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Pipe Flow Characteristics of Alternative Agent/Nitrogen Mixtures (NISTIR 5499)



Thomas G. Cleary, M D. King, Jiann C. Yang, William L. Grosshandler


The evaluation of alternative agents for application in engine nacelle fire protection includes delivery efficiency of agent from a remote storge bottle through piping to the nacelle injection loacation. Present military requirements for halon systems specify a maximum discharge time from the remote bottle to the injection location of 1 second. A similar performance criterion for the replacement agent delivery will more than likely be required. The applicability of retro-fitting existing systems or optimal design of new systems necessitates a thorough understanding of the two-phase flow in piping. As part of the halon replacement project, an experimental pipe flow apparatus was constructed and is being used to examine alternative agent flow in various horizontal piping configurations and conditions. The selected agents for engine nacelle fire protection are CF3I, HFC-227ea, and HFC-125. Halon 1301 is included in this study in order to establish a reference for comparison.
NIST Interagency/Internal Report (NISTIR) - 5499
Report Number


fire research, pipes, nitrogen, nacelle fires, halons, fire suppression, fire extinguishing agents


Cleary, T. , King, M. , Yang, J. and Grosshandler, W. (1994), Pipe Flow Characteristics of Alternative Agent/Nitrogen Mixtures (NISTIR 5499), NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed June 15, 2024)


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Created September 1, 1994, Updated November 10, 2018