Effects of Thermal Thickness and Charring Properties of Solid Combustibles on Heat Release and CO Emission Characteristics

Abstract

In this study, a series of ISO 5660-1 cone calorimetry experiments were performed to understand how the heat release rate (HRR) and CO emission are affected by the thermal thickness and charring properties of solid combustibles. To this end, HRRs and CO emissions measured from burning Douglas-fir wood (which produces a charring layer during combustion) and poly methyl methacrylate (PMMA) (which does not produce a charring layer) in the ISO 5660-1 cone calorimetry experiments were compared. Relative to PMMA, Douglas-fir wood produced a lower rate of heat release and CO emission, helping lessen human damage in fires. Results obtained from the ISO 5660-1 cone calorimetry experiments clearly demonstrate that the heat release rate varies depending on the thermal thickness and the presence of charring layer within solid combustibles. Unlike PMMA, the charring layer developed for Douglas-fir wood during combustion further increases the thermal thickness, reducing the amount of thermal decomposition and the heat released from fire. The cone calorimetry experiment results also indicate that increases in charring properties of solid combustibles were directly correlated with reductions in the HRR and increases in the CO emission.