Maintenance relies on several methods to enhance the safety, efficiency, and reliability of valuable assets. One of these methods is non-destructive testing or NDT. Choosing an effective NDT technique depends on your industry, asset types, maintenance goals, and budget requirements.
What is Non-Destructive Testing (NDT)?
NDT can be any technique that tests the integrity, performance, critical parts, and functional properties of assets without causing damage. In contrast, destructive testing requires breaking, heating, cutting, using chemicals, etc. to test assets or their parts.
In maintenance, the use of NDT methods is especially valuable because facilities cannot afford to pull out assets and halt operations, let alone destroy them. Non-destructive ways of testing assets can be as simple as visual inspections and monitoring to complex techniques using sophisticated testing tools.
Benefits of Non-Destructive Testing (NDT)
Below are the benefits of including NDT in your maintenance strategies:
- Savings – The main benefit of using NDT methods is that it saves the machine and equipment, thus, saving you money and resources.
- Safety – Most NDT techniques, except those that use radiation, do not pose risks to human safety and wellness.
- Efficiency – Most NDT methods can be done quickly and do not require prolonged testing, extended downtime, or long hours of personnel time.
- Accuracy – NDT methods come with accurate tools and standard testing methods. These methods are also repeatable and provide reliable results.
Types of Non-Destructive Testing Methods
The following sections introduce and briefly discuss several non-destructive testing methods that can provide critical benefits to maintenance.
Acoustic Emission Testing (AET)
AET is a common NDT in maintenance and is used to evaluate the integrity of asset material or structure without damaging it. This method uses test objects that induce the emission of sound waves from materials or structures. Sensors then capture these acoustic emissions and a software program analyzes the digital data to identify cracks, leaks, corrosion, friction, and other material failure-causing abnormalities.
Ground-Penetrating Radar (GPR)
GPR is a technique that is especially useful for the maintenance of infrastructures. It works similarly to AET, only that GPR uses electromagnetic waves instead of sound waves. GPR sends electromagnetic waves into the infrastructure or material and analyzes the waves that bounce back. It is also effective for identifying material abnormalities to prevent future failures.
Laser Testing Methods
Using lasers is also an excellent method to examine and gain insights into the integrity of materials and surfaces without destroying them. These methods work by projecting laser beams onto materials and surfaces to measure dimensions, identify invisible defects, and examine overall surface conditions. Examples of methods using lasers include laser scanning, laser profilometry, and laser shearography.
Leak Testing
Leak testing is a non-destructive process of identifying fluid or gas leaks in containers or enclosed systems like pipelines, tanks, or valves. There are various techniques to test leaks depending on the asset being tested. Some of these techniques are pressure decay testing, bubble testing, vacuum testing, and mass spectrometry.
Magnetic Flux Leakage (MFL)
MFL is an NDT method ideal for assets made from ferromagnetic materials. This testing method works by detecting disruptions in magnetic fields caused by material defects. MFL testing is ideal for examining structural damage on steel machine parts, pipelines, or storage tanks.
Microwave Testing
High-frequency electromagnetic waves or microwave radiation can be used to inspect materials for defects or abnormalities. Microwave testing is valuable for identifying integrity issues such as cracks, moisture, or voids.
Liquid Penetrant Testing (LPT)
LPT is another NDT method for assessing surface defects in asset surfaces. Small cracks, porous spots, and other abnormalities can be spotted using colored or fluorescent dye applied onto the surface under testing. This is a common method used in the aerospace, manufacturing, and construction industries.
Magnetic Particle Testing (MPT)
Like MFL, MPT is also valuable in testing ferromagnetic materials, but MPT is a quicker and more affordable method. This test uses magnetic particles in powder or suspension form to locate surface or near-surface defects on asset parts.
Neutron Radiographic Testing (NRT)
NRT is a valuable method for inspecting the inside of assets without opening or damaging them. This method uses neutrons, a type of subatomic particle, beamed into assets. These neutrons create images of the asset’s internal structure as they pass through asset parts and walls. These images provide insight into the densities, cracks, and abnormalities on and within asset parts.
Radiographic Testing (RT)
RT is another common method of non-destructive testing that maps out an asset’s internal structure using X-rays or gamma rays. It is a method often used to test the soundness of material welds and internal structures.
Thermal or Infrared Testing (IRT)
IRT uses infrared radiation to detect changes in the surface temperature, providing data on heat loss, insulation abnormalities, electrical issues, and similar signs of failure. IRT allows the safe and quick collection of these data that otherwise require hazardous methods to collect. With these benefits, IRT is especially valuable in predictive maintenance strategies.
Ultrasonic Testing (UT)
Similar to AET, UT uses a device called a transducer that emits sound waves into an asset. UT analyzes the ultrasonic waves that interact with the asset parts and materials. UT can provide information on the presence, size, and location of defects.
Vibration Analysis (VA)
VA is another common NDT in asset maintenance and involves testing the moving parts of assets to detect any abnormalities that can cause failures. VA methods use sensors that capture vibrations and convert them into electrical signals. Specialized software then analyzes these signals and identifies faults such as imbalances, misalignments, wear, and other issues. These issues are often not easy to detect without VA. Correcting these issues can effectively prevent failure, improve performance, and prolong an asset’s lifespan.
Visual Testing (VT)
Visual examination involves the use of human visual acuity or visual aids to detect visible signs of asset defects. Inspectors must have the necessary knowledge, training, and expertise to perform visual testing of assets.
CMMS Support for Non-Destructive Testing
More and more facilities are now recognizing the valuable benefits of NDT methods in improving their maintenance strategies. Whether large or small, modern facilities are now using multiple NDT methods together for optimum asset maintenance. In such cases, a CMMS or computerized maintenance management system
is indispensable. Redlist’s CMMS allows the integration of other sensors and software to bring all your NDT data together in one easy-to-use platform. Redlist integrations make it easy for separate NDT software systems and sensors to upload data right into one secure but accessible database. This way, data collection, reporting, and analysis take a shorter time to perform and are more accurate. Redlist CMMS is the best support for any NDT method in use at your facility. Schedule a free demo to experience Redlist today!
