Envirco NSF Biohazard Cabinet User Manual
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Re-certification
It is recommended that the ENVIRCO Biohazard Cabinet be re-certified every six
(6) months and the HEPA filters are replaced if necessary. An Authorized Service
Contractor can provide this service upon request and should be contacted directly.
On-Site Testing Procedure
HEPA Filter Leak Testing
The approved method of testing is to challenge the integrity of the HEPA
filters by introducing a cold polydispersed aerosol
2
upstream from the HEPA
filters while using a light scattering photometer to detect any aerosol
penetration at the downstream surface of the filter.
Test Equipment Required
1. Air operated “Laskin Nozzel” type aerosol generator to produce an
aerosol with a mean particle size of 0.7 micron
2. Light Scattering Aerosol Photometer
3. Silicone RTV
4. Rubber-base solvent cement
5. Silicone stopcock grease
Preparation
1. Remove perforated aluminum diffuser screen at top of work area to
expose the recirculating supply HEPA filter.
2. Open the electrical control panel by removing two bolts at each end. Pull
the rubber tubing off the magnehelic gauge.
3. Disconnect warning buzzer at left-hand side of harness.
4. Remove the work tray.
5. Turn cabinet blower "ON."
6. Locate aerosol generator output hose so that aerosol is fed into the return
air plenum at the back of the work area.
2
NSF 49 (1992 edition)