The Smoke Detectors and Fire Protection Systems of Aircraft

During flight operations, fires present a major safety risk due to the amount of flammable and combustible materials that are onboard. As such, it is crucial that fires are discovered right away so that their damage and spread can be mitigated. One way in which fires are identified is through their smoke, that of which can be detected with numerous aircraft fire protection systems. In this blog, we will discuss smoke detectors and flame detectors, allowing you to better understand how aircraft maintain fire safety across the vessel.

Smoke Detectors

Smoke detectors are often situated in areas such as lavatories and cargo baggage compartments, capable of detecting smoke for the means of indicating a fire. For their method of detection, smoke detectors gather samples of air. As such, they must be placed in a strategic location that allows them to detect smoke before the heat of a fire activates a heat detection system. Smoke detectors may come in two types, those of which are light refraction and ionization types.

Light Refraction Detectors

Light refraction smoke detectors contain a photoelectric cell, allowing them to detect light that is refracted by smoke particles. As smoke wafts around a room, the particles will refract light, causing it to reach the photoelectric cell. When enough light is sensed, the light refraction detector will generate an electrical current to indicate the possible presence of a fire.

Ionization Detectors

With an ionization type smoke detector, the identification of smoke is made possible through the detection of ion density changes as smoke fills a room. In order to be powered for readings, the ionization detector is supplied power from the aircraft through a 28 volt DC electrical source. The alarm can also be tested for its output and sensitivity through the use of a test switch that is located within the control panel.

Flame Detectors

Flame detectors differ from smoke detectors in their method of operation, capable of identifying the presence of specific radiation emissions that source from hydrocarbon flames. Also known as optical sensors, such flame detectors may come in the form of infrared (IR) and ultraviolet (UV) types, each of which differ in the emission wavelengths that they detect. IR flame detectors are typically found on light turboprop aircraft and helicopter engines, exhibiting optimal dependability and an economical price point that makes them beneficial for such vehicles.

As radiation is emitted by a fire, it will pass into the detector and strike the sensing device filter. The filter ensures that only certain wavebands are capable of passing onto the radiation-sensitive surface, typically being those that are 4.3 micrometers. As the radiation hits the sensing device, small temperature increases will result, causing thermoelectric voltage to be produced. The voltage is then passed through the device’s output and into electronic processing circuits.

Beyond such examples, one may also use other various fire detection systems and safety devices, those including carbon monoxide detectors, thermal switch systems, thermocouple systems, and more. As fire safety is paramount for flight operations, one must always ensure that all their systems and detectors are functional and regularly inspected. If you find yourself in need of a detector or spare parts for your existing systems, look no further than Buy NSN.

Buy NSN is a premier purchasing platform owned and operated by ASAP Semiconductor, and we are your sourcing solution for top quality smoke detector parts and other safety system components. Take the time to explore our vast set of offerings at your leisure, and our team of industry experts is always ready to assist you through the purchasing process however necessary. Get started with a competitive quote on items for your comparisons when you fill out and submit an RFQ form through our website today.

1. john symond
2. Posted on November 3, 2021
aviation

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