One、What is fire-resistant coating?
Fire-resistant coatings are special coatings used on combustible substrates to reduce the flammability of the coated material surface, prevent the rapid spread of fire, and improve the fire resistance of the coated material. These coatings are applied to combustible substrates to alter their fire resistance and prevent the rapid spread of fire, or to building components to improve their fire resistance, and are commonly referred to as fire-resistant coatings.
What is the fire-resistant principle of fire-resistant coatings?
1、The principle of ultra-thin or thin fire-resistant coatings
The fire-resistant and insulating principle of applying ultra-thin or thin steel structures coated with fire-resistant coatings on steel structures is that the coating expands and foams when exposed to fire, forming a foam layer. This layer not only insulates against oxygen but also possesses good thermal insulation properties due to its loose texture, which can slow down the transfer of heat to the protected substrate. According to the physical and chemical principles, the process of foam generation during coating expansion and foaming exhibits an endothermic reaction due to the expansion of volume, which also consumes heat during combustion, thereby reducing the temperature of the system. These effects result in significant fire-resistant and insulating effects for the fire-resistant coating.
2、Principle of fire-resistant coating for thick steel structures
The fire-resistant and thermal insulation principle of applying a thick steel structure fire-resistant coating on steel components is that the coating does not undergo significant volume changes when exposed to fire. However, the coating has a low thermal conductivity, which slows down the transfer of heat to the protected substrate. The coating itself is non-combustible, providing a barrier and preventing heat radiation, thus protecting the steel components from direct attack by flames and high temperatures. Furthermore, some components in the coating react with each other upon exposure to fire, generating non-combustible gases through exothermic reactions, which absorb heat and lower the system temperature, resulting in significant fire-resistant and thermal insulation effects, providing efficient fire protection and thermal insulation for steel structures.
Additionally, these types of steel structure fire-resistant coatings do not undergo volume changes when exposed to fire, forming a glassy protective layer. This layer can effectively prevent oxygen from reaching the combustible substrate, thereby preventing or reducing combustion reactions. However, the glassy protective layer formed by these coatings often has a high thermal conductivity, resulting in poor thermal insulation. To achieve a certain level of fire and thermal insulation, thick-coat fire-resistant coatings typically require a thicker coating to meet the required fire and thermal insulation performance.