Envirco NSF Biohazard Cabinet - Manual (Page 21)

21
XI. FILTER REPAIRS
Caution: If the cabinet has been used with infectious agents, decontamination
is necessary before removing access panels.
Shipping movement and handling may cause filter leaks. These leaks can normally
be repaired as follows:
1. Caulking with silicone RTV can usually repair small leaks in the filter media
or at an adhesive joint from the downstream side of the HEPA filter.
2. Leaks at gasket seal may also be stopped with the RTV sealant on the
downstream side. If leaks cannot be stopped from the downstream side, the
cabinet access panels must be removed.
3. To seal major leaks in gasket or filter media, first remove main access panel
then the inner filter access panel to expose upstream side of filter. Remove
filter and seal leaks by pouring rubber base cement down into leaking area.
Check for separation at gasket corners and repair with silicone RTV. Put
silicone grease on gasket surface before re-installing filter to improve gasket
seal.
4. Re-install filter access panels, and retest. Put silicone grease on exterior
door gasket before re-installing on the cabinet. Do not over-tighten access
panel screws. Replace the tubing on the magnehelic gauge and reconnect
the warning buzzer. Replace the filter screen and exhaust damper housing.
Set the damper with blades about 3/8 inch open to begin airflow adjustment.
Figure 7: Supply HEPA Filter