Pressure test issues
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Experts, I have a question I’d like to ask you: For the SZL15-1.6 type boiler, which is a coal-fired horizontal double-drum vertical chain steam boiler with a working pressure of 1.6 Mpa and a capacity of 15 tons, according to the relevant boiler standards, during the overall pressure test, the pressure should first be raised to 1.6 Mpa and held at that level for observation; then it should be increased to the test pressure of 2.0 Mpa (1.25 times the working pressure), and held at this level for 20 minutes; finally, the pressure should be reduced back to 1.6 Mpa and held there for a sufficient length of time. If the pressure is maintained at the test pressure of 2.0 Mpa for more than 20 minutes, say up to 10 hours, will it have a negative impact on the boiler? How should it be dealt with?
Pressure has little impact, but attention should be paid to the test temperature to prevent brittle transformation.
Hello! Thank you for the answer. But I want to ask: Why is it said that stress has basically no impact? Is the national standard 20 minutes?
Because the test pressure is calculated to be greater than the allowable stress. According to the regulations, it should be understood as no less than 20 minutes; the current approach is to maintain the pressure for a sufficient length of time
Thank you for the reply! The regulations state that it should be held at the test pressure (under overpressure) for 20 minutes; based on the way the information is presented in the relevant sections of the boiler regulations, it indeed should be understood as 20 minutes. The holding pressure should be at the design pressure for a sufficient length of time. I’m not sure if this understanding is correct!