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Real-Time Suppressant Concentration Measurement (NIST SP 890)



William M. Pitts, George W. Mulholland, B D. Breuel, Erik L. Johnsson, S Chung, Richard H. Harris Jr., D E. Hess


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.
Special Publication (NIST SP) - 890
Report Number


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


Pitts, W. , Mulholland, G. , Breuel, B. , Johnsson, E. , Chung, S. , Harris, R. and Hess, D. (1995), Real-Time Suppressant Concentration Measurement (NIST SP 890), Special Publication (NIST SP), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed May 24, 2024)


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Created November 1, 1995, Updated February 19, 2017