Flame detectors detect which light spectra?

Flame detectors detect which light spectra?

• A. Ultra-violet / infrared
• B. Visible / ultraviolet
• C. Infrared / microwave
• D. X-ray / ultraviolet

Answer: (A)

Flame detectors respond to radiation emitted by flames, primarily in the ultraviolet and infrared portions of the spectrum. Ultraviolet detectors pick up the flame’s prompt chemiluminescence from excited radicals, giving a very fast indication of fire with relatively low interference from normal lighting. Infrared detectors sense the heat radiated by the flame, which is useful for larger flames or in smokier environments. Some detectors use both types to improve reliability. Visible light from flames isn’t relied on because it’s easily confused with ambient lighting, and x-ray or microwave emissions aren’t produced by flames, so those ranges aren’t used.

Flame detectors respond to radiation emitted by flames, primarily in the ultraviolet and infrared portions of the spectrum. Ultraviolet detectors pick up the flame’s prompt chemiluminescence from excited radicals, giving a very fast indication of fire with relatively low interference from normal lighting. Infrared detectors sense the heat radiated by the flame, which is useful for larger flames or in smokier environments. Some detectors use both types to improve reliability. Visible light from flames isn’t relied on because it’s easily confused with ambient lighting, and x-ray or microwave emissions aren’t produced by flames, so those ranges aren’t used.