Calorific value and fire risk of selected fast-growing wood species

Abstract

This study deals with heat of combustion of selected fast-growing woods. The study also investigates the impact of heat flux on fire risk of the selected fast-growing woods. The hybrid poplar J-105 (Populus nigra × P. maximowiczii), white willow (Salix alba L.) and black locust (Robinia pseudoacacia L.) woods were measured. The heats of combustion were determined by a bomb calorimeter. Fire risk was evaluated with a cone calorimeter at different heat fluxes. The net heat of combustion occurred in the interval from 17.68 MJ kg−1 (black locust) to 18.02 MJ kg−1 (hybrid poplar). Fire risk was assessed on the basis of the critical heat flux, maximum average rate of heat emission, carbon monoxide yield, smoke yield and time to flashover. The hybrid poplar had the lowest critical heat flux (12.8 kW m−2), and the white willow had the highest critical heat flux (17.4 kW m−2). The maximum average rate of heat emission and the smoke yield increased with the increasing heat flux. On the other hand, carbon monoxide yield decreased with the increasing heat flux. The differences between the times to flashover of the measured wood species were not significant.