Which type of NDT is characterized as non-destructive and involves mapping thermal patterns?

Thermography is the type of non-destructive testing (NDT) characterized by mapping thermal patterns. This technique involves the use of infrared cameras to detect variations in temperature on the surface of an object. By identifying these temperature differences, thermography can reveal potential issues such as insulation failures, electrical faults, or leaks that might otherwise remain hidden.

This method is valuable because it allows inspectors to assess the thermal behavior of materials and structures quickly and without causing any damage. It is particularly effective for inspecting electrical systems, mechanical components, and building conductance, providing a comprehensive view of an object's condition through thermal analysis.

In contrast, the other methods mentioned focus on different principles: X-ray NDT utilizes radiation to examine the internal structure of materials, ultrasonic NDT uses high-frequency sound waves to detect discrepancies in materials, and tap-testing is a subjective method that involves striking a material and listening to the sound produced to identify flaws. Each of these methods has its own applications and capabilities but does not involve thermal pattern mapping like thermography does.