Experimental and Numerical Evaluation of a Near Infrared Fire Detector.
Experimental and Numerical Evaluation of a Near Infrared
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,
fire protection engineering; infrared fire detectors;
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.