Pipe wall thickness calculation
Thread Content
When calculating the pipe wall thickness, should it be determined based on the hydrostatic test pressure? Is this the way to ensure that the hydrostatic test strength is sufficient? I would appreciate some guidance from experts, thank you!
I saw several formulas for calculating wall thickness, all of which use the design pressure; the hydrostatic test is also determined based on this design pressure. I think using the design pressure is sufficient
The \"Code for Selection of Materials for Petrochemical Piping Design\" (SH/T 3059-2012) and the \"Code for Design of Industrial Metal Piping\" (GB 50316-2000) contain clear regulations regarding the calculation of pipe wall thickness; it’s easy to find this information, so there’s no need to assume anything.
I checked the pipeline standards, and it’s indeed not necessary to calculate based on the test pressure. The following is the test pressure applied to the pipelines at the time of manufacture; after calculation, this value is much higher than the required test pressure for the pipelines
There is no need to consider hydrostatic testing; the wall thickness selected alone can be verified for pressure resistance to meet the requirements of hydrostatic testing
If you’re worried, you can check the stress under the conditions of the hydrostatic test; generally, since the standards don’t specify this, it’s likely that the stress won’t exceed the strength of the material
When performing the design calculations for our steel pipes, we use an allowable stress that is one-third of the material’s tensile yield stress. The pressure used in the hydrostatic tests is 1.5 times the design pressure; thus, there is still a safety factor of 1.5 during these tests, so there is no need to worry.