What is Non-Destructive Testing?

 

What is NDT?

Non-destructive testing is a process of inspecting, detecting, and evaluating the properties of material and component – it is an umbrella term used in engineering for the analysis techniques which are used to identify the flaws in material and differences in characteristics without causing damage and affecting the serviceability and utility of the component.

NDT is a well-known technique used for visual examination and in-service equipment or material inspection. It’s the process of measuring variations in material or equipment properties and characteristics such as material strength, ductility, roughness, and uniformity. Non-destructive testing is a great way of identifying incipient faults before it causes equipment to cease to operate completely.

Non-destructive testing is an essential tool in condition monitoring – it’s an in-service inspection and measuring device that evaluate and collect data about material without altering it in any way. It has no disastrous effect on the material being tested – while ensuring safe operations and quality control it safely measures the size, shape, and the presence and absence of other discontinuities.

NDT cannot be restricted to one type of testing – it has no set boundaries – the broad range of testing & inspection comes under this technique – from simple visual examination to well-established tools such as radiography, infrared thermography, magnetic particle detection, ultrasonic, acoustic emission, etc. NDT is also referred to as non-destructive examination (NDE), nondestructive inspection (NDI), and non-destructive evaluation (NDEX).

Aforesaid non-destructive testing tools are being widely used in the industries for the health monitoring of the equipment under the umbrella of a condition monitoring program for the diagnosis and prognosis of the developing faults, and so is the goal of NDT – to ensure that the critical assets are properly maintained in a safe, reliable, and cost-effective manner without experiencing a catastrophic accident or shutting down of plant operations.

NDT is one of the fastest growing technologies in terms of its uniqueness and innovations – the effective use of diagnostic tools can save the equipment from catastrophic events by reducing the chances of functional failures. With the recent advancement in equipment improvement and modification, the use of non-destructive testing has been widely accepted by many industries.

Applications of Non-Destructive Testing:

NDT is now a vital part of almost all industrial processes – whether it’s manufacturing and fabrication services, Medical pharmaceutical process, or power utility. In industries, Non-destructive tests are used to examine and evaluate raw materials before and under processing for process control, ensure product integrity and quality, control the manufacturing process, and lower production cost. With NDT, equipment and personnel safety is also ensured.

Industries that are using non-destructive testing in their processes are:

1-     Oil & Gas

2-     Power Utility

3-     Manufacturing

4-     Mining

5-     Pharmaceuticals

6-     Automotive etc.

This technology of non-destructive testing is also embedded in our daily lives – a process that we perform or come across daily – for example, the process of vending machine is so based on non-destructive testing on coins that we deposit for candy or drink, when deposited it goes through many different tests that measure the size of the coin, material, weight, and shape very quickly.

Since the NDT techniques are based on visual inspections, sensing temperature variations, examining irregular surfaces, and hearing abnormal noises – then we can say that non-destructive testing is an extension of human senses – with the sense of sight one can evaluate the size, color, and irregularities of the object being inspected, a human can even sense the hot places without even touching the material – determination of the unpleasant odor can be made through a smell – all these features makes human being a unique NDT instrument.

Misconception about Non-Destructive Techniques:

One of the major misunderstandings is that adapting non-destructive testing will not cause any equipment to experience a breakdown, or the process is a guarantee that all components and parts will remain healthy. Although, monitoring through non-destructive testing has the utmost importance in condition monitoring program but considering that only using this testing will ensure equipment reliability is a false image because, indeed, NDT is a vital tool for reducing the faults because of its equipment monitoring – timely and effectively but some other factors do come along and contribute to failure – those factors are an inadequate design and improper application of the object.

Similarly, it is assumed that since the NDT devices are mostly hand-held so it’s very easy to apply but this misconception also needs to be cleared that despite using the proper tool and adapting standards & procedures, it may produce unsatisfactory results when the tool is used by an unqualified person. Thence it is important to ensure qualified and trained personnel for conducting the non-destructive tests.

Non-destructive Testing is a valuable technique that can provide useful information about the asset, but it is hereby important to deploy trained personnel for interpreting the data derived from the non-destructive tests. Multiple benefits can be reaped if it follows the approved procedures and is conducted by qualified personnel.

Checks for the Effective Non-Destructive Testing:

• All the limitations associated with the component, equipment, or product must be known before selecting the appropriate test – for example: if the equipment’s surface is rough and have a complex shape then it is impractical to do the ultrasonic test on it and one should select radiography as a rightful option.
• Equipment, product, or component must be testable.
• It is essential to follow the approved testing procedures.
• A qualified person must be deputed for conducting the tests owing to avoid misinterpretations and catastrophic results.
• Annual calibration of the tools is required.
• At the end of the examination, proper documents must be completed for further analysis and interpretation.