I have a question regarding pipeline pressure testing
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For vacuum tube pressure testing, a negative pressure is specified in the design, but no equipment is available. I would like to ask the instructor whether positive pressure can be used as a substitute; if so, what should be the experimental pressure level, given that the negative pressure is set at -p?
The \"Code for Selection of Materials for Petrochemical Piping\" (SH/T3059-2012) stipulates that vacuum pipes shall be designed to withstand external pressure. When equipped with safety devices, the design pressure shall be calculated as the lower of 1.25 times the maximum difference between internal and external pressures or 0.1 MPa; in the absence of such safety devices, the design pressure shall be 0.1 MPa. Therefore, for the pressure testing of vacuum pipes, the hydrostatic test pressure should be 1.5 times the design pressure.
First of all, thank you. The design pressure for the vacuum pressure pipe here is -0.1 MPa. Can positive pressure be used for testing the pipeline? If so, should 0.15 MPa be used for the testing?
Is there any hydrotesting equipment? Our factory generally uses air pressure, as it’s convenient
Thank you. Is it correct to use the same positive and negative pressure?
It depends on which standard you follow. GB 50184 and GB 50235 require testing for both positive and negative pressure. But it doesn’t state how much negative pressure should be applied. GB50136 only specifies that the pressure increase rate should not exceed 5% within 24 hours. I think it’s sufficient to create a negative pressure along with the system and then maintain that pressure. Since a pressure test has been conducted, the strength and sealing performance of the pipeline can be basically guaranteed.
It should be different @WisdomBright @RedLee_ZZHI @ylb913 @rjs999
First, the positive pressure test, then the vacuum pressure increase rate test