Infrared Thermography: Everything You Need to Know

A powerful technology that enables the visualisation of heat and temperature variations in objects and environments. By using specialised cameras, this non-invasive technique detects and converts infrared radiation into detailed thermal images.

Let’s delve into the principles, applications and limitations of this fascinating technology.

What is Infrared Thermography

Infrared thermography is a technique that uses an infrared camera to detect and create images based on the infrared radiation emitted from an object. This technology makes it possible to "see" heat and temperature variations.

Key Concepts in Infrared Thermography

Key concepts in infrared thermography revolve around measuring and interpreting thermal energy to identify potential issues in equipment and facilities:

• Infrared Radiation: All objects emit infrared radiation based on their temperature.
• Electromagnetic Spectrum: Infrared radiation lies just beyond visible light in the electromagnetic spectrum.
• Thermal Imaging: Infrared cameras detect infrared radiation and convert it into a thermogram, showing temperature variations.
• Passive Detection: Infrared cameras operate passively, without emitting any radiation themselves. However, reflections from surrounding objects can affect the readings.

By using these principles of thermal energy, radiation and temperature variation to provide valuable insights into the condition of equipment and facilities for predictive and preventative maintenance.

How Does Infrared Thermography Work

Infrared thermography works by detecting infrared radiation emitted by objects with temperatures above absolute zero. The higher the temperature of an object, the more infrared energy it emits. 

This radiation is invisible to the naked eye but can be captured using an infrared camera, which converts it into a visible image called a thermogram. These thermograms display temperature distribution, often using colour-coded visuals to represent different temperatures.

How Does it Operate?

Infrared cameras consist of lenses and detectors that capture and process infrared radiation. Here's a breakdown of the process:

1. Lenses and Detectors: The camera lens focuses infrared radiation onto a detector, which converts the radiant energy into an electrical signal.
2. Image Processing: Algorithms process the electrical signal to create a colour-coded thermal image.
3. Temperature Measurement: The camera measures infrared radiation levels to provide quantitative temperature data. However, factors like emissivity and reflections can affect accuracy.

Important Camera Features

To ensure accurate and effective thermal imaging, it’s essential to understand the key features that define a thermal camera’s performance. These technical factors influence how well the camera captures, interprets, and displays thermal data:

• Emissivity: Refers to how efficiently an object radiates thermal energy. Materials with low emissivity, like shiny metals, may appear cooler than they actually are.
• Resolution: The number of pixels in a thermal image. Higher resolution provides more detail.
• Thermal Sensitivity: The smallest temperature difference a camera can detect.

Types of Thermography

Infrared thermography can be categorised into two main types:

Passive Thermography

In passive thermography, thermal images are captured while the system is operating under normal conditions, without any external heat source applied. This is commonly used in predictive maintenance and building diagnostics.

Active Thermography

Active thermography involves applying an external energy source to create temperature differences in a component. This method reveals how heat flows through materials and includes techniques such as:

• Flash Thermography: Using a brief burst of energy to heat the surface.
• Vibrothermography: Applying vibrations to generate heat.
• Lock-in Thermography: Using periodic heating to study material properties.

Types of Infrared Cameras and Thermometers

Infrared thermography tools come in various forms, each suited to specific applications:

• Spot Infrared Thermometers (Pyrometers): Measure temperature at a specific point. Ideal for hard-to-reach areas.
• Infrared Scanner Systems: Scan large areas, commonly used in manufacturing.
• Thermal Imaging Cameras: Capture two-dimensional thermographic images in real-time, useful for detailed analysis.

Applications of Infrared Thermography

Infrared thermography has widespread applications across industries. Here are some key use cases:

1. Condition Monitoring and Predictive Maintenance

Infrared thermography plays a crucial role in identifying potential issues before they escalate into costly failures:

• Detecting hotspots, faulty connections, and overloads in electrical systems.
• Inspecting mechanical components like motors, bearings, and belts for signs of wear.
• Checking insulation in furnaces and boilers.
• Identifying leaks in pipes and valves.

2. Building Diagnostics

Thermal imaging helps assess building structures for:

• Insulation problems and air leaks.
• Moisture detection.
• Energy loss through building envelopes.

3. Medical Imaging

Infrared thermography is used in healthcare to monitor conditions such as:

• Peripheral vascular disease.
• Thyroid abnormalities.
• Inflammatory conditions.

4. Other Applications

Here are some other applications that can be considered for the purpose of benefits:

• Firefighting: Seeing through smoke to locate trapped individuals.
• Gas Detection: Identifying leaks of hazardous gases.
• Security and Surveillance: Monitoring for unusual temperature changes.
• Research and Development: Analysing heat distribution in products.
• Quality Control: Ensuring consistent temperature during manufacturing processes.
• Maritime Applications: Detecting leaks in boat hulls.
• Corrosion Monitoring: Identifying areas of corrosion in structures.
• Animal Health Monitoring: Assessing temperature variations in livestock.

Infrared thermography is a versatile tool for identifying potential issues across various applications. It provides a non-invasive way to monitor equipment, detect faults and ensure safety.

Analysis and Interpretation of Thermal Images

Interpreting thermal images accurately requires a combination of technical knowledge and practical experience. Key methods include:

• Comparative Thermography: Comparing similar components under identical conditions.
• Baseline Thermography: Establishing a reference temperature for a system when it is in good working condition.
• Thermal Trending: Tracking temperature changes over time to detect anomalies.
• Severity Criteria: Setting thresholds for temperature variations to prioritize maintenance.

Environmental conditions such as wind, rain, and sunlight can impact the accuracy of readings. Proper focus and image adjustments are also essential for obtaining reliable data.

Limitations of Infrared Thermography

While infrared thermography offers numerous benefits, it also has limitations:

• Cost: Infrared equipment can be expensive.
• Surface Temperatures: It primarily detects surface temperatures, which may not reflect internal conditions.
• Material Transparency: Infrared cannot penetrate non-transparent materials like glass.
• Expertise Requirement: Accurate interpretation of thermal images requires training and experience.
• Environmental Factors: Conditions like wind and rain can affect temperature measurements.

The Importance of Training

Proper training and certification are crucial for effective use of infrared thermography. Certified thermographers learn essential skills, including:

• Understanding heat transfer.
• Operating infrared cameras.
• Adjusting images for accuracy.
• Recognising the impact of emissivity and reflections.

Inframatrix offers certified Level 1 and Level 2 thermography training programs in Malaysia and Brunei, equipping professionals with the knowledge needed to harness this technology effectively.

Final Thoughts

Infrared thermography is a game-changing technology that offers invaluable insights into temperature behaviour, enabling industries to enhance predictive maintenance, ensure safety, and improve efficiency. By understanding its principles, applications, and limitations, businesses can unlock the full potential of infrared thermography for diagnostics, inspections, and research.

If you’re looking to harness this infrared thermography in your business, look no further. Inframatrix is Malaysia’s leading supplier of infrared cameras and thermography training. Contact us today!