4.0.1 the service life depends on the coating thickness
Anti-corrosion coating design goal is to life. Life of the coating has two meanings: one is the use of the interval to the next maintenance period; the other is the use of the period to lose the protective effect. It is based on the life of protected objects, value, ease of maintenance determined. Anti-corrosion coating life in general settings should be more than 5 years. Longer the higher the effectiveness of the application. Whenever maintenance problems or for maintenance will cause greater economic losses of the occasion, the re-coating cycle, the longer the better, such as bridges, elevated tower, airport design life of 20 years. So the longer the life of anti-corrosion coating to set, then under certain conditions the thicker the film thickness.

4.0.2 determine coating thickness corrosive environment
We pollute the environment according to the corrosion resistance of the medium, concentration and state, temperature and location (outdoor or indoor) and other conditions to determine the corrosion level of difference, that is strong, medium and weak. Corrosive media, the stronger the higher the level of corrosion, the protective layer thickness should be thicker set. At the same time in the same film thickness, the choice of protective materials resistant to chemical stability, permeability, physical mechanical, construction and so the better overall performance, longer service life, economic value as possible.

4.0.3 Coating of the supporting
Protective coating is generally divided into primer, intermediate coat, top coat. Primer adhesion and corrosion inhibition effect, the role of intermediate permeability from paint, paint resistance to corrosive media and from the destructive effects of external stress. Through the middle and lower to play with better overall results. At the same time take into account the multi-channel construction of the overall construction schedule and the coating, such as the primer coating in the plant, until the components were transported to the scene painted after installation to repair, and finally add the middle of paint or finish coating. But the shop primers should be chosen with the overall design of the anti-corrosion coating product names, specifications, technical data consistent. Temporary protection should be based on two primer is appropriate, shall adopt the provisions of the dissimilar materials designed for temporary protection.

4.0.4 Selection of anti-corrosion coating
Selected because of their anti-corrosion coating vinyl resin, fluorine resin, fluorine phosphorus iron pigment is different, the acid salt, chemical resistance, mechanical properties were significantly different. So in the selection of material, according to media characteristics and selection of appropriate materials, environmental pollution, in order to achieve a better protective effect, in Table 4.0.4.
 

Table 4.0.4 Selection of anti-corrosion coating