Outdoor Non-Expanding Fire Retardant Coating for Steel Structures

Outdoor non-expansive steel structure fire-retardant coating refers to a fire-retardant coating for steel structures with a coating thickness greater than 7 mm and less than or equal to 45 mm, featuring a granular surface, lower density, and low thermal conductivity, with a fire resistance limit of over 3 hours.

Due to the inorganic composition of non-expanding fire-resistant coatings, their fire-retardant properties are stable and offer good long-term performance. However, the larger particle size of the coating components results in an uneven finish, affecting the overall aesthetics of the building. Consequently, they are mostly used in concealed structural work. During fires, these coatings utilize the granular surface of the material, its low density, and low thermal conductivity, or the material's heat absorption properties to delay the temperature rise of steel, thereby protecting it.

This type of fire-resistant coating is made by mixing appropriate inorganic binders (such as water glass, silicate sol, aluminum phosphate salts, refractory cement, etc.) with inorganic lightweight insulating aggregates (like expanded perlite, expanded vermiculite, sea spathic, polystyrene beads, fly ash, etc.), fire-retardant additives, chemical agents, reinforcing materials (such as aluminum silicate fibers, rock wool, ceramic fibers, glass fibers, etc.), and fillers, offering the advantage of lower cost.

Construction commonly employs spraying, suitable for concealed steel structures indoors and outdoors with fire resistance requirements exceeding 2 hours, as well as high-rise full-steel structures and multi-story factory steel structures. For example: The fire resistance of columns in high-rise civil buildings and columns supporting multiple floors in general industrial and civil buildings should reach 3 hours, and non-expansive fire-resistant steel structure coatings are required for protection.