Comparisons of predicted and experimental charring rates at various moisture contents of selected Southern Nigerian structural wood species
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Abstract
Investigation of the performance of Nigerian structural wood species under fire exposure to predict structural collapse have not been adequately researched. In this study, the charring rate of six identified structural wood species were determined. They are Terminalia superba (Afara), Milicia excelsa (Iroko), Khaya ivorensis (Mahogany), Mansonia altissima (Mansonia), Nauclea diderrichii (Opepe), and Tectona grandis (Teak). The wood densities values at three moisture contents (MC), 9, 12, and 15%, were determined. Fifty-four wood samples, nine block specimens of dimensions 150 mm x150 mm x 510 mm from one board of each of the six species were tested in three groups. Fire exposure tests were carried out on the selected wood samples at three different controlled temperatures of 20 °C to 230 °C for 30 minutes, 230 °C to 600 °C for 30 minutes, and 20 °C to 300 °C for 60 minutes. Empirical statistical models using ANOVA at α = 0.05 were developed for the experimental charring rate of the wood samples. The results were compared with the values of the predicted charring rates of the wood samples. At fire temperatures between 20 °C and 300 °C and fire exposure times of (0 - 60) minutes, the values of the coefficient of correlation, R, of the wood samples of 9%, 12%, and 15% MC, were 0.682, 0.582, and 0.578, respectively. The values indicated that there exist a strong positive correlation of actual charring rate that can be explained by the relationship to the predicted charring rate of the wood samples.
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