Burning Characteristics of Ancient Wood from Traditional Buildings in Shanxi Province, China

Abstract

Due to long-term natural degradation, the surface morphology of traditional building wood differs significantly from that of modern wood. It is more combustible than modern wood and its combustion characteristics are important evaluation indicators for fire simulation and fire protection of traditional buildings. In this paper, ancient wood from six traditional buildings were tested by a surface morphology fractal method and conical calorimeter. Additionally, their combustion properties such as ignition time, heat release rate, total heat release and charring time were analyzed to determine the combustion behavior of ancient wood and their differences with modern wood. The results showed that the ignition time of the specimens was significantly influenced by the surface morphological features. The higher the fractal dimension grade of the morphological features, the shorter the ignition time. The ignition time of Ulm wood with fractal dimension class 3 was 15 s, while that of Ulm wood with fractal dimension class 1 was 23 s. Under the same fractal dimension class, the total heat release per unit time of ancient softwood was higher than that of ancient hardwood. The average heat release rates of Larch wood and Ulm wood were 66.21 kw·m−2, 72.07 kw·m−2 and 57.26 kw·m−2, 67.30 kw·m−2. The basic charring rate of ancient wood of the same species was mostly higher than that of modern wood by more than 6%, with the basic charring rate of ancient Larch wood being 0.8559 mm/min, which was 15.66% higher than that of modern Larch wood, 22.27% higher than that recommended in the European EC5 standard, and 6.87% higher than that calculated in the American AFPA. The results of the study are important guidelines for fire risk assessment and fire protection of traditional buildings.