Envirco NSF Biohazard Cabinet - Manual (Page 18)

18
Testing
1. Calibrate the photometer with the aerosol generator so that the upstream
concentration is 100 percent. The upstream concentration for all HEPA
filters may be sampled by removing the pipe plug from the penetration
provided on the top front of the cabinet and inserting the photometer
probe in the penetration fitting. Set the photometer to ZERO and verify
the 100 percent upstream and zero downstream readings are achieved.
Set the range switch to read a minimum of 0.01 percent.
2. Carefully scan the faces of the recirculating supply and exhaust filters,
particularly around the edges of the sealing gaskets and adhesive seal.
Hold photometer probe about one inch from the filter surface and scan at
about two inches per second.
3. Identify and repair any leaks greater than 0.01%.