Fume Hoods

Louisiana State University has approximately 1,000 fume hoods located on the main campus and various auxiliary sites.

Fume hoods are critical to the safety of researchers, faculty, and students, as they provide the primary means of preventing exposure to airborne hazardous materials on campus. Therefore, it is extremely important that the hoods be maintained in good working order.

All laboratory fume hoods are inspected annually by the Office of Environmental Health and Safety (EHS) according to requirements of National Fire Protection Association (NFPA) “45 Standard on Fire Protection for Laboratories Using Chemicals”; and University Policy Statement 19. The State Fire Marshall’s office routinely inspects laboratory hoods to insure that annual inspection requirements have been met.

If you suspect a problem with your hood or the inspection sticker is expired (over a year from the current date),call EHS at 8-5640 or email: Tom Walsh, Safety Officer, Environmental Health and Safety. Fume Hood Inspection Procedure Per NFPA guidelines referenced above, the following items are inspected on each hood.

  • Body – The exterior and interior body/frame is examined for damage(s) that could impact safe operation.
  • Sash – The sash is examined for damage (glass breakage, sticking, etc.). Hoods requiring multiple vertical sashes are observed to determine if an adequate number of sashes are in place (usually a minimum of 3). If present, the sash alarm is tested.
  • Bench-Top – The hood bench-top should NOT be used for routine storage of hazardous materials if it is being used as a protective working surface. If a hood must be used for routine storage, it should be labeled appropriately and NOT be used as a protective working surface. Equipment and/or other materials on the bench-top should not block air flow into the hood.
  • Light – The hood light must be working.
  • ID Number(s) – Exhaust fan and/or equipment ID numbers are observed and recorded.
  • Face Velocity – Face velocity is tested with a calibrated flow meter to insure that it meets minimum face velocity requirements as follows.
    • 85 feet per minute (fpm) for handling extremely hazardous materials, and
    • A minimum of 50 fpm for handling any hazardous material
    • Less than 50 fpm is unacceptable.
  • Note: Hood face velocity measurements are taken with the sash fully open to insure that the OSHA recommended velocity of 100 fpm is attained when the sash is moved to various user working levels. However, a fume hood may be tested at a lower sash height, perhaps increasing the flow rate to permissible levels, if the following requirements are met: 
    • A functioning airflow warning alarm is in service; or
    • A mechanical device limiting sash elevation (Sash-Stop) is installed with a warning sign posted to indicate sash height limitations.

Caution and Danger Warning Signs

Hoods found to have serious deficiencies are posted with warning signs to indicate usage limitations (see below). Since hood face velocity (average flow rate of air being pulled into the hood) is the primary function necessary to prevent exposure to airborne hazardous materials, insufficient face velocity most often results in warning signs being posted to limit or restrict use of the hood. 

Caution Sign Clarification

If EHS determines the hood face velocity to be less than 85 fpm, but above 50, a "Caution" sign is posted to warn users that the face velocity does not meet requirements for handling extremely hazardous materials with a high degree of hazard.

However, the hood may still be used to handle materials that are not considered extremely hazardous (low degree of hazard) as determined by the researcher or other responsible person knowledgeable with the hazard(s).

Questions regarding the degree of hazard may be directed to EHS.   

Danger Sign Clarification

If hood face velocity is found to be less than 50 fpm, a "Danger" sign is posted to warn users that the hood has been "placed out of service"  and cannot be used for handling any hazardous material until repaired.

A  "Danger" sign may also be posted if a hood is otherwise determined unsafe for use.

Repair Procedure

Fume hood deficiencies requiring repair are reported to Facility Services through the MAXIMO Work Order system and are tracked by EHS to completion. On completion of the work order, EHS re-inspects the hood to insure that all requirements are met.

Once a hood has passed inspection, a sticker is placed on the hood (usually on the frame) as shown below. The inspection date should not be expired and the face velocity should be 85 fpm or greater.

Inspection Date: _______________________

Rm #: ________________ Fan #: _________

Avg. Face Velocity: _______________ FPM

Inspected By: _____________________

Sash:                   Half             Full

Note: Inspection expires one (1) year from date above. Contact EHS at 8-5640 if date has expired.