Design pressure in GB/T151-2014 Clause 4.7.4
Thread Content
4.7.4 For shell-and-tube heat exchangers in which the design pressure of the tube side is higher than that of the shell side, the testing method and pressure for the tube ends shall be specified in the drawings. Does the “design pressure” mentioned here refer to the hydrostatic test pressure or the design pressure of the shell and tube itself?
It’s already been made very clear – the design pressure
It’s already been made very clear – the design pressure
As a precaution, my company conducts pressure tests; the reason given is that if the pressure test for the shell is carried out at a lower level than that for the tube side, there will be certain gaps in the inspection of the tube ends.
It refers to the design pressure of the shell and tube side itself.
Literally speaking, it refers to the design pressure; however, for theoretical and experimental purposes, I believe that test pressure is a more appropriate term. Since the purpose is to test the tube ends, if the test pressure in the shell side is higher than or equal to the test pressure in the tube side due to temperature reasons, then, just like in the conventional testing methods for heat exchangers with fixed tube sheets, there is no need to establish a separate testing method for the tube ends. Personal opinion, for everyone’s discussion and consideration.
You’re absolutely right. If temperature factors are taken into account, and if the test pressure in the tube side is not lower than that in the shell side, then no additional inspection requirements need to be imposed on the pipe fittings. However, the pressure referred to in the standards here is the design pressure
The design pressure for the tube side and the shell side: when the design pressure on the tube side is high, in order to test the welding strength of the tube ends, it is generally necessary to increase the hydrostatic test pressure on the shell side to match that of the tube side. However, this presents a problem – if the design pressures for both sides are too high, the design strength of the shell side may not be sufficient. There are two solutions to this issue: first, if the design strength of the shell side is roughly comparable to that under the increased hydrostatic test pressure, then simply increase the design thickness of the shell side. Second, if the design strength of the shell side is closely related to that after the hydrostatic test, the hydrostatic test pressure can be calculated based on the design pressure of the shell side. Once the pressure test is successful, an ammonia leakage test, or a halogen leakage test, or a helium leakage test can be conducted
This post was last edited by YUNCAI77 on 2018-7-3 at 13:32; it’s repeated