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Are your fume hoods equipped with proper airflow monitoring devices?

Laboratories of all types use fume hoods as a means of protecting their employees from chemical exposure and the processes and experiments that are performed. A fume hood is generally considered the most important engineering control in any laboratory environment to provide protection from the inhalation of harmful chemicals as well as from fires and explosions.

However, based on a recent ANSI/ASHRAE evaluation of fume hood effectiveness, a significant portion of the hoods tested (28% to 38%) do not meet required performance standards. So how can you be sure that your employees are being protected?


Industry standards and regulations that address proper fume hood performance include:

  • ANSI Z9.5-2012 (Laboratory Ventilation Standard), Section 8.10: “All hoods and exposure control devices shall be equipped with a flow indicator, flow alarm, or face velocity alarm indicator as applicable to alert users to improper exhaust flow.”


  • ANSI Z9.2 -2018 (Fundamentals Governing the Design and Operation of Local Exhaust Ventilation Systems): “Hood performance monitoring devices or testing procedures shall be provided. A real-time continuous hood performance monitor shall be provided if failed hood performance could result in hazardous conditions for persons using the hood.”


  • NFPA 45-2015 (Standard on Fire Protection for Laboratories) Section 7.8.7: “A measuring device for indicating that the hood airflow remains within safe design limits shall be provided on each chemical fume hood. The measuring device for hood airflow shall be a permanently installed device and shall provide continuous indication to the hood user of adequate airflow and alert inadequate hood airflow by a combination of an audible and visual alarm. Where an audible alarm could compromise the safety of the user or the research, alternative means of alarm shall be considered.”  


  • 29 CFR 1910.1450 (OSHA Laboratory Standard): Chemical Hygiene Plans must include “a requirement that fume hoods and other protective equipment are functioning properly and specific measures that shall be taken to ensure proper and adequate performance of such equipment.”


In order to meet the OSHA requirement that specific measures are taken to ensure proper fume hood performance, a continuous visual air monitoring device should be installed on every fume hood as specified in the ANSI and NFPA standards.  Ideally, the air monitoring device should be connected to an audible alarm. Performance monitoring equipment allows the hood user to check and monitor the reliability of the hood system over time. These devices may not be added by the manufacturer, or at the time of fume hood installation, and may need to be addressed once the fume hood is installed. Air monitoring devices and alarms should be on an annual preventative maintenance and calibration plan.

If you have any questions on fume hood air monitoring devices or alarm requirements, please email [email protected].

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