Pipes have been classified in this standard as LA, A and B according to their thickness. Class LA pipes have been taken as basis for evolving the series of pipes. Class A allows a 10 percent increase in thickness over Class LA. Class B allows a 20 percent increase in thickness over Class LA. For Special uses, Classes C, D, or E may be derived after allowing corresponding increases of thickness of 30, 40 or 50 percent respectively.
Pressure Pipes Special Aspects
Pressure Pipes Testing at Works
Mechanical Test – Mechanical tests shall be carried out, during manufacture. Tests for every four hours of production shall be conducted. The results obtained shall be taken to represent all the pipes of all sizes made during that period.
|Description||Type of Test with limits|
|Ring Test 80 to 300 DN||Modules of rupture 390 (Min.) MPa|
|Tensile test 350 to 600 DN||Tensile strength 200 (Min.) MPa|
|Brinell Hardness Test||Max. 230 BHN|
Hydrostatic Test – Pipes shall be tested hydrostatically at the pressure specified in below table. To perform the test, the pressure shall be applied internally and shall be steadily maintained for a period of minimum 10 s. The pipes shall withstand the pressure test and shall not show any sign of leakage, sweating or other defects.CI Fittings Hydrostatic Test Pressure for Castings:
|Description||Hydrostatic Test Pressure for Works, MPa(Upto DN 600)||Suggested Maximum Hydrostatic Site Test Pressure in MPa(Upto DN 600)||Suggested Maximum Hydraulic Working Pressure (Inclusive of Surge) in MPa(Upto DN 600)|
|Spigot and Socket Spun Pipes Class LA||3.5||1.6||1.0|
|Spigot and Socket Spun Pipes Class A||3.5||2.0||1.25|
|Spigot and Socket Spun Pipes Class B||3.5||2.5||1.6|
Available Joints - Push-on Flexible Joint (Tyton Joint / Rubber Gasket Joint), Semi Rigid Lead / Drip Seal Joint & Flanged Joint.
Chart of Dimensions as specified by the Bureau of Indian Standards:
Class – LA
Class – A
Class – B