Effectiveness of fire protection of wood with an organic-mineral coating with the addition of aluminum hydroxide

Abstract. Today, there are two methods of fire protection for wood. The first is impregnation with flame retardants, most often based on inorganic salts. When wood is moistened, fire retardants dissolve in a humid environment and gradually wash out to the surface, and then the fire retardant effect decreases over time. Acid-based products do not have a significant leaching problem due to changes in wood moisture, but penetrating deep into the wood structure and interacting with the cellulose, they reduce strength parameters. Therefore, it is not safe to use this product for critical load-bearing structures. The second method is to apply an organic or inorganic binder coating to the wood surface. Organic binder-based products have increased smoke generation and toxic substances, so their use is dangerous. Therefore, coatings capable of forming a heat-insulating layer on the surface of a building structure, which significantly reduces the processes of heat transfer to the material, have recently become widespread. As a result of the studies, it was found that the introduction of aluminium hydroxide into the composition of the organo-mineral coating in the amount of 2...8% reduces the swelling coefficient from 30 to 18 to a certain extent. However, for a coating containing 4%, an increase in the efficiency of fire protection of wood was found, namely a decrease in the loss of sample mass and flue gas temperature due to the formation of heat-resistant compounds on the surface of the fire protection layer when aluminium hydroxide interacts with ammonium polyphosphate. The use of aluminium hydroxide in the fireproofing composition provides the required level of protection of wood from thermal effects at the required amount of 4%, which leads to a reduction in cost and an increase in the efficiency of the coating. In further studies, it is planned to investigate other types of fillers, their properties and impact on the fire protection efficiency of wood in fireproof organic-mineral coatings.