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.
• 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. TIP: 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.

The following actions will improve fume hood efficiency and provide maximum protection for the user:

• Attend Labsafety training offered through EHS.
• Close all windows and doors to the lab when working in a fume hood.
• 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.
• Do not place your head inside a fume hood.
• Use well controlled movements when hands and arms are in the fume hood. Avoid movements that may draw contaminants out of the hood.