Abstract:
Many studies have been carried out on fire resistance properties of wood species to determine the rate of heat released, ignition and burning rate of woods, ignition time and ignition temperature, smoke release rate and rate of flame spread. However, little emphasis has been laid on the effect of some wood properties such as moisture content; density and calorific value on the fire properties of wood. In this study, attention is focused on the effect of these wood properties. Some selected wood species: Rubus hawaiensis, Gmelina arborea, Mansonia altissima, Milicea excelsa, Alstonia congensis, Khaya senegalensis, Tectona grandis, Cordia platythyrsa, Pterygota macrocarpa, Aningeria spp, Hevea brasiliences and Pterocarpus mildreadii were examined using two different tests, that is, ignitability test using induction furnace and proximate analysis of the wood species to determine the moisture content. The calorific values of the various woods were also determined using the bomb calorimeter. The result of ignition data obtained from
ignitability test showed that; Hevea brasiliences (softwood) with density 497.33 kg/m3 ignites at temperature 306 oC at 1436 s., while Tectona grandis with density 800.00 kg/m3 ignites at temperature 342 oC at 1531s. this showed that the higher the density , the higher the temperature at which the wood ignites. The results of proximate analysis showed that hardwoods: Tectona grandis, Aningeria spp, Khaya senegalensis, Milicea excelsa, Mansonia altissima and Rubus hawaiensis with moisture contents 9.15 %, 9.104 %, 8.535 %, 7.92 %, and 6.85 %, have better fire resistance respectively, while softwood woods: Alstonia congensis , Gmelina arborea, Pterygota macrocarpa and, Hevea brasiliences with moisture contents; 7.69 %, 7.252 %, 7.106 % and 6.746 % respectively have the least fire resistance. The value obtained for the calorific value of the samples increases from sample K (Hevea brasiliences), 16.146 MJ/kg to the highest value for
sample G (Tectona grandis), and 18.232 MJ/kg. Hence, to improve the fire resistance properties of wood species used as building materials, lignin and extractive content that influence high calorific value of wood should be considered.
