Non-destructive testing (NDT) combines the application of science of physics, maths, chemistry and biology to create a comprehensive process that can be used for inspecting, examining and testing of materials or components to find flaws, defects or discontinuities on the surface or subsurface areas, while maintaining the serviceability of the component after inspection, without causing any damage to its original form or usefulness.
As a quality control and quality assurance management tool, NDT plays a vital role in industries such as aerospace, pipelines, bridges, refineries and oil platforms as well as power stations as it can help prevent failures that could have an adverse impact on safety, reliability, and the environment. It is an important process that underpins all of their operations. However, in order to utilise it effectively, a comprehensive understanding of various methods available, their advantages and disadvantages and the knowledge of different specifications and relevant standards is crucial.
Why is NDT important?
All equipment, products and materials have a standard design requirement and projected life. However, sometimes due to the defects which may go undetected during the production, fabrication or service delivery, they may need to be replaced or undergo extensive repair, otherwise unsafe conditions or catastrophic failures might be the consequence of neglecting their unfit conditions for service. The resulting cost, due to project shut down, can be large in such cases.
Having non-destructive testing procedures in place throughout a material or component’s construction process or service life can safeguard assets and personnel, helping companies to ensure that they are adhering to regulations and standards. From oil rigs and pipelines, to bridges and railway lines, from aircrafts and trains to high-speed theme park rides, NDT is widely used in everyday things that need regular inspection and maintenance. Additional to the need for security, NDT is used to ensure the efficiency and durability of the equipment. This is known as asset integrity management, which consequently translates to better output and profitability for companies.
What are the advantages of NDT?
Performing NDT tests is very convenient, given that the components under test don’t need to get dismantled or even stopped from operation. The portable size of NDT equipment also makes their use very convenient, which also helps with efficiency of the testing techniques being used while the equipment is in service.
NDT is a part of many companies’ everyday operations because of the many benefits it offers. Some of the most prominent advantages include:
Safety assurance
Non-destructive testing is carried out to ascertain that the components or materials being used are not damaged or faulty and are fit to be used by personnel. The result of testing can show whether the components need to be repaired or if they are safe for operation.
Since the methods are mostly non-invasive to the component, and harmless to the operator, after the testing, the integrity of security of the items being tested can be assured. When properly used in industries involved with volatile high pressure machinery, NDT can not only prevent catastrophic failures and identify and resolve disastrous problems, it can even save lives.
Failure prevention
If a component fails or breaks down, not only is the business going to suffer drastically due to the unexpected shutdown but, in the worst cases, it can end up in irreparable catastrophes which can cause harm to people and the environment. Proper use of NDT can prevent these failures by identifying the areas of concern before they become a problem through failure analysis procedures.
Quality assurance and asset reliability
Non-destructive testing offers reliable and accurate results which can provide stability. Since this testing method does not damage the components, all pieces of equipment and machinery can be tested which can minimise the inaccuracy of test results and any undermined irregularities. The reassurance gained from the meticulous testing is an invaluable advantage of NDT. Knowing that all the machinery in a factory is regularly tested and complying with the standards adds a level of confidence in quality and security of the equipment as well as the safety of the operators of this machinery.
Cost efficiency
Various industries need to comply with different sets of rules and regulations and meet different types of safety standards. To meet the industry requirement for safety, machinery need to be regularly tested and non-destructive testing offers some of the most cost effective methods of inspection.
On the other hand, the result of regular testing can prevent failures, malfunctions or breakdowns, which would be far more costly to mend instead of undertaking regular maintenance and repairs when needed.
What are the disadvantages of NDT?
Although very few, there are some drawbacks to non-destructive testing. These pitfalls are subjective and dependent on the type of NDT technique used. Some examples include:
- Some of the tests can only be used on materials that are conductive
- To carry out some tests, such as magnetic testing or penetrant testing, the components need to be cleaned before and after the test
- Electricity supply is required for some tests and this can be a limitation when operating in remote areas
- Sometime the coating of the component or the finish of the surface area under inspection can have a negative impact on the accuracy of the test results
The majority of the points mentioned above are limitations of conventional NDT. However, advanced methods of NDT also come with some disadvantages that need to be highlighted:
- Conducting advanced methods of non-destructive testing requires equipment which is typically very expensive to acquire
- Equipment needs to be repaired and calibrated regularly to ensure the accuracy of the test results. Therefore, maintenance costs will always be an inseparable part of owning the assets
- Carrying out these advanced methods of inspection requires highly skilled and certified inspectors. This can add to the cost of training or hiring inspectors who know the advanced NDT techniques
When can NDT be used?
Non-destructive testing can be used in all stages of production, fabrication and service in almost all industries, including engineering, aerospace, automotive, rail, construction and power, including for the construction of a power plant, refinery, an offshore platform or in the production line of a jet engine turbine or railway. Various methods of NDT, from the conventional methods of visual testing, penetrant testing, magnetic particle testing, radiographic Inspection and eddy current testing (ET) to advanced methods of ultrasonic testing such as phased array ultrasonic testing (PAUT) and time of flight diffraction (ToFD), are utilised to ensure the safety, security and reliability of items throughout their life.
Of course, not all methods of NDT suit the same project. In order to acquire relevant data and correct business decisions, companies either use their internal team of trained and certified experts or engage with a third party inspection service provider who can advise them on the available options, their pros and cons and the best options to meet regulations and industry standards.
Depending on the operations and the project, the inspection will be carried out during the production process to evaluate the product and identify areas of wear, flaws or discontinuities. The interpretation of results are used for troubleshooting accident prevention as well as safety assurance of the structure.
What is the career path in Non-Destructive Testing?
The fact that NDT is being used in a wide range of industries globally makes the job opportunities in this field countless and career prospects can be very lucrative for those who are eager to invest their time and effort in gaining the required qualifications. Since NDT plays an important role in maintenance of safety and integrity, having an up-to-date knowledge and refreshed skills for inspectors is a necessity.
Getting into NDT does not have an age limitation or prerequisites. Whether you are a fresh graduate from college or ex-military, there are opportunities to get in to this line of work for those who enjoy hands-on jobs with a good comprehension of physics and mathematics.
To be a successful NDT practitioner, one should be intelligent enough to learn the concepts and master the subject. Have curiosity to explore and discover the problems and the dexterity to apply the techniques to solve the problem while being capable of adapting to new environments and circumstances. The ability to work independently is also an important factor as, in many cases, the operators may need to work alone.
You can choose a particular method of NDT to specialise in up to an advanced level. However, in today’s competitive job market, having the knowledge of different techniques to complement each other and being certified for those techniques not only increases the opportunities for employability but also opens up the doors to international job markets. This is the guarantee for a career path that never gets stagnant and can always keep you engaged with new challenges.
Check out the career map of an NDT inspector on our website and get in touch with us to discuss the best training courses to attend to start your journey in the NDT field at inquiry@twisea.com .