For a better experience, click the Compatibility Mode icon above to turn off Compatibility Mode, which is only for viewing older websites.

Chemical Fume Hood


A well-designed chemical fume hood, when properly installed and maintained, offers a substantial degree of protection to the user, provided that it is used correctly and its limitations are understood. Work involving chemicals with high vapor pressures or low occupational exposure limits (OELs) must always be done within a chemical fume hood.

The required face velocity for chemical fumes hoods at the university ranges from 80-120 feet per minute (fpm) with an optimum face velocity of 100 fpm at a sash position of 18 inches. During use, the sash should be opened to 18 inches or less; each chemical fume hood is labeled to indicate this position.

An audible and visual air flow alarm is present on the face of each chemical fume hood. This alarm indicates whether or not the chemical fume hood has sufficient exhaust. The alarm will provide an audible signal and a red light when the exhaust is not sufficient. In addition, some chemical fume hoods have sash position alarms to prevent the personnel from working with the fume hood sash in the full open position.  The sash must be returned to the eighteen (18) inch mark to clear the audible and visual alarm.

Work must immediately stop if the air flow alarm is activated. Contact EH&S at 215-895-5919 or via email at

Review the Chemical Hygiene Plan or Laboratory Safety Manual for a detailed discussion on the proper use and limitation of chemical fume hoods.