The use of infra-red (tympanic) temperature as a guide to signs of heat stress in industry

Previous IOM research, showed that the use of a simple infra-red (IR) ear thermometer did not provide a reliable prediction of core body temperature for use in industrial situations (Graveling et al, 2009). The aim of this research was to explore the use of an IR ear thermometer further, and to determine whether the consistency and accuracy of the measurements obtained could be improved sufficiently to provide a reliable indication of the risk of an individual suffering from heat strain.

Published studies where IR temperature has been compared with core temperature benchmarks such as rectal temperature to provide further detail on likely sources of variation in measured tympanic temperature were re-examined. Based upon the factors identified, a number of experimental studies were carried out to explore the influence of these factors, together with revised measurement methods aimed at reducing their influence.

The results showed that the technique devised as a result of these studies did give more reliable results than those found previously although the predictive relationship determined showed that IR tympanic temperature could still not be used to predict actual core body temperature with a sufficient degree of accuracy for it to be used in industry. However it is suggested that this provides a possible basis for the use of IR thermometry as a screening tool in monitoring hot workplaces for possible risks of thermal strain.