Chemical Fume Hoods

A standard chemical fume hood is a fire and chemical resistant ventilated enclosure with an opening in front (face) with a moveable window (sash) to allow a user access. It is designed to protect personnel and prevent contaminants from escaping into the laboratory environment.

Use a chemical fume hood when

  • Handling chemicals with inhalation hazards
  • Conducting procedures with exothermic reactions
  • Handling materials with significant vapor pressure
  • Working with chemicals that can cause a fire hazard
  • Working with compounds that have an offensive odor or unknown toxicity


​​How to verify the fume hood is working properly

  • Check the certification card. EH&S certifies hoods annually; if yours has not been certified in the last year, do not use the hood and contact EH&S.

  • Check monitor. If monitor reads between 80 and 125 fpm (feet per minute), the hood is pulling an appropriate amount of air. If the readings are less than 80 fpm or more than 125 fpm, do not use the hood and contact EH&S . For monitors without a digital reading, a green light indicates the unit is pulling the appropriate amount of air; contact EH&S at (515) 294-5359 and do not use if other colors are illuminated.

  • Check tissue paper. For hoods without a monitor, a piece of tissue paper or a Kim wipe taped to the bottom of the sash will indicate direction of air flow. If wipe is being pulled inside, the unit is pulling air and may be used.  If the wipe is pushed out of the hood, DO NOT use the fume hood and contact EH&S.


How to protect yourself and others

Before Work During Work After Work
Verify the hood is working properly Keep your head outside of the hood  Clean up work surface
Set sash height (no higher than arrows     on side) Avoid rapid movements Limit storage of materials in hood - too many items may disrupt air flow
Do not position fans toward hood Conduct work at a minimum of 6 inches from     front (face) of hood Lower hood sash
Do not modify hood design Minimize traffic in front of hood Make sure all containers in hood are closed
  Do not obstruct hood opening or baffles - keep items in the hood at a minimum  

If the alarm sounds at any time, stop work, lower or close sash, and contact EH&S. DO NOT MUTE OR IGNORE THE ALARM. Be sure to notify others that the fume hood is not working properly. 

Do you see one of these on your fume hood?



  • A yellow ‘Caution’ sign indicates that the hood did not meet all safety criteria; however, if operated under specific conditions, the hood can still provide a safe working environment. Conditions for use are listed on the sign.

  • A red ‘Warning’ sign indicates that the hood is unsafe and cannot be used for work or storage under any circumstances.

  • EH&S and Facilities Planning & Management (FP&M) will coordinate repairs for the hood; no action is needed by laboratory personnel.

  • EH&S is responsible for sign removal and will only do so when the hood has undergone repairs and passed certification testing.