TWI Knowledge Summary

Thermography

How does it work?

Thermography is the simplest of all thermal inspection techniques and involves using an infrared camera to look for abnormally hot or cold areas on a component operating under normal conditions. For example, areas of corrosion thinning on plant carrying hot gas or liquid will show up as unusually hot areas on a thermal image. Most modern thermal cameras are able to detect temperature differences of less than 0.25°C and enable thermal images to be recorded on video or computer disk for future analysis.

What will it find?

Thermography is a useful technique for the detection of corrosion/erosion damage in plant operating at elevated temperatures. In addition, it can be used to check for fouling or internal plugging of piping systems and to check the quality of refractory linings. It can also be used for leak detection, composition changes, disbonds in laminates and others.

Where is it used?

Thermography is a remote technique that can be applied to most areas of plant, but which is particularly suited to plant operating at elevated temperatures. However, it is a surface technique and it cannot be used to look through thick layers of lagging for defects in the underlying structure.

Further information

TWI offers training courses on thermographic testing.

TWI Industrial Members and JoinIT North East users have access to the NDT Selector Toolkit

Additional information about thermography can be found in the items detailed below:

Thermography - technology file

An evaluation of infrared NDT techniques applied to thermally sprayed coatings (Industrial Members Report No. 614 - July 1997) PDF file, 8769 Kbytes Available only to Industrial Members

Non-destructive techniques for the inspection of surface mount solder joints - review and experiment (Technology Briefing No. 443 - April 1992) Available only to Industrial Members

You can use the Weldasearch literature database to supplement what you find in JoinIT.