Fume hoods, more properly referred to as chemical hoods, are often the primary control device when using flammable and toxic chemicals in the laboratory.  They are intended to contain contaminants within the hood and exhaust the contaminated air outdoors.

Testing of Chemical Hood Exhaust

Prior to occupancy of newly constructed research facilities, a Test and Balance contractor ensures that chemical hoods are functioning according to design specifications.  After occupancy, DEHS tests the airflow of chemical hoods at least annually.   If deficiencies are found the information is forwarded to Physical Plant to initiate repairs.  The yellow hood certification label affixed on the left side of the hood indicates the most recent test date of the hood.  If your hood has not been retested by the expiration date, contact the Industrial Hygiene Manager.

Daily Monitoring of Hood Exhaust

Chemical hoods should be equipped with an air flow monitor/alarm.  Older hoods may not have a monitor/alarm and should have, at a minimum, a plastic "flow check ribbon" installed on the sash.  When there is proper exhaust flow the ribbon is drawn gently inside the hood.  Be alert to the monitor or ribbon.  If there is a problem with the hood, contact the Physical Plant Work Control office for repair.  If your hood does not have a flow monitor or flow check ribbon, contact the Industrial Hygiene Manager.

Biological Safety Cabinets

Chemical hoods should be differentiated from Biological Safety Cabinets (BSC's), "culture hoods" and clean air benches, which have a HEPA-filtered, laminar flow supply component that protects specimens/products inside the cabinet from contaminants in the laboratory ambient air.  BSC's may also exhaust contaminants outside the building, but more commonly recirculate HEPA-filtered exhaust air back into the lab.  For this reason recirculating BSC's do not provide personnel protection from flammable and toxic gases and vapors.  For more information on certification requirements and proper use of BSC's see Biological Safety.