17.14);

c) an assessment to establish whether the stonework above the spider should be supported temporarily inposition before the tie rod is released, particularly where the structure is in poor condition;

d) any overhanging or corbelled stonework when the weight of the structure above is removed;

e) the need for temporary bracing.

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20 Completion of the works

20.1 Safety and health

On completion of the demolition works the site should be left in a safe and secure condition.

All pits, trenches, sumps or voids should be left filled, securely covered and marked, or guarded in a safecondition.

The site drainage system should be thoroughly cleaned and tested to ensure that it continues to operate.

Any walls that are to remain, in particular to act as the boundary to the site, should be checked to ensure thatthey remain stable under anticipated loadings.

All contaminants should be removed or left in a condition such that they present no hazard to health or to theenvironment. Records of all contaminants, where they remain on site or whether they have been removed,should be identified in the Health and Safety File. Where they remain, all details should be notified to those whowill have the responsibility for the site so that they can, for instance, control entry to these areas.

The planning supervisor should ensure that the Health and Safety File has been prepared and handed to theclient on completion of the works.

20.2 Health and Safety File

The Health and Safety File (see 4.2.9.4) should include all the relevant information from 20.1. In addition, allservice disconnections, drainage terminations, etc. should be recorded in the Health and Safety File, which iscompiled as the work progresses and is usually co-ordinated on behalf of the client by the planning supervisor.

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Annex A (informative)

Training and competencies

A.1 Demolition

A.1.1 Background

The National Demolition Training Group (NDTG) in conjunction with the Construction Industry Training Board(CITB) and the National Federation of Demolition Contractors (NFDC) are the focus for training in the industry.The NDTG was established under the CITB Group Training Association Scheme and membership is available toall demolition firms who are registered with the CITB. Full details of training courses available can be obtainedfrom the NDTG Training Adviser at the CITB (see B.6).

NOTE Professional institutions and other organizations (see annex B) also provide means of improving competencies by, e.g. runningconferences, symposia and courses.

A.1.2 Training schemes and courses

A.1.2.1 The National Federation of Demolition Contractors

The NFDC, on behalf of the NDTG, administers the following scheme and courses for demolition operatives,supervisors and managers.

The Scheme for the Certification of Competence provides a certificate to operatives who have achieved asatisfactory level of competence at work, in accordance with the competencies laid down by the CITB TrainingSpecification Ð Demolition (NTS 013). Copies are available from the CITB (see B.6).

The scheme applies to all operatives employed within the demolition industry, and includes the followingcategories of operatives:

a) demolition operative 1 (labourer);

b) demolition operative 2 (mattockman);

c) demolition operative 3 (topman).

The Demolition Supervisors Course has been incorporated into the scheme for the Certification of Competence.It is a sixteen weeks distance learning course, with the syllabus based on the CITB Construction Site Safetycourse and General Supervisory Management in Construction packages.

The Demolition Managers Course is a twelve week distance learning course with a residential weekend at theCITB Bircham Newton Training Centre (see annex B.6). Full details of the scheme for the Certification ofCompetence, Demolition Managers and Supervisors courses are available from the NFDC (see annex B.4).

National Vocational Qualifications/Scottish National Vocational Qualifications (NVQ/SNVQ) are a measure ofcompetencies of an operative's capabilities to carry out a range of work to the performance criteria which havebeen set out by industry. Demolition NVQs that are currently available are: NVQ Level 2 Ð Demolition and NVQLevel 3 Ð Demolition. Further information is available from the CITB (see annex B.6).

The Scheme for the Certification of Training Achievement: Construction Plant Operatives aims to ensure that allplant operatives certificated under the scheme have attained acceptable standards of basic skills and safetyawareness. Further information is available from the CITB (see annex B.6).

A.1.2.2 The Drilling and Sawing Association

The Drilling and Sawing Association (DSA) runs a CITB approved scheme for the training and certification ofdrilling and sawing operatives. The objective of the scheme is to ensure that all operatives certificated under thescheme have attained acceptable standards of basic skill and safety awareness. Further details are available fromthe DSA (see annex B.4).

A.2 Explosives training

Training in shotfiring and explosives engineering is available. Successful completion of either course includes aperiod of practical experience under qualified supervision. Details of suitable training and competencies forshotfirers and explosives engineers are given in BS 5607.

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Annex B (informative)

Useful contacts

B.1 Professional bodies

The Institute of Demolition Engineers

P.O. Box 142

Scunthorpe

North Lincolnshire

DN17 4YW

Tel/Fax: 01724 798903

E-mail: [email protected]

http://www.ide.org.uk

The Institute of Explosives Engineers

Centenary Business Centre

Hammond Close

Attleborough Fields

Nuneaton

Warwickshire

CV11 6RY

Tel: 024 7635 0846

Fax: 024 7635 0831

http://www.iexpe.org

The Institution of Civil Engineers

1 Great George Street

London

SW1P 3AA

Tel: 020 7222 7722

Fax: 020 7222 7500

http://www.ice.org.uk

The Institution of Structural Engineers

11 Upper Belgrave Street

London

SW1X 8BH

Tel: 020 7235 4535

Fax: 020 7235 4294

http://www.istructe.org.uk

Royal Institute of British Architects

66 Portland Place

London

W1N 4AD

Tel: 020 7580 5533

Fax: 020 7255 1541


http://www.architecture.com

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Chartered Institute of Building

Englemere

Kings Ride

Ascot

Berkshire

SL5 7TB

Tel: 01344 630700

Fax: 01344 630777


http://www.ciob.org.uk

Royal Institution of Chartered Surveyors

12 Great George Street

Westminster

London

SW1P 3AD

Tel: 020 7222 7000

Fax: 020 7222 9400


http://www.rics.org.uk

Institute of Wastes Management

9 Saxon Court

St Peter's Gardens

Northampton

NN1 1SX

Tel: 01604 620426

Fax: 01604 621339


http://www.iwm.co.uk

Institution of Chemical Engineers

Davis Building

165-171 Railway Terrace

Rugby

Warwickshire

CV21 3HQ

Tel: 01788 578214

Fax: 01788 560833

http://www.icheme.org.uk

The Institute of Petroleum

61 New Cavendish Street

London

W1M 8AR

Tel: 020 7467 7100

Fax: 020 7255 1472


http://www.petroleum.co.uk

106 BSI 09-2000

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Association of Consulting Engineers

Alliance House

12 Caxton Street

Westminster

London

SW1H 0QL

Tel: 020 7222 6557

Fax: 020 7222 0750


http://www.acenet.co.uk

London District Surveyors' Association

London Borough of Ealing

Chief Building Surveyor

Perceval House

14-16 Uxbridge Road

London

W5 2HL

Tel: 020 8579 2424 Ext. 53447

District Surveyors' Association

Avalon House

Chesil Street

Winchester

SO23 OHU

Tel: 01962 848151

Fax: 01962 848130


County Surveyors' Society

Department of Planning

Wiltshire County Council

County Hall

Trowbridge

BA14 8JD

Tel: 01225 713318

Fax: 01255 713400

Convention of Scottish Local Authorities

Rosebery House

9 Haymarket Terrace

Edinburgh

EH12 5XZ

Tel: 0131 474 9200

Fax: 0131 474 9292

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B.2 Government departments, agencies and authorities

Department of the Environment, Transport and the Regions

(Headquarters)

Eland House

Bressenden Place

London

SW1E 5DU

Tel: 020 7994 3000

http://www.detr.gov.uk

Health and Safety Executive (HSE) HSE Infoline

HSE Information Centre Tel: 0541 545500

Broad Lane Fax: 01787 313995

Sheffield

S3 7HQ

http://www.hse.gov.uk

HSE Books

PO Box 1999

Sudbury

Suffolk

CO10 2WA

Tel: 01787 881165

Fax: 01787 313995

http://www.hsebooks.co.uk

Environment Agency

25th Floor

Millbank Tower

21-24 Millbank

London

SW1P 4XL

Tel: 020 7863 8609

Fax: 020 7863 8650

http://www.environment-agency.gov.uk

The National Assembly for Wales

Cathays Park

Cardiff

CF1 3NQ

Tel: 029 2082 5111


http://www.wales.gov.uk

Also at:

Gwydyr House

Whitehall

London

SW1A 2ER

Tel: 020 7270 3000

108 BSI 09-2000

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Health and Safety Executive for Northern Ireland (HSE NI)83 Ledas DriveBelfastBT6 9FRTel: 028 9024 3249Fax: 028 9023 5383http://www.hse-ni.org.uk

Scottish ExecutiveRural Affairs DepartmentEnvironment Protection UnitWaste TeamVictoria QuayEdinburghEH6 6QQTel: 0131 244 0237Fax: 0131 244 0245http://www.scotland.gov.uk

Scottish ExecutiveDevelopment DepartmentBuilding Control DivisionVictoria QuayEdinburghEH6 6QQTel: 0131 244 7440Fax: 0131 244 7454http://www.scotland.gov.uk

Scottish Environment Protection AgencyErskine CourtCastle Business ParkStirlingFK9 4TRTel: 01786 457700Fax: 01786 446885E-mail: [email protected]://www.sepa.org.uk

HM Customs and Excise Landfill Tax HelpdeskDobson HouseRegent CentreGosforthNewcastle-upon-TyneNE3 3PFTel: 0845 912 8484Fax: 0845 912 9595http://www.hmce.gov.uk

The Stationery Office51 Nine Elms LaneLondonSW8 5DRTel: 0870 600 5522Fax: 0870 600 5533E-mail: [email protected]://www.the-stationery-office.co.uk

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B.3 Utilities/Services regulators

The Office of Gas and Electricity Markets (OFGEM) (in England and Wales)

130 Wilton Road

London

SW1V 1LQ

Tel: 020 7828 0898

Fax: 020 7932 1600

http://www.ofgem.gov.uk

OFGEM (in Scotland)

Regent Court

70 West Regent Street

Glasgow

G2 2QZ

Tel: 0141 331 2678

Fax: 0141 331 2777

Office for the Regulation of Electricity and Gas (OFREG) (in Northern Ireland)

Brookmount Buildings

42 Fountain Street

Belfast

BT1 5EE

Tel: 028 9031 1575 (electricity)

Tel: 028 9031 4212 (gas)

Fax: 028 9031 1740

http://www.ofreg.nics.gov.uk

Office of Water Services (OFWAT)

Centre City Tower

7 Hill Street

Birmingham

B5 4UA

Tel: 0121 625 1300

Fax: 0121 625 1400


http://www.open.gov.uk/ofwat

Office of Telecommunications (OFTEL) (England)

Export House

50 Ludgate Hill

London

EC4M 7JJ

Tel: 020 7634 8913

Fax: 020 7634 8943

Northern Ireland Advisory Committee on Telecommunications (NIACT)

22 Great Victoria Street

Belfast

BT2 7QA

Tel: 028 9024 4113

Fax: 028 9024 7024


110 BSI 09-2000

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Scottish Advisory Committee on Telecommunications (SACOT)

2 Greenside Lane

Edinburgh

EH1 3AH

Tel: 0131 244 5576

Fax: 0131 244 5696


Welsh Advisory Committee on Telecommunications (WACT)

Caradog House

St. Andrews Place

Cardiff

CF1 3BE

Tel: 029 2037 4028

Fax: 029 2066 8536


B.4 Industry associations

Construction Confederation

Construction House

56-64 Leonard Street

London

EC2A 4JX

Tel: 020 7608 5000

Fax: 020 7608 5001

E-mail: enquiries@the CC.org.uk

http://www.theCC.org.uk

National Federation of Demolition Contractors (NFDC) Ltd.

Resurgam House

1A New Road

The Causeway

Staines

TW18 3DH

Tel: 01784 456799

Fax: 01784 461118


http://www.demolition-nfdc.com

Asbestos Removal Contractors Association (ARCA)

Friars House

6 Parkway

Chelmsford

CM2 ONF

Tel: 01245 259744

Fax: 01245 490722


http://www.arca.org.uk

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Drilling and Sawing Association (DSA)PO BOX 16BelperDerbyshireDE56 4HYTel/Fax: 01332 842463E-mail: [email protected]://www.drillandsaw.org.uk

Water Jetting Association17 St. Judith's LaneSawtryHuntingdonCambsPE28 5XETel: 01487 834034Fax: 01487 832232

Engineering Construction Industry Association5th FloorBroadway HouseTothill StreetLondonSW1H 9NSTel: 020 7799 2000Fax: 020 7233 1930E-mail: [email protected]

National Joint Utilities Group30 MillbankLondonSW1P 4RDTel: 020 7963 5720Fax: 020 7963 5989

National Federation of Master Steeplejacks and Lightning Conductor Engineers4d St. Mary's PlaceThe Lace MarketNottinghamNG1 1PHTel: 0115 955 8818Fax: 0115 941 2238E-mail: [email protected]://www.nfmslce.co.uk

L.P. Gas AssociationPavilion 16Headlands Business ParkSalisbury RoadRingwoodHampshireBH24 3PB

British Metals Federation16 High StreetBramptonHuntingdonCambsPE28 4TUTel: 01480 455249Fax: 01480 453680E-mail: [email protected]://www.britmetfed.org.uk

112 BSI 09-2000

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B.5 Research organizations

BRE Centre for Waste and Recycling

Garston

Watford

WD2 7JR

Tel: 01923 664200

Fax: 01923 664010


http://www.bre.co.uk

CIRIA

6 Storey's Gate

London

SW1P 3AU

Tel: 020 7222 8891

Fax: 020 7222 1708


www.ciria.org.uk

B.6 Training bodies

Construction Industry Training Board (CITB)

Resource Centre

Bircham Newton

King's Lynn

Norfolk

PE31 6RH

Tel: 01485 577577

http://www.citb.org.uk

Waste Management Industry Training and Advisory Board (WAMITAB)

P.O. Box 176

27 Marefair

Northampton

NN1 1SB

Tel: 01604 231950

Fax: 01604 232457


http://www.wamitab.org.uk

NOTE Other organizations and bodies, including those elsewhere in this annex, also provide training and run seminars etc. indemolition related subjects.

B.7 Heritage and countryside/nature bodies

The Countryside Council for Wales

Plas Penrhos

Penrhos Road

Bangor

LL57 2LQ

Tel: 01248 385500

Fax: 01248 355782

http://www.ccw.gov.uk

BSI 09-2000 113

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CADW Welsh Historic Monuments

Crown Buildings

Cathays Park

Cardiff

CF10 3NQ

Tel: 029 2050 0200

Fax: 029 2082 6375


http://www.cadw.wales.gov.uk

Scottish Natural Heritage

12 Hope Terrace

Edinburgh

EH9 2AS

Tel: 0131 447 4784

Fax: 0131 446 2277

http://www.snh.org.uk

English Heritage

Customer Services

PO Box 569

Swindon

SN2 2YR

Tel: 01793 414910

http://www.english-heritage.org.uk

English Nature (The Nature Conservancy Council for England)

Northminster House

Northminster

Peterborough

PE1 1UA

Tel: 01733 455100

Fax: 01733 568834

http://www.english-nature.org.uk

National Trust

42 Queen Anne's Gate

London

SW1H 9AS

Tel: 020 7222 9251

Fax: 020 7222 5097

http://www.nationaltrust.org.uk

RSPB

The Lodge

Sandy

Beds

SG19 2DL

Tel: 01767 680551

Fax: 01767 692365

http://www.rspb.org.uk

114 BSI 09-2000

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Annex C (normative)

Hazards associated with prestressed materials

C.1 General

Prestressing is a means by which materials such as brick and concrete are given a built-in compression prior tothe application of further loads. The large amount of energy stored in structural elements constructed fromprestressed materials requires that special care be taken when they are demolished. It is important to identify thesize, type and number of tendons used in a member, since the force contained can vary from a few tonnes insmaller wires up to 1 000 tonnes in some multi-strand cables.

Prestressing can also be present in some steel structures, e.g. steel beams with a concreted flange.

C.2 Investigatory examination

The investigatory examination should, where possible, identify the type of construction, the method ofprestressing, the manufacturer of the prestressing system and likely tendon forces, and the probable tendonlayout (see also clause 7). In addition, the condition of the materials and tendons should be determined. Thesefactors are likely to affect the choice of demolition technique and the method of working. Any sequentialstressing during construction should be identified and taken into account.

All available records should be thoroughly inspected to establish whether the construction conforms to theserecords. If none are available, a careful examination of the structure can often reveal any prestressedelements. C.4 lists the major features to be considered in ascertaining whether an element is prestressed or not.

Unless it can be established beyond doubt that the structure is prestressed or otherwise, expert engineeringadvice should be sought.

C.3 Nature of prestressing

Prestressing is applied to concrete elements by means of highly stressed individual or groups of wires, strands orbars anchored into the concrete. The type of anchorage depends on the prestressing system used. Inpretensioned members, the tendons are anchored through direct bond with the concrete. Post-tensioning tendonscan be anchored by cones, wedges or screw threads with locking nuts. Wires, strands or bars can be anchoredseparately or in groups. In long spans, continuous members of segmental structures, anchors and/or couplersmay occur at intermediate positions. Intermediate anchors can be placed in recesses or external to the mainbody of the structure.

By prestressing concrete it is able to work more effectively and the required area of plain reinforcement can beconsiderably reduced. However, by reducing the quantity of plain reinforcement, the element will behave in amore brittle fashion when individual tendons are cut during the demolition process.

After post-tensioning tendons have been anchored, it is common practice to fill internal ducts with grout. Thegrout performs two functions: it protects the prestressing steel from corrosion and bonds the tendon to theconcrete along the length of the duct. However, even when specified, it is not always the case that full groutingof ducts occurs, leaving the tendons unbonded or only partially bonded. It is the presence of bonds whichrestricts the violent release of tension during the demolition process. Therefore, it is of utmost importance todetermine whether an element contains fully bonded, partially bonded or unbonded tendons.

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C.4 Recognition of prestressed members

C.4.1 General

Exposure of non-tensioned reinforcement is not conclusive evidence as to whether a member is prestressed ornot. The following criteria should be used when determining whether a structure is prestressed or not (someprestressed members may not meet any of the criteria and further investigation may be necessary):

a) age of construction; prestressing did not become a popular form of construction until after 1945;

b) span/depth ratio; the pre-compression induced in the member allows it to carry greater loads with ashallower depth of section than for comparable reinforced concrete sections;

c) uneven soffit; creep deflection is usually seen in the form of hogging at midspan of beams and slabs;

NOTE 1 The deflected shape can vary between adjacent floor slab panels or beams and the difference in camber may be visibleonce finishes are removed.

NOTE 2 Precambering of precast prestressed concrete beams is particularly common in bridge decks.

d) shape of section; pretensioned units often come in ªstandardº shapes other than rectangular e.g. ªTº, ªUºand ªIº sections and hollow boxes; post-tensioned sections can come in a variety of shapes and are usuallyharder to identify, although ªIº and box sections are common;

e) joints; in segmental construction, individual sections are post-tensioned together to form a unit;

NOTE 3 The joints between the sections can vary in thickness and are formed of cement mortar, concrete or a thin resin layer.

f) concrete strength; to avoid crushing of the concrete under the applied pre-compression, the strength of theconcrete should be fairly high;

NOTE 4 Strengths in excess of 50 N/mm2 are usual and may be higher. Thus, testing for compressive strength may provide anindication of prestressed concrete. Concrete strengths can be estimated by non-destructive means. However, if cores are removed,particular care should be exercised to avoid cutting tendons.

g) ends of members; with pretensioned members it is common for the ends of the tendons to be cropped flushwith the ends of the concrete; signs of burning may be evident or the ends may have been coated withbitumen or a similar protective layer; in some instances the tendons may be easily visible due to the draw-in ofthe steel which occurs at transfer of compression to the member;

NOTE 5 In post-tensioned members the tendons are normally cut off flush with the anchor, which is then encased in a protectivelayer of concrete. The end of the concreted recess is often visible and confirms the presence of post-tensioned cables. It is sometimespossible to identify the prestressing system from the shape of the covered area. However, it should be recognized that the ends ofprestressed members are very rarely open to immediate inspection and are often built into the rest of the structure (see C.5 forinspection hazards).

h) resilience; if, during the demolition process, a member exhibits a high degree of resilience to normaldemolition techniques, there is a likelihood that the element may be prestressed.

NOTE 6 Further investigations should be made before the demolition process is allowed to proceed.

C.4.2 Tanks

It is common practice to prestress circular tanks, resulting in thinner walls than for ordinary reinforced concreteconstruction. The wires may consist of a series of individually stressed hoops or a continuous spiral, tightlywound onto the concrete shell and covered with a layer of concrete or mortar. On large tanks there may be twoor more layers of wires. Portions of the covering may be chipped away to reveal the presence of prestressingsteel. Where the wires are stressed as a series of hoops, anchoring buttresses are likely to be present at intervalsaround the tank. Further confirmation may be given by the presence of anchorages along the top edge of thetank, but the absence of these does not imply that no prestressing is present.

C.4.3 Columns

It is not common practice to prestress columns, although portal frames and some raking columns on bridges maybe prestressed.

C.4.4 Retaining walls

Deep retaining walls are sometimes stressed vertically, with the anchorages located at the top of the wall, usuallywithin the thickness of the ground slab. Where a deep wall is considered to be of slender section, with noapparent form of horizontal support, then the possibility of the presence of prestressing should be considered.

Masonry retaining walls, either of brick or concrete blockwork, may be prestressed vertically usually with barsrather than strands. This type of wall is difficult to identify as there may be no anchorages apparent. Masonryretaining walls, which have no other apparent means of structural support, should be viewed with caution.However, the levels of prestress in this type of structure tend to be lower than in prestressed concrete elements.

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C.4.5 Ground anchors

Many structures, such as retaining walls, dry docks, cofferdams, tall buildings, suspension or arch bridges,tension roofs and transmission towers, are constructed using anchors prestressed into a load-bearing stratum toprovide a counterbalance for the structural forces. If structures of these types have no apparent method ofstructural support, prestressed ground anchors may be present. The termination of these anchors may not alwaysbe visible.

C.4.6 Types of prestressed members

There are five main categories of prestressed member. The form of the members in a structure should beidentified before attempting demolition, bearing in mind that any prestressed structure can contain elements ofmore than one category.

Category 1. Members prestressed before the application of the superimposed loads and having all the cables ortendons fully bonded to the concrete or grouted within ducts.

Category 2. As category 1, but the tendons are left deliberately ungrouted. This type of construction cansometimes be recognized from the access points provided for inspection of the cables and anchors. Morerecently, unbonded tendons have been used in the construction of beams, slabs and other members; these areprotected by grease and surrounded by plastic sheathing, instead of the usual metal duct.

Category 3. As category 2, but with the tendons placed external to the structure. This type of construction iseasily identifiable as the protective plastic sheath or concrete layer covering the cables can be seen duringinspection. The use of external unbonded cable has become more common in the construction of bridges as ithas the advantage that the tendon can be replaced.

Category 4. Members that are post-tensioned progressively as the building construction proceeds and the deadload increases, using bonded tendons as category 1.

Category 5. As category 4, but using unbonded tendons as in category 2, which could present an even greaterhazard if it is not possible to reduce the prestress gradually.

Examples of progressively prestressed members may be found in the podia of tall buildings or some types ofbridge, particularly segmental. The greatest care should be exercized in demolishing such members to avoidupward or hogging failure, which could have catastrophic results. Such failure may occur when part of the deadload has been removed. Therefore, it is essential that cables or tendons are cut in succession as the load isremoved, in order for a reasonable state of equilibrium to be maintained.

C.5 Hazards

C.5.1 Stored energy

Post-tensioned tendons contain a large amount of stored energy which makes demolishing structures that containthem a problem. This is particularly the case when the tendons are unbonded or partly bonded, since there isnothing to contain the energy and prevent the anchorages being projected from the end of the member like amissile. Therefore, it is important that the following safety precautions are taken when demolishing prestressedconcrete structures:

a) no personnel should pass behind the end anchorages during the demolition process;

NOTE 1 If anchorages remain unprotected, no cutting of cables should be allowed and alternative methods should be found.

b) end anchorages should be covered and shielded by timber, concrete or steel plates and the demolitionmethod approved by the engineer in advance of the works;

c) the minimum number of people necessary to carry out the work should be in the area of the cuttingoperation;

d) all cutting operations should be supervised and monitored;

e) propping or counter-balancing should be provided where necessary.

NOTE 2 The capacity and positioning of props should be such as to allow for a sudden, uncontrolled release of prestress.

It should be remembered that locking nuts are used as anchorages at the ends of prestressed bars and these areas potentially dangerous as other forms of anchorage. Any inadvertent release of prestress due to the unscrewingof these locking nuts should be avoided.

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C.5.2 Handling

Prestressed members are usually designed to resist applied loads in one direction only and should be handledwith this in mind. Sudden failure of the element can occur if handled incorrectly. Elements with multiple tendonsare normally prestressed symmetrically and asymmetric release of stress should be avoided where possible, so asto minimize any uncontrollable sideways buckling. However, damaged members may fail even though handledcorrectly.

Segmental structures need to be handled with particular care since any reverse or transverse bending can causethe section to become unstable, particularly when no steel crosses the joints. Where the member containscorroded and partially bonded cables, mishandling may lead to a sudden loss of prestress that could cause thesection to fail at a joint.

C.5.3 Continuous members

Members continuous over more than one support may have tendons which run over more than one span oralong the full length. Demolition of one section may release and collapse the adjoining spans. Progressivecollapse is a real possibility, particularly in the case of category 2 partly grouted tendons and structures.

C.5.4 Progressively prestressed members

Category 4 and 5 structures provide additional hazards, as the construction process cannot easily be reversedduring demolition. It is important to ensure that the removal of dead weight does not impair the stability of thestructure and cause premature collapse. Possible secondary effects of this failure should be considered, such asthe collapse of wall cladding panels as a result of the removal of dead load. Rupture may be preceded by upwarddeflection, with excessive deformations causing collapse.

C.5.5 Signs of damage or deterioration

In a prestressed concrete element, if the concrete is found to exhibit signs of damage or deterioration or if thetendons or anchorages show signs of damage or corrosion, extreme care should be exercized when lifting themember. In some cases, such as in the deterioration of high alumina cement concrete or in structures affected byalkali-silica reaction, it may be advisable to add temporary bracing before the element is removed.

C.5.6 Inadvertent collapse

In some cases, sudden collapse can occur where incorrect demolition procedures have inadvertently been used.Failures of this type occur with little or no warning and as such are of particular danger to site personnel.

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Bibliography

Standards publications

BS 5744, Code of practice for safe use of cranes (overhead/underhang travelling and goliath cranes, highpedestal and portal jib dockside cranes, manually operated and light cranes, container handling cranes andrail-mounted low carriage cranes).

BS EN ISO 9000, Quality management and quality assurance standards.

Other publications (see B.2 for sources of publications from The Stationery Office andHSE Books)

[1] The Construction (Design and Management) Regulations 1994. London: The Stationery Office.

Associated ACOP: Managing construction for health and safety L54:1995. Sudbury: HSE Books.

Associated guidance: Designing for health and safety. A guide for designers on the CDM Regulations:1995.Sudbury: HSE Books.

[2] The Utilities Contracts Regulations 1996. London: The Stationery Office.

[3] The Nuclear Installations (Dangerous Occurrences) Regulations 1965. London: The Stationery Office.

[4] The Control of Industrial Major Accident Hazards Regulations 1984. London: The Stationery Office.

[5] Town and Country Planning Acts 1990. London: The Stationery Office.

[6] Planning (Listed Buildings and Conservation Areas) Act 1990. London: The Stationery Office.

[7] The Building Act (England and Wales) 1984. London: The Stationery Office.

[8] The Building (Scotland) Act 1959. London: The Stationery Office.

[9] The Building (Scotland) Act 1970. London: The Stationery Office.

[10] The Highways Act 1980. London: The Stationery Office.

[11] The Roads (Scotland) Act 1984. London: The Stationery Office.

[12] The New Roads and Street Works Act 1991. London: The Stationery Office.

[13] The Party Wall etc. Act 1996. London: The Stationery Office.

[14] The Building Operations (Scotland) Regulations 1975. London: The Stationery Office.

[15] The Building Procedure (Scotland) Regulations 1981. London: The Stationery Office.

[16] The Building Procedure (Scotland) Amendment Regulations 1991. London: The Stationery Office.

[17] The Road Traffic (Temporary Restrictions) Act 1991. London: The Stationery Office.

[18] Traffic signs manual, Chapter 8, Traffic safety measures and signs for road works and temporary situations,volumes 1 and 2:1991. London: The Stationery Office.

[19] Code of Practice for Signing and Guarding at Road Works under the New Roads and Street WorksAct 1991. London: The Stationery Office.

[20] The Environmental Protection Act 1990. London: The Stationery Office.

[21] The Clean Air Act 1993. London: The Stationery Office.

[22] The Health and Safety at Work etc. Act 1974. London: The Stationery Office.

Associated guidance:

A guide to the Health and Safety at Work etc. Act 1974, 5th ed. L1:1992. Sudbury: HSE Books.

A guide to risk assessment requirements. Common provisions in health and safety law. IND(G) 218L:1996.Sudbury: HSE Books.

Five steps to risk assessment. IND(G) 163L:1994. Sudbury: HSE Books.

[23] The Management of Health and Safety at Work Regulations 1999. London: The Stationery Office.

Associated ACOP: Management of health and safety at work L21:2000. Sudbury: HSE Books.

[24] The Construction (Health Safety and Welfare) Regulations 1996. London: The Stationery Office.

Associated guidance: Health and Safety in Construction. HS(G) 15O:1997. Sudbury: HSE Books.

[25] Provision and Use of Work Equipment Regulations 1998. London: The Stationery Office.

Associated guidance and ACOP: Safe use of work equipment L22:1998. Sudbury: HSE Books.

[26] The Lifting Operations and Lifting Equipment Regulations 1998. London: The Stationery Office.

BSI 09-2000 119

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[27] The Control of Substances Hazardous to Health Regulations 1994 (as amended). London: The StationeryOffice.

Associated ACOP: General COSHH ACOP, Carcinogens ACOP and Biological Agents ACOP L5: Revised 1999.Sudbury: HSE Books.

[28] The Reporting of Injuries, Diseases and Dangerous Occurrences Regulations 1995. London: The StationeryOffice.

Associated guidance: A guide to the Reporting of Injuries, Diseases and Dangerous OccurencesRegulations 1995 L73: Revised 1999. Sudbury: HSE Books.

[29] The Confined Spaces Regulations 1997. London: The Stationery Office.

[30] The Environmental Protection (Duty of Care) Regulations 1991. London: The Stationery Office.

[31] Waste Management Ð The Duty of Care Ð A Code of Practice 1991. A joint publication by DETR and theScottish and Welsh Offices. London: The Stationery Office.

[32] Workplace transport guidance for employers. HS(G) 136:1995 and The safe use of vehicles on constructionsites. A guide for clients, managers and workers involved with construction transport. HS(G) 144:1998.Sudbury: HSE Books.

[33] Material Information Exchange database (MIE) BRE 1998. Available at: http://helios.bre.co.uk/exchange orby free faxback service on: 01923 664786.

[34] The Data Protection Act 1998. London: The Stationery Office.

[35] The Scheme for Construction Contracts (England and Wales) 1996. London: The Stationery Office.

[36] The Housing Grants Construction and Regeneration Act 1996. London: The Stationery Office.

[37] Decommissioning, mothballing and revamping: Institution of Chemical Engineers, 1997 (see B.1 forsource).

[38] Occupational exposure limits. HSE Guidance Note EH40:2000. Sudbury: HSE Books.

[39] Controlled asbestos stripping techniques for work requiring a licence HS(G) 189/1:1999. Sudbury:HSE Books.

[40] Working with asbestos cement HS(G) 189/2:1999. Sudbury: HSE Books.

[41] The Ionising Radiations Regulations 1985. London: The Stationery Office.

[42] Leptospirosis: Are you at risk? IND(G) 84:1994. Sudbury: HSE Books.

[43] The Transport of Dangerous Goods (Safety Advisers) Regulations 1999. London: The Stationery Office.

[44] Waste Minimisation in Construction Site Guide 1997. CIRIA SP133 (see B.5 for source).

[45] The Water Resources Act 1991. London: The Stationery Office.

[46] The Wildlife and Countryside Act 1981. London: The Stationery Office.

[47] The Control of Pollution Act 1974. London: The Stationery Office.

[48] The Waste Management Licensing Regulations 1994. London: The Stationery Office.

[49] The Special Waste Regulations 1996 (as amended). London: The Stationery Office.

[50] The Control of Asbestos at Work Regulations 1987. London: The Stationery Office.

Associated ACOPs:

The control of asbestos at work L27: 3rd ed. Revised 1999. Sudbury: HSE Books.

Work with asbestos insulation, asbestos coating and asbestos insulation board. Control of Asbestos at WorkRegulations 1987 ACOP L28:1999 3rd ed. Revised. Sudbury: HSE Books.

Associated guidance: Managing asbestos in workplace buildings IND(G) 223L:1996. Sudbury: HSE Books.

[51] The Asbestos Licensing Regulations 1983. London: The Stationery Office.

[52] The Controlled Waste (Registration of Carriers and Seizure of Vehicles) Regulations 1991. London: TheStationery Office.

[53] The Noise and Statutory Nuisance Act 1993. London: The Stationery Office.

[54] The Water Industry Act 1991. London: The Stationery Office.

[55] The Public Health Act 1961. London: The Stationery Office.

[56] Environmental handbook for building and civil engineering projects, Part 3: Site clearance and demolition.CIRIA publication C512, Part 3, 1999 (see B.5 for source).

[57] Guidance on waste legislation 1994. Department of the Environment Circular 11/94. London: The StationeryOffice.

[58] Guidance on waste legislation for Scotland 1994. Scottish Office Environment Department Circular 10/94.London: The Stationery Office.

BS 6187:2000

120 BSI 09-2000

[59] Protecting the Public ± Your next move HS(G) 151:1997. Sudbury: HSE Books.

[60] Fire safety in construction work. Guidance for clients, designers and those managing and carrying outconstruction work involving significant fire risks HS(G) 168:1997. Sudbury: HSE Books.

[61] Permit to work systems in the chemical industry IND(G) 98:1991 (reprinted 1997). Sudbury: HSE Books.

[62] Guidance on permit to work systems in the petroleum industry HSC(OIAC): 1997. Sudbury: HSE Books.

[63] Electrical safety on construction sites HS(G) 141:1995. Sudbury: HSE Books.

[64] Hot work on small tanks and drums IND(G) 314: 2000. Sudbury: HSE Books.

[65] Safe work in confined spaces. Approved code of practice. Regulations and guidance HSE ACOP L101:1997.Sudbury: HSE Books.

[66] Avoiding danger from underground services HS(G) 47:2000. Sudbury: HSE Books.

[67] Avoidance of danger from overhead electrical power lines GS6:1997. Sudbury: HSE Books.

[68] The Special Waste Disposal Regulations 1996. London: The Stationery Office.

[69] The Manual Handling Operations Regulations 1992. London: The Stationery Office.

Associated guidance: Manual handling L23: Revised 1998. Sudbury: HSE Books.

[70] Working alone in safety: controlling the risks of solitary work IND(G) 73:1998. Sudbury: HSE Books.

[71] First Aid at Work, Approved Code of Practice (ACOP) (Reference L74). Sudbury: HSE Books.

[72] The Noise at Work Regulations 1989. London: The Stationery Office.

[73] NFDC Guidance for deconstruction of tower blocks over ten storeys 1997. National Federation ofDemolition Contractors publication (see B.4 for source).

[74] Drilling and Sawing Association Code of Safe Working Practice (see B.4 for source).

[75] Safety in gas welding, cutting and similar processes IND(G) 297:1999. Sudbury: HSE Books.

[76] The safe use of compressed gases in welding, flame cutting and allied processes HS(G) 139:1997. Sudbury:HSE Books.

[77] The Control of Lead at Work Regulations 1998. London: The Stationery Office.

[78] The Water Jetting Association's Code of Practice (see B.4 for source).

[79] Crane stability on site: an introductory guide 1996. CIRA SP 131 (see B.5 for source).

[80] Cleaning and gas freeing of tanks containing flammable residues CS 15:1985 Sudbury: HSE Books.

[81] Personal protective equipment at work. Guidance on the Personal Protective Equipment at WorkRegulations at work L25:1992. Sudbury: HSE Books.

Further reading

BS 302, Wire ropes for cranes, excavators and general engineering purposes.

BS 349, Specification for identification of contents of industrial gas containers.

BS 638, Arc welding power sources, equipment and accessories.

BS 1397, Specification for industrial safety belts, harnesses and safety lanyards.

BS 2092, Specification for eye protectors for industrial and non-industrial use.

BS 5240, Industrial safety helmets.

BS 8093, Code of practice for the use of safety nets, containment nets and sheets on constructional works.

BS EN 1050, Safety of machinery Ð Principles for risk assessment.

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BS 6187:2000

BSI389 Chiswick High RoadLondonW4 4AL

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