Fume hoods are anaylzed and reported on annually to assess preformance standards. For a list of approved fume hoods click here . The hood operator should determine whether it is functioning before beginning any work. This can be done with an electronic safety monitor or checking the airflow with a thin strip of paper. If necessary adjust the hood baffles properly before setting up any work.
Most fume hoods have adjustable rear baffles.
The total air volume exhausted by the hood will not change when adjusting the baffles. Use of heavier than air fumes are best exhausted with the lower baffles opened. Use of fumes lighter than air or when high loads of heated fumes are generated, it is best to exhaust with the upper baffles opened. Select proper exhaust speed setting. Some fume hoods have a two speed exhaust fan with a local control at the hood.