What are the properties of fire-resistant coatings for steel structures?
Thin coating steel structure fire retardant coating refers to the coating thickness of more than 3mm, less than or equal to 7 mm, with certain decorative effect, high temperature expansion and thickening, fire resistance within 2 H steel structure fire retardant coating. The fire retardant coating for steel structure is made up of suitable water polymer as base material, compounded with flame retardant compound system, fireproof additive, refractory fiber, etc. the principle of fire protection is super thin. For this kind of fire retardant coating, the water borne polymer must have good adhesion, durability and water resistance. Its decorative properties are better than those of thick fireproof coatings, which are inferior to those of super thin steel structure fire retardant coatings. The average fire resistance is within 2 h. Therefore, spraying construction is often used in steel structure fire protection engineering which is less than 2 h fire resistance limit. This kind of products occupy a large proportion in a period, but with the emergence of ultra-thin steel structure fire retardant coating, its market share is gradually replaced.
Ultra thin structure fire retardant coating refers to the coating thickness of 3mm (including 3 mm) less than, decorative effect is good, high temperature can expand foaming, fire-resistant limit is generally less than 2 H steel structure fire retardant coating. This kind of fire retardant coatings for steel structures is generally solvent system, bonding strength, weathering has good water resistance, good leveling, good decorative features such as superior; subjected to fire slow expansion foam fire insulation layer to form a dense solid, the fireproof layer has a strong impact resistance, the temperature rise of steel delay, effective protection of steel member. Ultra thin intumescent steel structure fire retardant coating can be sprayed, brushed or rolled. It is generally used in building steel structures with a fire resistance requirement of less than 2 h. At present, there has been a fire resistance to meet or exceed the new ultra-thin fireproof coating for steel structure of 2 varieties of H, it is mainly based on the special structure of the poly methyl acrylate or epoxy resin and amino resin, chlorinated paraffin, compound as base adhesive, with high degree of polymerization of ammonium polyphosphate, melamine and pentaerythritol, double as the fire retardant system, adding titanium dioxide, wollastonite and other inorganic refractory material, using 200# as solvent and solvent oil compound. At present, all kinds of light steel structure, grid and so on, use this type of fire retardant coatings for fire protection. Because this type of ultra-thin fireproof paint coating, making use of thick and thin fire retardant coating for steel structure is greatly reduced, thereby reducing the total cost of the project, the steel structure has been effective fire protection, is currently promoting varieties on the market.
Thick steel structure fire retardant coating refers to the steel structure fireproof coating with coating thickness greater than 7 mm, less than or equal to 50 mm, granular surface, little density, low thermal conductivity, and refractory limit of 2 h or more. Because of the thick fire retardant coating composition for inorganic materials, so the fire performance is stable, long-term effect is good, but the coating components of larger particles, the coating appearance is not smooth, affect the overall appearance of the building, so most structure for concealed works. In the fire, the material has a granular surface, a smaller density, a low thermal conductivity, or a heat absorbing property in the coating, delaying the temperature rise of the steel and protecting the steel. This kind of fire retardant coating is suitable for inorganic binder (such as water glass, silica sol, aluminum phosphate salt, refractory cement, etc.) together with inorganic light insulation aggregate materials (such as perlite, vermiculite, bouldering, sea and fly ash cenosphere), fire retardant additives, chemicals and materials (enhanced such as rock wool, aluminum silicate fiber, ceramic fiber, glass fiber and filler) mixed together, has the advantages of low cost. Spraying is often used in construction. It is suitable for indoor and outdoor concealed steel structure, high-rise steel structure and multi story steel structure with requirements of fire resistance above 2 h. Such as: high-rise building columns, general industrial and civil buildings in support of multi-storey columns of fire resistance should reach 3 h, the need to use this thick fire-retardant coating protection.
