The service of galvanized steel is more than 30 years, while the lifespan of color coated steel coil is more than 20 years. Why? It is because the useful life of galvanized steel is mainly determined by the zinc coating thickness. Generally, the thicker the zinc coating, the longer the service life. While the galvanized steel used in PPGI usually has a thin zinc layer. That’s why its expected life is shorter. But you can prolong the service life by using high-quality painting. If you have special requirements, please let us know.