1.1 ISO 12944 deals with the corrosion protection of steel structures by protective paint systems. 1.2 ISO 12944 covers only the corrosion-protective function of paint systems. Other protective functions, like the protection against: — microorganisms (marine fouling, bacteria, fungi, etc.), — chemicals (acids, alkalis, organic solvents, gases, etc.), — mechanical action (abrasion, etc.) and — fire are not covered by ISO 12944. 1.3 The field of application is characterized by: — the type of structure, — the type of surface and surface preparation, — the type of environment, — the type of protective paint system, — the type of work and — the durability of the protective paint system. Although ISO 12944 does not cover all types of structure, surface and surface preparation, it may, by agreement, also be applied to those cases which are not covered by the standard. The various aspects of the field of application are described in more detail in 1.3.1 to 1.3.6. 1.3.1 Type of structure ISO 12944 concerns structures made of carbon or low-alloy steel (e.g. in accordance with EN 10025) of not less than 3 mm thickness, which are designed using an approved strength calculation. Not covered by ISO 12944 are concrete structures reinforced with steel. 1.3.2 Type of surface and surface preparation ISO 12944 deals with the following types of surface consisting of carbon or low-alloy steel, and their preparation: — uncoated surfaces; — surfaces thermally sprayed with zinc, aluminium or their alloys; — hot-dip-galvanized surfaces; — zinc-electroplated surfaces; — sherardized surfaces; — surfaces painted with prefabrication primer; — other painted surfaces. 1.3.3 Type of environment ISO 12944 deals with: — six corrosivity categories for atmospheric environments, — three categories for structures immersed in water or buried in soil. 1.3.4 Type of protective paint system ISO 12944 covers a range of paint products which dry or cure at ambient conditions. Not covered by ISO 12944 are: — powder coating materials, — stoving enamels, — heat-cured paints, — coatings of more than 2 mm dry-film thickness, — linings of tanks, — products for the chemical treatment of surfaces (e.g. phosphating solutions). 1.3.5 Type of work ISO 12944 covers both new work and maintenance. 1.3.6 Durability of the protective paint system ISO 12944 considers three different durability ranges (low, medium and high). See 3.5 and clause 4. The durability range is not a "guarantee time".