Chemical Fume Hood Use

Tips for Effective Fume Hood Use

Perform all work that involves hazardous and noxious materials in the hood.
Keep the sash height at or below the arrow on the hood inspection label. This indicates minimum working height to maintain the hoods face velocity at ~100 FPM.
Elevate large apparatus at least 2 inches from the hood deck to allow air to flow around the object and eliminate “dead-air” zones. (Except where rotating equipment is used that may become unstable if elevated.)
Work at least 6 inches into the face of the hood to reduce the effect of turbulence. Use a piece of tape to mark the deck of the hood.
Work extending arms under or around the sash, placing the head behind the sash, with the glass between the worker and the chemical source. The sash will act as a primary barrier in the event of spill, splash or explosion.
Assure that the controls for all services (i.e., vacuum, gas, electric) are located outside of the face of the hood.
Put the minimum amount of materials in the hood required for the current operation. Each additional item in the hood creates additional turbulence and potential for gas/vapor escape.
Have a safety plan that includes emergency operations for each procedure that you begin in the hood. What will you do if the hood breaks down or an accident occurs?
Collect large amounts of chemical vaporized in an operation by distillation or other means. Dispose of collected material as a waste. Minimize waste by adding a step to render the waste non-hazardous.
Do not walk directly behind someone working in a hood. (Your draft can pull fumes out of the hood.)
Do not Raise or lower the sash quickly. (Same drafts.) · Cover air vents, move ceiling tiles, use small fans, open windows or otherwise alter the air distribution patterns in the lab. Air distribution in the room affects hood function.
Never store chemicals, waste or equipment in the hood. They block the baffles and create “dead-air” zones.
Only use perchloric acid in a water-washed hood.
Only use chemicals in a chemical fume hood. Biosafety cabinets are used for infectious materials.

Hood Maintenance

Hood inspection stickers should be current within one year.
Face velocity should measure between 80 –120 fpm.
If you use flammable liquids be sure you have an explosion proof fan motor attached to your hood. (Vapors from some distillations can exceed 20 % of the lower explosive limit of some solvents.)
Report suspected hood malfunctions to Environmental Health and Safety to have the hood tested and ECU Facilities Services for specific repairs.