Citation

Staggs JEJ. Fire Safety J. 1999; 32(1): 17-34.

Copyright

(Copyright © 1999, Elsevier Publishing)

DOI

unavailable

PMID

unavailable

Abstract

A theoretical framework for characterising single-step Arrhenius degradation kinetics in terms of a characteristic temperature and temperature range is developed. It is demonstrated that for the purposes of practical calculation, the reaction order may be assumed to be unity and also that a first-order approximation to an nth-order TG curve remains a good approximation over an order-of-magnitude variation in heating rate. This fact implies that when the pyrolysis of much larger samples of material is modelled, the error involved in using first-order kinetics is small. The equivalent first-order approximation is then applied to a global in-depth model of polymer degradation in order to predict mass loss rates in bench-scale experiments such as the cone calorimeter test. The mass loss rate curves obtained from the equivalent first-order approximation are found to compare well with the full nth-order model. Finally, an estimate of the average or steady mass loss rate is developed which fully accounts for the interaction between the degradation kinetics, the external heat flux, the heat losses and the latent heat of vaporisation.