Unit - 6
Specifications
It can be defined as finishing detailed information about qualities of material, their property proportion in which they are to be mixed. Specification includes the provision of overall information such as description of all workmanship, material and method of working to complete engineering project.
Purpose of specification:
Specifications help to decide cost of overall quality of work.
It also required to describe quality and quantity of different materials required for different construction work.
It is also necessary to specify material tools and plants to be engaged in work
It is essential contract document and it require for arbitration
As the cost of work is directly related to work.
Key takeaway:
1. Brief specification
2. Detailed specification
a) General specification
b) Technical specification
c) Standard specification
1. Brief specification:
These are the specification that describe briefly the term of construction and are useful to quantity survey in preparing estimate of work
Without going through lengthy procedure only general information of quantities of material nature and class of work can be known from brief specification.
2. Detailed specification:
Detailed specifications are the part of contract document detailed specification foe different items or prepare separately
Physical chemical electrical test to be conducted to ensure material quantity are also mention in it
Type of machinery tools plants and methods of execution is also mention
Specification are prepare by state government agencies such as PWD and publish in form of booklet named as standard specification
3. Detailed specification are classified as
The general provisions which are known as condition of contract are applicable to the work as whole.
The conditioning governing the contract are mention in such document and have been already explain
2. Technical specification:
In technical provision the detailed are regards desired quality of finish product item of construction are clearly specify and arrangement for inspection and testing to be carried out during the constructions stage to ensure the desired quality and workmanship is also included into technical specifications.
In general it includes
Specification related to material to workmanship
For performance
For proprietary commodities
3. Standard specification:
These are drawn up by engineering department for different material this saves valuable time labor stationary expenditure and completes work with less time.
The booklet is also called as red book due to its red cover.
Key takeaway:
Specification should be clearly understood by contractor supervisor staff workman etc.
As the specification from important of contract document and very useful during execution of the work they should be described in simple concise correctly worded
2. Language:
Specification should follow rules of grammar the style and tense should be maintain same throughout
3. Dual meaning:
The wording of sentence should convey single meaning and dual meaning sentences are avoided
4. Information:
Specification of different item should furnish the exact required information.
5. Practical consideration:
The specification should not be two lengthy and theoretical but should be written by taking all practical difficulties of contractor.
6. Use of abbreviation:
To avoid lengthy description correct abbreviation should be use to describe specification
7. Fairness:
The specification should be balance and fair to be both owner and contractor.
Key takeaway:
2. Burnt brick masonry first class in cement mortar
b. Preparation of cement mortar: Cement and sand should be mixed first in dry condition in predetermined proportion by volume and then just sufficient quantity of water should be added to it and then turned upside down and forward direction till a homogeneous mass of cement mortar is obtained.
c. Brick lying: Brick firstly thoroughly soaked in water for 2 hours before used in masonry, so that it should absorb water.
3. Mild Steel Bar Reinforcement for RCC Work
4. RCC work for slab:
b. Proportion of mix: The cement, sand, aggregate are mixed either on volumetric or weight basis in proportion of 1:2:4.
c. Mixing: The concrete should be prepared in mechanical mixer the drum being rotated at least for 2 minutes. The water cement ratio should be 0.55 or as directed by engineer – in
d. Form work: The form work conform to pare 7.2 of IS 456 charge of 1957.
e. Placing of concrete: Before placing of concrete, entire formwork and reinforcement is checked by engineer - in charge. The concrete is then laid to required thickness throughout as shown in drawing. Entire work is to be completed in one continuous operation. Labors should not be allowed to cross over freshly laid concrete.
f. Compaction: Compaction should be carried out either manually by road, or mechanical vibrator so as to get homogeneous dense mass of concrete without any cavities.
g. Curing: Lime concrete layers should be kept wet at least for two weeks after it is laid in position only clean water be used for curing.
h. Mode of measurement and payment: The mode of measurement of should be as per I.S.1200 of 1965 in cubic meters of slab laid to correct thickness as shown on drawing. The contractor should be paid at the agreed rate on per cubic meter basis.
5. General specification for second class building:
1. Foundation and plinth: Foundation and plinth shall be of 1" class brickwork with lime mortar over time concrete.
2. Damp proof course: DPC shall be 2cm thick cement concrete 1: 2 mixed with 1 kg per bag of cement
3. Super structure: Super structure shall be second class brickwork in lime mortar.
4. Roofing: Roof shall be of R.B. slab with 7.5 cm lime concrete terracing above veranda roof may be of A.C. sheet.
5. Flooring: Floors shall be 2.5 cm cement concrete over 7.5 cm.
6. Finishing: Inside outside walls should be plastered with cement mortar 1:6.
7. Doors and windows: Door frame shall be RCC with well seasoned Sal wood, glazed or partly glazed as required, fitted with iron fittings.
Key takeaway:
References:
