• Hostikka, Simo
• Rinta-Paavola, Aleksi

Abstract

The reduced cross section method for the calculation of timber structures’ fire resistance is based on empirical and numerical assessment of charring propagation. The current work aims to construct a model for the pyrolysis and oxidation of spruce and pine woods to allow coupled simulations of cross section reduction and burning rate in fire models. A pyrolysis model for these woods is formulated based on thermogravimetric analysis (TGA), and supported by heat of pyrolysis and heat of combustion measurements by differential scanning calorimetry (DSC) and microscale combustion calorimetry (MCC), respectively. The results from small scale measurements (TGA, DSC and MCC) are consistent with each other. Therefore, heat of pyrolysis and heat of combustion was determined for the wood primary components by fitting a simulation into these experimental results. Experiments in a ventilation-controlled cone calorimeter in near-zero oxygen content under an inert nitrogen flow are performed to estimate material properties of the pyrolyzing solid and to validate the model. As a future work, cone calorimeter experiments in an oxidative atmosphere are performed to evaluate the effect of surface oxidation of wood and char.

Topics

• pyrolysis
• impedance spectroscopy
• surface
• experiment
• simulation
• Oxygen
• Nitrogen
• combustion
• thermogravimetry
• differential scanning calorimetry
• wood
• oxygen content