This topic is a false proposition.
on the basis of a blank in the past, China's fire-retardant coatings have been developed, and various types of products have been developed all over the country. Relevant departments have formulated corresponding technical standards and application specifications. According to the requirements of relevant national fire-retardant specifications, fire-retardant coatings have been widely used for coating protection of industrial and civil buildings, petrochemical enterprises, power cables, etc., which has avoided or alleviated many major fire losses, promoted the progress of fire-fighting science and technology, and made remarkable achievements. According to the similar technical experience of foreign developed countries and the higher requirements of our users, there are still some gaps and problems in the development and application of fire retardant coatings.
there are some problems with fire retardant coatings, but there is no harm in itself!
1. Toxic and harmful gases will be generated in case of fire
At present, most intumescent fire retardant coatings adopt C-N-P or C-N-P-CL system, which uses a large number of chemicals such as melamine, ammonium polyphosphate, ammonium borate and chlorinated paraffin, and decomposes toxic and harmful gases such as NH3, HCL, NOX and CO after being heated, all of which can generate. Therefore, when selecting materials, fireproof coatings with less toxic and harmful gases should be selected, which can not only reduce the harm of fire to buildings and people, but also reduce the harm of smoke generated by materials themselves to people.
2. The service life of the coating is shorter than the design life of the steel structure
Like other coatings, the fire-retardant coatings for steel structures have to be tested by factors such as sunlight, ultraviolet radiation, vibration, rain and snow, etc. However, due to the addition of many organic or inorganic materials, such as polyols, organic amines and other chemicals, their bonding performance and aging resistance have been reduced to varying degrees. GB14917-2112 "Fire-retardant Coatings for Steel Structures" clearly stipulates the fire-retardant coatings' resistance to sudden heat, wet heat, acid, alkali and salt spray corrosion, and further investigates their fire resistance on the basis that these items are qualified, stipulating that the attenuation value of the additional fire resistance of the products qualified in the above items should not be greater than 35%. The main design life of steel structure is generally 51 years, while the service life of fire retardant coating for steel structure is less than 51 years, which is likely to cause the fire retardant coating coated on the steel structure to fail to play a fire prevention role in the later period of use.
3. The testing method of fire resistance is backward
At present, the method of testing the fire resistance of fire-retardant coatings for steel structures is the method specified in GB14917-2112 Fire-retardant Coatings for Steel Structures, that is, the design load specified in GBJ17 is loaded on the I-beam 136b or 141b, and the combustion test is carried out on a horizontal combustion furnace, and the required calculation span is not less than 4211mm. This simulation test method has high cost and wastes a lot of steel, gas and inspection expenses. Only a few inspection institutions in China have this inspection ability, so it is difficult to detect the quality of coatings in the actual use process, which has great limitations. The on-site inspection of engineering acceptance is only to detect the physical indicators such as the thickness of the fire protection layer, and the fire protection performance is often replaced by the type inspection report of that year. This practice is not conducive to improving product quality, but also leaves a fire hazard.
The solvent-based fire retardant coatings widely used in China do not meet the requirements of environmental protection, and their use will be more and more strictly restricted because people pay more and more attention to environmental pollution and personal health. This requires the development of pollution-free coatings, such as water-based fire retardant coatings and inorganic fire retardant coatings. Waterborne coatings have become the main development direction of architectural coatings because of their non-toxicity, safety, resource saving and environmental protection.
note: the solvent-based fire retardant coating is strictly forbidden to meet open flames when the cover is opened and the solvent is not volatilized.