Fume hoods capture, contain and expel emissions generated by hazardous chemicals. They protect against spray and splash and facilitate the renewal of clean air.
The purpose of fume hoods is to prevent the release of contaminants into the laboratory. This is achieved by drawing air from the laboratory into the fume hood through the operator.
The ability of the hood to provide adequate protection depends on the following controls:
- Velocity control at the front of the hood (flows 80 to 100 feet per minute)
- Air movement and flow path in the room (directly related to the location of the hood in the room).
- Effect of the operator's presence on the flow path at the front of the hood.
- Turbulence inside the hood.
Recommendations for the use of fume hoods:
- Work should always be at least 15cm away from the hood frame.
- The fume outlets of the reactors should be directed towards the inner wall and, if possible, towards the hood ceiling.
- The hood should not be used as a storage area for chemicals. The work surface should be kept clean and clear.
- Caution should be exercised in situations that require lowering the sash window to achieve a minimally acceptable face velocity. The window should be placed within 50cm of the work surface.
- Fume hoods should always be in good working condition. The operator should not detect strong odors coming from the material inside. If they are detected, make sure that the extractor is in operation.