In cast iron pipe coating standards of A1 and A2 levels in the relevant fire protection levels, which can be used to evaluate the fire resistance of building materials such as paint. The differences between A1 and A2 paints are as follows:
Different test standards
A1 paint: must pass both non-flammability test and combustion calorific value test. The standard requires a temperature rise of △T≤30℃ and a mass loss of △m≤50%; the EN ISO 1716 standard requires a heat release value of PCS≤2.0MJ/kg.
A2 paint: must pass either EN ISO 1182 or EN ISO 1716, and meet specific standards in the EN ISO 13823 single-body combustion test, such as FIGAR≤120W/S, LFS＜edge specimen, and THR600S≤7.5MJ.
Different performance
A1 paint: It is a highly non-combustible material that does not produce any smoke toxicity. It releases almost no heat, no harmful smoke, and no burning drips during the combustion test, and can prevent the spread of fire and smoke to the greatest extent.
A2 paint: Although it is also a non-combustible material, compared with A1, it allows slightly looser conditions in some tests, and there may be a certain amount of smoke.
Selection basis in practical applications
Environmental corrosion
A1: Suitable for dry indoor environments (such as drainage pipe brackets in buildings)
A2: Must be used for buried pipes, sewage treatment pipes, coastal high humidity and high salt areas, etc.
Coating system matching
A2-level surfaces can be matched with high-performance coatings (such as polyurethane, epoxy powder), which significantly improves chemical corrosion resistance and wear resistance
For example, the polyurethane coating of ductile iron pipes (GB/T 24596-2021) requires the substrate to be rust-free to at least Sa2.5 to ensure the impact resistance and adhesion of the coating
Cost and maintenance cycle
A1-level processing costs are low but require frequent maintenance; A2-level initial costs are high (sandblasting equipment is required), but the economic benefits over the entire life cycle are better
How to choose the color of cast iron pipes?
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Post time: Jun-12-2025
