Sequence of helium leak testing and pressure testing
Thread Content
As the title suggests, which comes first, helium leak testing or pressure resistance testing? What is the reason? Especially for heat exchangers.
Generally, a pressure resistance test is carried out first, which mainly checks the strength and stiffness of the equipment. Helium leak testing is used to determine whether there are any leaks in the weld joints between the tubes and the tube sheets; it belongs to the category of leak tests, in accordance with the regulations for 150.
As stated in the GN version, the pressure test is carried out to verify strength, stiffness, and sealing performance, whereas ammonia leak detection and helium leak detection are used only after the hydrostatic test on the shell side has been successful, with no leaks existing elsewhere on the shell side aside from those at the pipe joints, and when the pressure test cannot determine whether there are leaks at the pipe joints; therefore, the pressure test must be conducted first.
Whether it’s from the front or the back, what everyone says makes sense. Moreover, the various regulations at present are rather chaotic. It would be better for the owner to specify the details in the technical requirements based on the actual conditions of the equipment and those of the manufacturer.
Helium leak testing is performed after the pressure test; this is normal； Unless the company’s quality management is out of control and there is a high risk of leakage, PT inspections should be conducted first
This post was last edited by HSLJHZ on 2019-7-16 at 13:57. I agree with the view expressed regarding sofas: generally, a pressure resistance test is carried out first, which is mainly used to assess the strength and stiffness of the equipment. Helium leak testing is used to check for leaks in the weld joints between pipes and tube sheets; it falls under the category of leak tests.
This question can be done first or later. First, it is to prevent a water seal from remaining after the water pressure is applied, as this could affect judgment ； If you pressurize the water and then remove the moisture, it’s also possible to do that after pressurizing the water.
Regarding the welding of tubes and tube sheets that are inspected in heat exchangers, it is recommended to carry out this work before the hydrostatic test: 1) It is difficult to ensure that there is no moisture left after the hydrostatic test, and moisture can affect the results of helium leak detection. 2) If repairs involving hot work are carried out, a repeat hydrostatic test may be required for verification.