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

Class of pipesWorking pressure (PN)Class 1 0.25 MPa (2.5 kg/cm 2 )Class 2 0.4 MPa (4.0 kg/cm 2 )Class 3 0.6 MPa (6.0 kg/cm 2 )Class 4 0.8 MPa (8.0 kg/cm 2 )Class 5 1.0 MPa (10.0 kg/cm 2 )Class 6 1.25 MPa (12.5 kg/cm 2 )5.5 DIMENSIONS OF PVC PIPES5.5.1 The mean outside diameter, outside diameter at any point and their tolerances shall beas given in table 5.2.5.5.2 Mean outside diametersThe permissible variation (d em _d n ) between the mean outside diameter (d em ) and thenominal outside diameter (d n ) of a pipe shall be positive in the form +x, where x isless than or equal to the greater of the following two values:a) 0.3 mm, andb) 0.003 d n rounded off to the next higher 0.1 mm.5.5.3 Wall thicknessThe wall thickness of plain pipe and the plain portion of socket ended pipe shall beas given in table. 5.2.5.5.3.1 Tolerance on wall thickness.5.5.3.1.1 For pipes of minimum wall thickness 6 mm or less, the permissible variation betweenthe minimum wall thickness (e min ) and the wall thickness at any point (e), (e-e min )shall be positive in the form of +y, where y= 0.1 e min + 0.2 mm5.5.3.1.2 For pipes of minimum wall thickness greater than 6 mm, the permissible variation ofwall thickness shall again be positive in the form of +y, where y would be applied intwo parts.5.5.3.1.3 The average wall thickness shall be determined by taking at least six measurementsof wall thickness round the pipe and including both the absolute maximum and theabsolute minimum values. The tolerance applied to this average wall thickness fromthese measurements shall be within the range 0.1 e min + 0.2 mm (see table 5.2)5.5.3.1.4 The maximum wall thickness at any point shall be within the range 0.15 e min . (seetable 5.2)5.5.3.1.5 The results of these calculation for checking tolerance shall be rounded off to thenext higher 0.1 mmUrban Administration & Development Department Page 55