- Detect anomalies in structures such as loss of insulation, wiring faults, hidden moisture and voiding, damaged waterproofing.
All objects emit infrared (black body) radiation. An object will emit radiation proportional to its surface temperature. Thermal imaging records the intensity of the radiation and corresponding relative temperature across a surface. For a homogenous material, the heat transfer through the material is uniform and therefor has a uniform surface temperature. The presence of anomalies within an object will alter the flow of heat through the material resulting in variation in surface temperature. A thermal camera is able to detect and record these variations in surface temperature.
This technique is especially useful in detection of voids which consist mainly of air, so will have a lower thermal conductivity relative to their surrounding material. As such during heating or cooling cycles, voids just below the surface result in faster surface temperature changes than for the surrounding material. This creates a temperature anomaly when viewed through a thermal camera. This technique however cannot differentiate surface temperature variation if there is no temperature gradient to allow heat transfer to occur or to detect anomalies which are too deep.