HEPA Filter Storage

*Glass Fiber HEPA filter shelf life.

Much study has been conducted with regard to the storage of HEPA filters and still our industry does not fully understand what would constitute an acceptable shelf life.
What is understood regarding HEPA storage?
1. Storage temperature should not exceed 120°F and should not fluctuate widely e.g. outdoors in trailers or sheds without climate control.
2. Storage humidity should not exceed 80% or fluctuate widely.
3. Filters should be stored with pleats orientated vertically so that the media is not placed under unnecessary stress.
4. Filters should be stored in manufacturer’s original packaging in a location that will not require frequent movement. Shock damage could occur to the delicate media from constant movement.
5. Media damage can occur from storage areas that come into close proximity with accidental fluid or chemical spills, spraying or fire.
If any adverse storage has occurred it is advisable to have your supplier or an independent test facility review the filters and if acceptable supply re-certification test data. Due to the aging effects on binder materials and possible uncertainty regarding storage conditions it is recommended that filters having been in storage for long periods are re-certified if they may be needed for critical applications or emergency situations. These recertification tests should not only test the filter efficiencies but also the mechanical integrity of the seals and media. Contact filter manufacturer for advice on testing for recertification.

*Note this discussion is related only to Glass Fiber (mechanical) HEPA filter media. The electrostatic charge of synthetic filter media is known to degrade under certain conditions and would require separate study.