Unit – 4

Specifications and Rate Analysis

4.1 Specifications:-

Definition: -

• Specifications including provision of overall information such as description of contains as like as workmanship, material, various type of method of construction, etc to working the complete as engineering projects. 
• It can define as, furnishings details information about qualities of materials, their property, proportion in which are to mixed. 

4.2 Purpose of specifications:-

• Specifications help to decide of overall quantities of work. 
• It also requires to describe quality and quantity of different materials required for different construction work. 
• It also necessary to specify materials, tools and plants to engage in work. 
• It essential contract documents required for arbitration. 
• As the cost of work which is directly related to work. 

4.3 Types of  specification: -

a)  Brief specifications. 

b) Detailed specification. 

1) General specification. 

2) Technical specification. 

3) Standard specification. 

There are explain as follows: -

a)  Brief specification: 

• These specification which briefly described the item of construction and useful to quantity surveyor is preparing estimate of work. 
• Without going the lengthy procedure only general information for quantities of materials nature and class of work is called as brief specification. 

b)  Detailed specification: -

• Detailed specification is the become part of contract documents. 
• It is for different item prepare are separately. Physical, chemical, electrical test are conduct for the ensure the material quantities are mention also. 
• The machinery, tool, plant, and method of executives is mentioned, 
• Specification are prepared for state government agencies like P. W. D. And publishing in form booklet name as standards specification. 
• Detailed specification are classified as below: -

1)  General specification: -

• There specification which known as conditions of contract are applicable of whole work. 
• The condition of contract are mentioning in such documents and have been already explain. 

2)  Technical specification: -

• There specification provision the details as regards desired quality is finished product or item in construction are specified are clearly. 
• An arrangement for inspection and testing is carried of during construction stage to ensure desired quantities and workmanship is also includes this specification. 
• In general it includes: -

• Specification related to materials and workmanship. 

• For performance. 

• For proprietary commodities. 

3) Standard specification: -

• These are drawn up engineering department of different materials. 
• There save valuable time, labour, stationary, expenditure, and complete work in less time. 
• These specification are punishment by government department like PWD and available in form of booklet called standards specification. This booklet is also called as red book due to red cover. 

4.4 Requirements of good specification: -

1)  Wording: -

• As specification from important of contract document and useful during executing of work, they should describe in simple, concise, correctly worked. 

2) Language: -

• Specification which follows of grammar. The style and tenses shall maintain same throughout. 

3) Dual meaning: -

• The wording of sentence should be single meaning and dual meaning sentence are avoiding. 

4)  Information: -

• Specification of different item should furnish the exact require information. 

5)  Practice considered: -

• The specification which not be too lengthy and theoretical which written by taking all practice difficulties of contractor. 

6)  Use of abbreviation: -

• To avoid lengthy description correct abbreviation which used to describe specification. 

7)  Fairness: -

• The specification which balances and fare to both owner and contractor. 

4.5 Detailed specification for common item of building work: -

a) Excavation for foundation: -

1) Site clearance: -

• Before earthwork is starting then whole are area is clean like grass, roots of tree and other obstruction. 

2) Line out: -

• The centre line of work is Mark on plot drawings with correct dimensions of plan and excavation is started. 

3) Excavation: -

• It carried out to exact dimensions is indicated in drawing. 

4)  Disposal: -

• The excavation materials which disposal of away from site and should not be nearly than 1.5 m from outer edge of excavation. 
• Engineer in charge have responsibly to dispose off excavation material dumper.

5) Dewatering: -

• The excess quantity of water having in trenches it should remove by pumping or other suitable method. The trench water replacement with ramming of soil. 

6)  Shoring: -

• It important to provide shoring to side of excavation to avoid them from collapse. 

7) Protection: -

• All excavated area is properly close and marked with red light to avoid accident during night. 

8) Backfilling: -

• After ending foundation concrete work, shoring should be removed and space between foundation and side of excavation is refill to original grounds level. 

9)  Mode of measurement and payment: -

• Measurement is done term of cubic meter of excavation. No payment should made to excess work carry out by contractor, payment is depend on type of strata. 

b) Plains cement concrete: -

1) Material: -

• Cement – used cement is open conforming to IS 269 – 1958.The cement should measure on weight basis and whole bag, each bag weighing 50 kg which is equal 35 lit in volume. 

• Fine aggregate – Aggregate which pass through 4.75 mm IS sieve No. 480 is called fine aggregate, such aggregate which coarse, consisting of sharp, angular grain, sea sand is not used. 

• Coarse aggregate – It should is broken hard stone obtained from approval quarry. It should strong, hard, dense, clean and durable. It should clean from dirt and dust, the aggregate is well graded to obtain a compact and dense volume of concrete with workability. 

• Water  - water used free from injurious quantities of deleterious materials like oil, salts etc. 

2) Mix of concrete: -

• Two methods are used for mixing concrete is hand mixing or machine mixing which are used depending upon grade, quantities and quality of concrete. For pcc work concrete of grade 1: 2: 4 is used. For one bag of cement weighing 50kg.

3)  Laying of concrete: -

• The concrete prepare is laid is position before 30 min of adding water to mix concrete not dropped from heights more than 60cm but laid gently position to avoid segregation. 

4) Compaction: -

• Compaction is important to fulfill each and everyone corner of members. Hence concrete shall be compacted by road after laying is position to get dense concrete without any honey comb. 

5)  Curing and protection: -

• Freshly laid concrete to bring protected from rain by suitable coverings. Concrete after it began harden after laying cured with wet gunny bag for period of 14 day. 

6) Mode of measurements and payments: -

• The quantity of concrete is measured for  L x B x Has is cubic metre and paid according to dimension limited to given on drawings. 

c) Courses Rubble Masonry in cement mortar: -

1)  Material: -

• Stone – stone used are strong, hard, durable, and obtain from approved fresh quarries of trap etc, it should impervious, whether resistant and free from defect. Water absorbed capacity should not exceed 5℅ by weight. 

• Cement – used cement is open. The cement should measure on weight basis and whole bag, each bag weight 50 kg which is equal is 35 litre in volume. 

• Sand – It is either natural river sand or broken stone satisfying all Is requirements. They is clean, strong, hard, particles size is 5 mm maximum. 

2)  Dressing of Stone: -

• The  stone are dressed to have straight hori and vertical side which is perpendicular to adjacent side. The face portion have plane. Such stone have it breath larger than it heights. 

3)  Hearting and backing: -

• Stone should be as larger as possible. One third of such stone should be 0.010 cubic metre in volume for 50 cm thick wall. 

4) Quoins: -

• It have good quality stone whose heights should be that coarse is laid. 

5)  Through stone: -

• These should have height equal to height coarse and it width equal to it height. 

6)  Laying of stone: -

• They is laid horizontal coarse of about 15 cm in heights. All stone in one coarse have same heights and all course have same heights. 

7)  Joints: -

• The thickness of joints shall not more than 10 mm. In case of masonry is pointed, the ranking of joint is carry out depth equal to thickness of joints when the mortar is still fresh and green. 

8)  Raising if masonry: -

• The whole masonry is raised uniform limit to 60 cm heights in one day. 

9)  Sticking of joint: -

• For face which not plastered should be struck carefully when mortar is fresh and green. 

10)  Scaffolding: -

• Single or double scaffolding should be provided by contractor sufficient care being taken to ensure safety. 

11)  Mode of measurements and payments: -

• The mode of measurements for this item if construction is cubic metre for complete work subject to limiting dimensions shown on plan and contractor is paid as per agrees rate per cubic metre. 

d) Plastering in cement mortar: -

1)  Material: -

• Cement – it should fresh Portland cement and sand is clean ,free from organic matter. 

• Sand – it form burning of 1st class brick, they should clean, strong, hard, particles size is 5 mm maximum. 

2)  Preparation mortar: -

• The material which first mixed dry through out uniform in colour is proportional and then mix wet adding water slowly and gradually at least four times to give uniform paste. 

3) Preparation of surface: -

• Before doing plastering surface should clean, brush and  wetted with water, in case of cement plastering on surface of cement concrete surface is made roughened are cleaning. 

4)  Laying: -

• The plastering is started from top and work toward the ground. The whole surface is made flush with wooden straight edges and rubbed with wooden float to ensure and surface. 

5)  Curing: -

• Curing to plastering is start after 12 hr from plastering and it done at least 7 day. 

6) Mode of measurements and payments: -

• All measurements of plastering work is carried our in square metre allow for necessary deductions as per rule for opening. 

e) Ceramic tile flooring: -

1)  Ceramic tile: - 

• The tile is approved make confirm to IS 777-1970. They is flat and true to shape and free from crack, corner. The tiles is normally size as 150 x 150 x 150 mm and 100 x100 mm. 

2)  Preparation of surface: -

• While the flooring is being joint rake out depth of at least 15 mm in masonry wall. In case concrete wall surface rough with wire brushes. 

3)  Laying: -

• 12 mm thick plastering of cement mortar 1: 3 coarse sand or mix specified applied and allowed harden. The tile is soaked in water washed clean and coat of cement slurry applied is back of tiles and correctly to proper plan and line. 

4) Curing and finishing: -

• Joint is clean off grey cement grout with wire brush to depth 2 mm or 3 mm. Surface be kept wet for 7 day. 

5)  Mode of measurements and payments: -

• The item of work are measured in sq. m. The contractor is paid at agree rate on per sq. m basis. 

4.6 Rate analysis: -

Definition: -

• It is method of determined correct and reasonable rate per unit of work. 
• The basis is assigned at correct and reasonable rate per unit work / supply for particular item. 
• Following it specifications and detailed survey of materials, labour, equipment etcare required for unit work and their  rate called as analysis of rate. 

4.7 Purpose of rate analysis: -

• To find out present rate per unit of item at locality. 
• To examine the rate offers by contractor. 
• To find out of quantity of materials and labour required for completion of projects work. 
• To finalize the labour contract rate. 
• To workout economical use of material and process to completing particular item. 
• To work out cost extra item is not provided in contract bond, but are to done per the direction of department. 
• To revise schedule of rate increases in cost of material and labour or due change in techniques. 

4.8 Factor affecting rate analysis: -

1) Quantity of materials and cost: -

• The estimator takes off the quantities of various materials required per unit quantity of item. Calculate cost from local market rate. 

2)  Labour cost: -

• To calculate the labour cost which important to know the number and wages of different categories of labour, skilled and namely Mason or carpenter etc, required for each unit work. 

3) Cost of equipment, tools, plants: -

• Wherever possible the cost of equipment and ordinary T and P those required for general use should be assign to specify item of rate. 

4)  Overhead charge: -

• This includes miscellaneous item such as office, rent and depreciation of it equipment, salaries of office staff members, lighting, traveling, small tool overhead classified as below, 

a) General overhead. 

b) Job overhead. 

This are explain as below, 

a) General overhead: -

• It includes established charge of office staff, telephone bill, printing, travel expenses, rent etc 

b)  Job overhead: -

• It includes job overhead are salaries of supervisors staff, material handling charges repair charge labour welfare amenities , workmen compensation expenses insurance charge, losses on advance, interested on investment, paid holiday bonus. Etc. 
• Overhead charge are expenses to incurred by contractor for particular work site but can not be included under basic cost of any item of construction. 

5) Establishment charge: -

• The permanent head office of contracting company is different temporary office at worksite. The amount to spent for running head office such as salaries of quantity surveyor, accounts, clerk etc are all including under establishment charges. 

6)  Contractor profit: -

• Contractor profit is charged generally is 10 – 15  ℅ of total cost of construction of item. 
• It equal to total amount received contractor for completion of item minus initial investment of contractor is made of completion. 
• Net profit amount to about 10 – 15 ℅ of return of rolling capital may be higher even up to 100℅ per year as contract provide for interim payments to made contractor after fixed internals of time depending upon the volume of work complete by him. 

7) Cost for water: -

• A sum of  0.5 – 1℅ of cost of material and labour will be added for water charges. 
• Data  of quantity depends on following factor of rate analysis: -

1)  Specification of item indication quality and proportion. 

2) Market rates of material. 

3) Daily wages. 

4) Cost for tools, equipment, overheads etc. 

5) Cost of transport. 

6) Profit of contractors. 

7) Availability of water. 

Problem: -

1)  Calculate quantity of material for  dry volume 25 cu. M concrete with 1: 1: 2 proportion. 

Ans -

Total part = 1+1+2 = 4

Volume per part  = Total volume / No. Of part. 

= 25/4 

= 6.25 m3 

1)  Volume of cement = 1 x 6.25

= 6.25 m3. 

No of bags = volume /  0.035 

= 6.25 / 0.035

= 179 bags

2)  Volume of sand = 1x 6.25

= 6.25 m3. 

3) 3)  volume of aggregate = 2 x 6.25

= 12.5 m3. 

4.9 Market rate of material: -

• Market rate are vary from place to place. Following table as given rate as thane during 2007-08.

4.10 Estimating labour: -

• Preparation the estimate of labour is  due to allowance is made for variations in wage, working conditions and different class of labour required for different kind of work. 
• The length of time required to do certain pieces of work is vary for according to skill and mental development of workman and also according to working conditions to particular job. 
• When work is plentiful, labour scared and job is easy to get the time required for labour to  certain a after few months, when he have number of workman under enable time estimate quite accurate the length of time is workman will need to do certain job. 
• The recommended of all India standard schedule the rate of different kind labour as required to certain pieces work is adopted to prepare the analysis of rate. 

• No. Of labour days required ( 8 hours working days) as per all India schedule of rate Table as follows

4.11 Task work ( out turn) : -

• It is quantity of work which can done artisans or skills labour of trade working for 8 hr a day. 
• The out turn is not mean that quantity of work can complete only by labour, but the type of labour or helpers are also engaged to complete the quantity of work 
• Ex. A Mason can complete 1.5 cm2 of brick work per day providing is helped two mazdoor to carry and mix the ingredient of mortar and carry and place all other materials at his disposal etc. 
• Instructions from head Mason for few hours is also necessary to complete the quantity of brickwork. 

• The task work varies from person to person, place to place and depend on various factor such as physical fitness and skill labour, type, nature, place of work. 
• Various task work formal as given below:

4.12 Factor affecting the task work: -

1)  Output of different skilled workers varies according to their skill. 

2) Output of individuals worker also varies according to their skill. 

3) Efficient site organization and management increase the labour output, faulty or    slack organizing will decrease it. 

4) Site conditions may have some effects on output. 

4.13 Transportation of materials and it cost.: -

• Various materials required for construction of structures is carried work site for short distance usually Bullock carts are used as well as for long distance truck is used. 

1)  Transport by truck: -

• The cost of transportation of materials by truck depend on, 

a)  The maximum load the vehicle can safely carry. 

b) Distance to which materials is to be transportation. 

c) Cost of hire charge. 

d) Speed of vehicles. 

e) Labour required for loading and unloading. 

2)  Transportation by Bullock carts: -

• Bullock cart are capable of transport 1 tonne, of materials the average speed being assumed as 3 km/hr includes time required for loading and unloading of materials. 
• The number of trip can complete in day 8 working hr can calculate by formula state above and total quantity of materials that carry per day of total number of day required for transportation the materials is found out. 
• Weight carry capacity of other modes: 

a)  Basket – 0.015m3/ trip. 

b) Wheel barrow – 0.06 m3 / trip. 

c) Donkey load – 0.08m3 / trip. 

Problems: 

1)  Calculate cost of 18m3 RCC with mix proportion 1: 1.5: 3,take 1.2℅ steel. 

Ans: 

Consider 10 cu. m

Increase by volume by 40℅ for dry volume. 

Dry volume = 1.4 x 10 = 14m3

Increase by 10℅ for wastage. 

Total volume = 1.1x 14 = 15.4 m3

Total parts = 1+ 1.5+3 = 5.5m3

Volume of each part = Total volume / no of part

= 15.4/ 5.5

= 2.8 m3

Volume of cement = 1x 2.8 = 2.8 m3

No. Of bags = 2.8/0.035 = 80 bag

Volume of sand = 1.5 x 2.8 = 4.2 m3

Volume of aggregate = 3 x 2.8 = 8.4m3.

Volume of steel = 1.2 ℅ of net volume 

= (1.2/100) x 10

= 0.12m3.

Quantity of steel = volume x 7850

= 0.12 x 7850

= 9.42 quintal 

Cost for 10 cu. m of RCC = Rs 120274.18/-

Cost for 1 cu. m of RCC = 120274.28/10

= Rs. 12030/-

Cost for 18 cu. m of RCC = 18 x 12030

= Rs. 16540/-

2) Prepared rate analysis for pointing using cement mortar 1: 5

Ans: -

Consider 100 sq. m

Wet volume of pointing = 0.5 cu. m

Increase by 30℅ for dry volume 

Dry volume= 1.3 x 0.5 = 0.65 m3. 

Increase 20℅ for wastage 

Total volume = 1.2 x 0.65= 0.78m3.

Volume of each part = 0.78 / 6 = 0.13 m3. 

Volume of cement= 1 x 0.13 = 0.13 m3. 

No of bag = 0.13 / 0.035

= 4 bag. 

Volume of sand = 5 x 0.13 

= 0.65m3.

For 1 cu. m = 9912.92 / 100

Rs, 100/-

3) Determine the basic material required for construction of 135 cu.m if brick masonry (1:6).

Ans:-

Number of brick @ 599 per cu m

= 135 x 500

= 67500 brick

Volume of dry mortar = 30 % of volume of brick

= 30 / 100 x 135

= 40.5 cu.m

Volume of one part = 40.5 / 1 + 6

= 5.787 cu.m

Quantity of cement = volume of one part / 0.035

= 5.787 / 0.035

= 166 bags

Quantity of sand = volume of one part x 6

= 5,787 x 6

=34.722cu.m