The measurement standards for the service life of color-coated plates are different, and the results are inconsistent. In fact, due to their different perspectives, the measurement standards for evaluating the service life of paint or color-coated plate manufacturers and color-coated plate application departments cannot be completely consistent. Take the above two service lives as an example, and compare the rust of about 600,000 square meters of color-coated plates (made in Japan) used in the first and second phases of Baosteel in my country. The service life of color-coated plates should not be a problem under normal conditions. However, when designing and selecting materials, it is necessary to correctly select appropriate substrates and coating varieties according to processing and use conditions, which is a reliable guarantee of service life. The service life of color-coated plates is analyzed based on the coating structure characteristics and mechanisms of color-coated plates. In essence, it refers to the unified embodiment of the effective use limits of the two properties of corrosion resistance and weather resistance of organic coatings under actual application conditions. If the measurement standards for the use limit are not unified, the concept of service life cannot be consistent. The service life of color-coated plates is standardized by using outdoor hanging long-term exposure tests under various typical atmospheric environments and corrosive media working conditions, and combined with the results of laboratory simulated use environment accelerated weather resistance test. Even if the life data obtained in this way only indicates or speculates the probabilistic life under the set working environment conditions, there will still be a gap with the actual service life of color-coated plates in buildings.

There are many types of color-coated plates, and the types and specifications of their substrates (different metal coatings and their coating thicknesses) are no less than ten. For the same hot-dip galvanized steel plates, the amount of galvanizing of different specifications has different corrosion resistance life. Moreover, there are more than ten types of coatings for color-coated plates. Even if we only consider the probabilistic life of various color-coated plates obtained by arranging and combining the two major categories of substrates and coatings, it is estimated that it is not something that can be clearly summarized by a simple mathematical model.