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Real-Time Suppressant Concentration Measurement.

pdf icon Real-Time Suppressant Concentration Measurement. (15770 K)
Pitts, W. M.; Mulholland, G. W.; Breuel, B. D.; Johnsson, E. L.; Chung, S.; Harris, R. H., Jr.; Hess, D. E.

NIST SP 890; Volume 2; Section 11; November 1995.

Fire Suppression System Performance of Alternative Agents in Aircraft Engine and Dry Bay Laboratory Simulations. Volume 2, Gann, R. G., Editor(s), 319-590 pp, 1995.

Available from:

National Technical Information Service
Order number: PB96-117783


fire suppression; aircraft engines; nacelle fires; simulation; halon 1301; halon alternatives; aspirated hot films; cold wires; concentration fluctuations; concentration measurement; infrared detectors; infrared absorption; temperature measurements


The development and testing of two approaches for recording real-time measurements (millisecond time resolution) of concentration for halon alternatives are summarized. Discussions of the background necessary to understand their operation is included. The first instrument is a combined aspirated hot-film/cold-wire probe which is calibrated to record both temperature and concentration. The second is a specially developed instrument based on infrared absorption near 8.5 mm which has been dubbed the Differential InfraRed Rapid Agent Concentration Sensor (DIRRACS). A series of tests of the instruments in the full-scale dry-bay test facility at Wright-Patterson AFB is summarized. The characteristics of the current devices used to measure halon 1301 concentrations - the Statham analyzer and Halonyzer - are reviewed. The final section contains a literature review assessing other potential techniques for making the required concentration measurements.