Oxygen index: Correlations to other fire tests

Abstract

An investigation has been carried out of the limiting oxygen index (LOI) test. A review of the literature shows that, although there is abundant information on the test, it is not clear that its results correlate well with those of any other test, or indeed with those of real fires. Theoretical considerations indicate that the test could be improved by using it with bottom ignition rather than with the standard top ignition. A number of materials were tested in the cone calorimeter and in the LOI, and various correlations were attempted. In general, correlations between some of the cone calorimeter properties measured and the inverse of the LO1 made sense. These correlations were not, however, sufficiently sensitive, even when investigating small effects on a single base polymer system, to justify using the LO1 as a proxy for the cone in any way. The LO1 is likely to continue to be used extensively. This work suggests that quality control and, possibly, mechanistic or other flame-retardant additive studies, are its only applications where the results can be justified.

Polymer/Clay Nanocomposites

“…Therefore the clay minerals are used together with a low fraction of conventional flame retardants (Wang et al, 2004). However the clay minerals and traditional flame retardants have considerable synergistic effect in the reduction of ignitability of polymers and various reports of organically modified clay nanocomposites combined with halogenated flame retardants (Weil et al, 1992;Wang et al, 2005) and phosphorous flame retardants (Zhang & Horrocks, 2003;Hao et al, 2006) were presented in literature. The synergic effect of clays on the flame retardancy of halogenated and phosphorous compounds causes to the reduction of their volume fraction needed in the polymer/clay nanocomposite systems.…”

Cone calorimeter testing of S2 glass reinforced polymer composites

“…By looking at various parameters measured by the cone calorimeter, one can correlate those measurements to other tests or understand why a material achieved a particular regulatory rating. Work on comparing cone calorimeter with other tests has included full-scale flammability tests [5], bench scale tests like UL-94 or limiting oxygen index [6][7][8][9][10] automotive material flame spread tests [11], wire and cable flame spread tests [12] and other types of fire tests/scenarios [13][14][15][16].…”

Influence of flame retardant additives on the processing characteristics and physical properties of ABS

“…The oxygen index testing does not measure or take account of flaming polymer drips, which become detached from the flame front. The author noted (as have others [140]) that many ofthe samples were prone to these drips, which ignited the sides of the sample. The results from these samples were not used in determining the LOI value for that material.…”

“…A paper by Weil et al [140], which questioned its correlation with other tests and real fire characteristics, did acknowledge its convenience and more importantly its precision.…”