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Smoke Production and Properties.


pdf icon Smoke Production and Properties. (951 K)
Mulholland, G. W.

NFPA SFPE 95; LC Card Number 95-68247;

SFPE Handbook of Fire Protection Engineering. 2nd Edition. Section 2. Chapter 15, National Fire Protection Assoc., Quincy, MA, DiNenno, P. J.; Beyler, C. L.; Custer, R. L. P.; Walton, W. D., Editor(s), 2/217-227 p., 1995.

Keywords:

fire protection; fire protection engineering; smoke production; size distribution; visibility; smoke detection; wood; plastics; particle size; equations; mass optical density

Abstract:

The term "smoke" is defined in this chapter as the smoke aerosol or condensed phase component of the products of combustion. This differs from the American Society for Testing and Materials (ASTM) definition of smoke, which includes the evolved gases as well. Smoke aerosols, vary widely in appearance and structure, from light colored, for droplets produced during smoldering combustion and fuel pyrolysis, to black, for solid, carbonaceous particulate or soot produced during flaming combustion. A large fraction of the radiant energy emitted from a fire results from the blackbody emission from the soot in the flame. The subject of radiant heat transfer is of such importance that it is treated in a separate chapter. This chapter focuses on smoke aerosols outside the combustion zone. The effects of the smoke produced by a fire depend on the amount of smoke produced and on the properties of the smoke. The following section presents experimental results on smoke emission for a variety of materials. The smoke emission, together with the flow pattern, determines the smoke concentration as smoke moves throughout a building. The most basic physical property of smoke is the size distribution of its particles. Results on size distribution for various types of smoke and techniques used for measuring particle size are presented in the section "Size Distribution." The section "Smoke Properties" focuses on those properties of greatest concern to the fire protection community: light extinction coefficient of smoke, visibility through smoke, and detectability of smoke. These properties are primarily determinded by the smoke concentration and the particle size distribution. References for other smoke aerosol properties, such as diffusion coefficient and sedimentaion velocity, are also provided.