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A chemical fume hood is designed to capture chemical vapors from containers used inside of the hood and to exhaust the vapors from the laboratory. Get properly trained before you work inside of a chemical fume hood to ensure you are kepping vapors from your breathing zone.

A number of factors about a chemical should be considered when deciding whether or not a chemical fume hood is required. These include a chemical's:

• physical state
• volatility
• toxicity
• flammability
• potential for eye and skin irritation
• odor, and
• potential for producing aerosols

Much of this information is found on the Safety Data Sheet provided by the chemical manufacturer. Complete a full risk assessment of chemicals and procedures before starting any lab work.

A chemical fume hood should be used if any of the following parameters are met:

• airborne concentrations might approach the action level or permissible exposure limit (PEL),
• flammable vapors might approach one tenth of the lower explosion limit,
• materials of unknown toxicity are used or generated, or
• the odor produced is annoying to laboratory occupants or adjacent units.

There are some procedures that can be performed safely on the lab bench outside of a chemical fume hood. Using chemicals on the bench safely depends on the general ventilation available in the area. Common materials used on the lab bech include the following:

• water-based or salt solutions
• very dilute acid, base or other reagents in solution
• liquids with very low volatility
• working with non hazardous solids
• closed systems that do not allow significant escape to the laboratory environment, and
• extremely small quantities of otherwise problematic chemicals.

The procedure and chemical should be evaluated for its potential to increase volatility or produce aerosols. The Lab Supervisor is responsible for assessing the materials in the lab and can contact Risk Management & Safety for assistance during any risk assessment.

Online "Laboratory Ventilation and Chemical Fume Hoods" training should be completed by anyone using a chemical fume hood. A "tell-tail" and sticker is placed on the fume hood sash to indicate that air is being drawn through the sash opening away from the user. If the tell tail is hanging in any other position, or flapping very quickly then the air speed moving across the hood surface may be too strong and maintenance may be required. Submit a Famis Work Request to have your fume hood checked by an HVAC specialist.

Risk Management & Safety provides the following stickers for fume hoods at ¶¶Òõ̽̽:

• Max working height
• Be safe work beyond this arrow
• Side view of hood

Please email us at safety@uvm.edu if it is time to update your fume hood stickers or tell tail.

Visually check that air is flowing INTO the hood befre starting work in your hood. Compare the angle of the tell-tail with the angle on the "Side View of Hood" sticker; the tell-tail should gently float inside the hood at approximately a 45 degree angle.

Fume hoods should never be used above the "Max Height" level.  Only open the hood sash above the max height level to load large equipment into and out of the hood.

Lower the sash all the way down when not using the fume hood.

Part of a laboratory safety project by Dartmouth College & The National Institute of Health "Chemical Fume Hood: How it Works to Protect You"

Chemical fume hoods that are newly installed or moved to a new location must go through an ASHRAE-110 certification prior to use. This takes place once a lab renovation is complete and the lab room air has been balanced properly.

is contracted to perform ASHRAE-110 tests and can certify chemical fume hoods for safe use.