Fire Detection and Extinguishers in Aircraft

When it comes to safety onboard an aircraft, fire protection systems are a critical component. These systems come in two parts: detectors and extinguishers. As their names imply, detectors sense the presence of a fire onboard the aircraft while the extinguishers snuff it out. When it comes to safety onboard an aircraft, fire protection systems are a critical component. These systems come in two parts: detectors and extinguishers. As their names imply, detectors sense the presence of a fire onboard the aircraft while the extinguishers snuff it out.

Detectors can come in two basic types: thermocouples and bi-metallic switches. A thermocouple consists of two dissimilar electrical conductors that generate a small voltage when it reaches a certain temperature, warning that a fire is present.

A bi-metallic switch relies on the basic principle that materials expand as they get hotter. In a bi-metallic switch, a strip of two dissimilar metals with different expansion rates distorts as it grows hotter. As it continues to distort, it contacts a switch, causing it to open or close depending on the type. Modern systems make use of heat-sensing infrared sensors connected to a circuit that alerts the pilot if any temperature has exceeded a pre-set range.

Once the fire has been detected, the extinguishers come into play. On aircraft, fire suppressants are stored in pressurized bottles that can be expelled via an electric trigger or triggered automatically by inertia switches in the event of a crash. To put out a fire, one of three elements sustaining the fire must be eliminated; air, temperature, or the combusting agent.

Water delivered by a sprinkler system reduces the temperature until is back below the burning point of the material on fire. On the other hand, fire-extinguishing agents focus on replacing air with an inert gas that will not burn. A variety of agents are used depending on where in the aircraft the fire is occurring.

Carbon dioxide (CO2), is typically used in cargo compartments or found in smaller handheld extinguishers in the cabin. However, given that humans cannot breathe CO2, the amount used must be in proportion with the cabin’s total air supply. Halon 1301, or bromotrifluoromethane, is another frequently used agent in engine and cargo compartments.  While Halon 1301 is a highly effective extinguishing agent, alternatives are being sought due to the chemical’s effect on the ozone layer of the Earth’s atmosphere.

Finally, dry powder is most often found in handheld extinguishers identical to what you might see in a building’s safety measures. Consisting of a propelling agent such as pressurized gas like nitrogen and a suppressing material like potassium bicarbonate, they are often used to suppress flames on typical combustibles like wood, fabric, and paper.

At Fulfillment 3Sixty, owned and operated by ASAP Semiconductor, we can help you find any aircraft fire detection and extinguishing equipment. We’re always available and ready to help you find all the parts and equipment you need, 24/7-365. For a quick and competitive quote, email us at sales@fulfillment3sixty.com or call us at +1-480-504-1299.


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March 11, 2021

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