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UNDERSTANDING AND INTERPRETATION OF THE QUANTITY SURVEYORS BILL OF QUANTITIES
BY F. O. ADETOLA MAQS, MRICS, FNIQS
Delivered at the Nigerian Institute of Architects (Lagos Chapter) Workshop
I would like to start by thanking God the almighty who from creation endowed us with knowledge, wisdom and understanding.
The Bible asks us to “seek knowledge and seek understanding” and further said, “knowledge is the principal thing”.
I therefore commend the executives of the Lagos chapter of the Nigerian Institute of Architects (NIA) for this opportunity to share knowledge with each other.
It is by sharing our professional knowledge that we can all understand the role and expectations of our professional colleagues and use them to the best advantage of the project.
The world is already a global village where the most and highly traded commodity is information.
For us to trade information amongst ourselves we must understand the importance of such information and how best it could be put to use by other members of the design team.
Since we are all working together as members of the design team for the same purpose, the sacred way we guard our profession within the same team should now be relaxed.
Whether we support it or not the sacred nature of our professional practice is gradually disappearing and we are likely to provide “one stop” services to our clients in future.
For this to happen we must start to make deliberate effort to understand how our colleagues operate and the reasons behind the way they disseminate or present information.
Having said this, we should also appreciate that the only person(s) in the best position to vet or audit another’s work is that person(s) who is professionally qualified to carry out such duties.
We should not be under an illusion that an Architect can vet or audit a Quantity Surveyors work or should a Quantity Surveyor feel he / she can do same to an Architects or an Engineers work. Since neither has the capacity nor the competence to do so.
Despite this I believe we should have the ability to be able to peruse the work of each other so as to ascertain that it represents the intention of the entire members of the design team.
It is with this background that I have re-titled this paper “Understanding and Interpretation of the Quantity Surveyors Bill of Quantities”.
QUANTITY SURVEYING - HISTORICAL BACKGROUND
Quantity Surveying as practice came into being from the master builders trying to prepare bids for construction projects. Each builder employing a person or persons to help in calculating quantities and pricing various items or elements of the building works which finally will form the bid.
As this process became more vigorous and elaborate, people started specialising in preparing bid or tender documents for various contractors to use in submitting their tenders.
Instead of various contractors employing their own men to prepare these documents, it became more economical to use these specialists to prepare the documents for all contractors so that tenders might be submitted on equal basis.
This is what gave birth to the practice of Quantity Surveying. The duty then, is to calculate various elements of woks for easy pricing by estimator.
The first recorded Quantity Surveying Practice came into operation around 1785 in Reading, England.
But today, through various re-engineering of the profession, quantity surveying has moved from mere calculations of quantities to more pragmatic and proactive ways of financial engineering of construction procurement and management processes.
Nowadays, the underlying concept is more of Cost and financial engineering rather than preparation of bills and financial statements.
Other functions include:
1. Preparation of feasibility estimate of construction cost in the early stages of formulation of building projects and giving advice on alternative specification of materials, types of construction and contract formation.
2. Cost planning during the design stage of a project to ensure that cost is realistically and evenly distributed amongst various elements of the project. This is to ensure that the tender figure is kept within the budget of the client and the client receives value for his money.
3. Examining and reporting on tender and priced bill of quantities.
4. Negotiating with contractors on rates for negotiated contracts and including dealing with package contracts like cost reimbursement contracts, design and build contracts etc.
5. Valuing and preparation of interim or stage valuation of work done and recommending same to Architects for inclusion in the interim payments certificates.
6. Advising on the contractual and ex-contractual claims.
7. Preparation of interim Financial Statements at various stages of the project development.
8. Preparation of Financial Account at the completion of the project or notional final account at the determination of a project.
The Quantity Surveyors Dilemma
The greatest obstacle hindering the Quantity Surveyor (QS) from fully demonstrating his / her professional skill to the fullest advantage of the project is the quality of information given to him by other members of the design team.
Within the design team, the Quantity Surveyor is the only one who needs to work on the information provided by all other members of the design team (Architect, Structural & Services Engineers and the Interior designers).
The quality of the Bill of Quantities produced will merely represent the quality of design, details, specifications and other information made available to the Quantity Surveyor by other members of the design team.
The RIBA “plan of work” defines various stages of project development from feasibility to completion stage. It is on few instances that this methodology or process is adhered to.
One disturbing aspect of a Quantity Surveying practice is, the Architect having produced sketch drawing without details expects the Quantity Surveyor to produce a full and detailed Bills of Quantities.
Whereas what the “plan of work” anticipates from the Quantity Surveyor with this quality of drawings is a preliminary estimate or at best Bills of approximate Quantities.
Most of the drawings given to the QS are great but they are always lacking in details and specification.
A QS cannot work with fantastic drawings alone but with details and specifications.
TENDER AND CONTRACT DOCUMENT
The manner with which a bill of quantities is produced has an impact on the overall cost of construction projects. We will examine this later.
The following document form what is commonly referred to as the tender documents, which may finally become contract documents.
· Article of agreement
· Conditions of contract.
· Pricing notes and Preambles.
· Bills of Quantities.
· Tender Drawings
· Tender form
Apart from the tender drawings, the Quantity Surveyor produces all other documents and they are in most cases bonded together and referred to as Bills of quantities.
A Bill of Quantities happens to be just a part of the tender documents. It is commonly treated, as the most important but all other documents are as important as the Bill of quantities.
The way the quantities and subsequent rates are arrived at may sometimes depend on the conditions of contract, the pricing notes and the preambles.
BILLS OF QUANTITIES
The Bills of quantities section of the tender or contract documents will contain the following bills:
2. Measured works
3. General summary
Schedule of drawings used in preparing the bills.
The measured work section will contain the quantities of various elements and trades of construction projects measured under items as directed or recommended in the standard method of measurement.
The term quantities means the amount of labour, materials and possibly plants required in the execution of various items of works.
There are various ways these items of measurement can be arranged in the Bill of quantities.
The methods include:
1. Trade: Here measurements are arranged in the term of trade including all items of works that make up that trade. Example is the concrete work. This trade will include all concrete work in the building except external works and will include associated works like formwork and reinforcement.
2. Elemental: Work according to their position in the building element.Each element is an integral part of the building and the element consists of all trades involved in that element e.g. internal walls, external walls, roof, windows etc.
Windows will include the window itself, the concrete lintel and sills and finishes around the opening
3. Operational: Here the Bill description follows the actual building process with the materials shown from labour and described in terms of the operation.
An operation is the work performed by a man or a gang with a defined scope in the work pattern.
The choice of method depends on the flair of the practice and the purpose to be achieved with the bills of quantities. The first and second methods are the most widely used.
The guiding principles in measurements are laid down in the Standard Method of Measurement (SMM). There are various versions but the latest Nigerian SMM is the NIQS SSM1 1996 revision.
The description and measurement must be such that the estimator will be able to price the item of measurement without any difficulty.
He must be able through the description and measurements have a clear understanding of the designers’ intention.
The general principle is that every item has three dimensions to it (length, breath and depth). These dimensions must be included in the measurement of such item.
They could all be in the description wherein the unit of measurement will be number (NR).
44mm Cedar veneered plywood solid core flush door (2Hr fire resistance) covered with 6mm veneered plywood on both sides with hardwood lipping on all edges overall size 825 x 2050mm high.
All could be in the dimension column; the unit of measurement will be cubic metre (m3)
Reinforced in-situ concrete Grade 25 (1 :1½ :3) poured into formwork and well tamped around reinforcement (both measured separately) in Column.
Where two are in the dimension, the other one must be in the description and the unit of measurement will be square metre (m2)
230mm Hollow sandcrete block wall bedded and jointed in cement and sand mortar (1:4).
A linear metre item will be an item where two of the dimensions are in the description and the remaining is in the dimension. Unit of measurement will be metre (m).
50 x 150mm Mansonia wrought treated hardwood x m.
Within a particular item, you may measure various items of unseen works e.g. concrete work will include
Accuracy of the items to a greater extent will depend on the quality of drawings and specifications available to the Quantity Surveyor.
UNDERSTANDING THE BILLS OF QUANTITIES
Clear understanding of the Bills of Quantities could be a very useful tool for Architects and other designers.
Let us have a look at some descriptions in the bills and the reasons for differences in measurement.
Depending on the standard method of measurement (SMM) used by the quantity surveyor; the description and the way the quantity for a particular item is represented could differ.
The Nigerian Institute of Quantity Surveyors SMM 1996 revision for example requires insitu - concrete items to be measured in cubic metre (m3) and the SMM5 of the UK requires some to be measured in square metre (m2) and others in m3.
Apart from the dictates of the SMM individual firms have their unique ways of measurement but they will still meet the requirements of the SMM used.
While a practice may for exigency may decide to measure and describe hinges with doors under Joinery (provided this variation form SMM is visible and clearly stated) another could stick to the requirements of SMM by measuring it separately with ironmongery.
The way an item is described could also influence the price the contractor may insert for such item.
Let us consider the following descriptions:
1. 50 x 100mm Sawn treated hardwood rafter nailed to
2. 50 x 100mm sawn hardwood timber treated with pressure
Impregnated treatment and screwed to hardwood timber
While the description in item (2) shows that the QS must have received from the Architect his preferred treatment method item (1) shows that no treatment method has been given.
This could lead to problems in administering the project for the contractor could claim that it is one hour natural air treatment he has allowed for in his rate while the consultant may be anticipating dipping of the timber members in “solignium” solution before drying in natural sunlight.
If a proper soil investigation is carried out the Engineer can specify that soil excavated during foundation could be used as filling to make up levels under floors.
This would save some of the project cost since there will be no need for imported earth filling and the cost of removing the excavated material from site will also be saved except the cost of stacking on site.
Another aspect of improper specification is common with floor tiles. Most drawings will only indicate ceramic tiles to floors. This is not enough.
The quality and type of ceramic is important. It could either be first, second or third choice. It could be vitrified, glazed or unglazed.
The method of fixing is also important. It could be random, symmetrical or patterned. The materials used in fixing; with screed or with glue. The cost will vary depending on the choice and method of fixing.
As for terrazzo floor finish the sizes or grades and types of stone, ratio of mix and type of cement colour finish required.
Also let us look at mosaic, which is another area of conflict when it gets to the time of fixing.
It is only on rare occasion that mosaic pattern is designed and the QS would naturally assume a random pattern but the Architect may expect the contractor in a specific pattern or at times as mural. The fixing cost of which may vary by 100 to 200percent.
Whenever we are perusing bills of quantities area of concentration should be items that have major cost effect.
These could include:
Substructures: Concrete and Reinforcement. De-watering especially in areas prone to high water table and flooding.
Frame: Concrete, reinforcement and steel works
Roof: Roof structure and covering
Pre erection treatment required for trusses. The gauge and types and colour of covering must be specified.
Finishing: The type, size including thickness, quality and fixing method and pattern.
Joinery: It is not enough to specify hardwood. Is it sawn or wrought? Type of timber, seasoned or unseasoned, selected or general grading.
Also, items such as frames, lining, architrave, cornices and railing should include rebate, splaying, types of mouldings and other special features should be clearly defined.
Services; Pipes types must be clearly stated and referenced.
Horsepower of a pump is not enough, the specific name of the pump and manufacturers with catalogue reference number must be stated. This also applies to fittings and accessories. Apart from cable sizes, rating, manufacturers and reference number must be clearly defined.
Finally, I believe the purpose of this talk is to equip the Architects with relevant information necessary to verify and confirm that their design intention and that of other members of the design team have been fully and adequately represented in the QS bills of quantities.
I hope I have been able to satisfy this purpose in the last one hour.
The intention is not to make QS out of you. This takes an average of seven solid years.
Thank you, and May God bless us All.