Thermal treatment modifies the calorific value and ash content in some wood species

Thermo-treated wood is a new material that has recently been introduced to the market. Thus, the increase in the amount of treated wood in the wood industry and in the interior of buildings creates demands for the evaluation of its fire risk. However, few evidences have yet been published on the calorific evaluation and fire load, required in case of building code, for thermo-treated wood products. The main goal of this research was to evaluate how different treatments affect the calorific values and the relative ash content for three cases of thermo-treated woods (Norway spruce, Common ash, and Turkey oak). Norway spruce and Common ash were thermally treated at 190 °C for two hours. Turkey oak logs were initially steamed at 110 °C for 24 h, dried until the 0% of moisture content and then thermo treated at 160 °C for three hours. Low and High calorific values (LCV, HCV) and ash content were evaluated. Ash content and HCV are related to dry mass. After thermo-treatment, the LCV and HCV increased, while the ash content changed significantly in Turkey oak.