McMaster University

McMaster University

VentAlert Air System Alarm - MUMC Laboratories

•A VentAlert Air System Alarm is attached to a fume hood and works with the exhaust system.  It is preset to a limit. It alarms when it detects a 25% reduction in air volume.

•This alarm is designed to notify you if the fume hood is not performing as desired which could lead to exposure to hazardous materials.

•It is very important to make sure the alarm system is operational before you start your work

VentAlert Air Alarm System battery replacement guidelines

•If you have a VentAlert Air System alarm, please remember to change the 9-volt battery yourself at minimum every two years.  There are 4 easy steps to changing the battery.


Height of VentAlert Air System Alarm

•Due to the height of the VentAlert on the fume hood, a stepladder may be required.  Ladder training is required to use a stepladder at McMaster University.
•Ladder Safety in Mosaic.  Course code: LADDER

•Ensure that the alarm is in the off position.

Replace the faceplate with the 4 screws

•There are 4 screws on the box.
•Use an 2mm Allen Key 
•Remove the screws and faceplate using the correct size Allen key.
•Change out the old battery for a new battery.

•Test the VentAlert Air Alarm System for alarm for operation. 

Discarding of batteries at McMaster University according to the guidelines

•Did you know used batteries are considered hazardous waste and should not be disposed of in regular garbage?
•(RMM# 506: Battery Recycling and Disposal Program).
•Used Alkaline, Lithium-Ion, and Nickel-Cadmium batteries need to be separated. If a used battery does not meet the above sorting criteria, EOHSS, or where applicable, FHSc Safety Office should be contacted to make arrangements for proper recycling and disposal.
•Battery Disposal in MUMC is through the Health Sciences Stores (HSC-1G3).


Fume hood Operation with VentAlert Air Flow Alarm in the on position

•Always keep the airflow alarm on at all times.
•Always test the airflow alarm before using the fume hood.
•If the alarm does not activate, initiate the process to replace the battery and move your work to an another fume hood with a working VentAlert Air Flow Alarm.
•The alarm on the laboratory chemical fume hood is designed to notify you if the fume hood is not performing as desired which could lead to exposure to hazardous material.


If the alarm is triggered, take the following steps: 

•Shut down your experiment.  Close all containers and turn off all equipment.  Take steps to contain all airborne hazards.
•Once contained, safely remove all hazardous materials and equipment out of the fume hood.
•Store them appropriately for your experiment.
•Close the sash.
•Notify the FHS Safety Office at


If you have changed the battery and your VentAlert is still not functioning (constant/intermittent beeping), place a workorder to have the issue addressed.











Updated 2022-07-15


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