Laboratory Fume Hood/Ventilation Equipment Alarm Indicators

There are different types of Audible/Visual (AV) indicator systems used on fume hoods at the University of Delaware. Your fume hood must have one of the indicators listed below. These indicators have an audio and/or visual indicator which alerts laboratory personnel if there is insufficient airflow in the fume hood or laboratory ventilation equipment.

There are four different indicators installed on fume hoods around campus:

  • Active Devices
    • Guardian Air Monitors:
      • Face velocity indicator with an audible and visual alarm if the face velocity goes below or exceeds a safe level.
    • Safe Air Monitors:
      • Sash height, voltage and temperature alarm sensors.
    • Ever Watch Face Velocity Monitor:
      • Green indicator light for normal operation.
      • Red indicator light and audible alarm when the velocity goes below or exceeds a safe level.
  • Passive Devices:
    • Magnehelic:
      • Qualitative flow indicator only. The gauge should read greater than 0.1 inches of water.

When an AV system indicates a problem with the fume hood or ventilation equipment:

  • Stop all processes and remove all chemicals to an appropriate storage area. If the chemicals cannot be moved, assure that they are sealed/capped.
  • Contact DEHS at X8475.
  • Do Not simply press the silence button on the AV indicator and continue working. You may expose yourself and others to hazardous chemicals.

Questions or requests for more information may be addressed to Ann Woodall or call 831-7026.

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