Citation

Rasbash DJ, Pratt BT. Fire Safety J. 1980; 2(1): 23-37.

Copyright

(Copyright © 1980, Elsevier Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Some of the major difficulties that confront the estimation of smoke that may be produced at fires are considered. They include the confusion over the units in which smoke is expressed, reliability of laboratory test methods for smoke production developed so far, and the factors which may cause a difference between laboratory tests on the one hand and fire tests in general, and fire ground conditions on the other. Information on some of the latter factors is reported in the experimental results on the smoke produced by samples of materials of different height, burning freely, both singly and as combinations of two materials comprising the sides of a small, square chimney. It was found that within the range of heights of chimney of 3.2 - 15 cm the smoke potential of materials, Do (smoke produced per unit weight of volatiles), reduced as the height increased by a factor of 1.5 - 2. In general, also, the contribution of different materials was additive unless one of them did not burn well by itself, in which case less smoke was produced than expected.In addition, a number of approximate working formulae have been developed to estimate Do of materials burned in fire tests, from measurements of smokiness, DL, obtained in the test, together with other data, such as gas analyses or temperature, that may be available. Do is expressed in units of ob m3/g, which is based on a new unit for smokiness, the obscura (ob), used to express DL. On the whole, values of Do obtained in this way did not differ radically from values obtained under flaming conditions using bench tests, but there is evidence that under ventilation-controlled conditions with vertical vents, substantially higher values of Do may be obtained than under fuel-controlled conditions. From information on Do thus obtained, combined with information on Do available from bench tests, a tentative list of values of Do is given, for different materials burning under different conditions, which may be used as a first step towards predicting smoke output and smokiness in fire situations.