How to conduct the pressure test and leak detection of the air separation plant?

Both pressure test and leak detection are the air tightness inspection of the air separation plant. Its purpose is to examine the quality of installation, piping and welding. There are two kinds of pressure tests for the air separation plant: one is strength pressure test, which tests the safety of the equipment. Generally, the single equipment is carried out before installation after the manufacturer or the equipment arrives at the site. The second is air tightness test, the purpose is to check leakage. Generally, the whole system pressure test during the installation of the air separation plant refers to the latter one. The pressure level and test method of the air tightness test are different according to the tested object, and should be conducted according to the technical documents of the manufacturer. Generally, after the installation of the air separation plant, the whole system pressure test should be conducted and the residual rate should be calculated. If the residual rate is required to be above 95%, it is qualified. The calculation method of residual rate is as follows:
A=P2•T1/(P1•T2)
In the formula, A -- residual rate, %;
P1 -- the absolute pressure of gas before stopping pressure, MPa;
T1 -- the absolute temperature of gas before stopping pressure, K;
P2 -- the absolute pressure of gas after stopping pressure, MPa;
T2 -- the absolute temperature of gas after stopping pressure, K.