Mid-Wall Defect
or Corrosion?

Knowing the Difference Can Save
You Millions

June 8, 2020 | 3 min read

In Advanced NDE, having the expertise to identify a mid-wall defect versus incorrectly labeling it corrosion can mean the difference between thousands and potentially millions of dollars in unnecessary expenses. A well-trained Advanced NDE technician, with the right tools, has the ability and expertise to locate, identify and report the disparity.


The Difference

A mid-wall defect is generally caused during manufacturing. For example, sometimes when raw material is rolled in preparation to manufacture pipe, a foreign object may be introduced in the process. Subsequently, an air bubble or void is created in the material. In other words, a mid-wall defect is a flaw in the material and is located between the inner and outer layers of the pipe. Unlike corrosion, these types of flaws are fixed and do not grow or spread.

Corrosion, on the other hand, is a problem that causes wall-loss. Corrosion begins from the outer or inner walls of a pipe and is typically caused by air mixing with water, oil, sludge, or alternative currents. Corrosion is problematic because it eats away at a pipe and spreads over time.

Catastrophic Inaccuracies

Choosing the right Advanced Non-Destructive Evaluation (Advanced NDE) professional is essential to ensure a correct determination between mid-wall defects and corrosion. The Industrial Inspection & Analysis Field Services Division is the premier provider of Advanced NDE services for new construction projects. Some Advanced NDE companies inaccurately, yet commonly, classify mid-wall defects as corrosion. Once a report like this is received, many times companies have no choice but to replace that particular section of piping, which can be catastrophic in terms of time and money wasted.

For example, before working with Industrial Inspection & Analysis, a nuclear energy company received testing data that revealed greater than 80% wall loss (i.e., corrosion) in some places on a run of pipe nearly 200 feet in length. In other words, the inspection report delivered to the nuclear energy company by the previous Advanced NDE service provider indicated the pipe had degraded to the point where replacement was necessary.

Seven Million Saved

Subsequently, the nuclear energy company hired the Advanced NDE professionals within IIA’s Field Services Division to inspect the same area of pipe. Upon inspection, IIA conclusively determined that the defect was not nearly as significant as reported by the previous company. Further, and most importantly, the issue was definitely not due to corrosion. In a matter of days, IIA delivered an in-depth Advanced NDE Inspection Report, and the report indicated there were, in fact, several mid-wall defects but none significant enough to warrant replacement of the pipe.

Before contracting for a second opinion with IIA Field Services, the nuclear energy company was preparing to cut out and replace an elbow of pipe at a cost of approximately $7,000,000. The Advanced NDE Inspection performed by IIA Field Services cost the Nuclear Company just under $30,000.

Rely on Accuracy

The professionals in IIA’s Field Services Division are experts in providing inspection services, such as X-Ray, Magnetic and Penetrant Testing, as well as Phased Array Ultrasonics. Advanced NDE offerings include corrosion inspection services for buried pipelines and fixed equipment as well as Remote Visual Inspection (RVI) Services. Be sure you are relying on accurate testing and data by calling on the experts at Industrial Inspection & Analysis. We understand your time, reputation, and money are all on the line. We value your business and recognize the importance of accuracy, especially when it comes to Advanced Non-Destructive Evaluation.

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