Can a pressure test of pipelines be replaced with 100% PT and RT?
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Dear everyone, I have a question: high-pressure pipelines are required to undergo hydrostatic testing, with the test pressure being around 66 barg. Is it possible to skip the hydrostatic testing and instead conduct 100% PT and RT tests? If not, why? Are there any regulations or mandates? Additionally, the material and requirements for the pipes are in accordance with American standards.
Can’t anyone help answer? One more question: for turbine exhaust pipes that are under negative pressure inside and only subjected to external pressure, is there any standard stating that in such cases a hydrostatic test is not required, and that filling them with water to check for leaks is sufficient?
It can’t be substituted; I’ve forgotten which standard it is. Anyway, I’ve seen it before; I welcome experts to provide more details. In short, it means that meeting 3 conditions can serve as a substitute for a hydrostatic test. 1. 100% RT for welds, 2. 100% PT, 3. A very complicated testing method for the material. It seems to be a standard related to welding. Please, experts, add more!
Why not do it? Our maximum pressure is 10,000 psig = 690 bar. But there are very few such projects. Under normal circumstances, all welds are subject to pressure testing. For those weld joints that cannot be subjected to pressure testing, namely the “golden joints”, 100% RT inspection must be carried out, and such weld joints must be clearly indicated on the drawings. It constitutes a potential hazard.
There are some special cases, such as pipes that are modified on-site and do not meet the conditions for hydraulic testing. Well, after all this time, that post has been found too
Is it afraid of delaying production? Tubes always encounter flange connections; the entire pipe section is removed for a pressure test in the workshop. I didn’t even check what year the post was from. :L was still upset, thinking that I had really become a fake product. :'( What was done later?
Yes, they didn’t get in touch with us later and we didn’t know what to do.
Oh, well then, there must be someone in charge who made the decision.
For your question, please refer to the provisions of 8.6.2 in the \"GB 50235-2010 Code for Construction of Industrial Metal Piping Projects\". For reference, 8.6.2 Alternatives to pressure testing shall comply with the following provisions: 1 For GC3 class pipelines, with the consent of the design and construction parties, a pressure test may be conducted using the fluid that will flow through the pipeline during commissioning. When the fluid being transported is a gas or steam, a preliminary test shall be conducted in accordance with paragraph 5 of clause 8.6.5 of these specifications prior to the pressure test. 2 When the design pressure of the pipeline is greater than 0.6 MPa, and the design and construction units consider a hydraulic test to be impractical, a pneumatic test specified in Article 8.6.5 of these specifications may be used as an alternative to the hydraulic test. 3 With the consent of the design and construction units, a hydraulic-pneumatic test may also be used in place of a pneumatic test. The hydraulic-pneumatic test shall comply with the provisions of Article 8.6.5 of this specification, and the pressure in the parts of the pipeline filled with liquid shall not exceed the values specified in paragraphs 4 and 5 of Article 8.6.4 of this specification. 4 When the on-site conditions do not permit hydraulic or pneumatic testing of the pipes, the following methods can be used as alternatives to pressure testing, provided that the consent of the project owner and the design team is obtained: 1) 100% radiographic testing or 100% ultrasonic testing must be carried out on all circumferential, longitudinal butt welds, as well as spiral welds. 2) All welds other than those specified in Item 1 of Paragraph 4 of Article 8.6.2 of these specifications (including the welds connecting pipe supports to pipe components) shall undergo 100% penetrant testing or 100% magnetic particle testing. 3) The design unit shall conduct a flexibility analysis of the piping system. 4) The piping system shall be subjected to leak testing using sensitive gases or immersed liquids, and the requirements for such testing shall be clearly specified in the design documents.
Key points: Design and owner approval; design checks meet requirements; pressure testing verifies not only the welds but also the integrity of the pipeline components
Thank you to everyone who replied above; this post can now be closed~