A guide to the updated ISO 12944 norm

Corrosion is the natural result of the deterioration of metal due to its chemical reaction with the surrounding environment.

Any steel-made product or structure that is unprotected and exposed to air, water, or has continual contact with soil, will corrode and as a consequence will cause repair cost. To avoid corrosion damage, one of the most common protection methods is to coat the object with a paint or paint system.

When our customers choose SELEMIX® for their light industrial coating requirements, they do so in the knowledge that the paint they will apply is certified to the most prestigious international standard for protection against corrosion, the ISO 12944.                                                                                                                                  

What is ISO 12944?

That standard, ISO 12944 was introduced in 1998, revised in 2007 and updated for a second time in 2018 with some significant changes and additions. It now has nine parts and covers paint and coatings for steel structures in atmospheric, immersed, and buried environments.

Part 6 of the standard (IS0 12944-6) specifies the laboratory test methods and conditions for the assessment of paint systems for the corrosion protection of carbon steel structures and is the part relevant to Selemix offer when certified the first time or when re-certified.

Industry professionals (such as asset owners, corrosion protection or construction companies) use the detailed, unambiguous and easily understandable standards set down in the second part of ISO 12944 to ensure that the coatings they are specifying and/ or providing will deliver the intended level of corrosion protection in the environment that the product or structure will be subject to.

Therefore, when our customers choose SELEMIX®, for their light industrial coating needs, they will know exactly what they will get.                                                                                                        

Environment Classification & Coating Durability

The standard takes into account two factors when protecting steel from corrosion:

1. Environmental corrosivity; the standard segments environments into different categories that are then evaluated on their ability to corrode unprotected steel.

In the updated version from 2018 a series of changes have been made to the corrosivity categories C1 to C5 (ranging from very low to very high), while a new category, CX (Extreme), has been included for offshore and industrial environments with high humidity.

2. Coating durability; the standard gives guidance on the expected lifetime of a coating system until its first major maintenance. In 2018 a new durability classification of “more than 25 years” was added aligned with the inclusion of the new immersion category Im4 and which applies for marine environments.

These characteristics are evaluated as defined in ISO 12944-6 by artificial-ageing tests to measure the paint cycles resistance to water or moisture and to salt spray as an indication of wet adhesion and barrier properties. The tests have the aim to ensure with a high probability that a paint system really has the characteristics needed for the durability required in the intended application.

The 2018 update of ISO 12944 introduced changes to these laboratory test methods. For categories C4 very high, C5 high and C5 very high, cyclic testing has been introduced so as be more representative of real-world corrosion conditions.

PPG welcomed the introduction of these updated test methods as we feel that they provide a much more realistic representation of what actually occurs in real-world corrosion conditions. These updated standard allow customers to have even more confidence in the durability of the coating for goods under different conditions.