Ignition Properties of New Zealand Timber
This project investigated the ignition properties of New Zealand Timbers and timber products. The ignition test on the wood was according to the British Standard BS 476: Part 13, 1987 using ISO ignitability apparatus. The ignition time for each sample was recorded and correlated by seven correlations. These seven correlations are: 1) Mikkola and Wichman 2) Tewarson 3) Quintiere and Harkleroad 4) Janssens 5) Toal, Silcock and Shields 6) Delichatsios, Panagiotou and Kiley 7) Spearpoint and Quintiere Six types of wood, Macrocarpa, Beech, Rimu, Radiata Pine, Plywood and medium density fiberboard (mdf) were tested at constant heat flux lower than 40 kW/m² until ignition did not occur within 20 minutes. Each type of wood was tested at two different thicknesses, 20 mm and 40 mm. The repeatability and reproducibility were also determined. It was found that the results such as critical heat flux, thermal inertia, ignition temperature, Thermal Response Parameter (TRP), Flux Time Product (FTP) and so on were different from one correlation to another. It is hard to say which one is the best technique in estimating the ignition properties ofNew Zealand wood, but one can get an idea of which methods will give higher or lower results. Another words: the tendency of each method to under-predict or over-predict the results. Both the 20-mm and 40-mm wood behaved as thermally thick (some thermally intermediate) solids and they have very close values of minimum heat flux and critical heat flux.