Corrosion protection of steel structures according to ISO 12944
ISO 12944 is the international standard for corrosion protection of steel structures
This standard gives detailed instructions for the selection, design, application and maintenance of corrosion protection systems. The objective of ISO 12944 is to ensure the long-term protection of steel structures from corrosion and to reduce maintenance costs. The standard is relevant to industries such as shipbuilding, oil and gas, bridge-building, construction and other branches where steel structures are used.
Corrosivity categories and protection duration
ISO 12944 differentiates between six corrosivity categories for atmospheric environments (C1, C2, C3, C4, C5, CX) and four categories for structures in contact with water and soil (Im1, Im2, Im3, Im4). Im1 to Im4 as well as CX are covered by our partner Hempel.
In addition to the corrosivity categories the standard also distinguishes between four different protection durations*, i.e. the expected service life of a coating system until a first partial renewal is necessary:
- Low (l) up to 7 years
- Medium (m) from 7 to 15 years
- Long (h) from 15 to 25 years
- Very high (vh) more than 25 years
Corrosivity categories and examples for typical environments
(source ISO 12944-2:2018):