Factors that Affect the Performance of a Fume Hood
The following are common situations that can arise in laboratories that may negatively affect fume hood performance:
- Objects obstructing the return ducts and baffle areas.
- Objects placed in close proximity to return ducts and baffles tend to interfere with air being pulled from the back portion of the fume hood. Place large equipment on stands to allow air
flow underneath, remove unnecessary chemicals and equipment, and place them in a proper storage location.
- Objects and equipment too close to the front of the fume hood.
- This has the potential to create unwanted air currents that may allow contaminants to leave the front area of the fume hood and cause unwanted exposures. All equipment and materials should
be placed at least 6 inches from the face of the fume hood. Use a length of tape to mark out six inches.
- Secondary currents created by portable fans and traffic in front of the hood.
- These currents draw contaminants out of the fume hood. Do not direct any other ventilation (portable vans, HVAC ductwork) towards a fume hood. Limit pedestrian traffic in front of the hood
while in use.
In general, make the following changes to the work area to increase the capture of the fume hood and to achieve maximum protection for the user:
- Obtain fume hood education from DEHS.
- Close all windows and doors.
- Limit pedestrian traffic in front of the fume hood.
- Limit operator's body movement as much as possible.
- Lower sash to the operating level indicated by certification sticker.
- Redirect heating and air conditioning vents away from fume hood. Contact DEHS for guidance.
- Do not place your face inside a fume hood. Keep hands as far out as possible.
- Use well controlled movements when hands and arms are in the fume hood. Avoid movements that may draw contaminants out of the hood.
Questions, requests for more information or training on proper use of fume hoods may be addressed to Ann Woodall or call 831-7026.