National fire code question

[Phil Thien]

Anyone here "up" on the national fire codes, specifically as they apply to commercial fire alarm systems?

I'm getting conflicting information in terms of whether the code requires that heat or smoke sensors be replaced at a certain interval?

I've been told by someone that the # of false alarms by heat detectors (I think he was talking about heat, but maybe he was talking about smoke) INCREASE as the units age. He said they become more and more sensitive.

But he was an alarm salesman, LOL.

[Brian Tymchak]

I don't know about commercial units and what code calls for, but what your alarm salesmen says is consistent with my personal experience with residential smoke detectors and what I've read. They do degrade and will provoke a false alarm. (For some reason, in my case, always in the middle of the night.. )

Here's a link to a website I found a while back with some info: http://www.healthsafetyexperts.com/f...okealarms.html

[david mcnamara]

Phil,
When it come to the national fire alarm code and replacement of detectors in commercial installations, it depends on what the manufacturers recommendations are. I don't remember any specific intervals for replacement on smokes, it's more based on whether they pass their required testing at regular intervals. The code is very specific on when and how devices are tested. The same goes for heat detectors, but you need to know whether they are renewable or not. Working on commercial fire alarm systems is something that I would caution a person against. There are numerous requirements based on the national fire alarm code and a tremendous amount of liability that a person takes on when you work on one.
The second part of your question as to whether or not detectors become more sensitive based on age, the simple answer is yes. Environmental conditions, dust, humidity, whether or not the detectors have been cleaned correctly all have an effect on the device. Once again the NFPA72 is going to tell you follow the manufactures recommendations. Hopefully this helps you with your question.
David

[Peter Elliott]

Coming from a person who runs 1000's of fire alarm calls (Me, in Washington, DC). I would say heat detectors would rank #1 in false activation. Fact, I'd say it would have a pretty large margin over Smoke, CO or a Combo head. This is for a moderate size commercial building and larger. Every detection component has a life and typically that is told by the manufacturer.