A smoke detector is a sensitive device designed to detect a fire from the by-products of combustion. You can read more about the operation of fire detection and alarm systems and smoke detectors in our popular series of articles titled "Principles of Fire Safety".
Earlier today I received an email from CW (alias) who asked the question "what are the requirements for testing the sensitivity of collective smoke detectors in accordance with Australian Standard AS1851:2012?"
I received an email (below) from a customer (MB) who had experienced an alarm, likely caused by steam from a shower in a washroom.
Sent: Wednesday, 17 April 2013
Subject: Smoke detector
We had a fire alarm last week in toilet/wet area due to pressure hosing. Evidently it was a smoke detector set off due to water mist.
Could you please provide feedback whether thermal detectors suffer potential false activations from minor water spray or if this is really only likely from smoke detectors?
Unfortunately there are a great deal of other particles that when built up over time can adversely affect the performance of a smoke detector.
This adverse affect can be reflected in two ways;
The fourth instalment of the Principles of Fire Safety series looks at smoke, gas and flame detectors. Again, research and development has continued to improve well established detection technologies and provided an array of new technologies to improve fire detection while also being less susceptible to the causes of false alarms.
A VESDA is a brand of aspirating smoke detector designed and manufactured by Xtralis. From a maintenance perspective, an aspirating smoke detector (also known as an ASD) needs to be maintained differently than the common point type smoke detector.
While this article specifically considers the VESDA, there are other brands of aspirating smoke detector available that these general principes apply.