Hydrostatic test

[isg1968]

I have a serous question about pressure test for pipe. According to ASME B31.3 the test pressure sould not be less than 1 1/2 time design pressure wich is in my case 152 barg . so the test pessure equal to 1.5*152=228 barg.
In the pipe certificate it mentioned that this pipe has been tested at 196 bar.
The conclusion is : if we carry out the hydrostatic leak test at site at 228 bar g as requiered by B31.3 , the pipe will blow out.
Please if any one has met this kind of troubles , i'll appreciate his help.

 

[BigInch]

They went to mill test pressure, which might only be 90% of yield stress pressure, or something similar. Have you verified that the pipe's yield pressure is less than 228 barg? If not, what are the pipe's diameters, wall thicknesses and material designations?

If the pipe does have a yield pressure that is less than your required test pressure, then you do have a problem.

Two solutions are possible, neither one is good.

1.) Replace the pipe with pipe that has the appropriate strength for your service conditions,

2.) Derate the system's maximum allowed operating pressure to the test pressure / 1.5



BigInch-born in the trenches.

http://virtualpipeline.spaces.msn.com

 

[Kataklop]

There might have been a special reason to reduce the test pressure (such as testing with equipment attached or gas pressure test)? Anyway better check the actual strength first