Heat Detectors in Grid and False Alarms

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Senior Team
Senior Team
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For those of you with rate of rise heat detectors in your grid... have you ever had a false alarm due to heat produced from stage lighting?
 
Do they actually measure temp changes to trigger the alarm? Interesting...

I had one smoke detector (the only one on the stage side) to a heat detector - its on the theatre side of the stage door. Never had an issue, but it doesn't get the heat from stage lights. Otherwise I have sensors inside the return air ducts.
 
I've never heard of that, though anecdotes report a fire safety curtains closing in Texas from heat and fusible link.

Most heat detectors today are combination rate of rise and fixed temperature. Definitely the best automatic fire detector.
 
Ive dealt a lot with fixed temperature and less in rate of rise, both in installation and inside a theatre. To me rate of rise should be fine as long as it is far enough from lighting fixtures, as they can pump out a lot of heat in a short period of time (going from cold to full on, and left on).

Aren't rate of rise typically 9ºC over one minute rise typically? And yes they are typically combination. (that is rate of rise also does fixed)

So 9ºC/60s (15ºF/60s) or 38ºC (100ºF) or 66ºC (150ºF) will set a rate of rise off.

Someone get out some temperature sensors and lets see how close to a source-4 750w we can get and not fill into that delta!!!

As is I've changed a lot of detectors out for the 150ºF versions after the 100ºF ones have gone off as a nuisance (usually in a kitchen or such). Sucks when its not the middle of summer as it's not going to go off as quick or such, but a hot kitchen with no A/C in the middle of the summer when it's already 30+ degrees out (Celsius that is) it becomes necessary. Deep Friers, Grills, Ovens, Stoves, and such packed into kitchens put out a hell of a lot of heat.
 
Ive dealt a lot with fixed temperature and less in rate of rise, both in installation and inside a theatre. To me rate of rise should be fine as long as it is far enough from lighting fixtures, as they can pump out a lot of heat in a short period of time (going from cold to full on, and left on).

Aren't rate of rise typically 9ºC over one minute rise typically? And yes they are typically combination. (that is rate of rise also does fixed)

So 9ºC/60s (15ºF/60s) or 38ºC (100ºF) or 66ºC (150ºF) will set a rate of rise off.

Someone get out some temperature sensors and lets see how close to a source-4 750w we can get and not fill into that delta!!!

As is I've changed a lot of detectors out for the 150ºF versions after the 100ºF ones have gone off as a nuisance (usually in a kitchen or such). Sucks when its not the middle of summer as it's not going to go off as quick or such, but a hot kitchen with no A/C in the middle of the summer when it's already 30+ degrees out (Celsius that is) it becomes necessary. Deep Friers, Grills, Ovens, Stoves, and such packed into kitchens put out a hell of a lot of heat.

The ones we have are 15ºF over 1 minute OR 135ºF, whichever comes first. In truth you have to wail on thing with a heat gun pretty hard before it trips.
 
The ones we have are 15ºF over 1 minute OR 135ºF, whichever comes first. In truth you have to wail on thing with a heat gun pretty hard before it trips.
If you look at the spec sheets:

Reading this I decided to double check spec sheets instead of relying on my memory, yay I was correct...

Edwards CR-135-2
UL Temperature Rating 135°F (57°C)
UL Max Ambient Temp. at Ceiling 100°F (38°C)
Fixed Temperature and Rate-of-Rise Rate-of-rise: 15° F (9° C), self restoring

Typical Rate of rise detector I would usually install (depending on alarm system type).

So yes the rating is 135, however is the room is at 100 ambient already... boom. Seen it a number of times. not fun.
 
Seems low, in arenas I have seen 130 in the grid, on 80 degree days, when the AC has not been on recently, and considering I like my coffee at 170+ ...
 

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