Table Of Content

• Fundamental Principles of Infrared Thermography Testing
• What is an Infrared Wave?
• Types of Thermography Inspection
• Applications of Thermography

In the realm of Non-Destructive Testing (NDT), where the quest to unveil hidden flaws and ensure the integrity of critical components is paramount, one method stands out as a true marvel of modern engineering: Thermographic Testing.

Thermography Testing in NDT is a method that doesn't rely on physical probes or invasive procedures but instead harnesses the power of heat and the keen eye of thermal imaging.

Thermographic Inspection is a Non-destructive Testing Method that involves visualization of heat radiations from an object and the method is a non-contact inspection technique. 

It is also simply called IR – Infrared Thermography Inspection, Thermal Imaging technique, or Thermography.

Fundamental Principles of Infrared Thermography Testing

Infrared testing Non-destructive Testing is based on the principle that every object emits infrared radiation (heat) proportional to its temperature.

While this radiation remains invisible to the naked eye, thermal cameras can effectively capture and detect it.

The sensors in Infrared Thermography NDT capture Infrared radiation from any object above absolute zero temperature (-273.15°C), and display heat distribution images on screen.

Defective areas emit more heat due to more heat distribution around the defects.

What is an Infrared Wave?

Infrared waves are a type of Electromagnetic Radiation like Light Radiation that is not visible to human eyes, because of their longer wavelength.

The wavelengths that are longer than the wavelength of red light (i.e.  700 nm) are called Infra-Red (i.e., That of inferior Frequency than Red Light),

The amount of Infrared Radiation captured in Thermography NDT is equal to the heat dissipated from that area, therefore Infrared cameras can be used to capture images of heat distribution.

Infrared and vibration inspection are versatile Non-destructive Testing Techniques with applications across various industries, helping to improve safety, energy efficiency, and the overall reliability of systems and structures.

Its non-invasive nature and ability to reveal hidden problems make it an invaluable tool in preventive maintenance and quality control.

Types of Thermography Inspection

Thermographic inspection can be broadly categorized into the following categories based on the source of thermal excitation. They are as follows:

1. Passive Thermography

• Infrared Thermography

• Tetra Hertz Thermography

2. Active Thermography

• Pulsed Thermography

• Lock-In Thermography

3. Flash Thermography

4. Vibro-Thermography

Also Read, Key Thermal Testing Test Profiles

Thermal Inspection Classifications Explained as Follows:

1. Passive Thermography

This method involves scanning the component during its operation or Immediately after the operation (e.g. Running motor shaft), It does not require an external heat source for heating, it uses the heat generated in the material during its operation.

2. Active Thermography

This method requires an external heat source to heat the component and monitor the flow of heat inside the material.

3. Flash Thermography

This method uses flashes of light, to identify the discontinuities that obstruct the flow of heat inside the material.

4. Vibro-Thermography

This method uses an acoustic sound source, and a thermography sensor to detect the heat distribution inside the material, the acoustic sound vibration causes more heat at the edges of cracks due to friction during vibration.

Applications of Thermography

Thermography inspection, a technology that entails the capture and analysis of thermal images, finds extensive use across diverse industries owing to its capability to identify temperature discrepancies and irregularities.

• Electrical Inspections

In the electrical industry, a Thermography test is used for overheating detection for components in electrical systems such as circuit breakers, switches, and wiring.

These hotspots can be early indicators of potential failures, enabling preventive maintenance.

• Building Diagnostics

Thermography Inspection NDT helps identify insulation deficiencies, air leaks, and heat loss in buildings. It's a valuable tool for conducting energy audits and improving energy efficiency.

• Moisture Detection

Thermal imaging can locate hidden water leaks within walls or roofs, preventing mold growth and structural damage.

• HVAC System Inspections

It's used to check the performance of heating, ventilation, and air conditioning systems, ensuring they operate efficiently.

• Mechanical Inspections

In manufacturing and industrial settings, thermography aids in predictive maintenance by identifying worn-out bearings, misalignments, and overheating motors. This helps prevent costly breakdowns.

• Aircraft Maintenance

Thermographic inspections are crucial for detecting defects in aircraft components like engines and composite structures.

• Medical Diagnostics

           a. Breast Cancer Screening

In medicine, thermography is used as an adjunct diagnostic tool for breast cancer screening. It can identify temperature differences in breast tissue, which may indicate abnormalities.

          b. Inflammation Detection

Thermography can help detect inflammation and circulatory issues in the body, aiding in diagnosing conditions such as deep vein thrombosis.

• Firefighting

Firefighters use thermal imaging cameras to locate hotspots and victims in smoke-filled environments, enhancing safety and rescue efforts.

Also Read, Thermal Imaging In The Detection And Tracking Of Drones

• Search and Rescue

Search and rescue teams utilize thermography to locate missing persons, even in adverse weather conditions.

• Industrial Process Control

In manufacturing, thermography is employed for quality control, ensuring products meet temperature-related specifications.

• Chemical Processes

It's used to monitor temperature variations in chemical reactions, helping maintain optimal conditions and product quality.

• Environmental Studies

Thermography is used in ecological studies to monitor wildlife behavior and assess the thermal properties of ecosystems.

• Astronomy

In astronomy, thermography is used to study celestial objects. It can detect heat signatures from celestial bodies and analyze their thermal properties.

• Security and Surveillance

In security systems, thermal cameras can detect human, or animal intruders based on their heat signatures, making them useful for perimeter security.