Different criteria also differ in the determination of leak detection results.
The US IEST-RP-CC034 stipulates that the on-site leak detection rate of the C, .D class high efficiency filter is 0.3 um, and the photometric scanning leak detection method is 0.01. The European Union EN1822 stipulates that the leak test is qualified as long as the local transmittance of the tested filter does not exceed the specified local value. The local transmittance of the H13 high-efficiency filter is 0.25%, but it should be noted that the transmittance here is It was obtained by a 0.3 um monodisperse phase DOP test. In the “clean factory design code GB50073-2001 and high efficiency air filter GB13554-92” in China, the leak test of the installed filter, the use of atmospheric dust or other aerosols, the use of particle counters to measure the leakage concentration.
For high efficiency filters, the penetration rate should not be greater than twice the acceptable pass rate of the filter. For the leak detection test of HEPA in pharmaceutical companies, in the actual test, if there is a leak, the photometric count value will increase significantly and it is easy to judge. The high-efficiency filter leak rate standard is set to 0.01% or less and does not affect the detection of actual leaks.