Background: Containment Level 3 (CL3) laboratories may require boundary integrity testing. Existing guidelines for CL3 room leakage are often subjective, lacking a definitive standard for what constitutes a "sealed" room.
Methods: This study reviews global biocontainment guidelines and standards, and it compares multiple test results from global CL3 facilities by standardizing test data to an equivalent test pressure of 250 Pa.
Results: Our analysis revealed that 55% of rooms constructed using typical CL3 methodologies met the proposed testing criteria. The United States Department of Agriculture (USDA) Agricultural Research Service (ARS) greenhouse leakage rate acceptance criterion of 0.139 L/s per square meter (0.027 cfm per square foot) at a room differential pressure of 250 Pa was found to be a challenging, yet achievable standard.
Conclusions: A two-step process is recommended for boundary integrity testing: (1) Initial leaks are identified using smoke pencil or soap bubble tests, followed by necessary repairs; (2) The room is then subjected to quantifiable leakage rate testing to verify it meets minimum requirements. In the absence of definitive local guidelines, we recommend the published ARS greenhouse leakage rate at a room differential pressure of 300 Pa of 0.152 L/s per square meter of surface area as an acceptable criterion for testing construction boundaries of CL3 laboratories built using current CL3 construction practices. For primary containment CL3 rooms, a more stringent criterion following the German Verein Deutscher Ingenieure guidelines at a room pressure differential of 250 Pa is noted as 0.03620 L/s per square meter of room surface area is more appropriate.
Keywords: containment; design; integrity; leakage; testing; validation.
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