Non-destructive testing (NDT) is quality assurance testing that provides information and data about a part or asset and how it performs in terms of things like condition, quality and reliability. This type of testing maintains the integrity of the assets, components and materials being tested and is used to detect defects and flaws within those pieces to ensure they are safe to be used.
NDT techniques are the only way to get this type of data about the item being tested without damaging it which is the key difference between it and destructive testing. Destructive testing is designed to push an asset to destruction by applying an extreme load or temperature so that the point of failure is identified.
This post looks at how NDT is conducted and its benefits for the construction industry.
How is NDT conducted?
How this type of testing is carried out will largely depend on what’s being tested. If metal is being tested, liquid penetrant testing might be the best option which involves applying a coloured liquid to the material’s surface and then using ultraviolet light to see whether it has seeped into any defects.
Non-destructive testing in construction on concrete structures, for example, involves methods such as visual inspection, penetration resistance tests, acoustic emission testing and radiographic testing.
In welding, non-destructive testing methods include:
- ultrasonic testing to detect issues in things like pipelines, structures, and tanks
- magnetic particle inspection can detect flaws in metal surfaces
- liquid penetrant testing detects surface-level defects in metal construction
- radiographic testing examines welds in dense materials
Non-destructive testing in civil engineering
An NDT test in civil engineering has a number of uses from being used to verify the quality of structures to identifying and quantifying potential defects without the need for the structure or material to be destroyed. This is a safer and cheaper alternative to destructive testing which involves destroying the item being tested.
Construction NDT methods are a crucial step in checking the integrity of materials and structures in the construction industry to ensure they are safe and fit for purpose. Visual testing is the oldest type of building inspection with a trained eye detecting surface defects such as cracks and craters. Aids such as endoscopes, inspection cameras, flashlights and more recently, robots and drones assist inspectors in being able to see more defects, particularly in less accessible areas.
The benefits of NDT testing methods in construction
Some of the benefits for using these methods in the construction industry include:
- Adaptability. Non-destructive testing equipment and methods can be used to inspect complex components such as pipelines.
- Cost-effective. NDT doesn’t damage the material being inspected and allows defects and weaknesses to be detected early in the manufacturing and construction process allowing these to be remedied relatively easily. This makes it a cost-effective testing solution as changes are cheaper to carry out at this stage rather than once the construction is complete.
- Improved quality control allowing more frequent inspections. It can measure material size and thickness helping to ensure the material or structure meets the appropriate regulations.
- Safety. non-destructive testing identifies safety issues quickly which helps to keep people safe. It helps to prevent accidents caused by structural failure and can also improve the reliability of a material or structure.
