HEPA h13 and h14 efficiency standards

For the unidirectional flow of ISO5, use ISO40H class (99.99% retention rate of low-penetrating particles) high-efficiency filters.



For non-unidirectional flow below ISO5, use ISO35H class HEPA filters (99.95% retention of low penetrating particles).



ISO35H and ISO40H class filter retention efficiency standards are as follows:



1. The high-efficiency filter at the end of the air-conditioning system (including the partition of the filter with a partition) should not use hydrophilic materials, and it is not suitable to use materials that are easy to breed microorganisms;



2. The filter materials of high-efficiency filters h13 and h14 are generally glass fibers, but they should not contain glass fibers with high sodium and potassium content that are easy to recede;



3. A pre-filter should be set up in the air supply system, and the pre-filter retention efficiency should not be less than 90%;



4. The pre-filter section should have a simple and practical resistance monitoring device, which accurately and intuitively gives information on filter replacement.



High-efficiency filter specification parameters are complete, what are the methods of leakage detection?



1. Using the particle scanning method can consider several groups of high-flow sampling head integration or the use of multiple counters to save time;



2. HEPA filters h13 and h14 do not block 100% of particles, e.g. a filter with 99.99% efficiency means that there is no more than 0.01% leakage overall;



3. Filter refinishing: In general, it is not recommended to refinish filters at the installation site.