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Suppression of Ignition Over a Heated Metal Surface.


pdf icon Suppression of Ignition Over a Heated Metal Surface. (283 K)
Hamins, A.; Borthwick, P.; Presser, C.

National Institute of Standards and Technology (NIST) and Society of Fire Protection Engineers (SFPE). International Conference on Fire Research and Engineering (ICFRE). Proceedings. September 10-15, 1995, Orlando, FL, SFPE, Boston, MA, Lund, D. P.; Angell, E. A., Editor(s)(s), 77-81 pp, 1995.

Keywords:

fire research; halogenated compounds; ignition; ignition suppression; ignition temperature

Abstract:

The objective of this work is to investigate the effectiveness of various agents in suppressing flame ignition. Experiments were conducted to determine the amount of agent needed to suppress the ignition of a gaseous propane flow over a heated metal disk. The disk was 14 mm in diameter and was a wound ribbon composed primarily of nickel. The metal surface was heated by a regulated power supply which provided up to 200 W. An optical pyrometer was used to measure the surface temperature of the heated disk. With power applied to the metal disk, a fairly uniform temperature (+30 deg C) was measured in an annular section of the disk. A coflowing mixture of air and gaseous fire suppressant flowed through a 78 mm tube about the fuel flow. With the fuel and oxidizer flowing, flame ignition occurred in a repeatable fashion by increasing the power through the metal disk. Various amounts of agent were added to the air flow and the temperature of the heated metal disk was measured at flame ignition using an optical pyrometer. The effectiveness of N2, HFC-125, HFC-227 and CF3I were compared in suppressing the ignition event.