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The effect of pyrolysis and combustion temperatures on smoke density
Author(s) -
Edgerley P. G.,
Pettett K.
Publication year - 1978
Publication title -
fire and materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.482
H-Index - 58
eISSN - 1099-1018
pISSN - 0308-0501
DOI - 10.1002/fam.810020105
Subject(s) - smoke , combustion , pyrolysis , opacity , flammable liquid , environmental science , flammability , chemistry , environmental chemistry , organic chemistry , physics , optics
The small‐scale smoke testing apparatus now proposed as a standard in France under the designation NF–T51–073 measures the total obscuration from a stream of smoke generated from a small sample. Although like other small‐scale fire tests, it is not claimed to be of relevance to real fire situations, it is possible by varying the temperature over a wide range (200–900°C) to obtain a plot of specific optical density for various materials which broadly corresponds with general experience and certain other smoke tests. The plots show that nearly all flammable substances give a rapid rise in smoke opacity in the 350–500°C region above which there is always a steep drop sometimes to smoke densities of virtually zero. Apart from one or two synthetic materials which show a very low smoke density through‐out, there is no general trend as between natural and synthetic substances. Oxygen depletion which often occurs in a real fire situation has some effect on the smoke density but it is not a major one. On the other hand, in some cases reheating the smoke can have quite a dramatic effect, due very probably to further pyrolysis and combustion.