NFPA 921 DEFINITIONS

Absolute Temperature. CORRECT ANSWER A temperature measured in Kelvins (K) or Rankines (R). Accelerant. CORRECT ANSWER A fuel or oxidizer, often an ignitable liquid, intentionally used to initiate a fire or increase the rate of growth or spread of fire. Accident. CORRECT ANSWER An unplanned event that interrupts an activity and sometimes causes injury or damage or a chance occurrence arising from unknown causes; an unexpected happening due to carelessness, ignorance, and the like. Ambient. CORRECT ANSWER Someone's or something's surroundings, especially as they pertain to the local environment; for example, ambient air and ambient temperature. Ampacity. CORRECT ANSWER The maximum current, in amperes, that a conductor can carry continuously under the conditions of use without exceeding its temperature rating. [70, Article 100] Ampere. CORRECT ANSWER The unit of electric current that is equivalent to a flow of one coulomb per second; one coulomb is defined as 6.24 × 1018 electrons. Arc. CORRECT ANSWER A high-temperature luminous electric discharge across a gap or through a medium such as charred insulation. Arc Mapping. CORRECT ANSWER The systematic evaluation of the electrical circuit configuration, spatial relationship of the circuit components, and identification of electrical arc sites to assist in the identification of the area of origin and analysis of the fire's spread. Arc Site. CORRECT ANSWER The location on a conductor with localized damage that resulted from an electrical arc.