ISO/TC 35/SC 14 - Protective paint systems for steel structures

This document describes the types of paint and paint system commonly used for corrosion protection of steel structures. It also gives guidelines for the selection of paint systems available for different environments (see ISO 12944‑2) except for corrosivity category CX and category Im4 as defined in ISO 12944‑2 and different surface preparation grades (see ISO 12944‑4), and the durability grade to be expected (see ISO 12944‑1).

ISO 12944-6:2018 specifies laboratory test methods and test conditions for the assessment of paint systems for the corrosion protection of carbon steel structures. The test results are intended to be considered as an aid in the selection of suitable paint systems and not as exact information for determining durability. ISO 12944-6:2018 covers protective paint systems designed for application to uncoated steel, hot dip galvanized steel according to ISO 1461 and steel surfaces with thermal-sprayed metallic coating according to ISO 2063‑1 and ISO 2063‑2. ISO 12944-6:2018 does not apply to protective paint systems for electroplated or painted steel. The environments for corrosivity categories C2 to C5 and Im1 to Im3 defined in ISO 12944‑2 are considered.

ISO 12944-9:2018 specifies the performance requirements for protective paint systems for offshore and related structures (i.e. those exposed to the marine atmosphere, as well as those immersed in sea or brackish water). Such structures are exposed to environments of corrosivity category CX (offshore) and immersion category Im4 as defined in ISO 12944‑2. ISO 12944-9:2018 describes paint systems for high durability according to ISO 12944‑1. ISO 12944-9:2018 is applicable to structures made of carbon steel and does not cover Cd/Bi Cr and Zn/Bi Cr surfaces. It is not applicable to surfaces under insulation or concrete. This document is applicable for paint systems intended for a service temperature range between −20 °C and +80 °C, and the performance testing is aimed at verifying suitability of the paint systems for this temperature range. ISO 12944-9:2018 is applicable for paint systems for submerged service (Im4) which are intended for ambient operating temperatures up to a maximum of 50 °C. ISO 12944-9:2018 specifies: - the test methods to be used to determine the composition of the separate components of the protective paint system; - the laboratory performance test methods for the assessment of the likely durability of the protective paint system; - the criteria to be used to evaluate the results of performance tests. ISO 12944-9:2018 covers the requirements for new work and any repairs necessary before start-up. It can also be used in relation to maintenance where complete refurbishment is carried out and the underlying metal substrate is completely exposed by abrasive blast-cleaning. ISO 12944-9:2018 does not address maintenance in general where methods of surface preparation other than abrasive blast-cleaning are typically used. ISO 12944-9:2018 deals with structures, made of carbon steel of not less than 3 mm thickness, which are designed using an approved strength calculation. The following are not covered by this document: - structures built of stainless steel as well as those built of copper, titanium or aluminium or their alloys; - steel cables; - buried structures; - pipelines; - the interiors of storage tanks.

ISO 12944-8:2017 covers the development of specifications for corrosion protection of steel structures using protective paint systems. It relates to new work and maintenance in the workshop or on site and is also applicable to the corrosion protection of individual components. ISO 12944-8:2017 covers the corrosion protection of steel structures exposed to different corrosion stresses by environments such as indoors, open-air and immersion in water or burial in soil, as well as special stresses, due for example, to medium or high temperatures. The need for different durability ranges is considered. Steel surfaces that have been hot-dip-galvanized, metal-sprayed, zinc-electroplated or sherardized, and previously painted steel surfaces, are also covered by ISO 12944-8:2017. In ISO 12944-8:2017, reference areas for assessing the quality of the corrosion protection work and the performance of the protective paint systems used are dealt with. ISO 12944-8:2017 provides detailed flow charts for planning new work and maintenance, which are taken into account when writing a specification. ISO 12944-8:2017 can also be used as a guide if extreme corrosion stresses or high temperatures occur, or if the protective paint systems are to be used on other substrates, such as non-ferrous metals or concrete, to define suitable specifications.

ISO 12944-4:2017 covers the following types of surfaces of steel structures 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. ISO 12944-4:2017 defines a number of surface preparation grades but does not specify any requirements for the condition of the substrate prior to surface preparation. Highly polished surfaces and work-hardened surfaces are not covered by ISO 12944-4:2017.

ISO 12944-2:2017 deals with the classification of the principal environments to which steel structures are exposed, and the corrosivity of these environments. ISO 12944-2:2017 - defines atmospheric-corrosivity categories, based on mass loss (or thickness loss) by standard specimens, and describes typical natural atmospheric environments to which steel structures are exposed, giving advice on the estimation of the corrosivity, - describes different categories of environment for structures immersed in water or buried in soil, and - gives information on some special corrosion stresses that can cause a significant increase in corrosion rate or place higher demands on the performance of the protective paint system. The corrosion stresses associated with a particular environment or corrosivity category represent one essential parameter governing the selection of protective paint systems.

ISO 12944-1:2017 defines the overall scope of ISO 12944 (all parts). It gives some basic terms and definitions and a general introduction to the other parts of ISO 12944. Furthermore, it includes a general statement on health, safety and environmental protection, and guidelines for using ISO 12944 (all parts) for a given project.

ISO 12944-7:2017 deals with the execution and supervision of paint work on steel structures in the workshop or on site. ISO 12944-7:2017 does not apply to - the preparation of surfaces to be painted (see ISO 12944‑4) and the supervision of such work, - the application of metallic coatings, and - pre-treatment methods, such as phosphating and chromating, and paint application methods, such as dipping, powder coating or coil coating.

ISO 12944-3:2017 deals with the basic criteria for the design of steel structures to be coated by protective paint systems in order to avoid premature corrosion and degradation of the coating or the structure. It gives examples of appropriate and inappropriate design, indicating how problems of application, inspection and maintenance of paint systems can be avoided. Design measures which facilitate handling and transport of the steel structures are also considered.

ISO 15741:2016 specifies requirements and methods of test for liquid epoxy paints and internal coatings of such paints in steel pipes and fittings for the conveyance of non-corrosive gas. It also deals with the application of the paint. Other paints or paint systems are not excluded provided they comply with the requirements given in ISO 15741:2016. The coating consists of one layer, which is normally shop-applied on blast-cleaned steel by airless spray or other suitable spraying techniques. The applied and cured paint film must be smooth to give the desired reduction in friction. Brush application is only used for small repair jobs.

ISO 19840:2012 specifies a procedure for the verification of dry-film thickness against nominal dry-film thickness on rough surfaces, including the adjustment of the instruments used, the definition of inspection areas, sampling plans, measurement methods and acceptance/rejection criteria. The procedure is based on the use of instruments of the permanent magnet, electromagnet and eddy current type. Instrument accuracy is verified both at zero and at a known thickness on a smooth surface and adjusted if necessary. It does not apply to nominal dry-film thicknesses less than 40 µm.

ISO 29601:2011 specifies procedures for detecting the presence of porosity in a protective paint system of any thickness on a steel or other metallic substrate. The procedures given are based on methods using two different types of test equipment, the choice of equipment depending on the dry film thickness. These procedures are only applicable to the testing of electrically non-conductive parts of a paint system. The test methods specified are mainly intended for use with new coatings, but can also be used for coatings which have been in service for some time. In the latter case, it is important to bear in mind that the coating might have been penetrated by substances in contact with the coating during service.

ISO 16276-1:2007 specifies procedures for assessing the fracture strength of a protective paint coating of any thickness on a steel substrate of thickness not less than 10 mm. The procedures given in this part of ISO 16276 are based on methods used with different types of pull-off test equipment. The results obtained using such different types of equipment are not comparable. This part of ISO 16276 also specifies suitable equipment and defines inspection areas, sampling plans and acceptance/rejection criteria. It does not give any values of the fracture strength of different protective paint coatings.

ISO 16276-2:2007 specifies procedures for rating the resistance of coating systems when a cut in the form of a right-angle lattice pattern (cross-cut) or in the form of an X (X-cut) is made into the coating, penetrating through to the substrate. It also specifies suitable equipment and defines inspection areas, sampling plans and acceptance/rejection criteria. It does not specify ratings for particular coating systems.

ISO 12944-6:2007 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 thermal-spray metallic coatings. The environments considered are those defined in ISO 12944‑2.

ISO 12944-5:2018 describes the types of paint and paint system commonly used for corrosion protection of steel structures. ISO 12944-5:2018 also gives guidelines for the selection of paint systems available for different environments (see ISO 12944‑2) except for corrosivity category CX and category Im4 as defined in ISO 12944‑2 and different surface preparation grades (see ISO 12944‑4), and the durability grade to be expected (see ISO 12944‑1).

ISO 20340:2009 deals with performance requirements for protective paint systems for offshore and related structures (i.e. those exposed to the offshore environment, as well as those immersed in sea or brackish water). It can also be used for other structures, provided that the paints or protective paint systems selected comply with ISO 20340. ISO 20340 includes: the test methods to be used to determine the composition of the separate components of the protective paint system; the laboratory performance test methods for the assessment of the likely durability of the protective paint system; the criteria to be used to evaluate the results of performance tests.

ISO 12944-5:2007 describes the types of paint and paint system commonly used for corrosion protection of steel structures. It also provides guidance for the selection of paint systems available for different environments and different surface preparation grades, and the durability grade to be expected. The durability of paint systems is classified in terms of low, medium and high.

ISO 19840:2004 specifies a procedure for the verification of dry film thickness against the nominal dry film thickness on rough surfaces, including the adjustment of the instruments used, the definition of inspection areas, sampling plans, measurement methods and acceptance/rejection criteria. The procedure is based on the use of instruments of the permanent magnet and inductive magnet type, adjusted to zero and to a known thickness on a smooth surface. It does not apply to nominal dry film thicknesses less than 40 micrometres.

ISO 20340:2003 deals with the performance requirements for the protection, by protective paint systems, of new offshore and related structures exposed to the offshore atmosphere, as well as those immersed in sea or brackish water. ISO 20340 can also be used for other structures, provided that the selected paints or protective paint systems comply with this International Standard. This International Standard places emphasis on high-durability paint systems, with the aim of minimizing maintenance, and hence reducing safety considerations and environmental impact. This International Standard includes the following: the test methods to be used to determine the composition of the separate components of the protective paint system; the laboratory performance test methods for the assessment of the likely durability of the protective paint system; the criteria to be used to evaluate the results of performance tests.