Specifications Part 1 - Water Supply, Sewerage and Tube Well Works

2.5 Thrust Blocks2.5.1 In case of bigger diameter pipes where the pressure is very high, thrust blocksof cement concrete (1 cement: 2 coarse sand: 4 graded stone aggregate of20mm nominal size) of adequate size and shape shall be provided on allbends/tees etc., to transmit the hydraulic thrust to the ground, spreading over asufficient areas, depending upon the type of soil met with, as per the relevantDrawings or as directed by Engineer.2.5.2 Mass for sockets, pipe barrels and flanges are calculated on the basis of thedensity of cast iron as 7.15 kg/dm 3 .2.6 Testing2.6.1 Mechanical TestsMechanical tests shall be carried out during the manufacture of the pipes asspecified in IS:1536.2.6.2 Hydrostatic tests at works.1. For hydrostatic tests, the pipes shall be kept under pressure for 15 seconds,they may be struck moderately with a 700 g hammer. They shall withstandpressure test without showing any leakage or any other defect of any kind. Asfar as possible the hydrostatic test shall be conducted before given any coatingto the pipes. These pipes shall be used upto half the hydraulic test pressure asgiven in the following table. The hydraulic test pressure for Centrifugally CastIron pipes as per IS: 1536, shall be as given below.Table 2.2Refer Table 1 of IS 1536:2001ClassHydrostatic Test Pressure for Works, MPaUp to DN 600 1 (Including) DN 700 and Above1 2 3LA 3.5 1.5A 3.5 2.0B 3.5 2.52. The specials shall conform to IS : 1538. The hydraulic test pressure of eachclass of specials shall be as follows:Table 2.3Refer Table 1 IS 1538:1993Nominal diameterTest pressureFittings without Branchesor With Branches notGreater than Half theFittings with Branchesgreater than Half thePrincipal Diameterprincipal DiameterMPa (kgf/mm 2 )Upto 300 mm (including) 2.5 (25) 2.5 (25)Over 300 mm up to 600 mm2.0 (20) 2.0 (20)(including)Over 600 mm up to 1500 mm(including)1.5 (15) 1.0 (10)Urban Administration & Development Department Page 26