Pneumatic testing
Pneumatic testing
(OP)
When doing a pneumatic test, what is the purpose of doing the leak test at test pressure and then dropping the pressure down to design pressure and doing another leak test. One would think that if the piping system held at the higher test pressure that dropping down to design pressure and leak testing again would be redundant. This is typically what engineers call for. Any thoughts?





RE: Pneumatic testing
1. When you pressure to test pressure some structural distortion may occur which may affect the test at design pressure.
2. Some systems are designed such that the pressure assist the sealing, therefore, in lower pressure the leak may be higher than at higher pressure.
RE: Pneumatic testing
RE: Pneumatic testing
I'm not sure what Code or Standard you are testing to.
ASME B31.3 clearly states the procedure under 345.5. I see where it addresses achieving the test pressure incrementally and holding to relieve the stresses and strains at each increment.
Then reduce to design, "before" examining for leakage.
Pneumatic testing harnesses a tremendous stored energy that just doesn't release like a pinhole in a pipe being hydro tested. It reaps havoc.
If the redundancy saves lives (Even One!), its well worth the effort.
" There is no Shortcut to anyplace worth going "