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How to Choose the Right NDT Method: A Comprehensive Guide

Non-destructive testing or NDT testing is a collective term used for different testing techniques used to inspect materials without leaving permanent damage.  

NDT testing is often used to assess possible defects or faults within materials such as cracking and corrosion and can also analyse different characteristics such as material composition.  

Since NDT testing does not cause damage to a part or material, it is a safe and reliable testing method which can be carried out at customer sites, or within a testing laboratory. There’s no need to shutdown operations with NDT testing, so it is also cost-effective for businesses.  

There are many types of materials that can be tested with NDT methods, including: 

  • Metals and alloys 
  • Plastics, Ceramics and Composites 
  • Concrete, Wood, and Rubber 
  • Glass and Fiberglass 
  • Electronic components 
  • Weldments 
  • Castings and Forgings

The importance of NDT testing

NDT testing is crucial for a variety of industries, as it can support the integrity, safety and quality of materials and components without causing damage. For some industries, regular NDT testing can provide accurate data for critical operations such as aerospace and automotive engineering.  

Some industries will have regular NDT testing and inspections as a mandatory requirement, like piping inspections and storage inspections, and for other industries like manufacturing, it can provide quality assurance by identifying defects and flaws in materials after manufacturing processes and confirm material verification that products have been manufactured from the right materials and are suitable for their intended use.

Factors to consider when choosing a Non-Destructive Test

Material Type

Each NDT method has its own suitability for certain materials, and each material has it’s own characteristics and behaviours. So, understanding what the material is and what information you need to obtain is the first step in choosing an NDT method.  

If you know the type of material your product or component is made of, this will help to narrow down the type of NDT test you need. For example, if your product is a composite material, then Ultrasonic Testing would be the most appropriate. If your product is made of metal, but you’re unsure exactly what type of metal, then Positive Material Identification would be a good place to start.  


Material Shape

When choosing an NDT method, you need to think about the shape and size of your sample, as some tests do not work as well as others. For example, if you have a curved material or a thin surface, then Ultrasonic Testing would not be suitable as it requires a thick, flat surface.  

You also need to consider the size of your material; pipelines and other large components will need extensive scanning or measuring to detect any faults and flaws, so multiple setups may be required to cover the entire area.  


Surface Condition

NDT testing will also depend on the surface or finish of your material. Rough or coarse surfaces can impact the effectiveness of certain tests; Eddy Current Testing needs considerable contact with a material surface, and some test methods will require preparation of the area before testing. Dye Penetrant Testing is not suitable for porous materials but are better suited for smooth surfaces so that the penetrant can effectively soak into defected areas.  


Defect Type

The type of defect present on your material and its severity will influence the type of NDT test method you need. Radiography is ideal for analysing internal defects, whereas Magnetic Particle Inspection is better for visible surface cracks. If you have a shallow hairline crack, then Dye Penetrant Testing may be more suitable.  


Location, Accessibility and Environment

This is a crucial consideration when thinking about your NDT requirements. If the material is in a difficult to reach location, such as underwater or underground, this can present challenges for certain NDT methods. It may be difficult to take certain pieces of equipment into confined spaces or remote locations where power sources are not accessible. Other considerations such as environment, temperature, and exposure to hazardous environments means that it might be necessary to use remote controlled, drone, or automated equipment for health and safety purposes.  


Standards and Regulations

The frequency of NDT testing will vary depending on industry-specific regulations. For example, piping inspections in accordance with API 570 provides guidance on the frequency of Ultrasonic Testing and Visual Inspections 

It is important to consult any necessary standards or guidelines within your industry to remain compliant with legal, quality and safety processes.  

As a general guideline, critical safety components should be inspected more frequently, while standard and low-risk components will have less-frequent inspections.  


Budget and Timeframe

The cost and speed of testing can vary depending on the sample size, location, number of samples needing to be tested, the equipment and resources involved.  

Larger material samples may need more resources and multiple inspectors to carry out the work within a specific timeframe. If the location is not easily accessible, then this could increase the time required to carry out testing and inspections, which may lead to higher costs.   

Different Methods of NDT testing

There are many different methods of NDT testing. Some of the popular methods of NDT testing include: 

Explore our Guide to NDT Testing Methods

Make Informed Decisions with BES Group

Selecting the right NDT method is crucial for maintain operational efficiency and ensuring product reliability. With our team of expert inspectors and technicians, we are committed to guiding you in choosing the most appropriate method for your specific needs.  

Let us help you enhance your quality assurance processes and ensure the integrity of your materials and components.  

Contact BES Group today for Expert NDT Consultation

Related services

Eddy Current Testing

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Liquid (Dye) Penetrant Inspection

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Magnetic Particle Inspection

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Positive Material Identification

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Ultrasonic Testing

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Phased Array Ultrasonic Testing

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Visual Inspection

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