Over the past few years infrared thermal imaging has been considered for a variety of engineering applications and the potential of this method is only now being realised with the range of applications still increasing (1 and 2). As a totally non-destructive method, it has the advantage of providing handsoff mformation quickly. As with other non-destructive or potentially destructive methods, however, there are particular factors which may influence the success of its application and, wherever possible, it should be used in the context of a combined testing approach (3). Because of the relative nature of data produced by a thermographic survey, the quantification of properties of a structure or the materials contained therein may require correlation by confirmatory localised 'destructive' sampling and/or inspection. This paper outlines the principles in operation, the conditions required for the survey to be successful and a range of situations where the technique has proved effective.