Fume hoods are an essential part in laboratories as the local exhaust/containment device and one of the most reliable engineering controls. With proper installation, maintenance, and usage, a well-designed hood offers extensive protection to the user
Successful hood performance is dependent on the face velocity of air entering the fume hood’s sash opening. The following factors affect the hood’s speed by:
cross-drafts created by the surrounding environment (movement of people, user’s presence, or hood and air currents from open windows and doors)
- amount and location of equipment in the hood
Basis for having a successful design of a fume hood is having a face velocity in the range of 60-120 ft/min. Too low a face velocity will not provide adequate exposure control while too high of a face velocity will increase turbulence and cause contaminants to escape.
Adequate personnel training must be provided when using ventilation equipment. Here is a partial list of guidelines for same fume hood use:
Chemicals, equipment not used, or waste, should not be stored in the hood.
Chemical waste should not be disposed of by evaporation in a hood.
Heads should be kept outside of the fume hood. ‘Walking in’ in an operating hood is not advised.
Fume hood’s sash should be as low as possible or below the indicated operating height when in use.
Check airflow through the hood face periodically.
Rear hood exhaust slots should be free from blockages.
Combustibles or any material that restrict airflow should be kept out of the hood.
Perchloric acid in a fume hood not explicitly designed for this purpose should never be used.