Safety Supervisor's Guidealp.active-learning-online.com/ADAS/OHS_Online/OHS_DPM_referenc… · • Special conditions must be observed if coffer dams or caissons are used, or if compressed

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SAFETY SUPERVISORSGUIDE 1987 SAFETY IN CONSTRUCTION No. 19

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Published by the Occupational Safety and Health Service Department of Labour, Wellington, New Zealand

First published 1973 Revised 1976 Revised 1979 Revised 1981 Revised 1984 Revised 1987

Reprinted 1987 Reprinted 1991

ISBN 0-477-03480-0

P44/5000/1991

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Contents Page

Part 1: Introduction to the Construction Act 7 1. The Construction Act 1959 7 2. Construction Work 7 3. Application of the Act 7 4. Notifiable Work 9 5. The Safety Supervisor 9 6. The Employer 9 7. Workers 10 8. General Safety 10 9. Excavation Work 10 10. Scaffolding 10 11. Plants, Tools and Gear 11 12. Explosives 11 13. Health and Welfare 12 14. Miscellaneous Safety Provisions 12 15. Certificates for Construction Workers 12 (a) Certificates of Competency (b) Certificates of Registration (c) Certificates for Powder Powered Tool Operators 16. Accidents 13 17. Construction Safety Inspectors 13 18. Safety Publications 15 19. Penalties 15 Part 2: The Safety Supervisor 15 1. The Safety Supervisor's Role 15 2. Vulnerability of the Safety Supervisor 16

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Page Part 3: Site Safety 17 1. General 17 2. Housekeeping 17 3. The Public 17 4. Tools, Plant and Gear 18 5. Working Places 18 6. Personal Protective Gear 19 7. Brittle Roofing 19 8. Access and Ladders 19 9. Crane Lifting of Workers 20 10. Powder Powered Tools 20 11. Falsework and Temporary Supports 20 12. Fire Protection 20 13. Explosives 21 Part 4: Health and Welfare 22 1. General 22 2. Asbestos 22 3. Sand and Abrasive Blasting 22 Part 5: Electrical Safety 24 1. General 24 2. Inspection and Testing 24 3. Leads and Plugs 24 4. Electrical Safeguards 25 5. Clearance from Power Lines 25 Part 6: Scaffolding 25 1. General 25 2. Notifiable Scaffolding 25 3. Certificated Scaffolders 26 4. Scaffolding Safety Rules 26 5. Scaffold Register 27 6. Proprietary Frame Scaffolds 27 7. “Mobile” Scaffolds 27 8. Suspended Scaffolding and Swinging Stages 29

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Page Part 7: Excavations 29 1. Notifiable Excavations 29 2. Support 29 3. Access to the Excavation 30 4. Other Hazards 30 5. Underground Services Part 8: Mechanical Plant 31 1. General Safety Rules 31 2. Lifting of Personnel 31 (a) “Riding the Hook” (b) Crane Lifted Platforms (c) Machine Lifted Platforms (d) Personnel/Materials Hoists 3. Materials Hoists 32 4. Ropes and Slings 32 5. Hired Plant 33 Part 9: Demolition 33 1. General Safety Rules 33 2. Recommended Safe Practices 34 Part 10: Underwater Diving 34 1. Underwater Construction Work 34 2. Construction Divers 35 3. Personnel 35 4. Diving Requirements 35 Appendix 1: Notification Form 36 Appendix 2: Safety Supervisor's decal 37 Appendix 3: Safety Supervisor's Check List 38

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Part 1: Introduction to the Construction Act

1. The Construction Act 1959 This was promulgated following a collapse of scaffolding in Wellington that killed and injured members of the public. The intention of the Act is to make better provision for the safety and welfare of persons employed and affected by construction work. It applies to work carried out in the course of trade or business, and not to home handyman activities.

2. Construction Work The definition of construction work is given in Section 2 of the Act. It is a broad definition and embraces all work concerned with the erection of buildings and structures; the provision of services such as power, gas, water, drainage and telephones; river and harbour works, irrigation channels and structures; road, aerodrome and earthwork constructions; tunnels and pipelines; the maintenance, painting and repair of any of the above, and their demolition. Certain underwater diving work is also included. Work prefabricating and preparing components that is done in a factory well away from the construction site is not construction work.

3. Application of the Act The Construction Act is applied in addition to other Acts. The requirements for safe use of electricity are set out in the Electricity Act 1968; those for the safe use of explosives are set out in the Explosives Act 1957; the requirements for the safe use of machinery are set out in the Machinery Act 1950. These acts, and all other legislation that concerns the safety of persons, apply on the site, along with the Construction Act. The safety provisions of the Act apply not only to workers, but to any person in the vicinity – the public is also protected by this Act.

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Towed work platform with an articulated boom.

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4. Notifiable Work Some work has been found to be more dangerous to workers than other work. The more dangerous construction work has been declared ‘noti-fiable’ by Section 8 of the Act and Regulation 5 of the Construction Regulations 1961. Notifiable work includes: • the construction or use of scaffolding more than 5 m high; • work where workers risk a fall of 5 m or more (except for work from a

ladder, minor maintenance work and work on residential buildings that are not higher than 2 storeys);

• work in narrow trenches or pits deeper than 1.5 m; • work in steep sided pits or holes more than 5 m deep; • work in certain tunnels and drives; • the use of explosives; • the use of lifting appliances to lift 500 kg or more to a height of 5 m or

more vertically, but excluding the use of mobile plant such as excavators, mobile cranes, forklifts and helicopters;

• work involving breathing of compressed air; • work with asbestos, excepting asbestos cement products. Such works must be notified to a construction safety inspector on a standard form, which is illustrated in Appendix 1. Notifiable work must be in the charge of a certificated safety supervisor.

5. The Safety Supervisor Section 9 of the Act deals with the appointment and duties of the safety supervisor, the person named by the employer to be responsible for safety on that work. The named person may be a site foreman, a manager, the employer himself, or any worker.

6. The Employer An employer is a person who, in the course of trade or business, is responsible for paying the wages of workers who are doing construction work. The term `employer' is very fully defined in Section 2 of the Act, and it includes a self-employed person who works on the site even if no other labour is employed by that person. A labour-only contractor, whether employing other labour or not, is an employer. The foreman or site boss, unless actually the owner of the constructing organisation is the employer's agent rather than the employer. Employers have a liability, set out in Section 22 of the Act to cause all the requirements of the Act to be observed.

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7. Workers Any person engaged in any task on the construction site is a worker, as defined in Section 2 of the Act. The employer, when actually undertaking physical work as part of the construction process, is also a worker. Section 23 of the Act requires that a worker does not do anything that is likely to cause danger to any person and to follow any instruction that is given to ensure the Act is observed.

8. General Safety Section 11 of the Act sets out general safety rules. They are: • that work shall be properly supervised by an experienced person to

ensure it is done safely; • that all reasonable safety precautions are taken; • that any temporary work (such as falsework or scaffolding) is suitable

and strong; • that only competent workers operate plant and gear; • that the public on roads and footpaths are kept safe; • that safety rules in other legislation are observed.

9. Excavation Work Section 12 of the Act and Part VII of the Regulations deal with this. Important points are: • Excavations must be fenced off to keep workers and the public from

harm; • Trenches must be either shored or have the sides cut at a safe slope; • Special conditions must be observed if coffer dams or caissons are used,

or if compressed air is to be breathed; • the person making the excavation must find the position of under ground

services and keep them safe. 10. Scaffolding This is any temporary structure, framework or hanging platform for the support of workers doing construction work. Standing scaffolding and hanging scaffolding that is more than 8 m high must be built and dis-mantled only by certificated scaffolders. The same restriction applies to all boatswain's chairs and swinging stages, no matter how high. Section 13 of the Act and Part VI of the regulations deal with scaffolding. The requirements are explained in detail in Safety in Construction No. 3: Scaffolding.

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Transverse Longitudinal

Bracing Bracing

11. Plant, Tools and Gear Sections 14 and 15 of the Act give the general rules for the safety of these items. The most important rules are that these are maintained in good order, and that the persons who use them are competent and use them safely.

12. Explosives Only certificated construction blasters and persons under their direct control may use explosives on construction sites.

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The explosives must be handled and used in accordance with the Explo-sives Act 1957, its regulations, and the construction regulations, Part XII. Section 16 of the Construction Act covers this subject.

13. Health and Welfare Section 17 of the Act and regulations 17 to 22 deal with these matters. The workers must have: • clean drinking water; • shelter for meals and for changing clothes; • clothes drying facilities (in some circumstances); • washing facilities; • reasonable access to toilet facilities; • adequate lighting and ventilation.

14. Miscellaneous Safety Provisions The Act and Regulations include requirements for: • the provision and use of safety helmets, glasses and footwear (Regu-

lations 32, 33 and 33A); • working on brittle roofing (Regulation 34A); • the use of mobile scaffolding (Regulation 59); • the use of trestles and tripods (Regulation 60); • the use of scaffolding and ladder brackets (Regulation 62); • the construction and use of ladders and step ladders (Regulations 106

to 109); • gas supply safety (Regulations 111 to 117); • underwater work, such as diving on construction work and work in

compressed air (Regulations 118 and 119); • fire protection measures on construction sites (Regulations 121 to 124); • safety on demolition sites (Regulations 125 to 127); • protection from harmful noise (Section 17A of the Act).

15. Certificates for Construction Workers There are three types of certificates. (a) Certificates of Competency are issued to qualified construction blast-

ers, safety supervisors, asbestos workers and scaffolders. The posses-sion of a current certificate entitles the holder to act as a blaster, or as a safety supervisor, or to erect movable suspended scaffolding, swinging stages, and hanging or standing scaffolding that is more than 8 m high. The relevant legislation is in Sections 13, 16 and 30(r) of the Act, and Regulations 8 to 16, 37, 47, 64, 97 and 101.

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(b) Certificates of Registration are granted to qualified crane operators, dogmen, riggers, and to construction divers. Apart from a require- ment that all diving on construction work be done by registered divers, there is no legal requirement for registration. The registers of crane operators, dogmen and riggers are kept as a service to the construction industry. (The law only requires these jobs to be done by competent workers.) See Regulation 118 and Section 11(d) of the Act.

(c) Certificates for Powder Powered Tool Operators are issued, by the distributors of the various tools, to workers who have been instructed and tested on the safe use of the tools. Only persons possessing a certificate may use the tools on construction work. Regulations 87 to 90 apply.

16. Accidents Sections 19 and 20 of the Act deal with this subject. Important points are: • accidents resulting in more than 2 days incapacity must be reported to the

inspector on the prescribed form as in the third schedule to the Regulations;

• generally the site of a serious accident must not be disturbed until the inspector has viewed it;

• the inspector may make such enquiries as necessary, and be assisted by any person, to determine the circumstances that led to the accident;

• the Minister may direct that a Court of Inquiry be set up to determine the cause of an accident.

17. Construction Safety Inspectors The tasks of the construction safety inspectors are to: • promote the safety and welfare of workers; • advise on safe practices; • see that the Act and Regulations (which are safety rules in legal jargon)

are applied; • investigate accidents and to take necessary steps to limit accidents. Inspectors must carry a certificate of appointment, and produce it on first going onto a site, and whenever reasonably asked to do so. The inspector may direct work to be done in a certain, safe way. The inspector may order work to cease if it is causing a hazard to workers or others. The inspector’s role is described in Sections 5, 6, 7 and 18 of the Act.

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Form of Notification of Accident

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18. Safety Publications The Chief Construction Safety Engineer issues safety publications for construction works. These are written after consultation with employer and union organisations with the aim of specifying sensible and safe practices. The publications may be purchased from any Department of Labour office.

19. Penalties The Act provides for a penalty of up to $5,000 in the event of any offence against the Act or Regulations. Charges are heard by a District Court Judge alone, in a summary manner. While only an inspector may lay information with respect to an alleged offence, in the event of an employer being charged, the employer may then lay information to have any other person he alleges to be the real culprit brought before the District Court Judge. Sections 24 and 28 of the Act deals with penalties and proceedings.

Part 2: The Safety Supervisor 1. The Safety Supervisor's Role The safety supervisor is the person named by the employer to be respon-sible for safety on the work site. This person must: • be experienced in the work being done; • have a certificate of competency as a safety supervisor; • ensure that the safety provisions of the Act and the regulations are

observed on the work; • report any breach of the Act, or any source of danger to persons or

property, to the employer; • be known, by other workers, to be the nominated safety supervisor.

The decal shown in Appendix 2 can be used for this purpose;

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• be on duty at such times as necessary to ensure the notifiable work is

done safely; • be free enough from other duties to allow the proper fulfilment of

the safety role. Section 9 of the Act and Regulation 97 cover this matter. It is the safety supervisor's responsibility to keep his site safe. The construction safety inspector may visit the site to see that the employer and safety supervisor are doing their jobs - not to do their jobs for them. The inspector, if dissatisfied with the safety supervisor's perfor-mance will take action to ensure better safety.

2. Vulnerability of Safety Supervisor If the safety supervisor is considered to be unsatisfactory then: • the employer may replace the safety supervisor, and advise the

inspector of the replacement's name; or • the inspector may direct the employer to replace the safety supervisor;

or • the Chief Construction Safety Engineer may, on grounds of improper

conduct of duties, either suspend or revoke the certificate held by any such person.

There are provisions for appeal against these last two options. Sections 10 and 21 of the Act and Regulations 14, 15 and 97 deal with these matters. It must be noted that the inspector has the power to stop construction work on grounds of danger to persons. The lack of a competent and certificated safety supervisor may sometimes be such grounds.

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Part 3: Site Safety 1. General The following is a summary of safety requirements that are applicable to most construction works. Appendix 3 is a checklist for the use of safety supervisors.

2. Housekeeping The work site should be kept as tidy as is practicable. Debris should be swept up regularly, formwork stacked and walkways and workspaces kept clear.

3. The Public The Construction Act offers the public the same protection as it offers workers. The following rules particularly concern the public: • avoid causing hazards to persons, such as unfenced and water-filled

holes, and protruding starter bars at the bottom of unfenced banks; • fence off the site to prevent persons wandering onto it; • when working alongside or on a road or footpath use signs, barricades

and flagmen to ensure public safety; • stop pedestrian traffic from passing under crane suspended loads,

unless there is robust overhead protection; • when the public is diverted onto a roadway, provide ramps at kerbs,

and barriers between the pedestrians and the road traffic; • erect a shelter over the footpath to protect the public if there is any

danger from falling debris; • have materials securely stacked so that they cannot slide or roll onto

the public or adventurous children; • have toeboards or kerbs at perimeters to stop tools and debris drop-

ping onto people; • beware of causing unnecessary noise;

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• if plastering or painting, erect mesh screens to contain splatter; • screen welding operations to avoid weld flash complaints.

4. Tools, Plant and Gear All must be maintained in good and safe order. Report defects to the employer; don't let defective gear be used.

5. Working Places Common faults on sites are the failure to: • keep work areas free of debris that may trip workers; • fit guardrails at floor perimeters and openings where there is any risk

of falls; • provide safe access (ladders or stairs) to work platforms; • cover holes in the floors with a robust fitted cover marked `Danger

– Hole Below'; • adequately illuminate stairwells; • provide safe platforms for work in lift wells; • secure the tops and feet of ladders.

“Next time we'll check the pipes”

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6. Personal Protective Gear The following rules apply: • safety helmets, provided by the employer, must be worn if there is

any risk of injury from falling objects AND IT IS IMPRACTICABLE TO FIX OVERHEAD PROTECTION;

• eye protection must be worn when there is any possibility of eye damage, from weld flash or debris such as concrete or wood chips, or grinding dusts. (Note that several persons have lost an eye, due to breaking off masonry nails by striking sideways with a hammer, the flying broken nail becoming lodged in the eye in each case.);

• footwear must be able to protect the workers feet. Usually only steel-capped safety boots can do that;

• noise protection must be worn if noise levels are high. (The noise of a portable circular saw or hammerdrill exceeds the safe limits at a range of 0.5 m);

• gloves may be necessary for some tasks, push sticks are always needed at the saw bench;

• respiratory protection is needed with asbestos work, sandblasting and with some sanding and grinding work.

7. Brittle Roofing Asbestos cement roofing, and rusted corrugated steel and aluminium roofing (unless fully sarked) will often collapse under workers. Workers frequently fall through Novalight and glass skylights. On average 2 per-sons a year die this way. A roof ladder or duckboards must be used if the brittle material is unsarked; sometimes a safety net may be used. Beware of corroded roofs over chemical and fertiliser works. Falling through brittle roofing is an awful way to die.

8. Access and Ladders Workers must have good safe access to the work place. Climbing there over scaffold frames or tubes is not permissible, fixed ladders must be provided. The maximum allowed length of a ladder is: • single ladder: 7.8 m; • two-piece extension: 13.5 m Portable ladders used on construction sites must meet the standards of NZS 5233 or 3609. Ladders must be restrained at the top by tying, and held at the bottom against sliding, they must extend at least 1 m above

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the upper landing when used for access. The slope of unfixed ladders should be 4 on 1 (i.e. about 14° to vertical).

9. Crane Lifting of Workers This is not allowed except in exceptional circumstances, when written permission is given by an inspector.

10. Powder Powered Tools These must be inspected and overhauled at 6-monthly intervals by the supplier. These may only be operated by a person holding a certificate of competency, issued by the supplier's agent.

11 Falsework and Temporary Supports Collapses of falsework can be disastrous for the workers on or under the supported material. Points to watch are that: • the temporary supports have been properly designed, and erected to the

design; • temporary supports are braced horizontally against forces from concrete

placing, settlements or impacts; • props are not overloaded or overextended; • ground bearing is good and that sole plates are used; • propheads are secure against displacement; • prestressed concrete units are propped at designed points only; • precast units are lifted only from designed lifting points; • end bearing for precast units is adequate, or that props compensate for

shortages; and that bearings are properly bedded to avoid high local stresses;

• damaged precast units are not used unsafely, and that all units are stacked and handled carefully;

• precast units are not placed before their strength is sufficient for safety of the workers.

The publication 'Falsework Guide 1982' has additional details of safe practices.

12. Fire Protection Requirements are given in Regulations 121 to 124 for fire safety. Essen-tially these prohibit the accumulation of combustible rubbish, require

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sources of ignition (including matches) to be kept away from combustible materials, and require that areas where combustible materials are used or stored be marked with a clear sign ‘Danger - No Smoking or Naked Light’. Where a Fire Safety Inspector declares a site (because of risk) a fire protection zone there must be mains water to within 9 m of the highest floor, and connections so that a 30 m hose can reach all parts of the work. In workshops, site offices, switchboard rooms, workers' accommo-dation and where welding or flame cutting is done there must be kept such fire extinguishers as the Fire Safety Inspector directs. Where the risks are such that evacuation of the site due to emergency is likely to be needed there must be: • an effective warning system; • a defined off-site re-assembly area; • trial evacuations at least every 3 months.

13. Explosives The following are general rules for the use of explosives on construction work: • the storage or use of explosives is notifiable; • only persons holding a certificate of competency as a construction blaster

may prepare and fire charges; • electric detonators must be used, except where special permission is

given for safety fuses and plain detonators; • explosives must be handled and stored in accordance with the Explo-

sives Act 1957; • the safety supervisor shares the responsibility for safety with the blaster; • nearby residents must be warned of blasts; • mats must be used to contain flyrock; • beware of ground wave vibration damage, take advantage of delay

detonators; • have the blast area well signed, and kept safe by flagmen. The publication `Safety in Construction No. 4: Blasting' has additional safety information.

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Part 4: Health and Welfare

1. General The basic requirements for shelter, washing and toilet facilities are given in part 1, section 13.

2. Asbestos Asbestos dust inhaled may result in serious lung disease. All work invol-ving asbestos, except that using hand tools on asbestos cement products, is classified as "restricted work involving asbestos" by the Asbestos Regulations 1983. Such work must be notified both to the Department of Health and the Department of Labour. This work may only be carried out under the personal control of a person holding a certificate of com-petency, for restricted asbestos work. All persons involved in the work must wear either disposable overalls or washable overalls. Workers must have respiratory protection; usually positive pressure facemasks, that provide filtered air to the mask at pressure. Recommended practice is to have the area where asbestos is being worked screened by impervious sheeting and have the air pressure in the enclosure reduced, to stop the escape of dust. Smoking increases the risk of lung damage to asbestos workers very greatly. The Asbestos Guide gives details of safe practices.

3. Sand or Abrasive Blasting Workers must be protected from the dust produced by abrasive blasting, often high silica sands are the only abrasive available; the dust from the sand can result in lung disorders.

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Operators must have overalls, helmets and gauntlets. The helmet bib and skirt must be dust-tight; the helmet must have Health Department approval. The air supply must be via a self-indicating filter and regulating valve. The operator's assistants must also have breathing protection to Health Department satisfaction.

Air Feed Respirator

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Part 5: Electrical Safety 1. General The safety requirements of the Electricity Act and Regulations apply to construction work. Some requirements that particularly apply on construction sites are included below.

2. Inspection and Testing Electrical installations and gear must be installed, tested and maintained only by persons authorised by the Electrical Registration Act 1979.

3. Leads and Plugs Only tough sheathed circular cables may be used for flexible leads. Plugs must be clamped to the cable, and the sheathing must cover the inner insulated conductors. Leads should be suspended overhead to avoid moisture and, damage, those on the ground must be protected from wheeled traffic. Long leads, when used while coiled on a drum or reel, may overheat and burn. Permanent wiring materials may not be used for flexible leads. Plugs must be sound and robust.

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4. Electrical Safeguards Safeguards must be used with portable tools on construction sites. The Electrical Wiring Regulations list those acceptable in Regulation 103. Those acceptable at mains voltage are: • double insulation • isolating transformer • residual current device All outlets should be protected by either an isolating transformer, or a residual current device, these protect the worker from faults in plugs and leads, protection that is not afforded by double insulated tools.

5. Clearance from Power Lines No part of a crane, digger, excavator, drill rig or structure may be brought closer than 4 m to an overhead line without the written consent of the electricity supply authority. If the distance between the supports of the line is great, a larger clearance is needed to avoid swaying lines. Two or 3 persons die each year from careless contact with overhead lines.

Part 6: Scaffolding

1. General The requirements for safe scaffolding are complex, they are covered in detail in Safety in Construction No. 3: Scaffolding. Selected information is given below.

2. Notifiable Scaffolding The inspector must be notified before any of the following is erected: • any rope-suspended scaffolding; • any boatswain's chair or swinging stage; • any other scaffolding, if it is intended to support working platforms that

are 5 m or more above ground.

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3. Certificated Scaffolders Scaffolding other than standing or hanging scaffolds under 8 m high must be erected only by certificated scaffolders. (A hanging scaffold is one that hangs from a structure, by tubes, bolts, rope slings or otherwise, and is stationary in that it is not made for raising and lowering.)

4. Scaffolding Safety Rules The most important rules are that: • the structure has a solid foundation; • the standards are not more than 2.4 m apart; • the standards are vertical; • transverse bracing is fitted at each end set of standards, and at every tenth

set in between; • one diagonal brace is fitted for every 3 bays (raked at about 40°) either as

zigzag or continuous braces; • braces pass through node points;

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• working platforms more than 3 m above the ground or floor must have guardrails at about 1050 mm above the platform, plus either midrails or toeboards;

• the platform guardrails must not be further than 200 mm (plan measure) from the edge of the platform. The toeboards must be at the platform edge;

• decking of platforms is to be with planks that meet NZS 3620, and that decking is to over-hang supports by 80 mm at least, but not more than 220 mm;

• decking is to he butted where possible, rather than lapped; • except as below, platforms must be at least 675 mm wide and have a

clear walkway of 450 mm at least; • light duty platforms for painting and other minor work may be minimum

250 mm wide if the inspector agrees; • adequate ties to the building are to be provided, equally spaced hori-

zontally and vertically, or else stability be obtained by bracing and rakers;

• toeboards must be fitted if there is a danger of material falling on persons below;

• ladder access must be provided to all platforms; • the scaffolding must be checked regularly by the safety supervisor; • planking must be tied or clipped in place.

5. Scaffold Register A register must be kept on site for scaffolds over 8 m high. The register forms are supplied by the construction safety inspector, at his office. The register must record the structure of the scaffolding, its working platforms and its duty (e.g. heavy, light or special) and it must be completed either by the safety supervisor or the certificated scaffolder. Alterations to the scaffold and the regular weekly inspections must be recorded in the register. Entries must be signed.

6. Proprietary Frame Scaffolds Providing these meet the strength and stability requirements as stated in Safety in Construction No. 3: Scaffolding, these may be used. A midrail is needed, in addition to cross-bracing. Ladder access to platforms must be provided.

7. “Mobile” Scaffolds These are useful but the following rules apply:

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• steel scaffolding must not be higher than three times its least plan dimension;

• aluminium scaffolding must not be higher than twice its least plan dimension;

• these must only be used on firm level surfaces (usually they are best suited for indoor use);

• beware of overhead powerlines; • wheels should be locked or chocked when platforms are in use; • the structure must not be moved when workers are on the platform; • it must be braced fully in horizontal and in vertical planes; • guardrails and midrails are to be provided all round the platform; • ladder access to working platforms is to be provided.

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8. Suspended Scaffolding and Swinging Stages These may be erected and altered only by certificated scaffolders. A register must be kept for these, and the daily inspections made by the safety supervisor or the scaffolder must be recorded. The safe working load for such platforms must be shown on the platform and in the register. Workers on these scaffolds are required to have an independent lifeline and a safety harness.

Part 7: Excavations

1. Notifiable Excavations An excavation must be notified to an inspector, and a certificated safety supervisor must be in charge of the work if: • it is more than 1.5 m deep, and workers have to work in a restricted

space in the excavation; • there is ground overhead, as in a drive or tunnel; • the height of any face of a pit or hole is more than 5 m and its slope

exceeds 2 on 1; • explosives are to be used; • workers must breathe compressed air (as in a caisson).

2. Support of the Trench's Sides The sides of the excavation must be either cut back to a safe slope, or supported by a shield, or be shored with timber, sheetpiling or other suitable material. The method of making the excavation safe must be described on the Notification. The sides of the excavation may be cut back to the safe slopes given in Safety in Construction No. 5: Excavations; or the sides of the excavation may be supported in one of the ways described there and using the details given. Alternatively, a registered engineer may, after making such soil tests as necessary, design safe slopes or shoring systems to suit a particular job. This alternative means of making the excavation safe must conform with the engineer's signed drawings and specifications for the work.

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3. Access to Excavation There must he good and safe access into the excavation so that, in an emergency, the workers can quickly evacuate the workplace. Ramps, stairs or ladders constitute safe access. A "jungle-gym" of timbering as access is unacceptable.

4. Other Hazards Dangers to workers can arise from: • other services. An electric cable can electrocute or severely burn the

worker who inadvertently strikes it. An adjacent water pipe can lose its anchorage and support, blow a joint and flood the excavation, causing the sides to flow in;

• soil from the trench, stacked too close to its edge may overload the support system and result in collapse;

• service trucks. Unsupervised trucks may cause the trench sides to collapse by overloading it near the trench; carelessly driven trucks may drive into the trench. Never have workers in the trench when trucks approach. Always have someone guide the trucks;

• excessive draw down of the water table. This can result in piping of sand, the undercutting of sides, and trench side collapse. Pay attention to the effects of pumping out water;

• the effects of the excavation on adjacent buildings. The extra load of a nearby building may make the trench unsafe;

• toxic gas in excavations. Hydrogen sulphide is a killer in the thermal areas. Hydrocarbons are dangerous near petrol storage sites. Natural carbon dioxide may asphyxiate in some localities. Watch for signs of trouble, and if you see any, don't go down to help unless you are equipped and there are other people equipped and ready to save you if necessary;

• bored shafts. If workers are to inspect these the linings must be in place. They must wear safety helmets, and wear a harness and independent rope to help recovery in the event of mishap.

5. Underground Services It is the responsibility of the person making an excavation to avoid damaging services. Although the owners of underground services will mark the approximate position of them on the surface, the responsibility for any damage to these remains with the person making the excavation, even if the original marking of position was in error.

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Part 8: Mechanical Plant 1. General Safety Rules Some safety requirements that apply to most sites are: • dangerous parts of machinery (such as transmissions, belts and chain

drives) must be securely guarded or fenced; • machinery and plant must be used only by competent operators; • machinery and plant must be maintained in good order and condition

(certificates of fitness issued by government departments may usually be taken as evidence of `good order and condition');

• mobile plant should be secure when parked, by use of hand brakes, chocking of wheels, or by dropping scraper bowls and grader blades;

• booms, blades, rippers and bowls should be lowered when parked; • cranes must be operated within their safe working load rating as given

on their certificates of inspection. Mobile cranes must be set up on solid foundations and have outriggers extended and packed;

• rigging of crane-lifted loads must be by experienced dogmen; • standard crane signals must be used between dogman and crane opera-

tor, see Safety in Construction No. 24: Cranes and Lifting Appliances; • beware of counterweights as cranes slew; • tip heads are to be controlled by a banksman, or else timber baulks

or soil windrows should be used to prevent dump trucks driving over the face.

2. Lifting of Personnel (a) `Riding the Hook' This is a dangerous practice and is discouraged. In exceptional circum-stances, where there is no other practicable way of reaching a work site, the inspector may authorise this in writing and require special safeguards.

(b) 'Crane-Lifted Platforms' The inspector may permit workers to use a platform hoisted by a crane, subject to conditions. Such approval is given in writing and standard conditions include: • the use of a properly designed platform, with guardrails etc, and marked

with its Safe Working Load; • the crane being down-rated to 50 percent of approved working load at

that radius;

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• that the operator is to be at the crane controls at all times the platform is occupied;

• that an independent lifeline and harness is used by each worker on the platform.

(c) 'Machine-Lifted Platforms' Appliances that meet the requirements of Safety in Construction No. 8: Power Operated Elevating Work Platforms may be used on construc-tion work. The devices must be examined by a competent person every six months and certified safe for use. The certificate must be displayed.

(d) Personnel/Materials Hoists These must conform to a good overseas standard (such as BS 4465 or AS 1418, Part 7) or the requirements of the Department of Labour, as advised by the inspector. A certificate signed by a registered engineer is required to show that the requirements are met. A further certificate is required at 6-monthly intervals to show that the hoist has been tested and examined and remains in good safe condition.

3. Materials Hoist These are to meet the requirements as advised by the inspector, or comply with a reputable overseas standard such as AS 1418 Part 7. Again a certificate from a registered engineer is required, stating that it meets the requirements. A further certificate is required at 12-monthly intervals, to show that the hoist has been tested and examined.

4. Ropes and Slings

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The factors of safety (i.e. ratio of ultimate breaking load to safe working load) to be applied are: • roles hoisting persons : 6 • 1 s hoisting materials : 5 • woven flat slings of man-made fibres : 6 • other slings : 5 All slings must be marked with their Safe Working Load. The safety supervisor is reminded that the tension in the legs of a multi-leg sling increases as the inclination of the sling changes from vertical to horizontal.

5. Hired Plant When an item of plant is hired with an operator to work under the direction of the hirer both the owner of the plant and the hirer have a duty to ensure that the machine does not jeopardise the operator on account of its condition or the work undertaken.

Part 9: Demolition

1. General Safety Rules The main rules are: • protect the public from rubble, dust and traffic by proper gantries

and fenced walkways; • be sure power, gas and water services have been disconnected; • never leave free standing walls that could be blown down by unex-

pected winds; • ensure that there is a clear space of 11/2 wall heights around any wall

that is to be toppled by pulling; • provide good access to working spaces; • do not overload floors with demolition debris. Have these checked

by a competent engineer; • beware of asbestos hazards from old insulations; • check empty tanks for explosive or toxic materials; • get professional advice before tackling prestressed concrete structures; • control noise at source, and provide helmets and hearing protection; • beware of fire in the debris; • keep the public from the site;

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• use flagmen to control site traffic over footpaths; • if controlled-collapse demolition is being used, don't let anyone enter

the building once the process has started; • when pulling by winch make sure that the winch tractor has full

operator protection (logging canopy); • beware of brittle roofing; crawl or duckboards should be used on roofs.

2. Recommended Safe Practices The publication Safety in Construction No. 23: Demolition, describes demolition procedures and specific safety requirements.

Part 10: Underwater Diving

1. Underwater Construction Work Any of the works listed in part 1, section 2 and such work carried out under water on ships, buoys, rafts and obstructions is construction work.

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2. Construction Divers Underwater construction work may only be done by registered construc-tion divers and trainees, as in 4 below. The divers must have registration for a class of diving that is appropriate for the work being undertaken.

3. Personnel The minimum team for underwater work is a team of 3 persons, 2 divers and a dive supervisor, for scuba diving. One of these persons must also be a safety supervisor. Other diving work may require more personnel. Safety in Construction No. 15: Diving on construction work, gives details of the various requirements.

4. Diving Requirements A brief summary of requirements is: • registered divers only may work (except for divers holding a basic diving

qualification who are being trained and supervised by a registered diver); • work must be notified; • the usual maximum scuba depth is 20 m; • a dive plan is to be prepared; • if decompression stops are necessary, a recompression chamber must be

available; • that divers must have reserve breathing supplies; • that scuba diving should involve `buddy' diving or a lifeline; • beware of exhaust gases when refilling breathing air cylinders; • log books must be kept; • if `buddy' system is not used, there must be a communication system; • a diving supervisor must be appointed to be in charge of the operation.

He may also be a diver; • the maximum diving depth using compressed air is to be 55 m, thereafter

helium/oxygen based breathing gas must be used; • special approval is needed for diving to a depth greater than 125 m.

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APPENDIX 1

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Appendix 2

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Appendix 3 Safety Supervisor's Check List Scaffolding

Notifiable? Register (if notifiable) Access Foundations Bracing Working platforms Ties Guardrails Proximity to power supply Registered engineer's design

Housekeeping Stacking of materials Floor areas Work places

Excavations Notifiable? Access Machinery Shoring Leads and plugs Bridge guards Push sticks Floor area (clean and stable) Conditions of saw blades/cutter Eye protection for grindstone,

circular saw etc General condition

PP Tool Six-month overhaul Certificated operators Adequate lock-up facilities

Blasting Notifiable? Certificated construction blaster Storage of explosives Electric exploder Cover nets tarpaulins etc Warning siren Neighbours notified Water hazard Gases Registered Engineer's Safety

Certificate Electrical

Three-monthly check by registered electrician for temporary power, supply

Condition of supply leads Positioning of supply leads Isolating transformers/residual

current devices Proximity to overhead supply

lines Mechanical Plant

Marine Division Certificates Warning device Operational set up (outriggers on

firm stable ground)

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Distance from electrical supply Personnel hoist (general

condition, certification) Machinery, Woodwork and Concrete

Riving knives Overhead guards Transmission guards Switches

Power Operated Elevating Work Platform

Safe Working Load markings Operating instructions Competent operator Current certification Secure set up

General Safety First aid kit Protective helmets Protective footwear Protection for hearing Warning signs displayed Site fencing Overhead hoardings Guardrails to floor openings Guardrails to excavations Guardrails to stairways/lights in

stairwells Guarding of water hazards Perimeter guardrails Ladders Fire protection Lighting

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Safety in Construction Publications These may be purchased from any office of the Department of Labour. No. 3 Scaffolding No. 4 Blasting No. 5 Excavation No. 7 Falsework Guide No. 8 Power Operated Elevating Work Platforms No. 15 Diving on Construction Work No. 16 Powder Powered Tool Guide No. 17 Roll Over Protective Structures for Earthmoving Machines No. 18 Work in Compressed Air No. 19 Safety Supervisor's Guide No. 20 Safe Use of Electricity No. 21 Portable Mechanically Powered Nailers and Staplers Guide No. 22 Asbestos Guide No. 23 Demolition: Recommended Safe Practices No. 24 Cranes and Lifting Appliances No. 25 Roadworks Safety Guide No. 26 Rigging

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