Keeping up with Air Filtration Industry
UNICA engineering professionals have prepared the text for the publication based on the article published in Controlled Environments in September/October 2016 (www.cemag.us) by Gordon Ely, IEST (Institute of Environmental Sciences and Technology).
About new IEST Air Filtration in Cleanrooms and Controlled Environments practices.
Filter production technologies keep on developing using both traditional (fiberglass) and new (PTFE) materials. New technologies require updating guidelines and practices on filter testing and maintenance.
IEST (Institute of Environmental Sciences and Technology) is an ANSI-accredited standards-developing organization. They provide technical guidance through International Standards, Recommended Practices, and education programs developed by experts in the fields of contamination control, environmental testing, and nanotechnology facilities. Handbook of Recommended Practices Relating to Air Filtration in Cleanrooms and Other Controlled Environments is the last document updated. It includes five Recommended Practices, representing innovations in technologies and evaluation techniques for filters and other devices in controlled environments.
Users and certifying organizations are expected to take advantage from this updates first. The most fundamental changes were made in IEST-RP-CC034 HEPA and ULPA Filter Leak Tests.
The last trend is growing interest for filter lifecycle cost. Community has come to understanding that not only initial equipment cost but also maintenance cost matters.
General conclusions about updated documentation:
IEST-RÐ-ÑÑ001/6 HEPA and ULPA Filters recommended practice describes 11 classes and 5 constructions of filters to be used in compliance with ISO14644 for air filtration in cleanrooms with 99,97% efficiency or higher for submicron particles.
IEST-RP-CC002.4 Unidirectional-Flow, Clean-Air Devices recommended practice describes efficiency evaluation procedures for air cleanliness classification according to ISO14644-1.
EST-RP-CC007-3 Testing ULPA Filters recommended practice contains guidance and testing criteria to evaluate efficiency of ULPA- and super-ULPA filters using particle counters in the facilities.
IEST-RP-CC021.4 Testing HEPA and ULPA Filter Media recommended practice now includes photometric methods of testing in addition to particle counting procedures for evaluating physical and filtration properties of HEPA and ULPA filter media.
IEST-RP-CC034.4 HEPA and ULPA Filter Leak Tests recommended practice describes methods of leak testing of filters for manufacturers and users after being installed in the cleanroom or clean air inlet device. Testing procedures for manufacturers and users are now set in separate chapters.