Using Temperature Switches for Fire Detection

Temperature switch requires that the heat of the fire be in close proximity to the switch. The fire would have to burn until it gets to the switch as you state an open area.

IR detection would sense the moment of combustion. Or temperatures that would lead to combustion. Which give mush better protection.

That is like a Fire Manager or final expert consultant in Fire Detection. I like it.

A temperature switch is just a bi-metallic thermostat configured for fire system use.

Yes, they can be placed in an open area (not against a ceiling) with the following caveats:

1. The device is not being used for life safety.

2. There is a heat collector installed above the device.

The criteria for selecting a heat detector rating has more to do with experience and does not have a standard.

That being said, a good rule of thumb is approximately 100 deg F above highest expected ambient.

Having won the bid to carry it out, is the entire design work now to be done by CR4 readers on a no-fee basis?

No.

For open area fire detection you can use area infrared + UV fire detectors for sensing fire at distance by sensing black body radiation. If fire is expected nearby and has material that can generate smoke then you can use smoke detector or combustion sensor. You can also use very sensitive heat flux sensor as supplementary sensor but normally Smoke and Black body radiation sensor combination will serve the purpose.

Assuming that there is public show or concert in open then many such sensors need to be installed and wired to fire alarm and fire safety system. There can be a trick to differentiate between cooking fire, smoking etc and the actual fire in something that is not supposed to go on fire.

No.

For open area fire detection you can use area infrared + UV fire detectors for sensing fire at distance by sensing black body radiation. If fire is expected nearby and has material that can generate smoke then you can use smoke detector or combustion sensor. You can also use very sensitive heat flux sensor as supplementary sensor but normally Smoke and Black body radiation sensor combination will serve the purpose.

Assuming that there is public show or concert in open then many such sensors need to be installed and wired to fire alarm and fire safety system. There can be a trick to differentiate between cooking fire, smoking etc and the actual fire in something that is not supposed to go on fire.

Open area fire detection...

....I think they use eyes to detect fires in the open.

Satellite remote sensing eye.

A combination of SEVERAL sensing methods should be used.

Optical detectors:
Infrared detection = detect hot spots at a distance.
UV detection (used with IR above) = certain combustion conditions (but not all of them) give off a characteristic UV signature.
Photo beam obscuration = smoke detection over a known time period and distance.
Photo chamber scattering = light scattering off of smoke particles within a special chamber near a smoke source.

Ionic detector:
Ionizing chamber current = detecting smoke particles charged by ionizing radiation within a specially designed chamber near a smoke source.

Thermal detectors:
Threshold temperature = ambient temperature above a fixed threshold.
Rate-of-RISE temperature (used with threshold above) = measures RATE of temperature rise to sense abnormal conditions which could be caused by a fire.

Which combination of sensors that work best for your application must be determined by a qualified person skilled (technical AND in-the-field experience) in fire detection methods during an ON-SITE evaluation.

Systems designed to save life and property should not be based solely on the advice from public forums.

Good Luck!

There are many ways to utilize Temperature Switches for Fire Detection. Some of them, but only a few of the many, are: heat detector-line type; heat detector/sensor (thermal detection) orientation not to be changed; combination rate of rise/fixed temperature; rate compensation; fixed temperature; rate of rise; high temperature switch; and others. From NFPA 170, 2013 edition.

http://www.nfpa.org/assets/files/aboutthecodes/170/170_f2014_fis-aaa_fd_cistatements.pdf

Other alternatives include: photoelectric; ionization; ultraviolet; infrared; ultraviolet/infrared; visible radiation; and others. Of course appropriate circuitry would have to be provided to activate alarms, fire suppression equipment, reporting, enunciators, local alarms, central station reporting. Best thing to do would be to consult with a fire protection engineer with a specialty in fire detection or a firm specializing in it such as Walter Kidde or its successors. Alternate would be a sprinkler installation contractor.

If you don't plan and install this according to codes it could result in numerous fines and fires. Also having to make those changes to bring it up to code.

Good Luck, Old Salt

A piece of sisal string can be used:

• Arrange for the taut string to hold a spring-loaded device in the OK position against the spring. When the fire burns through the string, the device changes state in response to thee uninhibited spring, thereby indicating fire.