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Experimental and Numerical Evaluation of a Near Infrared Fire Detector.


pdf icon Experimental and Numerical Evaluation of a Near Infrared Fire Detector. (782 K)
Zhu, Y. J.; Lloyd, A. C.; Sivathanu, Y. R.; Gore, J. P.

International Conference on Fire Research and Engineering (ICFRE2), Second (2nd). Proceedings. National Institute of Standards and Technology (NIST) and Society of Fire Protection Engineers (SFPE). August 3-8, 1997, Gaithersburg, MD, Society of Fire Protection Engineers, Boston, MA, 512-523 pp, 1998.

Sponsor:

National Institute of Standards and Technology, Gaithersburg, MD

Keywords:

fire protection engineering; infrared fire detectors; evaluation

Abstract:

Near infrared fire detector work on the principle of detecting fires based on a statistical analysis of the apparent source temperatures of fires. The apparent source temperatures are estimated from the radiation intensity incident on the fire detector at two near infrared wavelengths. However in some instances, the fires are not in the direct view of the detector, and most of the radiation which are incident on the detector reaches it after multiple reflections from the walls of the building. An experimental and numerical study of the effects of these reflections on the temperatures inferred by a near infrared fire detector are presented. The experimental evaluation was conducted using three open and two smoldering fires. The results shows that the near infrared fire detector is capable of discriminating open fires from reflected radiation. However, for smoldering fires, the intensities obtained from reflected radiation are too low to be successfully discriminated from background noise. Numerical evaluation of the performance of the near infrared fire detector in cylindrical and rectangular enclosures were conducted utilizing a photon tracing algorithm in conjunction with the discrete probability function method. The numerical evaluation confirms that the detector can successfully detect fires from reflected radiation if its sensitivity is sufficiently high.