FAA Powerplant Written Practice Test

Optical fire detection systems can be which of the following?

1. Infrared or ultraviolet

2. Thermal or electrical

3. Liquid or gas based

4. Photoelectric or vibrational

The correct answer is: Infrared or ultraviolet

Optical fire detection systems utilize specific types of light to identify the presence of a fire. The recognized categories in this context are infrared and ultraviolet detection. Infrared fire detection systems work by sensing the infrared radiation emitted by hot surfaces and flames. As a fire burns, it generates heat, which releases infrared energy; these systems are particularly effective at detecting fires before they produce significant smoke. On the other hand, ultraviolet fire detection systems monitor ultraviolet radiation, which is produced by flames, especially in combustion events like those from hydrocarbon fuels. This type of sensing can offer very rapid detection since flames emit ultraviolet radiation almost instantaneously. Both infrared and ultraviolet detection are robust methods that are widely used in fire safety systems, especially in areas where traditional smoke detectors may not function effectively. They target the specific wavelengths emitted by fire elements, enabling them to detect fires promptly and accurately. The other options might pertain to different detection methods or types of systems, but they do not specifically align with the optical fire detection classification recognized in aviation and industrial fire safety contexts.