Smoldering Combustion.
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.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899