The Problems, Language and Scientific Basis of Flammability Testing

Flammability tests are intended to provide a measure of the fire hazard of a material or product. The gross factors involved are the ease of ignition, the rapidity of combustion development, the severity of conditions produced by the combustion (heat, smoke and toxic gas loads), and the performance of a product under a fire load. Most flammability tests have been developed by practical people under external pressures (legal or corporate) to produce a believable, reproducible test requiring a minimum of effort, equipment, and manpower. The scientific understanding of the tests is a luxury usually denied the designers. The resulting tests each measure some aspect of flammability, usually reproducible and well. However, because of thtlack of basic understanding, related tests measure different aspects of flammability and correlate poorly. There is a need for increased effort in understanding tests scientifically to aid in correlating and interpreting the results. A side result of this situation is that a jargon has developed which often obscures the usage and basis of the tests. This paper will document the chaotic state of flammability testing, define some of the specialized terms, and close with some suggestions for the scientific interpretation of some aspects of wire and cable testing as an example of the approach which the author feels would increase understanding in this field.