Part 6 of 6: The Sustainable Approach of Reducing VOCs by Painting Less

Low VOC, UV-resistant topcoat on a filter screen structure

6-Part Blog Series: The Role of High-Performance Coatings in Shrinking the Carbon Footprint

To wrap up our blog post series on the role of high-performance coatings in shrinking the carbon footprint, our final piece of advice will address how sustainable practices such as painting less can help you reduce VOC emissions from liquid coatings. Although it may sound counterintuitive, a properly planned strategy of painting both sooner AND later will significantly reduce VOC emissions over time.

As a refresher, below are our previous blog posts from this series:

In the first two blog posts, we discussed the impact of VOC emissions on the environment, legislative efforts to reduce pollutant emissions, and how protecting steel from corrosion is one of the most environmentally positive actions that asset owners can take.

Although the benefits of corrosion prevention considerably offset VOCs emissions from high-performance coatings, the current legislative focus is on reducing emissions from coatings—not on preventing unnecessary replacement of steel assets. With that current focus in mind, our last few blog posts examined the coating types that can lower a job site’s VOC emissions, as well as the calculations needed to evaluate VOCs of different coating systems and how changing applicator habits can reduce emissions.

Why Painting Sooner Reduces VOC Emissions

The next strategy in this blog series for minimizing the impact of VOC emissions on the environment while protecting steel assets is a simple one—don't postpone routine coating maintenance. When the coating system starts precipitous degradation, it’s important that you paint sooner rather than later.

A coating system will require full rehabilitation if it is pushed as long as possible and allowed to deteriorate until widespread corrosion takes the steel. Full rehabilitation means full surface preparation and, typically, a full three-coat system—ultimately resulting in a significantly higher cost and VOC emissions.

On the other hand, if addressed "sooner" before complete failure takes place, it is possible to rehabilitate much of the existing coating system. For example, if only 30% of the surface has corrosion that requires surface preparation and priming, the remaining 70% will need minimal surface preparation, a tie coat and a finish coat. A significantly lower investment—and more importantly, from an environmental point of view, much fewer coatings—are needed to re-establish the corrosion protection of the asset in this scenario.

How Longer Coating Life Cycles Allow Painting Later

Although it is advisable to "paint sooner" to avoid full rehabilitation systems, the best coating systems also allow us to "paint later" because they have longer life cycles that increase maintenance painting intervals. Coating degradation is ultimately inevitable at some point, but these systems make it postponable.

The ultraviolet (UV) light in sunlight will break down the carbon bonds in organic coatings. This UV degradation is known as chalking. Epoxies that provide outstanding corrosion protection degrade when exposed to sunlight. They will chalk away at an industry average of 1 mil per year from UV degradation. UV-resistant finish coatings are commonly used to slow down the damage caused by UV exposure.

Unfortunately, not all UV-resistant topcoats are equal. It is essential that the specifier knows the quality and expected life cycle of the finish coats they specify. There are industry standards such as SSPC Paint 36 that provide performance guidelines. Coating manufacturers can also offer testing to certify the UV resistance of their finish coats. Premium UV-resistant topcoats can more than double the expected life cycle over lower-quality finish coats.

By doubling the expected life cycle of industrial coating systems, you halve the amount of future annual painting as a result. By reducing the coating required for corrosion protection, you in turn halve the potential VOC emissions from coatings. It is easy to do.

Premium topcoats are available for most industrial coating systems at a minimal cost. The labor costs are the same to apply a minimum-quality topcoat or a premium one. Topcoats in traditional, three-coat systems are typically only 2-3 mils (50µ - 75µ)* dry film thickness of the 10-12 mil (250µ-300µ)* total coating system. The same labor cost and high coverage rate of a topcoat means minimal impact to applied costs of the entire coating system.

That said, there typically seem to be two main points of reluctance for upgrading specifications to include premium topcoats—the first being healthy skepticism. Changes to specifications and established practice should be made with deliberation. The specifier needs to ask for testing and/or track records that clearly prove increased performance.

The second, and more common, obstacle seems to be the age of the decision maker—or, more accurately stated, their retirement age. When presented with longer-lasting coating system alternatives, a typical reply is often, "I'll be retired before this needs painting again."

It is hard to argue with that sentiment because I also plan to be retired before most steel assets painted today will need to be recoated. However, in the meantime, I hope to have contributed to a legacy where my colleagues and I, along with our partners in the industry, have helped companies successfully navigate the path between good fiscal practice and environmental responsibility.

*Values rounded off for illustrative purposes. One mil or a thousandth of an inch = 25.4 microns.

Need Help Selecting a High-Performance Coating for Your Project?

High-performance coatings are essential to steel sustainability and, ultimately, to obtaining carbon neutrality. Contact a local sales representative from Carboline's Technical Service team to find the right coating for your next project.