Inspection test pressure for air cooler
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I would like some advice on how to determine the test pressure for the tube bundle during the maintenance of air coolers.
The test pressure is determined as 1.25 times the design pressure or 1.25 times the operating pressure.
Our approach is to pressurize the new tubes to 1.5 times the operating pressure. The old tube bundles are pressurized to 1.2 times the operating pressure.
As for the test pressure for air coolers, in my opinion, it is necessary to determine whether the air cooler is considered as a standalone unit or as part of a system. (1) If used as a single unit, the standards for air coolers specify that the hydraulic testing of such air coolers shall be carried out in accordance with the requirements of GB 150. In accordance with the requirements of GB 150, 1.25X design pressure X (allowable stress at the pressure test temperature/allowable stress at the design temperature) ； (2) If it is incorporated into the system and a hydraulic test is conducted on the entire system, it shall meet the requirements for pipeline hydraulic testing.
Is there also this statement (2)? Pipe testing generally allows for the inclusion of associated equipment, but it must be carried out separately (the equipment and the pipes are tested individually). Airtightness tests can be carried out uniformly across the system.
There are cases where separation is not possible; for example, in long-distance pipeline projects, it is explicitly required that the equipment meet the requirements for overall pressure testing of the pipeline. Therefore, when designing the air coolers for long-distance pipeline booster stations, it is explicitly specified that these air coolers can undergo pressure testing as part of the pipeline as a whole.
According to GB150-2011, hydraulic testing is performed on externally pressurized vessels, with P_test = 1.25P_design； Pneumatic testing or a combination of pneumatic and hydraulic testing; P_test = 1.1P_design – the pressure used for airtightness testing is equal to the design pressure~~
I really haven’t heard of it being possible to pressurize the pipelines together; I need to learn about it*
Pressurize separately at 1.25 times the design pressure. The entire system is subjected to a comprehensive airtightness test before it is put into use