What is Non-Destructive Testing (NDT)?

Testing is one of the most important parts of maintaining equipment. Evaluating the structures, designs, components, and materials of your assets and products is best. Depending on the state of tested components, once testing is done, the process can be classified as non-destructive testing or destructive testing.

If components get destroyed or damaged during the process of testing, the testing methods used are described as destructing testing. On the contrary,non-destructive testing (NDT)is often conducted without causing any damage to the tested components of the equipment.

What NDT Is

NDT is an analysis technique and testing used by industries to determine the properties of a system, structure, component, or material for discontinuities and welding defects without causing any damage to original parts. It can also be NDE (non-destructive evaluation), NDI (non-destructive inspection), and NDE (non-destructive examination).

Types of Non-Destructive Testing

There are various NDT methods. All these techniques are used for various defects. So it is best to choose the right technique for the job. The most common types are:

  • Visual inspections. This is a way of checking the conditions of materials by looking at them. For a more detailed visual inspection, you will use a remote visual inspection device in order to have a closer look.
  • Ultrasonic testing. In this testing, an inspector will transmit high-frequency waves in a material or asset to spot property changes. A key type of this testing uses pulse echos.
  • Leak testing. This helps to find a leak in a pipeline or asset. The most affordable of all leak testing is the bubble leak test. It involves immersing a test asset in the liquid container and then applying a soap solution so as to find a leak.
  • Radiography testing. In this testing, radiographic films are placed on the opposite side of a metal part. Then technicians apply a source of radiation, like an X-ray, that passes through the film and tests the object.
  • Electromagnetic testing. This category includes Remote Field Testing, Alternating Current Field Measurement, and Eddy Current Testing. These three techniques can detect sub-surface and surface flaws. They often induce a magnetic field or electric current in a material. Any defect creates what is called a measurable response.


Non-destructive testing has many practical applications. But it can be divided into condition monitoring and quality control.

You can use NDT to assess manufactured parts’ quality to ensure they meet desired specifications. You can also use it to assess the conditions of parts already in service and if they are safe.

Advantages of NDT

When ensuring assets are well-maintained, the benefits of NDT can’t be over-stressed. The following are key reasons many companies use NDT:

  • Accuracy. NDT techniques are predictable and accurate, ensuring equipment longevity and personnel safety.
  • Efficiency. The method allows for a thorough evaluation of equipment, which is important for ensuring performance and safety at a job site.
  • Safety. Non-destructive testing is appealing because nearly every technique, except radiographic testing, is safe for people.

The Takeaway

Non-destructive testing remains an important assurance management tool needed to ensure the safety and integrity of everyday objects. Its capability to test structures and materials for defects or flaws without destroying or modifying original parts means qualities of materials can be assessed effectively.