12-04-2014, 11:39 PM
We are installing a BSL3 lab in a Institute in India.
Working of the system is: Fresh air is cooled in an Air Handling Unit filtered in 3 stages, 10micron, 5micron & 0.3micron (HEPA) and supplied to the room. Room air is exhausted into the atmosphere after HEPA filtration. The exhaust quantity is controlled by a VFD based on the Negative pressure to be maintained in the room. This system works fine.
There are 2Nos Biosafety Cabinets(BSC) (TypeA2) in the room that exhaust 30% air after HEPA filtration. The ducts are conneted by Thimble connection and connected to the same duct that exhausts the room air.
Is this correct or should we connect the BSC exhaust to dedicated exhaust blower? Even our exhaust system is a dedicated exhaust system for this room.
In our arrangement we have a few advantages viz. additional stage of HEPA filtration of BSC in the exhaust AHU; proper exhaust of air from the BSC through thimble connection, as power of room exhaust suction is more than that of individual blower for the BSC; the preset room negative pressure controls the quantity of air exhausted from the room, there is better control when air is exhausted through one blower; finally the room exhaust blower has a UPS backup to maintain the room at negative pressure for 15minutes or so even when there is power outing, in our case the BSCs also get this advantage (during sudden power outage air from the BSC workarea can come into the Lab and contaminate the room & occupants)
Kindly clarify if the arrangement we have done is good enough or should we go for separate exhaust system for the BSCs.
Working of the system is: Fresh air is cooled in an Air Handling Unit filtered in 3 stages, 10micron, 5micron & 0.3micron (HEPA) and supplied to the room. Room air is exhausted into the atmosphere after HEPA filtration. The exhaust quantity is controlled by a VFD based on the Negative pressure to be maintained in the room. This system works fine.
There are 2Nos Biosafety Cabinets(BSC) (TypeA2) in the room that exhaust 30% air after HEPA filtration. The ducts are conneted by Thimble connection and connected to the same duct that exhausts the room air.
Is this correct or should we connect the BSC exhaust to dedicated exhaust blower? Even our exhaust system is a dedicated exhaust system for this room.
In our arrangement we have a few advantages viz. additional stage of HEPA filtration of BSC in the exhaust AHU; proper exhaust of air from the BSC through thimble connection, as power of room exhaust suction is more than that of individual blower for the BSC; the preset room negative pressure controls the quantity of air exhausted from the room, there is better control when air is exhausted through one blower; finally the room exhaust blower has a UPS backup to maintain the room at negative pressure for 15minutes or so even when there is power outing, in our case the BSCs also get this advantage (during sudden power outage air from the BSC workarea can come into the Lab and contaminate the room & occupants)
Kindly clarify if the arrangement we have done is good enough or should we go for separate exhaust system for the BSCs.