Timber is one of the most sustainable and renewable raw materials available. Globally, it has been increasingly used for the manufacture of home and workplace furniture. Timber products are known to have ignition resistance and a low heat release rate. These characteristics delay burning and maintain the structural durability of a product, protecting both the occupants and their properties in a fire. Timber, however, experiences thermal degradation during combustion, yielding smoke, heat, toxic gases, and char when burned. To understand the fire conduct of timber, extensive knowledge in its process of decomposition is essential. This paper, therefore, reviewed the methods of flammability tests widely employed to investigate the reaction of timber and timber-based product to fire, namely cone calorimeter test, room-corner test, limiting oxygen index (LOI) test, furnace test, and single burning item test (SBI). In addition, an overview of the fire retardant treatments; impregnation and coatings was also presented. The potential effects of fire retardants on the durability, strength, hygroscopicity, corrosion, machinability, glueing characteristics, and paintability of the timber were also highlighted.
The information on the combustion properties of local timber is crucial in Malaysia as the archival material related to this subject matter is found to be very limited in scope and incomplete. The heat release rate (HRR) is the most precious variable of combustion properties as it provides the key to understand and quantify the hazard in fires. Thus, this work is to verify the reliability of the HRR obtained from cone calorimeter tests conducted upon six Malaysian wood species: Shorea laevis, Vatica rassak, Koompassia malaccensis, Heritiera, Shorea parvifolia and Cratoxylum arborescens. The single factor one-way analysis of variance (ANOVA) was used to investigate statistically significant differences between the means of the HRR dataset of each species during the combustion tests at three different heat fluxes. Later, the confidence interval estimation was occupied to determine the range around the HRR dataset, where the means of the data was likely to be found. The intraclass correlation coefficient (ICC) test was also implemented to assess the reliability of the heat release rate data obtained from the cone calorimeter test. From the surveillance, the P-values of all the six species were higher than α = 0.05, insinuating that the difference between the means of the dataset was not statistically significant. The confidence interval values consisting of the upper bound and lower bound limits indicate that the certainty that these ranges contain the true mean of the heat release rate dataset is 95%. Finally, the fact that heat release data received from the cone calorimeter test were highly reliable to statistically calculate the variation in measurements taken by a single instrument under the same condition confirmed by the ICC’s values of 0.82 to 0.99 that reflect good to excellent correlations.