The Principal Investigator is responsible for reviewing this material and determining applicability. Laboratory workers should review the chapter and sign their copy of the LSP Training Sheet . In addition lab spaces are negative in pressure relative to hallways and non-lab spaces to help control spills and keep vapors out of evacuation routes. Fume Hoods Laboratory processes that could create airborne hazards should be performed in a chemical fume hood. Hoods are for worker protection, not storage.
Uncluttered hoods are more effective.
Large equipment in hoods reduces the face velocity and prevents sash movement. If absolutely necessary, position equipment deep in hood and maintain a large air gap around equipment. This is the maximum opening for routine use, hoods should only be raised above this level for set-up. A face velocity of 100 lfm is approximately 1 mile per hour, higher face velocities cause turbulence. For hoods to be most effective users must control traffic and cross drafts which can easily overwhelm the face velocity.