Common Misconceptions That Contribute to Premature Coating Failures
Good communication and teamwork within industry concerning equipment design and coating specifications are critical to prevent premature coating failures.
There are a number of common expectations and misconceptions concerning coatings, alongside protocols that can help ensure the most suitable solution is chosen to complete a coating application project. Building upon the information presented in How Better Industry Teamwork Can Reduce Premature Coating Failures, we will explore the remaining factors that can adversely affect the quality and service life of any coating project:
- Application contractor experience
- Client expectations and misconceptions
- Understanding coating characteristics
Application Contractor Experience
It should be obvious that the application contractor and its employees are critical to the successful installation of any coating or lining project, and yet many clients still tend to choose contractors based on price. That’s like buying a bicycle because it is less expensive than a car, even though you are planning a journey from one end of the country to another!
They say that you get what you pay for and, for the most part, experience has shown this to be true – certainly when applied to the successful installation and consequent longevity of internal linings.
In recent years, many oil and gas industry asset owners and operators have begun to object to the investment required for application of specialist internal lining materials, only to have them fail prematurely. (Learn more in What is Coatings Asset Management?). This could be due to less-than-perfect application techniques, or deliberate corner cutting by contractors, who are desperate to maintain or increase their profit margins.
There is thankfully an increasing realization that careful selection of both the lining and the contractor is essential if the completed project is to reach its expected operational life. Clients are now beginning to insist that the contractors’ personnel be trained and validated by the linings manufacturers in order to be eligible to even bid for a project.
Most coatings and linings manufacturers would consider this to be a positive move within the industry, as it helps to set and underscore minimum standards. Furthermore, it benchmarks acceptable practice and contractor performance directly to the lining product specified.
Validated training improves application standards.
However, specific training such as this comes at a cost. For the linings manufacturer, this presents as manpower, facilities, and product and administration costs. Training affects the contractor in terms of training fees, release of manpower and a loss of chargeable days during the training course.
Fortunately, clients who are more enlightened realize that the cost of the lining application, when compared to the cost of the overall project, is minimal. Therefore, the contractor is allowed to include the cost of training within their bid for the work – the client, in effect, paying for applicator training themselves.
The philosophy is simple: It’s better to increase the known costs up front than have to cope with the possibility of much larger unknown costs at a later date following a premature coating failure. (Related reading: 5 Coating Defects That Can Be Avoided By Adhering To Coating Specs.)
Client Expectations and Misconceptions
For many years, problems have arisen, in part, due to the approach adopted by the manufacturers’ sales personnel in their interactions with clients. Being for the most part commercially oriented, their primary interest is directed towards achieving the sale. Historically speaking, their interests did not take into consideration what the client expected the product to achieve.
Consequently, this resulted in the client buying what the salesmen thought they needed, not what the client actually required.
To counter this problem, manufacturers introduced Technical Sales personnel who were trained to ask the right questions in order to correctly specify a product (via a coating specification) to match the needs of the client.
That said, the problem still occasionally occurs when certain crucial questions are overlooked. This is simply because Technical Sales personnel, although considered professional and capable, can wrongly assume certain critical facts, probably basing their assumptions on “experience” of similar applications. It should also be said that the cause of this problem couldn't all be laid at the feet of the Technical Sales personnel. The clients themselves need to educate themselves on the idiosyncrasies of the various lining products on offer.
As indicated above, this problem is now being addressed by the wide range of acceptance testing that is now mandatory for coating inclusion in client specifications.
However, the client also needs to realize that so far no manufacturer has been able to produce a lining product capable of coping with limitless service conditions. It is difficult to even imagine that there ever will be such a product available and as a result, there are many occasions where the client needs to be very specific with respect to actual service requirements.
Technical Sales personnel can provide assistance with coating selection.
Consider for a moment the specification for a process vessel. The client will usually quote a service temperature, pressure and, in most cases, they would additionally quote a design value for both. Common additional information would include a breakdown of the process fluids in terms of chemical constituents and their concentrations, dissolved gases and the type and quantity of any entrained solids.
This of course leaves the coatings manufacturer with a dilemma. Do they specify a product that will meet, or even exceed, the service condition, or do they specify a lining that will meet the design criteria?
The easy option for the client is to specify that the lining is required to meet the design criteria, since the design criteria is the maximum condition that the vessel should be expected to tolerate. This is always higher than the actual continuous operational condition to which the vessel would be exposed under normal operational circumstances.
Similarly, the same principles apply to coatings and linings. These also have their maximum design and continuous operational limits, but unfortunately, clients do not always understand the implications of this fact.
When asked the question, most clients would say that they specify to design criteria in order to embrace the possibility that the process condition may change over the operational life of the equipment. This would appear to be quite a rational assumption based on their experience of the operation of such equipment. Assumptions can lead to problems if they are not correct. For these reasons, clients also need to be educated to understand the vagaries of coating characteristics.
Understanding Coating Characteristics
There are two critical aspects to consider when faced with this situation. First, by way of illustration, if you had to drive your car over roads with a coating of black ice and you had the choice of riding on normal road tires or winter tires, which would you choose? Hopefully you have reasoned that there would be a greater chance of an accident if you continued driving on your normal road tires, so you would choose to change them for winter tires.
The same philosophy applies to process vessels. If the process changes drastically, the vessel will more than likely have to be modified internally to cope with the new conditions, just as the vehicle required modification to operate safely in new conditions. With respect to a vessel, however, any modifications would probably cause damage to the internal lining, in which case it would have to be reinstated.
So, there should be little reason to specify for the design criteria knowing that the coating can be upgraded at the same time, as any internal modifications are done to accommodate the new operating condition. Therefore, in most cases specification of a coating that exceeds the normal operating condition by a comfortable margin, rather than the ultimate condition, should be a reasonable compromise.
Secondly, if you gave a client a recommendation to use a lining with a maximum service temperature of 100°C (212°F) knowing the maximum service condition is 150°C (302°F), would the client accept it? Probably not, since they would reason that at the operating temperature, the coating would be damaged.
This is because the client has correctly deduced that the product has been formulated to perform up to a maximum temperature of 100°C (212°F) and that it would not be acceptable to expose it to temperatures above this limit.
However, if we reverse this scenario and offer a product that is formulated to work continuously at 150°C (302°F), but will only ever see 40°C (104°F) in operation, generally the client would accept this solution without question, assuming it was an economical solution. In fact, they may have just signed up for a premature failure of the coating.
Notably, products formulated to work at high temperature do not necessarily perform well at lower temperatures unless they can be force-cured before service. Experience tells us that this is not accomplished easily or economically in most cases.
Significantly, personnel employed in all the major industries, particularly the oil and gas industry, are becoming less and less aware of the capabilities of modern high-value coating and lining systems. Furthermore, this situation is set to become worse since the oil industry is losing its experienced workers faster than it can recruit and train replacements. (Counteract this problem by discovering the Secrets to Success as a Young Corrosion Engineer.)
According to John England, Vice Chairman and U.S. Oil and Gas Leader for Deloitte LLP, it is probable that 50 percent of skilled workers within the industry will be eligible for retirement by 2017.1
As the price of oil falls, the situation will only worsen, as more and more skilled workers are laid off and find jobs in other industries. This skill loss appears to be across all disciplines. From the coatings manufacturers’ viewpoint, this a serious problem affecting every aspect – from specification to application of their products.
Together, Everyone Achieves More
Clearly, for coatings and linings to become viable long-term solutions to the damaging effects of erosion and corrosion within the industry, it is vital for everyone involved to work together.
Currently, projects begin with an idea. This idea evolves into a design that, if accepted, is fabricated and coated if required. At this point contractors will be supplied with a specification and asked to bid for the work. Often, as in the case of new build, this means the site is unseen. At no point do all of the parties involved get together to discuss the project.
In the technological world we live in today, shouldn't this be possible? Certainly it is more possible than it was before the advent of the internet and its channels of communication.
Ideally the client, the lining manufacturer, and the design authority need to be in communication from the outset to agree on a suitable and compatible design and lining combination. As soon as possible, the chosen lining manufacturer should be able to liaise with the fabricators and be able to recommend trained reliable contractors to bid for the application of their product.
Lastly, as soon as it is possible, all parties should meet to discuss the application Method Statement, Quality Control plan and Specification. Only if this cooperation is achieved, can we truly say that risk has been minimized and that the applied lining has been given the best-possible opportunity to provide optimum performance. (Learn how to avoid problems by reading Common Misconceptions That Contribute to Premature Coating Failures.)
- Jill Tennant, “Making informed human resources decisions based on workforce outlook,” World Oil Online, September 2012.