Over the 10 years to 2027, Australian households, businesses and governments are expected to fork out $2.018 trillion in building new homes, commercial buildings, and civil infrastructure (ACIF forecast, Nov 17).
When you do this, you want to protect your assets. This includes protection from corrosion – the deterioration of metal components which results from chemical reactions with the environment.
The importance of this should not be underestimated. In 2009, Curtain University put the national cost of corrosion at $30 billion annually. Left unchecked, corrosion can cause train derailments, oil spills, bridge collapses, gas shortages and power outages. Action to avoid it, Western Australia Corrosion Research Group director professor Rolf Gubner said at that time, would save $8 billion each year.
This raises questions about common mistakes in corrosion prevention and strategies which asset owners should adopt. For answers, Sourceable spoke to Dulux Business development executive Adam Hockey and Queensland University of Technology associate professor Geoffrey Will, a researcher who specialises in corrosion and the electrochemical monitoring of corrosion reactions in industrial settings.
According to Hockey, the importance of corrosion protection will increase as population and industrial growth leads to greater release of chemicals such as nitrogen oxide from manufacturing facilities and a more acidic and corrosive environment. With the cost of maintaining buildings and infrastructure over their life cycle typically outstripping that of design and construction by a factor of 10 or more to one (an approximate rule of thumb), he says efforts to protect assets up-front through design and thus minimise the amount of maintenance required are worthwhile. Where they do reduce maintenance requirements, along with the associated need for manufacturing and transport, such investments also benefit the environment.
Hockey says mistakes fall into several areas.
First, there can be a lack of information about corrosion protection work. It is important for asset owners to understand the process and reasons which lie behind a given specification. Where this does not happen, they are not as readily able to evaluate the consequences of the given specification for corrosion prevention against those of cheaper alternatives.
Another mistake is failing to have appropriate quality assurance documentation to specify that the specification must be implemented exactly as per what it says. QA documentation, Hockey says, not only helps asset owners and operators understand what needs to be done but also helps them to provide evidence of appropriate operation and maintenance measures having been followed where problems do occur.
Finally, any absence of a robust maintenance program or lack of adherence to such a program will increase costs over the life of the project.
In terms of what should be done, Hockey has several recommendations.
First, specifications should be based around clear asset objectives. This includes how long owners want their assets to last.
Where relevant, older specifications should be updated. Prior to the 1970s, for example, protective coatings contained lead. Since lead is no longer used, any specifications which call for this need to be updated.
Third, it is important to consult with the manufacturer’s consultants and understand what type of protection they are using. One type of protection known as sacrificial protection involves protecting iron or steel by attaching a more reactive meal such as pieces of zinc or aluminium alloy. The more reactive metal becomes the anode and corrodes in place of the steel. Alternatively, barrier protection involves encasing the steel with a large envelope. Understanding the approach taken will help asset owners devise sensible solutions where they strike roadblocks, Hockey says.
Fourth, alignment between the specification and the program is important. Where you have a 32- or 48-hour window for shutdown but the desired specification would take seven days to complete, either the specification needs to be amended or the shutdown period must be extended.
Finally, as mentioned above, clear quality assurance documentation along with an effective maintenance program are critical. Simply keeping dirt off steel, Hockey says, will help prolong its life.
Will agrees that corrosion prevention is important.
He says the most common mistake is to afford insufficient attention to what is going on with the asset. This, he says, can lead to substandard materials and/or workmanship and the early onset of corrosion.
Second, people who are well-versed in corrosion are rare and do not always get brought into projects until a problem exists. Commonly, Will says, engineers are not well-versed in corrosion and thus tend to fall back upon reliance of standards – which he says can be overly conservative and prescriptive and may not always represent the best solution.
Finally, he agrees that effort up front is important. Insufficient adherence to design and standards (notwithstanding the above point) and a lack of good coating application, he says, leads to premature maintenance, earlier problems and a reduce design life.
Will says it is necessary to have a plan for corrosion and asset management. Whilst many materials will not last for the life of the asset, he says it is possible for the design to facilitate maintenance or application of certain corrosion prevention over the asset’s useful life. If this does not happen, he said, it may necessitate expensive retrofitting to accommodate maintenance down the track.
During design, there are also opportunities to embed technologies which detect and provide early warning signs of problems. These are being applied on several highway and tunnelling projects, he says.
As per the point above, Will says it is important to engage people who understand corrosion for advice.
Finally, regular inspections are important. Picking up corrosion early, Will says, could mean having to change only one bolt as opposed an entire beam.
“They (asset owners) don’t want to spend the money to get people in there,” Will said. “But if you get people in their early on, you can save yourself a lot of money.”
Australia is spending big on buildings and infrastructure.
To get the most from this, we must protect our assets.