The model, name, color, and validity period of the fireproof coating should match its quality certification documents, and there should be no skinning, clumping, or gelation after opening. The substrate for the fireproof coating should be free of oil, dust, and dirt such as mud and sand. Observations and inspections should be conducted. The fireproof coating should not have misapplication or missed spots, and the coating should be intact without delamination, hollow sounds, obvious depressions, powdering, looseness, or floating slurry defects. The papillae should be removed, and observations should be made. With the emergence of numerous super high-rise steel structures, the use of fireproof coatings on steel structures has become more widespread. Once a fire occurs in a high-rise building, due to the limitations of firefighting equipment, the fire cannot be extinguished in a short time. Therefore, during the design and construction of buildings, greater emphasis should be placed on fire protection for the surfaces of steel structures to increase their fire resistance limit, and necessary fire protection measures should be formulated during building design to ensure the safety of personnel and reduce asset losses.

Requirements for steel structure fireproof coatings:

Under the condition of scale fire heating, the thickness of the fire protection layer for steel structures is mainly related to the effective gravity load borne by the components and the section coefficient of the components. The surface of the steel substrate for applying fireproof coatings should be strictly cleaned of water and oil. After sandblasting to remove rust to reach Sa21/2 level (manual rust removal should reach St3 level or above), appropriate anti-corrosion coatings should be applied. According to the CECS24:90 technical specifications for the application of fireproof coatings on steel structures, when using thick fireproof coatings (i.e., W1/D1≥22, T1≥9mm) with a fire resistance limit of t≥1h, the calculation formula is as follows: where T1 is the thickness of the fireproof coating to be sprayed, in mm; T2 is the thickness of the coating during the scale test, in mm; W1 is the weight of the steel beam to be sprayed, in kg/m; W2 is the weight of the steel beam during the scale test, in kg/m; D1 is the perimeter of the contact surface of the fireproof coating to be sprayed, in mm; D2 is the perimeter of the contact surface of the fireproof coating during the scale test, in mm; K is a coefficient. For steel beams, K=1; for the thickness of the protective layer of the corresponding floor steel columns, it is advisable to multiply by the coefficient K, set K=1.25.

According to the EU fireproof standards and design manuals for steel structures, the calculation method for the coating thickness of suitable thick thermal insulation fireproof coatings for steel structures is: where A is the required thickness of the protective layer for the steel structure component within the specified fire resistance time; T is the fire resistance limit of the steel structure component; λ is the thermal conductivity coefficient of the coating; ξ is the section coefficient of the steel structure component, which is the ratio of the component's perimeter to its cross-sectional area or the ratio of the outer surface area to the component's volume.