Why Corrosion is a Serious Problem
It’s estimated that over $3.3 trillion is the annual global cost of corrosion. The amount actually constitutes over 3% of the global Gross Domestic Product or GDP. And these numbers are expected to rise as we build more pipelines, storage tanks and pressure vessels to support our national economic growth.
Corrosion is a natural and inevitable process. In fact, it’s the favoured process because it results to the lowest possible energy states (just like water flowing downhill). For instance, a common case of corrosion is the rusting of iron wherein it reacts with oxygen and water to form hydrated iron oxides (rust). Interestingly, these hydrated iron oxides share similar chemical compositions with the original iron ore. These ores are abundant in nature because they’re relatively stable and in the lowest possible energy states (doesn’t react readily with most environmental elements).
As a result, it takes active protection and maintenance to prevent or slow down corrosion. First, premature failures should be prevented by rigorous inspection before using the pipeline or storage tank for operation. Second, there should be a regular or ongoing inspection to identify corrosion sites or vulnerable areas. Third, repairs and replacements should be done promptly to prevent the further corrosion of the metals.
Economic impact of corrosion to industries
We mentioned earlier that corrosion costs constitute over 3% of the GDP. It’s in a global scale and other industries are included in that calculation of the GDP.
What about in individual industries? The effect of corrosion is more pronounced especially in industries that heavily rely on pipelines, storage tanks and pressure vessels for their business operations. Oil, water, mining and chemical industries could be the ones most affected by corrosion. It’s possible that a much higher percentage of the individual company’s revenue (compared to 3% of the GDP) goes to dealing with the problems brought by corrosion.
We also have to consider the expensive downtimes that lead to lost income and opportunities. A month’s delay due to corrosion and compromised tank for chemical processing could cost millions of dollars of lost revenue. This could also mean loss of long-term customers due to the delays (customers will find another supplier).
Corrosion’s direct and indirect consequences also include shutdown of equipment, product contamination (metal and metal oxide particles going with the water or chemical), product losses (e.g. leakage), damage of nearby equipment and efficiency losses (heat transfer rates become lower thereby resulting to higher energy consumption). On electrical transmission towers, corrosion could result to power interruptions or unstable electrical flow in the area.
Most importantly, we also have to think about the possible physical and health dangers brought by corrosion. This reaction makes certain parts of the pipes or tanks to be vulnerable, thereby introducing safety risks. Gradual and sudden failures could result to fires, explosions, structure collapses and release of toxic chemicals into the area and the atmosphere.
Effective ways for corrosion control
Due to the huge financial losses and serious safety risks brought by corrosion, upfront and ongoing several control measures are being implemented. The most common and straightforward way is to coat the surfaces so there will be no opportunities for the water and oxygen to react with the metal underneath. Basically, the coating makes the metal inaccessible to the reactants and the environment.
One way to accomplish this is by applying a metal coating that has a higher corrosion resistance (e.g. tin-plated steel). Another way is by applying a sacrificial metal that can readily undergo corrosion while still protecting the active metal or steel underneath. In either case, the goal is to make the target metal inaccessible to the reactants and environment.
Aside from applying coating, another effective corrosion control measure is cathodic protection. Basically it’s an electrochemical process that uses a “sacrificial metal” that corrodes instead of the protected metal. It’s commonly applied in protecting immersed and buried structures (e.g. water pipelines) although it’s also applied in overhead storage tanks.
Inhibitors can also be used to slow down corrosion. Generally these inhibitors decelerate the corrosion rate of metals by formation of a layer (similar to applying a coating to prevent access to the protected metal). Corrosion inhibitors (e.g. zinc phosphate) are often added to paints and pigments. Lowering the corrosion rate can also be achieved by removing the substances that accelerate it. For example, hydrogen sulphide in oil refineries is often removed or converted into polysulphides because hydrogen sulphide corrodes steel.
The above corrosion control measures all employ chemical means and treatment. It’s also possible to achieve effective corrosion control by intelligent physical design of the components and parts of the tanks, vessels and pipes. For instance, the presence and use of joints, elbows and supporting parts might promote corrosion because of the presence of microsites. In other words, the coatings and other corrosion protection methods might not reach those microsites. These sites are then vulnerable and they become starting points for widespread corrosion. But with minimal numbers of joints and elbows, there will be fewer vulnerable sites to start from.
Making more areas accessible or easier for inspection
As discussed earlier, corrosion is a natural and inevitable process. We can prevent it temporarily or slow down its widespread occurrence. And fortunately we can also take proactive measures through prompt inspections of all sites.
However, a prompt and thorough inspection is often a huge challenge because some sites are inaccessible or hard to reach. We have to deal with thousands of kilometres of buried pipelines. Elevated structures such as overhead storage tanks and electrical transmission towers also make inspection more difficult. In addition, offshore facilities and marine environments make several sites inaccessible. In these locations a prompt inspection could be more critical because saline environments often accelerate corrosion.
That’s why there are now specialists who perform drone and rope access inspections of the potential corrosion sites. Drone inspection is a fast and economic option in corrosion identification. In fact, it’s also used in the detection of cracks, hotspots, leaks and spillages. Drones are also now being used in the inspection of the following:
- Lighting poles
- Dam walls
- Pipelines
- Roof-mounted solar panels
- Radio and mobile phone towers
- Power lines
- Building facades
- Wind turbines
- Heritage structures
Aside from drone inspections, Rope Access solutions are also available. This is great for any type of project that requires working at heights or where access is difficult. The service often covers inspection of coating, insulation and welding.
In-line inspections and engineering assessments are also being performed for corrosion identification. This is crucial in the inspection of steam pressure vessels, boilers (gas, coal, and multi fuel), recovery boilers, water heaters, fired heaters, process vessels, storage tanks, process piping, heat exchangers, steam generators and reboilers.
Aside from ongoing or scheduled inspections of the existing assets, there are also specialists who can help develop and review the welding specifications to ensure integrity of the resulting asset. This may include review of the pre-fabrication documentation for better protection against corrosion and other vulnerabilities in the first place. Non-destructive testing (NDT) might also be performed to search and determine the vulnerabilities on the existing assets.
The main goal here is to protect the assets and possibly lengthen their usage lifespan. As discussed earlier, corrosion of assets results to expensive downtimes, repairs and replacements. More importantly, corrosion also poses safety risks because of leaks and product contamination. With prompt inspection and timely maintenance, engineers can minimise those dangers and risks.
Effective corrosion control is crucial because corrosion affects major industries (mining, oil and gas, transport, power generation and transmission, construction, telecommunications, water supply) and the delivery and processing of necessities in life (water, electricity, chemicals, food). As a result, slight improvements in corrosion control could translate to millions (or even billions) of dollars of cost savings and possibly additional revenue for these key industries.
Why corrosion is a serious problem & what to do about it
Corrosion is an inevitable process (with costly consequences) but we can still minimise its effects. That’s why here at Corrims Consultants, we specialise in corrosion control so you can better protect your assets.
We’ve already worked with various key industries such as oil and gas, petrochemicals, coal mining, power transmission, ports and terminals and water supply and treatment. We’re serious about integrity and independence in all the inspections and consulting we perform. And we also offer tailored solutions that fit our clients’ requirements for every application.
Contact us today if you want to protect your assets through a more effective and comprehensive corrosion inspection and control for higher cost savings in the long term.