Heat detectors in an attic?

[homejones]

All, I have a relatively large attic that covers about 1600 sq ft of my house. It gets VERY hot up there in the summer (Southern California) so I thought it would be prudent to install a few high-temperature heat sensors (I bought 3 194-degree heat detectors).
 
However, as I prepare to install them, I wanted to get others' opinion on this. Do people normally place heat detectors in the attic? Is it logical? Thanks!

 

[ano]

Yes, use them. I live in Phoenix and if mine have never gone off in the summer, I doubt yours will.   They are especially good to place near your furnace if its up there. Central heating systems cause over 7000 home fires a year in the US.

 

[BraveSirRobbin]

What are good brand/model recommendations?
 
I live in Las Vegas btw and have two units (AC compressors on the ground) up in my attic.
 
Ano makes a great point!
 
Thanks,
 
BSR

 

[ano]

I have always liked these from Edwards:
http://www.edwards-signals.com/files/S85001-0261_--_PL_Series_Heat_Detectors.pdf
 
They are cheap and many places seem to carry them.  I recommend the Rate-of-Rise models. In addition to a set point 194 degrees they will also trip if the temperature rises faster than would normally be expected.  They are a good no-hassle way to add protection and they are relatively cheap as well.  

 

[homejones]

I have the System Sensor 5601P.
 
Also, I saw this post on the Elk website about how to configure a 2-wire heat detector: "Define the Zone as 10, Type 5 4-Wire Smoke, install the 2.2Ω Resistor across the contacts of the Heat Detector"
 
Is this correct?

 

[johnlaroux]

So what do you do when one of these things goes off?

 

[homejones]

So what do you do when one of these things goes off?

Run...fast...
 
If the 194 degree model goes off, unless it's a failed sensor, there is a fire and I would run as fast as possible.
 
Hopefully the system will do its job, contact the Alarm company, who will then contact the Fire department.

 

[gatchel]

Also have 194 degree heats in my attic. No false alarms yet.

 

[ano]

So what do you do when one of these things goes off?

You get out of the house, then the fire department does the rest. 
 
On any fire alarm my home automation system also turns off all ceiling fans, unlocks all the doors, and if its night time, flashes an outdoor light. 
 
It would NEVER be smart for me to try to fight the fire, especially if it was in the attic.  I get out and everything else should happen automatically.
 
My home has fire sprinklers, but they won't help much for an attic fire.  I have heard that they sometimes will install sprinklers in the attic as well, but I do not have that, and I think its pretty rare.

 

[BraveSirRobbin]

Exactly, I was thinking like Ano, to just turn on lights (at night) and get everyone out!

 

[picta]

I also have regular temperature sensors in the attics, and I store the measurements several times a day together with outside temp. You can learn the pattern and define "warning" points if the data reach through a threshold. That could prove useful before the fire starts. This data are also used to control the attic fan.

 

[KenN]

I have always liked these from Edwards:
http://www.edwards-signals.com/files/S85001-0261_--_PL_Series_Heat_Detectors.pdf
 
They are cheap and many places seem to carry them.  I recommend the Rate-of-Rise models. In addition to a set point 194 degrees they will also trip if the temperature rises faster than would normally be expected.  They are a good no-hassle way to add protection and they are relatively cheap as well.  

 
These are great.  I've spec'd them on several light industrial jobs in the past and never a problem.  UL certified for use in a fire alarm system, or you can just use the dry contact and wire it back to your own alarm system.

 

[BraveSirRobbin]

How does one test those sensors?  I didn't see any kind of a test button when reading that PDF?

 

[ano]

Edwards has a proceedure for testing the ROR part:
 

The rate-of-rise test should be conducted by a qualified fire protection specialist using a 1,000-watt heat gun (or hair dryer). Under normal ambient conditions with an air velocity at the detector of 400 feet per minute, or less, the detector’s contacts should close within 10 seconds when the heat gun nozzle is located approximately 6 inches from the detector. For every additional 400 feet per minute of air velocity, the heat gun to detector spacing should be reduced by one inch (e.g. 400-800 FPM, 5 inches; 800-1,200 FPM, 4 inches, etc.). Caution must be taken to prevent operating the nonrestorable fixed temperature element (center disk) during this test. If the fixed temperature element operates, the detector must be replaced.

 

 
The actual 194 degree sensor part shouldn't need any testing, and once it triggers, the sensor will need to be replaced.  The sensor should last 15 years, after that I would just replace them. They only cost something like $14 each, so not a big deal. 

 

[video321]

My attic is around the same size as the OP (1600), but is long and narrow. How many detectors are recommended?