21. Hot-Dip Galvanized Coating Guarantees

Asset owners are becoming increasingly aware of the need to prolong the maintenance-free life of their buildings, plant and equipment. This has led to their project managers passing responsibility for materials performance on the suppliers, over and above what would be considered normal warranty periods.

With protective coatings, in particular, there has been an increasing demand for long-term guarantees on the coating’s performance. This is driven by the financial imperative that building (coating) maintenance adds no value, particularly on manufacturing or infrastructure projects.

For this reason, Industrial Galvanizers introduced a Coating Guarantee program that provides a simple and sustainable performance guarantee of hotdip galvanized coating performance on specific projects.

How the Coating Guarantee works

There is no practical upper limit on the term of an Industrial Galvanizers Coating Guarantee. While 10-25 years is the most common coating guarantee range nominated by project managers, guarantee periods of 50 years or more can be supported on specific projects given the location and environmental conditions to which the hot-dip galvanized coating will be exposed.

Once a client has expressed interest in having an Industrial Galvanizers Coating Guarantee raised on a project, the location and operating conditions to which the hot-dip galvanized coating is to be exposed are subject to review by Industrial Galvanizers staff. This includes the preparation of an Environmental Evaluation Report (EER) and may also include a site audit, depending on the scope of the project.

This information is forwarded for review and detailed analysis. This analysis includes reference to the Corrosion Mapping System to determine regional rates of corrosion for hot-dip galvanized coatings, followed by detailed topographical analysis based on local Geosciences Australia maps.

This analysis allows topographical features such as height above sea level, prevailing wind direction, classification of locality (urban, rural, industrial, marine) and other factors that will influence the durability of hot-dip galvanized coatings.

This analysis allows approximate corrosion rate to be established for hot-dip galvanized coatings. This corrosion rate can then be applied to the hot-dip galvanized coating, based on the coating thickness that will result from the hot-dipping of the sections involved in the project.

The coating thickness may vary from section to section, based in steel chemistry, method of manufacture and steel section thickness. This outcome can be predicted with a high degree of accuracy based on Industrial Galvanizers experience in processing over 100,000 tonnes of fabricated steel annually.

By combining the calculated rate of corrosion with the minimum average galvanized coating thickness of the project steelwork, a Coating Guarantee period can be established that becomes the offer to the client.

On negotiated acceptance of the Coating Guarantee offer in principle, the formal documentation is generated and forwarded for approval.

In some circumstances, the coating guarantee may not be approved.


Coating Guarantees may contain some exclusions to accommodate conditions that may affect the durability of the hot-dip galvanized coating that are outside the parameters determining the normal service life of the coating.

These logical exclusions include exposure to corrosive chemicals, mechanical damage, electrochemical corrosion through contact with incompatible materials and prolonged contact with certain chemicals. It will also define some housekeeping issues that are the responsibility of the operator.

Client Obligations

It is essential that clients who wish to avail themselves of a coating Guarantee advise Industrial Galvanizers of the requirement for a galvanized coating guarantee prior to the project’s commencement.

It is contrary to the strict protocols associated with the provision of these binding warranties to provide galvanized coating guarantees retrospectively.

In addition, it is not Industrial Galvanizers’ policy to issue coating guarantees on small quantities of steelwork because of the costs involved in the processing and administration of individual Coating Guarantees.


Since the commencement of the Industrial Galvanizers Coating Guarantee program, a large number of project-specific guarantees have been issued. These have ranged from less than 10 years (at the clients nomination) to 50 years on a number of infrastructure projects.

Industrial Galvanizers introduced formal coating guarantees on major projects, such as this 25 year guarantee on the galvanized coatings use on the Brick Pit Ring project at Homebush Bay, for the Sydney Olympic park Authority.
The galvanized steelwork supplied by Industrial Galvanizers to the M5 East Motorway project for the NSW Roads and Traffic Authority in 2003 has a 25 year coating guarantee