Corrosion at its base level can be described as the gradual destruction of materials by chemical reaction with their environment. This is a natural process, and is what we all recognise as rusting in metals. Corrosion can occur in other materials too, such as ceramics and plastics, but rusting in metal is what we more commonly associate it with. This process of electrochemical oxidation of the metal in reaction to an oxidant, such as oxygen or water, causes the metal to become weakened and lead to premature and sudden failure.
The cost of corrosion is great, NACE International, one of the world’s leading authorities on corrosion control, estimates that corrosion costs an industrial economy 3.1% of its GDP. This means that the cost for corrosion runs into the billions if not trillions. The offshore industry in the North Sea spends between £150,000 and 250,000 on bolts and fasteners alone, some corroding before an installation has even been commissioned, and some even within weeks and months of fixing.
According to the Pipeline and Gas Journal, in America the annual cost associated with the damage caused by corrosion is greater than the combined annual cost of natural disasters, including hurricanes, storms, floods, fires and earthquakes, with similar studies and findings from the UK, Germany and Japan.
Corrosion is inevitable, but there are ways that it can be slowed and inhibited. The application of various specialist coatings and wrapping systems is perhaps one of the more common and widely used methods to protect steel from the damaging impact of corrosion, and effective corrosion control can extend the useful lifespan of the metal structure greatly.
If we look at what conditions cause corrosion on unprotected metal, a combination of water/moisture together with oxygen/air is required to create the perfect environment for corrosion to occur. If one of these factors is removed then corrosion is inhibited, this is what these preventative systems, to varying extents, strive to do.
Unprotected pipelines are incredibly susceptible to corrosion, these could be buried in the ground, submerged underwater or exposed to the environment, all are vulnerable. Corrosion in pipelines is incredibly perilous, corrosion can damage the structural integrity of the pipeline, making it dangerous for transporting potentially hazardous goods, such as oil and gas.
Some pipelines may deteriorate slowly, while others may have exhausted their useful life after only a year of operation, some pipelines have even been found to have lost 70% to 90% of their mass due to corrosion. In fact one report on a pipeline running from Canada to America, obtained by online news sites, states that the pipeline suffered major corrosion only two years in to its operation and was up to 95% worn in some spots.
Many considerations come into play when looking at pipeline lifespan and how corrosion will impact upon it, these include quality of construction, the product that is transported, the environment it is operated in, the quality of the maintenance program for the pipeline, whether it is coated or similar protection applied, all factors have an impact on the life of the pipeline.
Pipeline repair due to corrosion can run into the millions and in some cases billions, operators need to consider quality preventative strategies, rather than locate and repair mentality. Costs for corrosion will continue to rise and pipelines will continue to deteriorate, without the proper prevention measures in place costs for repairing a corroded pipeline will continue to escalate. Whilst this locate and destroy method might save money in the short term, long term costs will significantly increase as problems worsen.
How can we control pipeline corrosion?
Pipeline corrosion can generally be controlled and inhibited in several ways:
Cathodic Protection is a technique to control the corrosion of a metal surface by making that surface the cathode of an electrochemical cell by use of a direct electrical current.
The choice of material for the pipeline can play an important part in controlling the spread of corrosion, materials such as stainless steel, special alloys and plastics are typically more resistant to corrosion.
Corrosion inhibitors are chemical compounds that when added to a certain environment, typically a liquid or a gas, decrease the rate of corrosion on the metal.
Specialist coatings and wrapping tapes are the primary tool for protecting against corrosion, they work by forming a corrosion resistant barrier between the pipe surface and the environment.
No matter which method, or combination of methods, is used only with an effective maintenance program can corrosion related problems be controlled and minimised. The cost of installing, monitoring and maintaining proper pipeline corrosion protection, is far outweighed by the increasing risks of pipeline failure.
A new approach to eliminating pipeline corrosion
A new method of pipeline corrosion protection, which provides the answer to both prevention and monitoring of corrosion, has recently been developed by North East based Abfad Limited.
Abfad are well known for protecting storage tanks from the problems associated with corrosion. They do this by applying specialist solvent free resins to fully encapsulate the internal steel of the storage tank, providing a corrosion resistant barrier, extending the life of the tank and saving the client a lot of money in the long term.
They also install their own solvent free double skin lining system, Fuelvac®, which has been developed and perfected over the years. This double skin lining system prevents corrosion, whilst also acting as a second tank almost, providing a safety net if there is ever a breach, either externally or internally, so stored product will be safely contained. Fuelvac® is a fully monitored system, containing an interstice between the two layers of protective solvent free resin, through which a vacuum is pulled. This vacuum not only increases the corrosion resistance of the system, but alerts the client if a breach occurs, as any breach would cause a drop in the vacuum which in turn would cause the system to alarm.
Due to Abfad’s success, over many years, with corrosion management in storage tanks, they have taken the step to adapt their knowledge and experience into the protection of pipelines with the creation of PIPEVAC®. This new development, based around there Fuelvac® technology, eliminates the conditions with which corrosion can occur by creating a vacuum around the pipe substrate, enabling the prevention of external corrosion to the pipeline.
If we look again at the conditions which must exist for corrosion to occur, we can see that by removing one element from the equation prevents the conditions for corrosion, with PIPEVAC®, two of the elements are removed from the equation, as the unique vacuum system prevents moisture and oxygen from attacking the substrate of the pipeline, thereby fully erasing any of the conditions for corrosion to take hold.
Utilising a vacuum around the pipe in this way enables leak detection monitoring to be integrated as part of the system, meaning that any problems with internal corrosion or damage to the outside of the pipeline can be easily notified and located. This leak detection feature of PIPEVAC® can be a useful tool in aiding maintenance and inspection programs, as a problem occurs along the pipeline and the incorporated vacuum is breached, the monitoring system alarms, notifying the client there is a problem and which section of pipeline the problem occurs in.
Adding to the versatility of the system, is the fact that it can be installed on both above and below ground pipelines, either in the factory on new pipe work, or in the field onto pipelines that are currently in-service.
Abfad see the PIPEVAC® system as a new approach to pipeline protection, employing vacuum technology to prevent corrosion from impacting on the pipe, avoiding any damage to pipeline integrity from corrosion, whilst at the same time allowing complete monitoring of the pipeline.
With the cost of corrosion so high, and continuing to rise, it’s important that operators ensure the highest level of protection for pipeline infrastructure whichever method of corrosion protection they choose to install, taking a proactive approach to protecting and preventing corrosion, rather than a reactive find and fix method.