Pressure for ammonia leak test
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NBT47013.8 states that the method to be used for detecting ammonia leaks is determined based on the space available in the container, but it does not specify any exact volume values Also, when using the method with 10%-30% by volume of ammonia gas for testing, is it up to one to choose arbitrarily between 30%, 20%, 15%, or 10%, or are there certain conditions that must be met? I have set the design pressure at 0.7 MPa; if 10% ammonia is used, the test pressure will be 1.0 MPa. Isn’t that too dangerous?
Concentration 30%, pressure 0.15 MPa, holding time 15 hours. Concentration 20%, 0.30 MPa, holding time 12 h. Concentration 15%, 0.60 MPa, holding time 6 hours. Concentration 10%, 1.0 MPa, holding time 4 hours. The permeation test pressure is related to concentration, and generally has little to do with the design pressure
Upon verification using the test pressure, there are formulas for checking the cylinder and head at 150; the maximum hydrostatic test pressure for pipe flanges is 1.5 times the highest allowable operating pressure at their hydrostatic test temperature.
For ammonia leakage tests, the pressure is set at the higher value specified in the standards, ensuring it does not exceed the design pressure; the higher the value, the shorter the testing time. The smell in the area where these tests are conducted is very strong, which is why no one wants to conduct the tests for long periods of time.
The appendix of HG/T20584 describes the specific test methods