The fireproof mechanism of steel structure fireproof coatings

The fireproof mechanism of steel structure fireproof coatings

Steel structure fireproof coatings delay the temperature rise of steel in fires through various mechanisms, ensuring structural stability under high temperatures.

The main fireproof mechanisms are as follows:

Thermal Barrier Formation

• Intumescent Coatings: When exposed to high temperatures, the coating expands to form a porous char layer, insulating against heat and oxygen, thereby slowing the steel’s temperature rise.
• Non-intumescent Coatings: Utilize fillers with high heat capacity and low thermal conductivity (e.g., aluminum hydroxide, magnesium hydroxide) to absorb heat and form an insulating layer.
• Endothermic Reactions

• Heat Absorption via Decomposition: Fillers such as aluminum hydroxide and magnesium hydroxide decompose under high temperatures, absorbing heat and reducing the steel’s temperature.
• Phase Change Heat Absorption: Certain fillers absorb heat through phase transitions at high temperatures, delaying the steel’s temperature rise.2Inert Gas Release

• Gas Emission: At high temperatures, the coating decomposes and releases inert gases (e.g., nitrogen, carbon dioxide), diluting oxygen concentration and suppressing combustion.Char Layer Protection

• Char Formation: Intumescent coatings form a dense char layer at high temperatures, shielding the steel from heat and oxygen.
• Char Layer Stability: The char layer remains stable under high temperatures, providing continuous protection.
• Chemical Reactions

• Flame Retardant Effects: Flame retardants (e.g., phosphorus-based, nitrogen-based) in the coating generate fire-inhibiting substances at high temperatures, suppressing combustion reactions.
• Physical Barrier

• Coating Thickness: Increased coating thickness enhances insulation, delaying the steel’s temperature rise.
• Dense Structure: The coating forms a compact structure, effectively blocking heat and oxygen.
• Steel structure fireproof coatings employ multiple mechanisms—thermal barrier formation, endothermic reactions, inert gas release, char layer protection, chemical reactions, and physical barriers—to delay the steel’s temperature rise during a fire, ensuring structural stability under high temperatures. These mechanisms work together to provide effective fire protection. 
• Ammonium Polyphosphate is a key product for intumescent coatings , usually working together with melamine and pentaerythritol . TF-201 is a popular grade for water based intumescent coating with good water stability in storage. More info., pls contact lucy@taifeng-fr.com