Fire resistance properties of some selected tropical timber species from South-western Nigeria after fire exposure

The research investigated changes in post fire density and strength properties of Nigerian wood species used for construction. The selected species are: Terminalia superba (Afara), Milicia excels (Iroko), Nauclea diderrichii (Opepe), Khaya ivorensis (Mahogany), Mansonia altissima (Mansonia), Tectona grandis (Teak). Densities and strength properties of the species were determined at Moisture Contents (MC) of 9.0, 12.0, and 15.0%. Species were exposed to fire at various temperature ranges. The results revealed that at 9, 12 and 15%MC, Opepe had the highest density values of 630±28.85kg/m³, 686±22.64kg/m³ and 752±17.22 kg/m³ respectively. At 9%MC, Mahogany had the lowest density (439±10.58kg/m³) while at 12 and 15%MC, Afara had the lowest density values of 444±4.18kg/m³ and 469±7.07kg/m³ respectively. Post fire exposure revealed that Afara had the highest percentage loss in density 29.2% and strength properties, while both Iroko and Mahogany exhibited the lowest percentage loss in both density and strength properties.