Protective Systems for Different Situations
The choice of coating system will be determined to some extent by the type of structure, its relative importance and the environment of exposure. Metal coatings will often provide long maintenance-free lives in mild environments: hot-dip galvanising, sprayed zinc and sprayed aluminium have all been used for this purpose without additional paint coatings. It should, however, be appreciated that the corrosion of zinc is closely related to the amount of pollution in the atmosphere. Consequently, bare zinc coatings are not generally suitable for any but the mildest of atmospheres. Even in these conditions, the appearance of metal coatings is not always particularly satisfactory.