Issues with the hydrostatic testing of high-pressure steam pipelines?
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This post was last edited by *exz on 2009-6-5 23:21. Urgent request for help: There is a high-pressure superheated steam pipeline with dimensions of 426×36 and a capacity of 20G; the design temperature is 405 degrees, and the design pressure is 11 MPa. Is it necessary to follow GB50235 for the hydrostatic testing of this pipeline? According to the requirements of GB50235, the hydrostatic test pressure for this pipeline is approximately 29 Mpa, which is an astonishingly high pressure! I would like to ask the experts: have you come across pipelines under such high pressure? Are there specific regulations governing the pressure testing of such pipelines? (It is said that according to electrical design specifications, a hydraulic test is not required as long as 100% PT of the welds is achieved; is this true?) ）
GB5310 specifies that the water pressure of pipes at the time of leaving the factory must not exceed 20 MPa. I’m not sure why, but can it be inferred from this that the water pressure after pipe installation also must not exceed 20 MPa?
Alternative tests can be used, eliminating the need for hydrostatic testing.
Why aren’t steam pipelines subjected to pressure testing? 17 MPa of air pressure is sufficient
For hydrostatic pressure tests, it is generally sufficient to reach 1.5 times the design pressure; if the design pressure is 11 Mpa, then a pressure of 17 Mpa should work fine. . . .
What was said on the 5th floor is right; 1.5 times is more than sufficient.
According to GB50235, the hydrostatic test pressure shall be 1.5 times the design pressure × (the ratio of the allowable stress at the test temperature to the allowable stress at the design temperature)!
If 100% flaw detection is carried out, could the hydrostatic test be waived?
What material is it? Please note that the design temperature is 405 degrees, and the design pressure is 11 MPa. The hydrostatic test is carried out at room temperature; therefore, according to the standards, it is necessary to take into account the difference in allowable values. Approximately 400 kilograms of test pressure is required!!!
In my opinion, from a practical application perspective, as long as the strength and temperature requirements are met, it’s fine; for 20G steel, there is no issue with temperature. It can be done like this: 100% RT, plus a strength test at 1.5 times the intensity. The strength of the material at high temperatures can be checked against 20G; there’s no issue. This is exactly how we handled the 60bar superheated steam pipelines in our company; they have been in use for 10 years with no problems. Be careful of R-rated movies at RT!