Why Protective Coatings Fail

(Note: This article has been adapted from portions of the Finishing Solutions Network white paper, “Coating Application Specialist (CAS): the new standard for quality, safety, and reliability in industrial painting.”)

Protective industrial coatings, according to the worldwide corrosion authority, NACE International, are “thin layers of solid material applied to a substrate, with the coating acting as a barrier to inhibit or prevent corrosion.” Coatings come in many forms, including both organic epoxies, polyurethanes, and polymers as well as inorganic metallic compounds. Each year, according to a NACE study, nearly $110 billion is spent on protective coatings in the U.S.

Protective coatings are the best line of defense against the damaging effects of corrosion. They can also help protect against extreme weather events and long-term exposure, as well as improve the aesthetic appearance of an asset. However, the benefits of any coating, no matter how durable and technically sophisticated, are only fully realized if it is properly specified and applied.

When Coatings Fail

When coatings fail, structures corrode and degrade. According to NACE, the cost of corrosion in the U.S. amounts to more than $450 billion annually. These costs include:

  • Labor and material costs to re-coat structures as quickly as 1-3 years after construction, instead of the normally intended 10-20 years
  • Lost productivity and/or revenue as workspaces and facilities are closed for repairs
  • Injuries or damages due to corrosion-related equipment failures
  • Surprise maintenance costs to mitigate corrosion and/or coating breaches that don’t yet require full replacement.

Why Coatings Fail

Industrial coating application involves many variables. Deficiencies in any one of them can lead to failure. These variables include the following:

Coatings – Has the manufacturer produced a coating that meets specifications?
Processes – Are the specifications correct? Does the application meet those specs? Has the surface been prepared adequately prior to application?
Equipment – Are the right application tools being used?
People – Do the applicators have the right experience? Training? Certification? Has the project been inspected by a qualified professional?

In search of the specific causes of coating failures, researchers George T. Bayer, Ph.D. and Mehrooz Zamanzadeh, Ph.D. found that five common selection and application errors account for most failures.

  1. Improper surface preparation – The substrate is not adequately prepared for the coating to be applied. Proper surface preparation may include washing, a solvent cleaning, an abrasive blast cleaning, or a power tool and hand tool cleaning.
  2. Improper coating selection – The paint or coating specified is not suitable for the environment in which it is used, or it is not compatible with the surface itself.
  3. Improper application – This problem can involve shop-applied or field-applied coatings. It occurs when required specifications for the application of the coating are not met.
  4. Improper drying, curing and over coating – This failure happens when specifications are not met post-application.
  5. Mechanical damage – This occurs when improper handling of the painted or coated surface results in a breach in the coating itself.

Fully 80% of coating failures are the result of improper application, whether in the surface prep, application, drying, or post-application process.

Yet, because people are behind every process – and because people must design the specifications for every coating and then apply them – the root cause of nearly every coating failure is, ultimately, people.

Because people failures are at the heart of the coating-failure problem, people should be the focus of any solution. And perhaps the most effective way to improve quality is to answer this question: What standards should apply to the people who apply industrial coatings?

How to Prevent Coating Failures

While corrosion remains one of the toughest and most costly challenges faced by America’s infrastructure owners, operators, and end users, the good news is that 50% of these costs are preventable – the vast majority through the use of properly specified and applied protective costings.

In order to ensure protective coatings are applied correctly and coating failures are eliminated or reduced, design engineers, facility owners, and contractors should incorporate, as part of any project specification, workers who have demonstrated training and experience in the highly specialized work of coatings application by earning the Industrial Coating and Lining Application Specialist (CAS) certification.

Read on to learn more about how implementing a corrosion management system and utilizing CAS-certified workers can help facility owners and operators save money, protect valuable assets, and safeguard public health and the environment.

“Whether it is a pipeline, an airplane, a water treatment plant or highway bridge, corrosion prevention and control is essential to avoiding catastrophic events before it’s too late.”
– Bob Chalker, CEO, NACE International

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