The pyrolysis kinetics of charring materials plays an important role in understanding material combustions especially for construction materials with complex degradation chemistry. Thermogravimetri...

http://spiral.imperial.ac.uk/bitstream/10044/1/25684/2/ef-2014-01380.pdf

Pyrolysis of Medium-Density Fiberboard: Optimized Search for Kinetics Scheme and Parameters via a Genetic Algorithm Driven by Kissinger’s Method

Combustion and charring properties of five common constructional wood species from cone calorimeter tests

Experimental and numerical simulation of multi-component combustion of typical charring material

Evaluating the mechanical and fire-resistance properties of modified fast-growing Chinese fir timber with boric-phenol-formaldehyde resin

A set of pyrolysis experiments were conducted on fir in inert atmosphere and different ambient pressures, to investigate the char shrinkage and cracking during combustion. The results show that the grain effect influences the char shrinkage. The shrinkage parallel to grain is only 1/4 of the shrinkage perpendicular to grain. The strong restriction on shrinkage parallel to grain leads to the major cracking perpendicular to the grain direction, whereas the cracking parallel to grain is relatively weak with only shallow and random fissures produced. The shrinkage gradient at cracking time increases with increasing heat flux and decreasing ambient pressure while the surface density behaves oppositely. The number of fissures is strongly affected by these two parameters and an empirical correlation is developed for predicting the number of fissures. Increasing the ambient pressure will enhance shrinkage, leading to early cracking with relatively low shrinkage gradient. Under the current experimental conditions, the occurrence of cracking requires a shrinkage gradient greater than 35 m −1 and a surface density lower than 0.8 of the original density.

Charring shrinkage and cracking of fir during pyrolysis in an inert atmosphere and at different ambient pressures

Modelling pyrolysis of charring materials: determining flame heat flux using bench-scale experiments of medium density fibreboard (MDF)

SUMMARY

To determine the fire origins for postflashover compartments, the char pattern and depth are investigated. A set of experiments was carried out using large-scale compartments made of medium-density fibreboard. A liquefied petroleum gas burner was used as the ignition source to mimic the fire origin. The burner was set at different locations in different experiments. It is found that time to flashover, intermittent flame of gas burner and ventilation condition have effects on the char patterns. The ‘ventilation patterns’ are likely to confuse the fire investigators; therefore, it needs to be identified from the ‘flame patterns’. In general, the ventilation patterns at the floor would initiate directly from the compartment opening. CFD simulations is used to reflect the ventilation conditions during fires thus assisting the identification of ventilation patterns. For those cases with less distinguishable char patterns, the profiles of total leftover material thickness and char depth were used to determine the fire origin. The char layer and total thickness in the flame regions were found to be respectively deeper and thinner than the rest parts of the compartment. The ventilation condition also affects the char depth profile; therefore, it cannot be ignored from analysis. At the end, a strategy of fire origin determination is proposed. Copyright © 2014 John Wiley & Sons, Ltd.

Jinhui Wang

Papers

Modelling pyrolysis of charring materials: determining flame heat flux using bench-scale experiments of medium density fibreboard (MDF)

An experimental investigation on char pattern and depth at postflashover compartments using medium-density fibreboard (MDF)