Why is paint suddenly degrading

People from the industry might be familiar with the following situation. During a management visit, the manager(s) sit down in the meeting room after the walk around of the installation, looking at everybody and say:

"It is one years since my last visit, and now the installation looks much worse with much more corrosion going. Why?"

Why does external corrosion over a relatively short period of time starts popping up everywhere, and quickly getting worse? And why is one module corroding much more that it's neighbours, even they all seem to be exposed to similar environment?

There are three reasons for such situations occurring:

• Lack of Fabric Maintenance (FM) - the paint systems are not maintained. You can read more about that in other articles I have published.
• Life time of paint systems.
• Lack of QA/QC during the project phase.

Let's look at the two last bullet points in more details as lack of FM is covered in a previous article.

LIFE TIME OF PAINT SYSTEMS

The reason for the manager's question is actually describes in the graph on the top of this article.

Paint systems are usually built up with primer, intermediate layer and a top coat. There are international procedures for surface preparation, how to apply the paint (thickness, curing, pot life etc) as well under which conditions to apply the coating (humidity etc).

As everything else in life, paint has a life time. At some point the paint breaks down and exposing the steel to the environment. And then you have the brown spots that are so visible during walk arounds.

Coating breakdown is a silent process, and everything usually looks fine for 5-8 years. There are some nicks and dings in the paint causing corrosion points, and areas with heavy use (like gangways) will look a bit worn. But overall, everything looks just fine.

But after some years, rusty spots start popping up a bit everywhere (how quickly is highly dependent on geographical location). Maybe the installation has a weather side, and then these spots will show up there first. But in not too long these spots will occur to some extent on all type of surfaces. And this is why:

All paint in an area has the same age, so these painted surfaces start breaking down around the same time.

And this breakdown (or the growth in external anomalies) is not linear, but exponential. So when these rust spots start showing up, you should assume the problem is quickly escalating.

QA/QC OF PAINT DURING PROJECT

Then you have areas or modules that get coating breakdown earlier than the rest of the installation. If these areas are not exposed to different environmental conditions than surrounding areas, this is why it is happening:

During any projects the design and production of modules will be contracted to sub-suppliers. These suppliers are selected based on various criteria (price will be one of the important one), but it is unlikely their ability to do superior paintwork is given much weight. That said, many suppliers do excellent paint workmanship prior to delivery. But some don't. And that should be picked up by project during QA/QC, as poor this workmanship will substantially influence maintenance cost of the module in the years to come.

I have seen modules leaking as a tea strainer after 10 years in operation, and where numerous pipes needed replacement. The neighbour modules did not have the same issues, and the only reason for the differences is poor paintwork before delivery.

CONCLUSION

Without a proper Fabric Maintenance strategy in place, coating and paint degradation is a silent process that will be ongoing for years unnoticed. Until the neglect becomes visible. The process is exponential, creating external corrosion on underlying steel. Getting back control over the integrity of the pain and steel might be very costly and work intensive.