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

Table No.3.8DimensionWall thicknessFlange thicknessWhere e = Thickness of in mm, andToleranceMm-(1+ 0.05e)3.10.3 Permissible in cast iron double flanged (horizontally cast) pipes deviation froma straight line. The pipes shall be straight. When rolled along two gantriesseparated by approximately two thirds the lengths of the pipes to be checked,the maximum deviation fm, in millimeters, shall not be greater than 1.25 timesthe length l, in meters, of the pipe under test, thus fm 1.25 l.3.10.4 Tolerances for the various dimensions of flanges not specified above shall beas follows:Table No. 3.9Description Size, DN (mm) Tolerance (mm)D (as cast) Up to 250 + 3.0- 1.0Above 250 + 5.0- 1.5C Up to 250 ± 1.0Above 250 ± 1.5d Up to 300 + 2- 0Above 300 + 3- 03.11 Sampling criteria for the selection/frequency of various tests, shall be as per IS:11606:1986.3.12 Flanged joints3.12.1 Flanged cast iron pipes, screwed / welded flanged cast iron pipes and flangedspecials are joint by means of flanges.3.12.2 The jointing material used between flanges shall be rubber insertion 3 mmthick. Each bolt should be tyton a little at a time taking care to tightendiametrically opposite bolts alternatively. The practice of fully tightening thebolts one after another is highly undesirable.3.12.3 In addition to flanged pipes and special, flanged joints are also encounteredwhile fixing flanged sluice valves, air valves, hydrants, meter connection whichsometime requires their removal for repairs.Urban Administration & Development Department Page 40