About Infrared Imaging
Sometimes known as Infrared Thermography, Infrared Imaging is use of an infrared imaging camera to see and measure thermal energy emitted from an object.
Infrared imaging offers a fast, non-invasive means of monitoring and diagnosing the condition of buildings.
Thermal Imaging can be a very effective, non intrusive building diagnostic procedure when used professionally for appropriate applications in the right circumstances. In essence each pixel of the cameras represents a temperature enabling fast assessment of surface temperature differences.
The outer skin of any object absorbs thermal energy from its surroundings. A building obtains thermal energy from the sun, atmosphere, and human activity.
This energy is emitted as thermal radiation which can be measured across a spectrum from "neat" infrared, or short wavelength, bordering on the red end of the visible light, to "far" infrared, or long wavelength.
The hotter an object or structure, the higher the thermal energy it emits, and the shorter the wavelength. The thermal output is measured by the camera and converted into a scanned video image.
Thermography is a versatile and useful tool. In many situations it is limited only by the resourcefulness of the project team. Thermography has been used to assess various structures from power station chimneys and concrete motorway bridges to listed historic buildings.
The usefulness of thermography surveys must be assessed on a case-by-case basis.
Limitations
Although powerful as a reconnaissance tool in the first stage of an investigation, thermography is limited by a number of technical and logistic factors:
- Needs the right thermal conditions - timing of a survey is therefore often critical
- Great care needs to be taken to produce meaningful results from very reflective surfaces, e.g. polished metal, glazed ceramics or reflective glass
- Surface finishes with different emissivity give apparently different surface temperatures - interpretation of data from highly variable or ornate surfaces is therefore complex
- In many situations it requires a detailed understanding of both thermographic principles and structural engineering practice to interpret the data.