Whether submerged in water and soil or located in a highly polluted atmosphere, unprotected steel is susceptible to damage from corrosion, which has the potential to incur substantial repair costs and compromise the health and safety of workers and the public. To achieve an adequate level of protection, industry professionals need accurate, up-to-date and technical information to determine which coating systems will prevent corrosion of steel structures, and the ISO 12944 standard was developed for this purpose.
What is ISO 12944?
ISO 12944 – also known as “Paints and varnishes – Corrosion protection of steel structures by protective paint systems” – is a set of international standards developed by the International Organization for Standardization (ISO). It includes a set of instructions and recommendations for the various types of paints and paint systems commonly used to protect steel structures from the effects of corrosion.
The susceptibility of steel structures to corrosion depends on a variety of factors, including the type of paint system and environment, the design of the structure, the standard of work applied, the condition of the substrates, joints, edges and welds prior to preparation and during application, and the application subsequent exposure conditions. All of these are considered in the standard, which consists of the following parts:
Part 1: General Introduction
Part 2: Environmental Classification
Part 3: Design Considerations
Part 4: Surface types and surface treatments
Part 5: Protective paint systems
Part 6: Laboratory performance test methods
Part 7: Execution and supervision of paint work
Part 8: Development of Specifications
Part 9: Protective paint systems and laboratory performance test methods for offshore and related structures
Who does the ISO 12944 standard apply to?
ISO 12944 is intended for industry professionals working with structural steel in different capacities:
Coatings, components and coatings manufacturers
Structural Fabricators, Architects and Engineers
thermal sprayer
Galvanizing machine
Contractors, Builders and Specifiers
Companies carrying out corrosion/protection work
Steel Structure Owner
planning
consultant
Protective Coating Inspector
What are the new changes in the ISO 12944 standard?
In 2018, ISO 12944-9 was implemented to test the adequacy of protective paint systems located in highly corrosive offshore marine environments and related structures. Consequently, a series of changes have been made to corrosivity categories C1 to C5 (from very low to very high), while a new category CX has been added for offshore environments and related structures. A new durability classification of 25+ years has also been developed to correspond to the new immersion category Im4, which specifies suitable conditions for the protection of submerged structures in marine environments from corrosion stress.
ISO 12944-6 has also been changed to include a wider range of laboratory test methods, all of which need to be adhered to in order to comply with the new corrosivity category. These include:
Introducing Cyclic Aging Tests
Additional parameters for rust limit and dash value
Removal of intercoat adhesion requirements
Curing time before testing reduced from three to two weeks
Reset glue failure to zero%
New requirements for including photographs in test reports
What is the laboratory performance testing method used in ISO 12944?
As mentioned earlier, the laboratory performance test method has been updated according to ISO 12944-6:2018 to introduce a cyclic aging test for protective paint systems with a corrosivity class of C4 or above. The procedure is designed to accelerate the aging of specific paint systems, resulting in accelerated corrosion reactions, thereby reproducing the natural weathering conditions to which each system will be exposed.
ISO 12944-9:2018 also recommends that protective paint systems located in marine and offshore environments be submitted to a seven-day test cycle to determine how effective they are at preventing corrosion of steel structures over an extended period of time. Exposure of systems to "real-world" environmental conditions, such as sunlight, humidity, sea spray, and wind chill, enables laboratory analysts to more accurately determine the extent to which each system is subjected to corrosive stress. The method consists of 72 hours of accelerated UV weathering, 72 hours of neutral salt spray exposure, and 24 hours of state cryogenic testing at -20 °C, which is repeated for up to 4,200 hours (25 cycles) to ensure that only Reserve the most durable paint system.
