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Review of Measurements and Candidate Signatures for Early Fire Detection.


pdf icon Review of Measurements and Candidate Signatures for Early Fire Detection. (2313 K)
Grosshandler, W. L.

NISTIR 5555; 36 p. January 1995.
Order number: PB95-189452

Keywords:

fire detection; fire detectors; fire gases; fire plumes; fire research; fire tests; smoke detectors; test fires

Abstract:

The physical and chemical transformations associated with a burgeoning fire are discussed and the results of past experimental measurements of these transformations are summarized. Standard test methods for the current generation of fire detectors and recent developments in detection technologies for which existing standards may not be suitable are described. The literature has been reviewed to determine the extent to which fires have been characterized in their early phase (<100 kW). In particular, measurements of CO, CO2, H2O, H2, O2, smoke and temperature have been examined. Ond finds dramatic variations in the measured magnitude and rate of growth of CO concentration in a vareity of standard fires. The variation is also large between repeat runs of the same tests. When scaled by estimated mass consumed of fuel, the different standard fires group a bit more systematically. Additional measurements of species, temperature and velocity just above the flame are suggested to get a more complete footprint of each fire type. Similar measurements of non-fire nuisance sources are required in order to discriminate between a fire and non-threatening situation with a high degree of certainty. The concept of a universal fire emulator/detector evaluator (FE/DE) is introduced. The objective is to have a facility that will eliminate the unavoidable run-to-run variations associated with full-scale tests, and to allow more well controlled environments. Computational fluid dynamics could then be used to insert the fire source into the space being protected to guide detector placement and to predict system performance, as well as to compare alternative systems and new conceptson a level, realistic playing field.