Thermal analysis of heat-treated silver fir wood and larval frass

Abstract

Among the widespread pests belongs Hylotrupes bajulus, which attacks mostly wooden beams in the roof of the houses. Heat sterilisation of wood is used to kill all forms of pests (eggs, larvae, adults) in solid wood materials. We compared thermal stability of heat sterilised silver fir wood to larval frass in regard to fire safety. The samples were treated at 60 and 120 °C for 10 h. Methods of chemical analysis, thermal analysis and statistical analysis were used. During the heat sterilisation of silver fir wood, only the amount of hemicelluloses decreased significantly. In larval frass samples, the holocellulose fraction decreased during the heat treatment. The hemicellulose yields in the larval frass samples were about 12% lower in average than in the wood samples. The major thermal degradation started at lower temperatures for untreated samples than for the heat-treated samples for both, silver fir wood and larval frass. Therefore, heat sterilisation does not deteriorate fire safety of wooden parts of buildings and can be used without significant alteration of the wood composition and properties.