MEASUREMENT Lecture note No: 01 outcome No: 2
Development of the Role of Quantity SurveyorThe profession
developed during the 19th century from the earlier "measurer", a
specialist tradesman, who prepared standardized schedules for a
building project in which all of the construction materials, labour
activities and the like were quantified, and against which
competing builders could submit priced tenders. Because all tenders
were based on the same schedule of information, they could be
easily compared so as to identify the best one.
The professional institution with which most English-speaking
quantity surveyors are affiliated is the UK based Royal Institution
of Chartered Surveyors (RICS) , Quantity Surveyors International
(QSi) and Institution of Civil Engineering Surveyors (ICES)
http://www.ices.org.uk/. Those who are qualified members of the
RICS are allowed to use the term "Chartered Quantity Surveyor" or
simply "Chartered Surveyor".
The QS is central to the decision-making process throughout the
management of a project from initial inception to final completion.
The QS handles estimating and cost control, the tendering process
and, after contract award, the commercial interface. All QSs are
able to carry out estimating and measurement of construction works
prior to tender, producing the bill of quantities; produce tender
documentation and manage the tender process; clarify and evaluate
tenders; and manage the resultant contract through monthly
valuations, variations control, and assessment of claims.
The QS is trained in techniques of cost control. Those QSs who
emphasize the cost discipline, often use the term "Construction
Cost Consultant". They ensure that projects are designed and
constructed in such a manner as to secure value for money, cost
certainty and programme dates.
Others emphasize contracts management. Trained to draft,
interpret and administer complex contracts, those QSs who operate
in the broader field of project management often adopt other titles
such as "Contracts manager" or "Construction surveyor". A number of
QSs work in procurement in the oil & gas industry, process and
power industries, and civil engineering. Their preferred title, in
countries where the QS profession is less known, is "Contracts
engineer".
Some QSs specialize in project management, the QS background
being a good foundation for understanding the complexities of
modern large-scale projects.
As well as in professional quantity surveying practices, the QS
finds employment in all parts of industry and government including
primary and secondary industry, national and local government
bodies and agencies, contractors and subcontractors, developers,
and financial and legal companies.
The QS is a major contributor to the success of all types of
projects in all sectors of the economy including industry,
infrastructure, healthcare, education, public buildings, retail and
commercial construction, residential construction, and leisure
projects.
Although all QSs will have followed a similar course of
education and training (for those entering the profession today,
this is usually to degree level), there are many areas of
specialization in which a QS may concentrate. The main distinction
amongst QSs is between:
1. Those who carry out work on behalf of a client organization:
often known as a "professional quantity surveyor", "professional
QS" or "PQS".
2. Those who work for construction companies: often known as a
"main contractor's quantity surveyor".
The functions of a consultant quantity surveyorTraditionally
referred to as a professional quantity surveyor or PQS) are broadly
concerned with contracts and costs on construction projects. The
methods employed, however, cover a range of activities which may
include cost planning, value engineering, feasibility studies, cost
benefit analysis, lifecycle costing, valuation, and cost
estimation.
The QS's traditional independent role on the team comprising
client, architect, QS and contractor has given him a reputation and
appreciation for fairness. This, combined with his expertise in
drafting and interpretation of contract documents, enables him to
settles issues, avoid disputes and ensure the effective progress of
a project.
Quantity surveyors control construction costs by accurate
measurement of the work required, the application of expert
knowledge of costs and prices of work, labour, materials and plant
required, an understanding of the implications of design decisions
at an early stage to ensure that good value is obtained for the
money to be expended.
The technique of measuring quantities from drawings, sketches
and specifications prepared by designers, principally architects
and engineers, in order to prepare tender/contract documents, is
known in the industry as taking off. The quantities of work taken
off typically are used to prepare bills of quantities, which
usually are prepared in accordance with a published standard method
of measurement (SMM) as agreed to by the QS profession and
representatives of the construction industry.
Contractor's quantity surveyorA contractor's QS is responsible
for the performance of operations that mirror those of the owner's
QS; i.e, the measurement and pricing of construction work, but
specifically that actually performed by the contractor (and the
contractor's subcontractors) as opposed to the construction work
described and measured in the construction contract between the
owner and the contractor. Such a difference in quantity of work may
arise from changes required by an owner, or by an architect or
engineer on an owner's behalf. Typically, the settlement of a
change (often referred to in a contract as a 'variation'). (see,
the following reference sources: "Fundamentals of Construction
Estimating and Cost Accounting," by Keith Collier (2nd ed.)
(Prentice-Hall, 1987); "Construction Contracts," by Keith Collier
(3rd ed.) (Prentice-Hall, 2001) These two texts each contain a
comprehensive glossary.
The role of a contractors QS will extend further than the day to
day running of building projects and will cover such other areas as
sub-contract formation, forecasting of costs and values of the
project, cash flow forecasts and the collation of the operation and
maintenance manuals of the project (O&M manuals). This increase
in the capacity of the surveying profession has led to an increased
demand for qualified personnel and goes some way to explaining the
popularity of related degrees at university.
Some contractors and others may attempt to rely on a general
accountant to deal with construction costs, but usually this is not
effective, primarily because an accountant does not have the
technical knowledge to accurately allocate costs to specific items
of work performed, especially at times prior to the particular
work's completion as required to make accurate assessment of the
amounts to be paid to the contractor during the course of the
work.Principles Of MeasurementsDimension paper
9mm
O
O
14mm15mm16mm55mm14mm15mm16mm56mm
Bs 3327.1970 specification for stationary for quantity surveying
specifies the paper size for dimension papers as A4 (210mm297mm)
ruled vertically as per the figures given below. The rulings
widths& purpose of columns on the face and reverse sides of the
dimension paper are illustrated in figures 1&2.Figure 1- face
Side
16mm
15mm
16mm
55mm
14mm
15mm
16mm
54mm
9mm
O
O
Figure 2- Reverse Side
Each dimension sheet is split in to two identically ruled parts
each consisting of four columns. The 9mm wide first column of the
face side and last column of the reverse side is the binding margin
for binding the dimension papers. The purpose of each column is
indicated below.
Column 1 is the timesing column where multiplying figures are
entered when there is more than one of the particular items being
measured.
Column 2 is the dimension column where the actual dimensions are
scaled or taken direct from drawings are entered. There may be one,
two or three lines of dimensions in an item depending on whether it
is linear square of cubic.
Column 3 is the squaring column where the length area or volume
obtained by multiplying together the figures in columns 1&2 is
recorded ready for transfer to the abstract or bill.
Column 4 is the description column where the written description
of each items entered the right hand side of the wider column is
used for preliminary calculations and other information needed in
building up the dimensions references to the location of the work
and is referred to as waste.Form of DimensionsThere are five forms
of dimensions as set down by the taker-off. They are as follows
1) Cubic measurements
2) Square or superficial measurement.
3) Linear measurement
4) Numbers or enumerated items.
5) Items.
Order of DimensionsA constant order of entering dimensions shall
be followed throughout and it is customary to write down in the
dimension column in the same order.
1) Horizontal length
2) Horizontal width or breadth.
3) Vertical depth or height.
Although the order will not affect the calculations of the cubic
or square measurement, it is very valuable in tracing measurements
later and an incorrect order in a description may even sometimes
mislead an estimator in pricing.
Entering dimensions
Dimensions are entered in meters with two decimals in dimension
column.When setting down the dimensions immediately under each
other in the dimension column each separate item is divided from
the next by a line.3.00
0.60
1.00
3.00
2.00
3.00
Indicating a cubic measurement of, 3.00m long 0.60m wide and
1.00 deep.
Indicating a superficial measurement, 3.00m long and 2.00 m
wide.
Indicating a linear measurement of, 3.00m long.An item to be
enumerated is usually indicated in one of the following ways.4/
4
Nr 4
1
Indicating four in number Sometimes the SMM requires the
insertion of an item which is a description without a measurement
quantity and indicated as follows.
Item
There is no need to label the dimensions cube super linear
etc
Timesing
Sometimes when the taker-off has written the dimensions, it is
found that there are several similar items having the same
measurements and to indicate that the measurement is to be
multiplied it will be timesed thus;
3/
5/3.00
0.60
1.003.00
2.00
Indicating that the cubic measurement is to e multiplied by
3
Indicating that the superficial measurement is to be multiplied
by 5
The timesing figure is kept in the first column and separated
from the dimension by a diagonal stroke. an item timesed can be
timesed again each multiplier multiplying everything to the right
of it .thus5/3/
2/5/3/
2/4/6/3.00
0.60
1.003.00
2.006.00
Indicating that the cubic measurement having been multiplied by
3.the result is to be multiplied by 5 i.e.(3*5) by 15.Indicating
that the square measurement is to be multiplied (3*5*2)by 20
Indicating that the linear measurement is to be multiplied
(6*4*2) by 48.
Dotting ON (.)
In repeating a dimension the taker-off may find that it cannot
be multiplied but added .where additional items occur the
dimensions may be increased by dotting on or added. Thus
.2/
4
.3/2/
13.00
0.60
1.00
3.00
2.00
Indicating that the cubic measurement is to be multiplied (2+4)
by 6Indicating that the square measurement is to be multiplied [2x
(3+1)] by8
Measurement of irregular figures
Sometimes it is necessary to measure the areas of triangles and
circles the circumferences of circles and the volume of cylinders
etc and the usual method of entering the dimensions are as
follows.
1
27
22
2 7
227
222.00
1.00 1.00
1.001.00
0.50
0.50
1.00
Area of triangle with a base of 2.0m and height of 1.0m.
Area of circle 1.0m radiusCircumference of a circle 1.0 m
radius.
Volume of a cylinder 1.0 m diameter and 1.00 m height.BracketsA
bracket is used whenever more than one measurement relates to a
description or group of descriptions. The bracket being placed
outside of the squaring column, a vertical line with a little cross
marks to indicate top and bottom. The total quantity indicated by
the measurements within the bracket is set against each related
description on the abstract.
Alteration of dimensions
When dimensions have set down incorrectly they shall never be
erased or altered.Incorect dimensions should be cancelled by
writing NIL in the squaring column alongside the incorrect figures
and the extent of the cancellation indicated by brackets and
arrowheads. The correct dimensions shall be written clearly in the
dimension column and this can be done thus:12.00
0.60
1.00
10.50
0.60
1.00
11.50
0.60
1.00
7.20
NIL
Excavating trenches width exceeding 0.30 m and depth 1.00m
&
Disposal of excavated material off site
6.90
14.10
Total quantity to be abstracted
Alteration of dimensions.
Waste calculations
Except in very simple cases dimensions shall not be calculated
mentally. Not only will the risk of error be reduced if the
calculations are written down, but another person can readily see
the origin of the dimension when they are checked. The preliminary
or waste calculations involved in determining the dimensions and
any related explanatory comments shall be written clearly on the
right hand side of the description column. the risk of error will
then be reduced since these calculations can be checked during
working up and in addition the process by which the dimensions
where determined will made clear of later reference.
Waste calculations are written to three decimal places and the
results reduced to the nearest 10mm (ie.above 5mm as 10mm and 5mm
neglected) before transfer to the dimension column.
Spacing of dimensions
All measurements and descriptions shall be spaced well apart, so
that it is quite clear where one begins and it ends. It is not
unusual for a taker-off to realize that after writing down the
measurements that some item has been overlooked and it is desired
to insert it in its proper place. if the dimensions are well spaced
out, it can be squeezed in, but otherwise it will have to be
inserted elsewhere and cross-references made which only complicate
the work.
The description
The description of the item measured is set down opposite the
measurement in the description column. Descriptions shall be
adequate, clear, concise and built up following the order set out
in the tabulated rules of the SMM together with the necessary
information from the supplementary rules.
The Ampersand or Anding ON (&)
When dimensions are to be repeated or other items this is
indicated by use of the ampersand sign(&) thereby preventing
repetition of dimensions however care must be taken when combining
linear with superficial items or superficial with cubic items.
Deductions
Measurements shall always be carried out working from whole to
the part i.e. measure overall and then makes any deductions if
necessary. Deductions of previously measured quantities are made in
the description column as shown below. the item must be preceded by
the word DEDUCT ( Ddt,) and to ensure that only the intended items
are properly deducted the next item shall be preceded by the word
Add for the avoidance of any doubt.
99.14
0.60
0.20 34.000
16.000 2/ 50.000 100.000
Ddt.4/215 .860
99.140
=====
In-situ concrete 1:2:4(20-agg.) in foundation, mass poured in to
ground.
& Ddt.
Filling to excavations. 450 mm avg.thickness a.b.d.
&
Add
Disposal of excavated material off site
Headings
Headings are essential in taking off in order that the dimension
sheets can be identified with a particular contract and also to
indicate the sequence of measurement for later reference. The title
of the contract must appear at the head of each dimension sheet. In
contracts with several buildings; the name of the building unit
shall be incorporated in the title on the appropriate dimension
sheets.
Column numbering
Numbering in sequence at the bottom of the column must identify
each column of dimensions.this useful for reference purposes and
provides a check which ensures that the dimensions are
complete.
Extra over items
Certain items are measured as extra over the item of work in
which they occur in which case the estimator will price the
additional cost involved as to some extent this item will have been
previously measured. An example of this type of item is bends on
rainwater goods.
Abbreviations & symbols
Many of the words entered in the description column are
abbreviated in order to save space and time in entering the items
by highly skilled technical staff. Many abbreviations have become
almost standard and are of general application. A considerable
number of abbreviations are obtained by merely shortening the
particular words.
Ex.Excavation Exc.
Trench- Tr.
Foundation- Fdn.
Earthwork support- Ewk.
[Ivor H. Seeley & Roger, W. (1999) Building Quantities
Explained: 5th.ed., Macmillan, pp379-389 (Appendix1) for the
complete list of standard abbreviations] Use of schedules
In addition to providing design information schedules can be
produced to facilitate the taking off process. Schedules can be
used to collect all the relevant specification information on
concise tabulated form for ease of reference to assist measurement
or they may be used for recording measurement and can become the
taking-off. The use of schedules for items, which repeat themselves
throughout the building, is advocated as a mean of saving time and
due to the more systematic approach reducing the possibility of
errors.
Drawn information
General rules clause 6 refers to three types of Drawn
information.
1. Location Drawings
2. Component Drawings
3. Dimension Drawings.With regard to dimension diagrams,
sometimes rather than a lengthy and possibly ambiguous dimension
description a sketch included in a bill of quantities can be more
appropriate. it has the advantage of showing clearly the shape and
dimensions of the work, although a bill diagram shall not replace
an item otherwise require to be measured.Deemed To Be Included
ItemItems, which are deemed to be included are mentioned in the
coverage rules of SMM(SLS 573:1999) and indicate that an allowance
is to be made by the estimator for these specific items, which are
not require to measure separately.
Query SheetsDuring the taking off process problems may arise
involving the interpretation of drawings, clarification of the
specification or additional information, which will require a
decision from the Architect or Engineer. in the event of this a
query sheet is to be produced by taker-off. The sheet is normally
divided down the centre to accommodate the queries on the left-hand
side of the sheet and the answers on the right hand side.O
OQUERYANSWER
Architects Signature
Order Of Taking OffThe order of taking off largely follows the
order of construction to simplify the work and to reduce the risk
of items being missed. The measured items will subsequently be
sorted in to bill order, which can embrace the work sections in SMM
to secure uniformity and assist with computerization.
The taking- off of dimension is usually divided in to sections
under three main sub-divisions.
a) Carcass: (1) Foundations( substructure)
(2) Frame
(3) External walls internal walls
(4) Partitions (5) Fires and vents
(6) Floors (7) Roofsb) Finishing (1) Internal & external
finishing
(2) Windows
(3) Doors, including openings without joinery
(4) Fixtures and surfaces
(5) Stairs and lifts
(6) Plumbing and engineering services
c) External Works: (1) Drainage
(2) Roads, paths, site layout, outbuildings etc
Accuracy In Dimensions
It is essential that all dimensions shall be as accurate as
possible as inaccurate dimensions are worthless. a generally
accepted limit of permissible error is around 1 percent based on
full working drawings and so one must exercise the greatest care in
arriving at dimensions.Taking-off procedure
1. Head the first sheet with the name of the project date, name
of the taker-off, drawing numbers and section of work measured and
adopt a similar system of identification for subsequent sheets.
2. Do not crowd dimensions and write legibly. Neat presentation
is paramount.
3. Signpost dimensions give occasional information and
sub-headings in the waste column
4. Approach drawings in a standard sequence. Eg.starting at the
top left-hand corner and allow clockwise pattern.5. Ensure that all
items are measured by taking-off in a logical sequence and that
dimensions follow on
6. Cross reference where dimensions are added back: when to take
notes has been cleared or where schedules are used. .
7. If necessary, correct dimensions in the right place; this is
normally where they are first recorded. But if this is not possible
use cross references.
8. Line through specification notes, taking off list items,
query lists, dimensions and schedules when items have been
measured.
9. Use to take notes when information is not to hand or as an
aide memoir and check that all to take notes are cleared before
completion
10. Check through drawings, query lists, T.O.
list,specifications and schedules on completion to ensure that all
items have been taken.Drawing No
T.o:
date
Substructure
T.o List
1. Cutting down trees2. Clearing site vegetation
3.Top soil Excavation
4. Disposal of excavated material for
Preservation
5. Trench excavation
6. Disposal of excavated Material
7. Trimming sides of excavation
8. Compaction of bottom of excavation
9. Earth work support
10 Disposal of surface water
11. Concrete in foundation
12.Brick work to dpc
13DPC
14.Filling to excavation
15. Filling to make up levels
16. DPM17. Concrete bed
Specimen taking off list
The Standard Method of Measurement
The Standard Method of Measurement, 7th edition, (SMM7) and the
Code of Measurement Practice (MC), both agreed by the Royal
Institutio of Charted Surveyors (RICS), set out rules for the
measurement and description of building work. SMM7 is a document
that provides not only a uniform basis for measuring building work
but also embodies the essentials of good practice. If all bill of
quantities are prepared in accordance with these rules then all
parties concerned are aware of what is included and what is to be
assumed. Contractors therefore tender on an equal basis and their
tenders can be more readily compared and evaluated. Without the use
of such a set of rules the quality of bills of quantities can vary
widely. The Code of Measurement Practice is a companion volume
which clarifies and explains the rules contained in the SMM.
SLS:573- 1999 version is the Standard Method of Measurement which
used in SriLanka, developed by Sri Lanka Standards (SLS) and
revised by Institute of Construction Training And Development
(ICTAD).Civil Engineering Standard Method of Measurement, 3rd
edition (CESMM3) is used for the measurement of civil engineering
work developed by Institution of civil Engineers and Federation of
Civil Engineering Contractors. (1991).Conclusion
In conclusion measurement is basically a practical skill which
involves the following key factors
1. A disciplined logical and consistent approach
2. A sound knowledge of construction technology to facilitate
the interpretation of drawings and three dimensional thinking
3. The ability to apply the rules of measurements as laid down
in the SMM or other recognized form of measurement.
4. Sufficient understanding and knowledge of mensuration
technique to calculate measurements.
5. the application of checks at all stages of the work.Group
Exercise
1. Make five groups of student
2. Four groups should select sixteen different measurement
procedures( each group will select four)
3. Study their significance in measurement process
4. One student from each group should make a presentation
regarding the significance of selected procedures in measurement
process for five minutes using multimedia or chalkboard
5. The fifth group will be presenting five minutes presentation
on significance of SMM in measurement process
6. Every group MUST make at least one comment on all five
presentation References 1. Ivor H. Seeley & Roger, W. (1999)
Building Quantities Explained: 5th.ed., Macmillan,
Pp, 1 to 36
2. Sandra, L.,William, T.,&Willis, A. (2005) Williss
Elements of Quantity Surveying: 3rd,ed., Blackwell, pp 1 - 483.
Standard Method of Measurement of Building Works, Seventh Edition
Revised 1998 (London: RICS Books, 1998).1NTK Lokuliyana. ACTAPage
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