A campus-wide Chemical Fume Hood Surveillance Program is coordinated by the Occupational Safety and Health Department (OSH). Fume hood face velocity is measured annually by OSH. If the velocity falls within the established operating range established by the campus of 80 and 120 linear feet per minute (fpm), or within the operating range established by the manufacturer and verified through as-installed containment testing, the hood will receive a green Chemical Fume Hood Evaluation tag bearing the date of the inspection as shown below in Figure 5. Approved operating flow range and maximum approved sash opening are listed on the white Chemical Fume Hood Operating Parameters sticker that is placed on the fume hood and shown below in Figure 6.
Figure 5: Green Chemical Fume Hood Evaluation card indicating the face velocity was within corresponding operating flow range.
Figure 6: White Chemical Fume Hood Evaluation sticker.
If research work in your fume hoods is critical, the Facilities & Services (F&S) Sheet Metal Shop can provide annual testing and immediate repair by requesting a Preventative Maintenance work order through the F&S Service Office.
If the face velocity is outside the range listed on the Chemical Fume Hood Operating Parameters a WARNING sign will be posted on the sash and the previous year's green tag will be removed. If a WARNING sign is present, contact your facility manager for Repair, OSH and DRS cannot initiate repair of failing hoods. Do not use hazardous material in the hood until it has been repaired and is working properly. The F&S Sheet Metal Shop will re-test the hood as part of the repair work. A copy of the WARNING sign is shown below in Figure 7.
Figure 7: WARNING sign indicating the face velocity was not within corresponding operating flow range.
The hood can function properly only if its integrity is not compromised. A hood with missing side panels or cracked sashes will not provide adequate exposure control.
Because the status of the chemical fume hood can change anytime, continuous air flow indicators are recommended. New chemical fume hoods must be equipped with air flow monitoring devices which will alert the user if there is a problem with air flow. For older hoods without air flow monitoring devices, a simple visible test to ensure flow into chemical fume hoods and other ventilating devices is to tape a tissue to the hood and note its movement when the exhaust fan is turned on.