Measurement of materials & works – QS
Units of Measurements
Units are the determinants of the quantities to represent them in a standard way. Commonly units are classified according to nature, shape and size. For the planning and execution of any projects the measurements and its accuracy is very much important.
General Rules for Measurement
Measurement shall be made for finished item of work. (Description of item shall include the details such as material, transport, labour detail, tools used, overheads).
When booking a measurement the order should be length, breadth, height / thickness.
The accepted tolerances for the measurement shall be,
Linear measurement – 0.01m / 1cm / 0.5” (half inch)
Area – 0.01 Sqm / 0.1 Sqft
Volume / cubic contents – 0.01 Cum / 0.1 Cuft.
If the type of work is same but done under different conditions & nature then they should measured separately.
A BOQ describe fully on materials, proportions, workmanship and accurate amount of work that should be executed.
In case of masonry the height levels should be mentioned clearly as, foundation to plinth / plinth to 1st floor and so on.
Taking out quantities
There are different methods of way to taking out of quantities. For massive works, the volume should be defined. So length, breadth, height / depth measurements should be needed to calculate. The common unit of measurement is Cubic meter –Cum. Exemplary works for the massive works are earth work, concrete for foundation, Random rubble masonry.
For narrow works or surface works the area should be calculated. So length and breadth / height measurements should be needed to calculate. The unit of measurement is Square meter – Sqm. Works such as plastering, thin brick or block work for wall partitioning are some examples for this type.
For lengthy works linear/ running length measurement should be considered. The commonly used unit is meter – m (RM – Running meter) and fencing, plumbing are the exemplary works for this type measurement.
Also some single unit works such as fixing of doors, windows, rafters, trusses the numerical value is considered as measurement. They are denoted in terms of No – Number. (Windows – 5Nos).