When a New Air Diffuser is Installed, Why is the Fire Alarm Company at Fault?
When the HVAC Air Diffuser is placed next to a smoke detector, the air coming out of the diffuser keeps any smoke in the room from reaching the detector.
By Douglas Krantz
I was at a lunch meeting where the State Fire Marshal (AHJ) was speaking. One of the things that he talked about was the spacing between an air diffuser and a ceiling smoke detector.
He said that after placing a ceiling smoke detector well away from any air diffuser, if the HVAC people install an air diffuser next to the smoke detector, it's going to be the fire alarm installer that gets "dinged" and has to move their smoke detector.
It seems unfair, fire alarm people being told to move their smoke detector because of someone else's action, but there is a reason for this unfairness.
Keep in mind, that the HVAC people don't really know the spacing requirements for smoke detectors. If they're told to move the air diffuser, they aren't going to know where to move it.
On the other hand, to keep the proper spacing, the fire alarm installer knows where to move the smoke detector.
Not caring who does the work, all the AHJ is looking for is proper spacing. It's the fire alarm installer that knows the spacing requirements, so it's the fire alarm installer that moves the detector.
Based on his electronics training, and his understanding of Life Safety, Douglas Krantz has compiled his knowledge of Conventional Fire Alarm Systems into the book Make It Work - Conventional Fire Alarms
. The book covers the basics of the Conventional Fire Alarm System, and shows how Life Safety and internal supervision affects the fire alarm system.
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