Manufacturing a filter with HEPA filter media does not mean that the filter itself meets true HEPA
efficiency requirements. Serious filter leakage cant go undetected if filters are not individually
tested and certified at the end of the manufacturing process. Even the tiniest pinhole leaks in the
media or breach of the seal between the media pack and the filter frame can cause the filter to fail
IEST requirements. The testing requires very specific procedures using a thermally generated
mono-dispersed aerosol and a laser particle counter. Some regulations also require field-testing
by the user prior to going into service and periodically thereafter.
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