The rise and rise of thermography

There are four major causes for the growth in demand for thermography; the economic situation is placing pressure on businesses to lower costs, energy costs are rising; regulatory pressure is driving improved energy performance and environmental pressures are forcing organisations to examine their carbon footprint.

Will Russell has been a technical support engineer with instrumentation specialist Ashtead Technology for over seven years, and in the course of this article he will discuss the reasons behind the growth in demand for infrared cameras and offer guidance on how to conduct an effective survey.

Conducting a survey
Companies frequently rent a camera in order to conduct their own initial survey and if this indicates a significant opportunity for improvement, it is likely that a thermographic consultant will be employed. However, in both situations it is important that the right camera is employed. A basic survey can be undertaken with a budget camera, but the user may discover that greater resolution is required or a video record is necessary, so it is often sensible to discuss the intended application with the instrument rental provider before choosing a camera. However, the advantage of hiring equipment is that it provides an opportunity to upgrade if necessary.

There are a few basic rules to ensure the success of a survey:
1. Choose the right camera specification
2. Know the temperature range to be monitored
3. Calculate the likely distance from the camera to the subject – if a long distance is required a high-spec camera can avoid the cost and hassle of gaining access
4. Conduct a pre-survey risk assessment
5. Scan each surface several times from various angles to derive a consistent reading and make a record of any irregularities – some materials are thermally transparent, whilst materials such as metals have low emissivity
6. From a safety perspective it is recommended for two people to conduct a thermographic survey
7. Be aware that lowered temperature can also indicate impending failure

Frequently, it is only necessary to identify cold or hot spots, so an entry-level device such as the FLIR E60 is the most effective, both in terms of cost and simplicity. Many mid-level instruments such as the T440 allow users to take visual images and even overlay them with the infrared image to improve interpretation, whereas more advanced instrumentation such as the T640 offers extremely high levels of infrared resolution for larger-scale predictive maintenance and research work.