Requirements cover toxic and combustible gas and vapor detectors and sensors intended to be portable or employed in indoor or outdoor locations in accordance with the National Electrical Code, NFPA 70. A gas detector and/or sensor and/or vapor detector, as covered by the requirements, consists of an assembly of electrical components coupled with a sensing means inside a chamber, or by separate components to detect toxic and/or combustible gases or vapors. The detector includes provision for the connection to a source of power and signaling circuit. These requirements cover sensors and sensing circuits intended for use with or in gas detectors, alarms or gas detection circuits within fuel cell systems.
Second edition published in March 2013 as an ANSI standard. Available at www.ul.com