Clean Room Certification - Part 3
By Ralph McBride, MBA, BS Pharm, RPh, BCSCP, HDDP, Pharmacy Surveyor
and Wayne A. Copeland, CEO, CEPA Operations, Inc., and CETA Past President
We continue our look at pharmacy clean room certification requirements that often need further clarification. This article focuses on the HEPA Filter Integrity Test.
USP <797> requires that all HEPA filters located within your classified clean rooms be tested for leaks “in situ,” in place, after initial installation and every six months thereafter. However, the chapter is not prescriptive regarding acceptable methods to accomplish the test. This lack of specificity leaves many providers confused and often results in deficiency findings by accrediting and regulatory bodies.
Why must this test be conducted?
HEPA filtration is an essential component of the clean room’s overall contamination control strategy. It is imperative to verify the filter's integrity, the bond that secures the filter pack to the holding frame, and the seal between the filter frame and the housing and/or overall support structure.
How does the test detect leaks?
The “Certification Guide for Sterile Compounding Facilities” (CAG-0030-2006) established by the Controlled Environment Testing Association (CETA) specifies that an aerosol photometer and a suitable challenge medium are used to conduct the test. The most commonly used challenge medium is poly alpha olefin (PAO), but others are acceptable if properly tested and the output is quantified. When the measured concentration at the face of the filter, bonding, gasket, or structure is greater than 0.01% of the measured upstream concentration, there is a leak.
If my certifier cannot measure the upstream concentration, may they “calculate” the theoretical upstream concentration of upstream challenge?
The answer is found in IEST-RP-CC034.4, which is a recommended practice for leak-testing HEPA filters published by the Institute of Environmental Sciences and Technology and is referenced by CAG-003-2006.
In short, unless you have a system that allows the direct introduction of the aerosol challenge into one plenum for one HEPA filter, you may not calculate the upstream concentration. This includes systems in which multiple filters are fed from one source, such as a low wall return. In these situations, the certifier is required to sample the upstream concentration at each filter plenum using an aerosol photometer.
How is the challenge introduced upstream to the HEPA filter?
Many HEPA filter manufacturers build their filter housings with room-side ports for the introduction of the aerosol challenge. This feature is optional when purchasing the filter housing and its use should be evaluated as to its impact on your testing plan and facility functionality.
If you have an existing HEPA filter or housing without room-side ports, or desire a testing plan that moves the aerosol introduction out of the interior clean room or outside the controlled spaces all together, a remote challenge system can be installed.
Whether you have a clean room in the design phase or an existing clean room, these options should be considered and decided upon before conducting the HEPA Filter Integrity Test. Working with your certifier or design team will ensure you select the best option for your clean room needs.
Bottom line: HEPA filter leak testing is required for any HEPA filter associated with an ISO classified area in the clean room. The test must be performed by your certification company following installation of the HEPA filter and then every six months thereafter.
Next month, our article will focus on staff attendance and participation during the clean room certification process and the importance of reviewing the certifier’s final report regarding compliance with USP <797>.
➡️ Read Part 1: Clean Room Certification Critical to Operations
➡️ Read Part 2: Clean Room Certification - Dynamic Smoke Study Test
➡️ Next month, our article will focus on staff participation during the clean room certification process.
For more information, please contact your Account Advisor, email customerservice@achc.org, or call (855) 937-2242, ext. 458.
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