Charring rates of timbers from Chinese species and comparison with various charring rate models

The charring rate is the most important property of wood with respect to its fire resistance and fire integrity. It is necessary to predict the charring rate of wood through a charring rate model due to the difference of various test methods and the variety of wood species. A power integral charring rate model, the CAF model, has been developed based on Chinese species using the cone calorimeter. Theoretical charring rate results of CAF model, EC5 model, Australian code AS 1720.4 and Ulg model were calculated from experimental details by Njankouo et al. (Constr Build Mater 19(5):376–386, 2005) and Cachim and Franssen (Fire Mater 33(3):129–143, 2009), respectively. Then, these theoretical charring rate results were again compared with tested charring rate results from Njankouo et al. (Constr Build Mater 19(5):376–386, 2005) and Cachim and Franssen (Fire Mater 33(3):129–143, 2009). The results showed that the cone calorimeter can be equal to the furnace for studying wood charring when the heat flux is considered. The precision of the power integral model is higher with the increase in burning time. The EC5 model, Australian code AS 1720.4, Ulg model and White’s model are not entirely satisfactory. The power integral model is acceptable for medium density as well as high density, while unsafe at a density of less than 290 kg/m³.