Strategies to Combat Maritime Asset Corrosion

File image courtesy EonCoat

Published Mar 21, 2018 2:32 PM by Merrick Alpert

The ravages of salt water can wreck even the sturdiest offshore and onshore structures. Wind-blown salt from bodies of saltwater can deposit on surfaces and accumulate over time. As one of the planet’s most abundant sources of corrosion, salt can combine with the chemicals and materials used in many maritime industries to create a worst-case scenario for carbon-steel assets.

Ships, boats, rigs, hulls, movable bridges, buildings, and machinery alike need to have top-of-the-line corrosion protection to prevent costly damage, decay, and downtime. Read on to learn the best ways of protecting these structures today.

The Costs of Corrosion at Sea

With the global cost of marine corrosion totaling anywhere from $50 to $80 billion every year, industry officials are constantly seeking innovative methods of mitigating and eliminating corrosion.

Transportation and shipping, national security, energy production (including offshore oil rigs and deep wells), and navigation are just some of the industries heavily reliant on maritime resources. For operations in these industries to be maintained, maritime resources must perform safely and efficiently, with little to no downtime. However, this isn’t always the case.

NACE International estimates that, over the lifetime of an asset, savings of up to 30% could be realized on actual costs of corrosion-related maintenance. The increase in costs directly related to corrosion can be explained as both a rise in labor costs to maintain assets and costs attributed to commercial depot maintenance. It’s important to note that this estimate does not include any savings realized from the prevention of downtime due to fully corroded or otherwise unsafe assets, which are likely considerable.

So why does costly corrosion continue to occur?

The Importance of Application

While a key step to preventing corrosion, the physical application of paints and other coatings can go overlooked.

When applying zinc coatings, it’s essential to use an agitator, as failure to do so will cause a separation of powder and resin. Applying primers and intermediate coats with a spray instead of brushes can leave unprotected corners, edges, and welds. Oftentimes, the wet film thickness gauge is not checked before application, and then there’s the all-too-familiar issue of failing to check the dry film thickness against a standard before using it. In short, paint mixtures and applications are eyeballed instead of being tested with the tools made for the job.

Beyond these common issues, high-quality coating jobs with traditional coatings should also carry out checks for any soluble salts present. What’s more, abrasive blasting for surface preparation needs to be measured carefully, as a re-blast is an expensive mistake.

These best practices are crucial, and skipping them could mean that the coating will not protect for its intended duration. But, for long-lasting protection, the coating you choose is also important.

Testing Against Corrosion

In order to find the best coatings to protect assets from the damaging effects of maritime environments, scientists and technicians have designed special tests. The seawater corrosion chamber test and the salt chamber test are two of the best possible designs to deduce which anti-corrosion coatings will hold up in the stress of seaside application.

- Seawater Corrosion Testing

One of the most rigorous and grueling tests that anti-corrosion remedies can undergo is the seawater corrosion test. Coatings are placed in a specially designed chamber and, instead of using a traditional chemical formulation, genuine Atlantic Ocean seawater is sprayed onto them. Heat lamps with 426-nanometer light waves then cook the test coatings in four-hour intervals in order to simulate the sun’s energy that often accompanies the spray of ocean water.

- Salt Chamber Testing

A second form of testing the effects of saltwater as a corrosive property is the salt chamber test. Initially developed by NASA as an aggressive test to intentionally promote corrosion on certain surfaces, a coating is placed in a corrosion chamber that alternates between two grueling settings. For twelve hours a day, the chamber sprays seawater on the samples – not the less aggressive “salt fog” often used in other tests. For the other twelve hours each day, the chamber shines a multi-spectrum (grow) light on the samples.

Ideally, the coating used to protect maritime assets should not only shield vessels and platforms from freshwater, saltwater, and brackish water, but also provide an extra level of protection to keep crew members healthy and free from the bacteria, viruses, fungi, protozoa, and microbes that flourish in such moist environments. With this kind of testing, it can also be determined whether a coating can protect workers as well as assets.

Predicting Problems and Education

In addition to a carefully applied, top-quality coating, prevention must be part of any good anti-corrosion policy. One of the chief goals of any experienced engineer tasked with reducing, mitigating, or eliminating corrosion is to consistently monitor and maintain equipment to scan for potential failure.

A well-trained crew that can handle corrosion problems on-the-fly will help maximize efficiency and the integrity of all assets. NACE International recommends that all organizations implement a Corrosion Management System, and they offer educational courses on basic corrosion, offshore corrosion assessment, and marine coating technologies.

Paying attention to critical details and leaning on acquired knowledge of corrosive elements will assist in combating maritime asset corrosion. With education and training, an engineer should be able to provide enough leeway and time for the organization to deploy resources to correct any potential failure and save on the costly downtime, repairs, and labor associated with corrosion.

How well are your maritime assets protected against corrosion? Have you already noticed your coatings failing to protect your carbon-steel structures? Talk to us in the comments section below.

Merrick Alpert is president and a member of the board of directors at coatings manufacturer EonCoat.

The opinions expressed herein are the author's and not necessarily those of The Maritime Executive.