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Smoldering Combustion.


pdf icon Smoldering Combustion. (1095 K)
Ohlemiller, T. J.

NFPA SFPE 95; LC Card Number 95-68247;

SFPE Handbook of Fire Protection Engineering. 2nd Edition. Section 2. Chapter 11, National Fire Protection Assoc., Quincy, MA, DiNenno, P. J.; Beyler, C. L.; Custer, R. L. P.; Walton, W. D., Editor(s), 2/171-179 p., 1995.

Keywords:

fire protection; fire protection engineering; smoldering combustion

Abstract:

Smoldering is a slow, low-temperature, flameless form of combustion, sustained by the heat evolved when oxygen directly attacks the surface of a condensed-phase fuel. Smoldering constitutes a serious fire hazard for two reasons. First, it typically yields a substantially higher conversion of a fuel to toxic compounds than does flaming (though this occurs more slowly). Second, smoldering provides a pathway to flaming that can be initiated by heat sources much too weak to directly produce a flame. The term smoldering is sometimes inappropriately used to describe a non-flaming response of condensed-phase organic materials to an external heat flux. Any organic material, when subjected to a sufficient heat flux, will degrade, gasify, and give off smoke. There usually is little or no oxidation involved in this gasification process, and thus it is endothermic. This is more appropriately referred to as forced pyrolysis, not smoldering. This chapter is restricted to consideration of post-initiation behavior of smoldering. There are a few models of smolder propagation in the literature but none sheds much light on any practical smolder problem. The state of modeling is reviewed elsewhere. Lacking any definitive theoretical description, this chapter is largely restricted to examining typical experimentally determined behavior. In this overview of smoldering, an attempt is made to convey some of the qualitative interplay of processes that determines overall behavior together with specific experimental results.