This part of ISO 12944 specifies laboratory test methods and test conditions for the assessment of paint systems for the corrosion protection of steel structures. The test results are to be considered as an aid in the selection of suitable paint systems and not as exact information for determining durability. This part of ISO 12944 covers protective paint systems designed for application to uncoated steel, hot-dip-galvanized steel and steel surfaces with thermally sprayed zinc coatings. This part of ISO 12944 does not apply to protective paint systems for electroplated or painted steel. Certain tests in this part of ISO 12944 are not applicable to many water-borne paint systems (see 4.2). Nevertheless, some water-borne paint systems are amenable to testing and evaluation using the procedures described herein, and their results could be taken into account. The environments defined in ISO 12944-2 are considered