1. The fire retardant coating itself has flame retardancy or incombustibility, which prevents the protected substrate from direct contact with air, delays the ignition of objects and reduces the combustion speed.
2. In addition to its own flame retardancy or incombustibility, the fireproof coating also has low thermal conductivity, which will delay the transfer of flame temperature to the protected substrate.
3. The fire retardant coating decomposes nonflammable inert gas when heated, which dilutes the combustible gas decomposed by the protected object, making it difficult to burn or slowing down the burning speed.
4. Nitrogen-containing fire retardant coating decomposes NO, NH3 and other groups by heating, and combines with organic free radicals to interrupt the chain reaction and reduce the temperature.
5. Expansion effect: Some fire-retardant coatings can also produce expansion effect through chemical reaction at high temperature. In a fire, when the paint encounters high temperature, its internal chemical composition will change, producing gas or swelling substance. This expansion effect can form a porous structure and increase the thickness of the coating, thus providing a longer fire protection period.
Generally speaking, these effects work together, so that the fire retardant coating for steel structure can effectively improve the fire resistance limit of materials and protect the safety of materials in fire.