Non-destructive testing (NDT) is a set of technical procedures that examine the structural integrity and operational capacity of many types of metals, materials and industrial components, thus verifying whether the inspected object is at risk of flaws and potential weaknesses. Contrary to other types of testing techniques, NDT is entirely non-invasive and causes no damage to the inspected materials, making it an efficient testing method. NDT can ascertain serviceability and functional performance in real time, and it’s commonly used in a number of interdisciplinary fields, such as manufacturing and energy.
Pipelines and nuclear reactors in particular make use of NDT because it enables service providers to determine the strength, safety and quality of the materials used on-site, both during construction and operation. Because operators of energy infrastructure must comply with a plethora of legal and regulatory safety standards while also securing the confidence of public communities surrounding select sites, the data provided by NDT is crucial.
Once testing is complete, operators have the information they need to make informed decisions about the asset’s integrity as it relates to the operation, repair or replacement of the infrastructure.
“Testing procedures used do not render the components or materials inspected unfit for future service.”
When NDT is needed
In many cases, NDT may be mandated by a legal authority or internal audit to achieve a certain industry standard or certification. Typically, a third-party in-service inspector comes on-site, collects data of the inspection and provides a detailed report of the findings.
NDT is needed for a variety of reasons, including:
- Assessing product reliability
- Preventing operational downtime or shutdown
- Providing relevant information pertaining to an agreed-upon requirement
- Monitoring manufacturing processes
- Ensuring enhanced design of future materials
- Adhering to industry regulations
- Avoiding associated environmental risks
- Developing safe protocols
- Ascertaining integrity of current assets
Testing for future service
The key underpinning to NDT is that the testing procedures used do not render the components or materials inspected unfit for future service. The testing itself does not harm or interfere with the overall ability of the component to function normally, allowing operators to be notified of potential flaws in the test subject without components being destroyed. This type of advanced technology is more frequently used in place of destructive testing because it provides operators with more options and doesn’t further contribute to downtime.
A report from the International Atomic Energy Agency noted equipment can be manufactured with design flaws and weaknesses from the start. Over time, these defects compound and may lead to even larger structural issues. Once defects reach dangerous levels, continued stress and pressure on weakening materials may cause cracking, corrosion or full breaks.
“There is, therefore, a need to detect these flaws and evaluate them in terms of their nature, size and location,” the report stated. “Further steps should be to assess (a) how severe and dangerous the flaws are in their present state, (b) whether they need to be removed by repairing the tested component, (c) if the component is scrapped, or (d) with known flaws, if the product can be allowed to go into service. These are done through inspection and testing.”
NDT is the most effective procedure in maintaining full service and supplying the energy industry with a measurement of quality assurance. For more information about NDT techniques, check out this video from Applus+ RTD.