Under what circumstances is it necessary to conduct a hydrostatic test again
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One of our towers was found at the time of delivery to have the padding plates for the ladder platforms not welded in place, but it has passed the hydrostatic test. Is it necessary to conduct another hydrostatic test after welding those padding plates? Are there any regulations regarding where it needs to be redone?
From a technical standpoint, a hydrostatic test should be carried out; I really haven’t paid attention to where exactly it is specified.
I think there’s no need to do it; it’s not a weld repair. The main body of the container was not damaged. If the body requires overall heat treatment, heat treatment after welding should be considered. If the matrix material has a tendency to crack, then testing and hydrostatic pressure must be considered.
If it’s just a problem with the shims, a new hydrostatic test should not be necessary. Reconducting a hydrostatic test is generally required only when significant repairs need to be made to the shell itself, such as when the shell has to be polished to a certain depth or more.
HG20585-1998 specifies that after the hydraulic test, no welding or other processing that may cause welding stress and notch stress concentration should be carried out on the pressure-bearing components; otherwise, re-applying pressure is required. GB150-1998 states that if a leak is detected during the hydrostatic test, it must be repaired before conducting the test again in accordance with the relevant regulations. I’m very confused; I don’t know if welding the gasket will cause stress or stress concentration at the notches. (No gasket plates will be welded on the weld seam)
It seems it’s not necessary; the shims just need to be welded simply, and this does not affect the safety performance of the main structure.
Equipment with no special requirements should not require further pressure testing.
From a purely technical standpoint, it is necessary to redo it, but in your case, there are two options: 1. Consult your supervisor; if they say it needs to be redone, then you should do so, as your responsibility is to identify problems and propose solutions； 2 Communicate directly with the client or the on-site supervisor; in most cases, there is no need to redo it
Regarding whether to conduct a hydrostatic test, please refer to the regulations on repairs in the Code of Practice.