Passive Fire Protection of Wood Substrates using Starch-based Formulations

Wood is the most sustainable, aesthetically pleasing and environmentally benign material. It often forms an integral part of structures and is the main source of furnishings found in homes, schools and offices around the world. Ligno-cellulosic materials such as wood also occupy a high-level hierarchy among natural materials, especially in the context of lightweight construction, which primarily derives from their near-carbon neutrality. However, wood-based construction materials often suffer from a major drawback, i.e. its relatively high flammability. In addition, the toxicity and associated hazardous nature of fire resistant formulations that are currently in use for wood-based substrates are considered as serious drawbacks. Therefore, it is highly prudent to devise means and methods of utilizing environmentally friendly, non-toxic and sustainable natural materials as passive fire protective agents for wood. In the present paper, we report the preliminary results on the development, subsequent application and testing of some environmentally friendly formulations that are suitable for passive fire protection of ligno-cellulosic materials. The primary aim of this study was to evaluate the effectiveness of starch-based colloids as fire protective coatings of softwood substrates. The formulations were comprised of either an aqueous starch colloid solution alone, or in combination with some inorganic salts. The fire performance of unprotected wood and the wood samples with formulations applied as surface coatings was determined using a range of standard techniques. They included thermo-gravimetric analysis (TGA), Fourier Transform Infrared (FT-IR) spectroscopy, bomb and cone calorimetries, and a steady-state tube furnace-FT-IR.