Local exhaust ventilation is the primary method used to control inhalation exposures to hazardous substances. Chemical fume hoods are the most common local exhaust method used in laboratories at Rensselaer.
When operating and used properly, chemical fume hoods:
- Prevent flammable, toxic and/or offensive vapors, fumes and odors from entering the general laboratory.
- Provide a physical barrier between the laboratory worker and the chemical experiment, when the hood sash is lowered.
- Provide a certain degree of spill containment in the event of a release.
- Confirm that the fume hood is operational either by checking the air flow gauge if so equipped, or “floating” a piece of tissue paper to check air flow. Face airflow should be between 60 and 100 linear feet per minute.
- To avoid turbulence at the sash edge and to allow for greater protection, keep your work at least 10 cm (4 in.) back from the edge of the sash.
- Instruments and/or apparatus should be raised off of the floor of the work surface to allow proper airflow through the hood.
- Fume hoods should not be used as storage cabinets for chemicals or equipment.
- Waste containers in fume hoods must be properly labeled and closed, except when adding to the container.
- Apparatus in hoods should be fitted with condensers, traps or scrubbers to contain and collect waste solvents, toxic vapors or dusts, before the exit gases are released into the hood system.
- The sash should always be kept in the lowest possible position, thus minimizing the face opening and exposure potential.
- Foot traffic at the face of the fume hood should be kept to a minimum as individuals walking in front of the hood can disrupt the airflow within the hood.
- Items such as hot plates, controllers, open flame devices and electrical connectors must be certified, and labeled, as being intrinsically safe for operation within a chemical fume hood.
- Your head should never cross the plane of the hood sash when you are dismantling equipment or at any other time.
Temporary shutdowns of fume hoods may be required for scheduled inspections, maintenance and roof access where exhaust system shutdown is required.
Temporary Shutdown of Fume Hoods: Instructions for Laboratory Personnel must be followed when laboratory personnel are informed by Facilities Customer Service Center (FIXX), Environmental Health & Safety (EHS), or a Building Coordinator that a temporary shutdown of fume hoods is necessary.
Chemical Fume Hood Shutdown Notice may be posted by Building Coordinators or laboratory supervisors to inform laboratory personnel and building occupants that the fume hood may not be used during the shutdown timeframe.
A number of buildings require fume hood exhaust ventilation to be shut down for the roof to be accessed. Roof Access Procedure - Fume Hood Shutdown identifies the steps required for a shutdown of this equipment to occur and can be used as a reference for when a fume hood shutdown occurs.
