Fume Hood Usage Guide: Standard Hoods

By following a few simple guidelines, the effectiveness of your fume hood can be increased significantly and your exposure to harmful substances can be reduced. Any questions can be directed to EH&S at x-3743, x-4899 or x-8787.

Always work with the sash at the level of the arrow sticker and close it when not attended. To adequately protect you, your hood should be producing a face velocity of 100 to 120 ft/min. EH&S tests your hood and posts the arrow stickers at the proper sash level to:

satisfy the required air flow and protect you (10 - 100 times more than full open sash) against airborne chemicals
protect you better from incidents within the hood.

Many newer hoods on campus are equipped with an air flow monitor and alarm to warn you if the air velocity is too low. If the alarm engages, lower the sash slightly until the alarm stops. Do NOT disengage or over-ride the alarm. If your alarm sounds consistently this indicates a real problem - call EH&S at the above phone numbers.

Store only a minimum of equipment and chemicals in your hood because:

Excess materials will block the air flow into the intake slots at the back of the hood and reduce performance significantly. Permanent equipment should be raised on a jack and kept at least 6" inside the hood to allow the air to flow into the lower slot.
Chemicals should not be stored in the fume hood - most fires and explosions occur in the hood during chemical manipulations. Minimizing the volumes will reduce the chances of a small accident escalating into a large one.

Improper use of perchloric acid has resulted in fires or explosions within a fume hood systems. If you want to use perchloric acid you must first contact EH&S (x-8787 or x-4899) for technical assistance on proper procedures and equipment.

Keep the lab windows closed. Drafts from open windows and doors can significantly affect your hood’s performance (100 ft/min is only a few miles/hr of air).