BILL OF QUANTITIES (BOQ)





BILL OF QUANTITIES (BOQ) DEFINTION:
A bill of quantities or schedule of quantities consists of a complete list of all various items of works for a project, giving the following: (see fig.1)

  • The item number 
  • Description of items 
  • Item unit 
  • Item quantity of work against each 

This data is enabling an estimated calculation of price of work. 

 
fig (1): BOQ for Electrical Works Division

THE PURPOSE OF A BILL OF QUANTITIES
A Bill of Quantities should make it easier for a contractor to price a particular project since all the materials and work to be carried out is listed. Each contractor should be working from the same information therefore a fairer system is employed when pricing competitively.



BOQ CREATION PROCEDURES:
  • Bills of quantities are prepared by quantity surveyors and or Building Estimators. 
  • The work of a project is usually divided into separate elements for payment purposes with respect to the kind of work involved, each element as a separate bill designated as a payment item. 
  • The bill of quantities is prepared by a “taking off” process in which the cost of a building or other structure is estimated from measurements in the Structural Engineer's drawings.
  • Similar types of work are then brought together under one item, a process known as "abstracting". (see fig.1)
  • The bill of quantities is arranged in a tabular form without completing columns of rate and amount. (see fig.1)
  • The total price of a bid is obtained by summation of the amounts for all items scheduled in the tender, arrived at by multiplying the estimated number of units for each item by the corresponding unit-price bid. (see fig 2&3)


fig (2): summation of one division



fig (3): summation of all division (Total Bid Sum)

Note: Estimating books provide the relevant costs of the materials and labor costs of the operations or trades used in construction. As the rates for materials and labor change due to inflation, these books are frequently republished. 


BOQ TYPES:
There are different styles of bills of quantities as follows:

  1. Trade Bill of Quantities 
  2. Elemental Bill of Quantities 
  3. Provisional Bill of Quantities 
  4. Non-Specified Bill of Quantities 
  5. Specified Bill of Quantities 
  6. Builder’s Bill 
  7. Operational Bill of Quantities 



1- Trade Bill of Quantities : see fig.1,2 &3

The traditional bill of quantities is arranged in trade order. The order of trade is normally in the same order as the specification.

Apart from being arranged in trade order, each trade has the facility for each description to be priced and totaled to give the total cost of each trade. The total trade cost is then transferred to a general summary to obtain the total project cost.

In order to be able to refer to any section in the bill of quantities, each description is given a separate and distinct reference. It is also normal practice for each page to be numbered and labeled with the project name and trade.


2- Elemental Bill of Quantities
A bill of quantities prepared in elemental format rather than the traditional trade order sequence.



3- Provisional Bill of Quantities : see fig.4



fig (4): Provisional Bill of Quantities

A bill of quantities containing provisional quantities and issued to tenderers on the basis that the billed quantities will be adjusted during construction where they differ from the actual quantities, it is normally used where the drawings and specification cannot be finalized prior to calling tenders


4- Non-Specified Bill of Quantities
As the name implies, this document contains only the items of work and their quantities as a stand alone document separated from the specifications documents of these works.


5- Specified Bill of Quantities
the specifications are incorporated with the bill of quantities in the form of preamble notes and the bill of quantities description. The quantities do not normally form part of the contract but preambles and descriptions are part of the contract.

It is Similar to the traditional BOQ but has the addition of a short type of specification included with each of the itemized materials and labor for each specific trade. Also at the beginning of the Specification Bill are clauses covering such things as:

  • notice to tenders 
  • general conditions of contract 
  • preambles etc. 


6- Builder’s Bill : see fig.5



fig (5):  Builder’s Bill 

This method is used by builders to obtain a quick guide or budget price. It is based on the price per square meter (m2) of similar types of work completed by the builder and is used mainly in the Domestic Housing field.

A similar method using the cube basis that is the cubic meter (m3) content of the building is used for the Commercial and Industrial field.

It must be emphasized that this method of calculating is used purely as a guide or budget price by the builder.



8- Operational Bill of Quantities
are a tendering document for estimating costs prepared by architects that describes a construction project in terms of the operations (which include labor and plant) needed to build it. 

Advantages:
  • Separates the costs of labor, materials and plant thus enabling cost control 
  • Increases the accuracy of estimating. 
  • Costs can be related to factors that directly determine them such as overall plant usage. Allows the reuse of information created in estimating for project management. 
  • Enables better estimation of variation in works.

Disadvantages :
  • Bulky and costly to produce so increasing the work of the contractor’s estimators. 
  • Radically changes the estimating process. 
  • Does not fit in with current contracts in regard to work variation. 
  • It needs computers to allow rapid manipulation of the data: this did not exist when it was originally proposed. 
  • The design team responsible for creating the operational bill need not be “very familiar with the build ability issues as they affect the construction process”. 


Difference between BOQ & BOM
The terms bill of quantities (BOQ) & bill of materials (BOM) are often confused or misused. bill of materials (BOM) should not be mistaken for bill of quantities (BOQ) since their definitions are different as follows:

Bill of quantities (BOQ): please review the definition in the top of the article.

Bill of materials (BOM): is a list of the raw materials, sub-assemblies, intermediate assemblies, sub-components, components, parts and the quantities of each needed to manufacture an end product. No physical dimension is described in a BOM. It may be used for communication between manufacturing partners, or confined to a single manufacturing plant.


in the next topic, i will explain the Schedule Of Execution. please, keep following.

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