Chemical Fume Hoods
Chemical Fume Hoods
1. Chemical Fume Hoods are ventilation devices that capture chemical vapors and ventilate them outside the building. This differs from a Biological Safety Cabinet that are designed to filter biological agents and other particulates out of the air circulating inside the cabinet. (Biological safety cabinets will be covered in a separate module.) It is important that all potentially harmful chemical work be conducted inside a properly functioning fume hood.
2. Self Contained Hoods (below, left) generally have a circulating fan mounted on the top of the hood, or beneath the workspace. Air is pulled through a filter in the front opening of the hood, before passing through the fan and pushed back into the contained workspace.
3. Perchloric Acid Fume Hoods Perchloric acid hoods are designed and constructed with corrosion resistant surfaces, ductwork, fan to withstand the caustic and corrosive effects of the acid. They are also constructed with a wash-down system. They have special regulations regarding their use and require specific fume hood use protocols. If you have questions or concerns about working with perchloric acid within a fume hood contact EHS for further guidance.
4. Floor Mount Hood is a chemical fume hood which sits directly on the floor and is characterized by a very tall and deep chamber that can accommodate large pieces of equipment. If you have a floor mount hood, contact EHS for operating protocol and inspection procedures.
5. Canopy Hoods are horizontal enclosures having an open central duct suspended above a work bench or other area. Canopy hoods are most often used to exhaust areas that are too large to be enclosed within a fume hood. The major disadvantage with the canopy hood is that it primarily ventilates and rather than contains. Meaning that contaminants are drawn away from the user's breathing zone but are not specifically contained and remain a risk factor.
6. Biological Safety Cabinets are designed to filter biological agents and other particulates from the air circulating inside the cabinet. This is different from a chemical fume hood that is designed to capture chemical vapors and ventilate them outside the building. If you are going to use or are using biological materials, please contact EHS for further information.
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Date last modified: April 2, 2009.
Developed By: KU Department of Environment, Health & Safety, www.ehs.ku.edu/
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