What is the purpose of a heat detector?
Protecting your home or business from a fire is a matter of utmost importance. Fires can be deadly – the smoke and carbon monoxide produced from a fire can kill residents, and the fire itself can cause devastating damage to the building and items within – potentially leaving you without a home or costing you thousands in replacing valuables lost in the fire. Thankfully, most buildings have smoke detectors readily placed throughout to properly inform occupants if a fire ever takes place. The ubiquity of smoke detectors, therefore, begs the question: what is the purpose of a heat detector? According to the NFPA, the risk of dying in a fire is 55% lower in homes with working smoke alarms than in homes with no alarms.
Heat detectors find their use when property protection becomes a major concern in your fire alarm system. Heat detectors are perfectly suited for protection against high-heat fires, caused by explosions and combustion. As the flames grow higher, the temperature in a room will rapidly increase, triggering the heat detector, typically before the fire smolders enough to trigger the smoke detector. Low-energy fires, ones that smolder, are more easily detected by smoke detectors, making having both on the property key to protecting you from both types of fire.
How does a heat detector work?
There are two major styles of heat detectors: rate-of-rise heat detectors and fixed temperature detectors. These two detectors use different types of sensors to do the same job: respond to high amounts of thermal energy from the fire – to detect the heat being given off.
- Rate-of-Rise Heat Detectors have a baseline temperature of 70 degrees Fahrenheit. When the heat in the room rises rapidly over 70 degrees, an alarm is then activated. This isn’t caused by the temperature merely going above 70 – to account for fluctuations, the detector instead only triggers the alarm if the temperature in the room climbs by about 15 degrees in less than a minute. In a high-heat fire, the temperature of the room increased very quickly, sometimes as fast as 30 degrees in less than a minute, which would trigger any rate-of-rise heat detector.
- Fixed Temperature Detectors focuses on the rooms actual temperature. Rather than measuring how quickly the temperature is increasing, these heat detectors will instead trigger when they reach a high temperature, usually somewhere around 135 degrees, which will trigger the alarm.
Thermal lag can occur when temperatures increasing rapidly can make a heat detector not alarm until the temperature is beyond the set point. Similarly, false alarms can take place with rate-of-rise heat detectors if the sudden increase in temperature is caused by something innocent, such as an air conditioning suddenly turning off, or a heating system suddenly on. Thankfully, many heat detectors can employ both options, essentially using one as a failsafe for the other – preventing thermal lag in fixed temperature detectors, and preventing false alarms in rate-of-rise detectors.
How do you properly place a heat detector during install?
Ensuring the proper placement of a heat detector is important to maximize their effectiveness. Avoid placing your heat sensor near vents and air ducts — this could cause incorrect readings and possible false alarms. Place your heat detector high up off the ground, either mounted to the wall or ceiling. This is especially helpful because heat rises – keeping them high off the ground not only keeps them protected, but keeps them in a location they’re most likely to detect excessive heat from. Heat detectors are best utilized alongside smoke detectors, acting as a failsafe – smoke detectors for low-energy, smoldering fires, heat detectors for high-energy, high-temperature fires.
Additionally, some rooms may not be best equipped for having a smoke detector installed. Rooms like kitchens, the bathroom, the garage, and the attic are spots that may not be appropriate to have a smoke detector installed. Kitchens and bathrooms can let off a lot of steam – whether cooking or running hot water through the shower – and this excessive moisture can give smoke detectors false alarms. Similarly, attics and garages can get very dusty, and this buildup of dust can get into a smoke detector, once again giving a false alarm for smoke being detected. In these rooms, heat detectors are excellent alternatives to smoke detectors, being able to use the heat detector on its own instead of a smoke detector.
What to do if a heat detector goes off?
When the alarm of a heat detector goes off, it’s important not to panic. Evacuate the building immediately and call the fire department as soon as it is safe to do so. Additionally, many heat detectors connected to a center fire alarm panel can automatically alert the fire department, and some can even activate a fire suppression system, such as overhead sprinklers, automatically when the heat detector goes off.
Why you should include a heat detector in your fire alarm system
Heat detectors provide additional protection against fires that a smoke detector may not catch wind of until its too late. As smoke detectors are best utilized to notice smoldering, smoky fires instead of nearly instantaneous, high energy fires, a heat detector will inform residents of the potential danger of these kinds of fires, giving ample time to leave the building and contact the fire department. Additionally, heat detectors are often used in industrial fire alarm systems as a mechanism to trigger fire suppression equipment, such as overhead sprinklers. Heat detectors aren’t interrupted by contaminants like smoke detectors, making them an excellent choice in rooms and areas that may have excessive dust or moisture. Heat detectors are less prone to false alarms and can’t be set off by dust.
Heat detectors are an excellent addition to any fire alarm system. In larger buildings, they’re especially useful for their ability to trigger fire suppression systems to put out the fire before it can spread to the rest of the building, but it isn’t without its uses around a home. Heat detectors are perfect for anyone who takes fire safety seriously but don’t want to deal with the frequent false alarms caused by steam and dust. Heat detectors allow users to notice fires a smoke detector likely wouldn’t, with fewer false alarms. Due to this, it’s important to remember that smoke detectors are still the best deterrent; heat detectors are not life saving devices, unlike smoke alarms. They are, however, excellent property protecting devices, able to notice fires that could cause you immense amounts of damage to pay for.