1-1 A Professional advice
There is a poor balance between the amount of air being discharged from the room and the amount of air being supplied to the room. If there is insufficient air supply, the room will be at negative pressure; if there is insufficient exhaust, the room will be at positive pressure, so there will be a wind noise and air will come and go suddenly when the door is opened.
What is common in the laboratory is that even if the exhaust fan of the fume hood tries to exhaust indoor air, but the room is under extremely negative pressure because no adequate air is supplied.
In such a case, it is the same as taking out air from an sealed container, so the required removal of air becomes unattainable, and thus the fume hood loses its efficiency, which affects safety.
It is therefore necessary to check that the air supply system is working properly and that gullies and filters that take in the air supply are not clogged..
1-1 Advice for Initioal support/correspondence
In cases such as when the room is under extremely negative or positive pressure, the most probable cause is the imbalance between air supply and exhaust.
Let’s check these points such as whether the switch for the air supply/exhaust equipment has been turned off, whether the laboratory air supply/exhaust fan is properly operating, and whether the air filter on the air supply side (if present) is clogged.
First of all, let’s check in the room if there is anything different from usual.
Next, check the equipment inside and outside the room.
Consult with the person-in-charge or supervisor of the laboratory, and inspect the condition of the supply and exhaust equipment associated with the laboratory.
