INTRODUCTION
With the globalisation of commerce and industry, there is an imperative to ensure that performance benchmarks are set in all jurisdictions. International standards are increasingly called up in specifications, and Standards Australia has adopted a policy of aligning all Australian standards with International Standards Organisation (ISO) standards as they are published or revised.

The importance of consistent standards in an international trading environment is essential to ensure that suppliers are competing on an equal footing in terms of product specifications and quality. While the world is rapidly moving towards uniform standards, there are still many regional, national and internal standards that are called up in specifications. These may include standards from:

United Kingdom - BSI
International - ISO, EC, ETSI
United States - ANSI, ASTM, ASME…
Germany - DIN
New Zealand - SANZ
Japan - JIS
Canada - CSA

There are now many Australian/New Zealand standards that have been released in recent times, related to coatings on steel in particular. Those related to zinc-based (galvanized) coatings on steel products are of particular interest, as most address identification issues that are important to specifiers.

Many zinc-based coatings look similar, but can vary significantly in durability performance as a result of the technology used in their application.

This chapter is aimed at listing the more important of these new standards, and highlighting the performance related issues addressed therein.

In addition, we have included a complete listing of current Australian standards associated with coatings for reference.

CATEGORIES OF COATING STANDARDS
There are six categories into which the current coating standards fall. These are:

1. Process applied coatings
2. Manually applied coatings
3. Product related standards that define coating performance requirements
4. Environmental classification standards
5. Methods of measurement standards.
6. Generic materials standards (e.g. zinc metal, organic and inorganic coatings etc.)

While most of these standards are designed as stand-alone documents, most reference related standards and hence form a matrix of information sources that can be quite complex.

1. Process applied coatings.
These include galvanized coatings of all types, powder coatings, electroplated coatings and any other coating that is applied to an item in a purpose designed facility. The coating’s characteristics are determined by the process and are usually maintained to tight specifications in a controlled environment.

2.Manually applied coatings.
These include most types of commercial and industrial paint coatings, where the surface preparation is at the discretion of the operator, as is the application of the coating. These coatings are heavily dependent on the skill of the applicator and the ability to deal with the variables of the environmental conditions prevailing at the time of application.

3. Product related standards that define coating performance requirements.
These types of standards reflect the shift to performance-based standards rather than prescriptive standards. The recently published AS/NZS 2699.3:2003 Built-in components for masonry construction – Lintels and shelf angles (durability requirements) is a good example of this new generation of standards. A minimum performance life (50 years) is nominated, and complying coatings are listed in the standard for a range of exposure classifications.

In 2008, Standards Australia released a new standards: AS 2309 – Durability of galvanized and electrogalvanized zinc coatings for the protection of steel in structural applications that defines the performance of the various types of zinc-based coatings for steel with respect to their thickness in atmospheric exposures in Australia.

4. Environmental classification standards.
These standards are intended to provide environmental classifications based on a range of corrosivity factors, which can then be overlaid on coating standards to determine system performance. AS/NZS 2312:2002 Guide to the protection of structural steel against atmospheric corrosion by the use of protective coatings, along with ISO standards ISO 9223, 9224, 9225, and 9226 cover the classification of environments. A new standard (AS 4312 – Corrosivity zones in Australia, has been developed by Standards Australia, that will be a single-source document for this application.

5. Methods of measurement standards.
There is a large number of very specific standards related to the measurements and test procedures associated with the application and performance of applied coatings of all types. These standards range from methods of measurement of coating thickness to the determination of surface cleanliness.

6. Generic materials standards.
These standards related to the quality requirements for the basic materials used in the protective coating process. Some are incorporated into the coatings standards. Examples include a standard for testing the metallic zinc content of zinc-rich paint coatings and the component requirements for two-pack epoxy paint designed for industrial applications.

The aim of all standards is to clearly define the requirements of the product or process for the purposes of specification and the assurance of the quality of the finished product. Most standards are quite product-specific, and rarely give rise to confusion in the specification process.

One exception is zinc (galvanized and electroplated) coatings, which until recently, have not been separated sufficiently the facilitate clear specification based on required performance.

For that reason, these standards will be dealt with in more detail in this summary.

THE ZINC-COATED (GALVANIZED) STEEL STANDARDS.

AS/NZS 4680:2006 – Hot dip galvanized (zinc) coatings on fabricated ferrous articles

AS/NZS 4680 – Is specific to after-fabrication galvanizing and specifies the heaviest galvanized coatings. In most cases, the hot dip coating will always exceed the specified minimum thickness because of the nature of the application process. Minimum coating thickness is specified on the basis of steel thickness. The coating is specified in grams/m2 which is usually converted to average coating thickness in microns so non-destructive measurement of the coating can be done.

AS/NZS 4534:2006 – Zinc and zinc/aluminium coatings on steel wire

AS/NZS 4534 – Is specific to continuously galvanized wire. The coating is applied in a continuous process. A number of coating classes are available that vary with wire diameter. A WXX identification system is used, with W10 being the standard class against which the other classes are rated. e.g. W20 is double the coating mass of W10 and W05 is half the coating mass of W10 for the same wire diameter

AS/NZS 4791:2006 – Hot dip galvanized (zinc) coatings on ferrous open sections applied by a continuous or specialised process.

AS/NZS 4792:12006 – Hot dip galvanized (zinc) coatings on ferrous hollow sections applied by a continuous or specialised process.

AS/NZS 4791 – Open sections
AS/NZS 4792 – Hollow sections
These two standards were developed specifically for OneSteel’s Duragal™ continuously galvanized hollow and open sections and Palmer Tube’s and Orrcon’s hollow sections manufactured from continuously galvanized (CG) strip. Some sections may be hot dip galvanized using a semi-continuous galvanizing process.

Where the hot dip galvanized coating is used, the coating class is designated by the classification HDGXXX, where the XXX numerals are the coating mass per square metre on each surface. e.g. HDG200 is 200 g/m2 average.

Where CG strip is used, the coating class is designated by the classification ZBXXX/XXX. The ZB indicates `zinc both sides’ and the XXX is the coating mass per side in g/m2. e.g. ZB100/100 represents 100 g/m2 coating mass average on both sides.

Where the coating is applied by an in-line process (Duragal ™), the coating class is designated by the classification ILGXXX, where ILG indicates in-line galvanized and the XXX is the single-side coating mass in g/m2. e.g. ILG100 represents 100 g/m2 on the outside of hollow sections and all surfaces of open sections.

AS 1397:2001 – Steel sheet and strip – Hot dipped zinc coated and aluminium/zinc coated coated

This standard has been virtually unchanged from previous editions and covers both galvanized (zinc), zinc/iron alloy and Zincalume™ coated steel sheet and strip. The Zincalume™ coating contains approximately 60% aluminium and 40% zinc.

The steel strength grade is designated by a GXXX classification, where the XXX represents the steel’s yield strength in megapascals (MPa). e.g. G350 indicates a 350 MPa minimum yield strength.

The coating type is designated by ZXXX for galvanized (zinc) coatings, ZFXXX for zinc/iron alloy coatings and AZXXX for Zincalume™ coatings, where the XXX represents the total average coating mass on BOTH sides of the sheet. e.g. Z350 indicates a galvanized coating with a total coating mass on BOTH sides of the sheet of 350 g/m2 or 175 g/m2 on each side of the sheet.

AS 4750:2003 – Electro- galvanized (zinc) coatings on ferrous hollow sections.

This standard was developed to complement the other in-line galvanizing standards, where the zinc coating is applied by a continuous electroplating process, rather than using a molten zinc bath.

There are a number of hot-dip galvanizing standards related to structural fasteners. These standards are similar with respect to coating specifications, but are differentiated by the types of fasteners.

These standards include:

AS 1214:1983 Hot-dip galvanized coatings on threaded fasteners (ISO Metric coarse thread series)

AS/NZS 1559:1997 Hot-dip galvanized steel bolts with associated nuts and washers for tower construction.

AS/NZS 1252:1996 High strength steel bolts with associated nuts and washers for structural engineering.

AS/NZS 1390:1997 Cup head bolts with ISO metric coarse pitch threads.

THE ENVIRONMENTAL CLASSIFICATION STANDARDS.
The most significant document in the Standards Australia library on the classification of environments for corrosivity is AS/NZS 2312:2002 – Guide to the protection of structural steel against atmospheric corrosion by the use of protective coatings.

The section in this standard covering classification of atmospheres is largely descriptive and makes no attempt to quantify corrosivity in given environments.

AS/NZS 2312 references a suite of ISO standards that are intended to provide the platform for classification of corrosivity or atmospheres. These standards are:

ISO 9223 - Corrosivity of atmospheres – Classification
ISO 9224 – Corrosivity of atmospheres – Guiding values for corrosivity categories
ISO 9225 – Corrosivity of atmospheres – Measurement of pollution
ISO 9226 – Corrosivity of atmospheres – Determination of corrosion rate for standard specimens for the evaluation of corrosion.

While these standards provide the metrics to determine atmospheric corrosivity, they have been developed for Northern hemisphere conditions, and fall short in some areas that are appropriate for the Asia-Pacific region.

These shortcomings have been recognized by Standards Australia and a local standard, AS 4312 Corrosivity zones in Australia (Draft) is under development in 2004 at Standards Committee level.

Standards of this type will become increasingly important as the determination of durability of construction materials will lead to more performance based, rather than prescriptive, standards being published and also incorporated in to building codes and standard specifications.

FINDING THE STANDARD
It is no longer necessary to reference a large printed catalogue of standards, or even purchase a printed standard from an authorized distributor. Standards Australia develops the standards and they are them sold through SAI Global which is a public company with exclusive distribution rights for Standards Australia publications.

Information about individual standards is available from the SAI Global web site, and any Australian or international standard can be purchased as a hard copy or as a downloadable .pdf file from the SAI Global site.

Students can register with Standards Australia and this will allow access to any standard for downloading for reference. These files are time stamped and copyrighted and have very short use-by date after downloading, but provide students with standards access on a 24/7 basis.

The Standards Australia web address is www.standards.com.au. The SAI Global web address is www.saiglobal.com.

COATING STANDARDS SURVEY
This listing contains most of the Australian Standards that cover industrial protective coatings. There are additional standards that deal with specialised coatings (gold plating, vitreous enamel, etc) that have been excluded for practical reasons from this listing.