Discussion and research on correlation of two air tightness testing methods in high-level biosafety laboratory envelope air tightness tests

 In this paper, the pressure decay method and constant pressure method are used respectively to test the air tightness of the envelope in the high-level biosafety laboratory, and the test results are calculated and analysed theoretically.The results shows that for the same test object, for the air tightness calculated by the pressure decay method in a fixed time, there is always a corresponding constant pressure test result based on a certain equivalent pressure difference. However, due to the influence of instrument precision, ambient temperature and test object volume, there are some differences in the leakage rate measured by the two methods. In terms of detection methods, there is no more stringent case between the two methods. In terms of test results, under the premise of clear evaluation criteria of pressure decay method and accurate volume of test objects, if the air tightness test results can meet the evaluation criteria by using constant pressure method and equivalent pressure difference determined by flow index approximately 1.0, the test results of pressure decay method will certainly meet the corresponding evaluation criteria.