Regarding equipment strength and airtightness testing issues
Thread Content
There is an enamel-lined reaction vessel with a design pressure of 0.4 MPa, but the normal operating pressure is at atmospheric pressure. The medium contained in this vessel consists of explosive and toxic substances. After it was installed, the deputy general manager (chief engineer) required that strength tests be conducted at 0.3 MPa and airtightness tests at 0.2 MPa. The reasoning behind this was that the manufacturer had already carried out the relevant tests in accordance with the design requirements at the time of production; since normal operation takes place at atmospheric pressure, there is no need to use 1.5 times the design pressure for hydraulic tests, nor is it necessary to use the design pressure for airtightness tests
I think such a proposal makes sense from time to time, because your design pressure is 4 bar, and you always need to test whether what you’ve purchased is worth it. If it’s at atmospheric pressure, why is the design set at 4 bar? I don’t know much about enamel products, but most customers prefer to think that way.
This post was last edited by realben on 2010-4-1 at 12:25. If your enamel-lined reactor is a pressure vessel and falls under the scope of relevant regulations, it should undergo a hydrostatic test at 1.25 times the design pressure; if it is not a pressure vessel and there are no requirements specified in the design drawings, then no such requirement exists. If, as you say, the manufacturer has already carried out pressure resistance and airtightness tests, then in my opinion there is no need for a pressure resistance test after installation, but an airtightness test is still necessary.
If it’s meant to be used as a pressure vessel at normal pressure, then why is it designed to withstand such high pressures? It’s not cost-effective to spend money on something that isn’t reliable. Just do what the regulations require
So you need to check whether the pressure test carried out by the equipment manufacturer is done in a horizontal or vertical configuration, as there is a difference between the two; for 10 meters, the pressure is 1 KPa. This is specified in the technical requirements for equipment manufacturing, inspection, and acceptance; you can check it there.
This involves testing after on-site installation; a leak test is sufficient, but the test pressure should be in accordance with the design pressure specified in the regulatory standards.
The operating pressure is at atmospheric pressure and is not subject to the containment regulations. With a design pressure of 0.4 MPa, it shall be designed in accordance with GB150. According to GB150, a pressure test must be conducted after the container is manufactured, usually using water as the testing medium, and the test pressure shall be specified. If the medium is highly or extremely toxic, a airtightness test shall be carried out, typically at the design pressure. If the corresponding tests have been carried out at the manufacturing plant, a hydrostatic test may not be necessary after the overall installation on site; however, it is required if the system demands it (such as for inspecting the final pipe welds, with the test pressure also determined according to the system requirements). A airtightness test should generally be conducted to check the sealing quality of various connections. It is likely that the pressure test conducted on this container on-site did not reach the minimum test pressure required by the standards (no calculation was carried out); it was not designed or manufactured in accordance with the standards, and this is related to the value of the design pressure.
The pressure test pressure for glass-lined equipment seems to be equal to the design pressure.