Radiant Energy-Sensing Fire Detector : A device that detects radiant energy, such as ultraviolet, visible, or infrared, that is emitted as a product of combustion reaction and obeys the laws of optics
NFPA 1 Fire Code, National Fire Protection Association (NFPA), MA, USA 2009 ed. https://law.resource.org/pub/us/code/ibr/nfpa.1.20 03.pdf, (Code: Nat Fire Protection Association Fr&LfSf Requir - Amer) {171 NFC}