Hydraulic test of modified equipment
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To comprehensively assess the reliability of the equipment, a hydrostatic test must be conducted after it has been manufactured. I would like to ask everyone to discuss whether, in the case of modifying equipment (assuming the equipment has a large diameter but low pressure), and merely making an opening of moderate size in it, a hydrostatic test is still required What are the criteria everyone uses to decide whether a hydrostatic test is necessary?
Special tooling can be used to perform a hydrostatic test near the opening
The hydrostatic test is a pressure resistance test for equipment; for modifications that do not affect safety in use, and when the equipment is not considered a pressure vessel, there is no issue with stress. I think it’s not necessary to conduct a hydrostatic test.
There’s no discussion possible – regulations are regulations, and hydraulic testing must be carried out, no matter how low the pressure. It is clearly stated in the relevant regulations that \"for the purpose of protecting people’s lives and property safety,-----------------\", and there can be no compromises.
Personally, I think it would be best to conduct a hydrostatic test if possible. If there are practical reasons that prevent the conduct of a hydrostatic test, then, provided that there are no issues in other areas, it is possible to raise the requirements regarding the material of the new connection points, as well as the welding standards (full penetration construction) and the inspection criteria. User consent is also required. For reference only
If the pressure is low, a hydrostatic test is not necessary, but non-destructive testing can be carried out.
It is recommended to conduct gas-liquid combined tests, which would be more appropriate.
For such equipment, it is generally possible to weld a temporary pressure test head inside the device at the opening, and conduct local hydrostatic tests on the newly added connections, including the corner welds of these connections as well as their flanges. If the pipe end dimensions meet the requirements, 100% non-destructive testing using radiography or ultrasound can be carried out on the internal welds of the pipe fittings, and 100% non-destructive testing of the welds between the pipe fittings and the flanges can be used as a substitute for hydrostatic testing.
This post was last edited by jizhanwei22 on 2016-6-15 at 16:00. The parameters listed by the original poster are not detailed; there are hardly any parameters at all, just a brief description. I don’t even know if this device is a pressure vessel! ! When considered as pressure vessels, according to the brief descriptions and the detailed provisions of the Pressure Vessel Regulations, major repairs to pressure vessels refer to the replacement, reshaping, patching, and welding of the main pressure-bearing components. How large is the large opening mentioned in the original poster’s brief description? If the nominal diameter is ≥250, it is considered a primary pressure-bearing component as specified by the fixed gauge. Therefore, according to the fixed-volume regulations, a pressure resistance test must be conducted. In addition, non-destructive testing and post-weld heat treatment (if any) must be carried out. All of the above actions must be subject to the written approval of the original design unit or a design unit with corresponding capabilities. Furthermore, the units engaged in the installation, modification, and repair of pressure vessels must be those that possess the appropriate qualifications. If it is not treated as a pressure vessel, approval from the original design unit is still required ； I can’t wait any longer, you know...
The above response is fairly comprehensive; the design firm agrees, the owner agrees, and the relevant regulatory provisions allow for it to be omitted. But it is estimated that no design firm is willing to take on this responsibility.