Comparison of different tracer gas dilution methods for the determination of clothing ventilation

Clothing vapour resistance (CVR) is an important parameter when evaluating the impact of the ambient workplace climate on the worker. It determines the worker’s ability to lose heat (sweat evaporation) to the environment and thereby to control his or her body temperature. This impact can be in terms of stress (heat or cold) or comfort. These evaluations are used for the classification of existing workplaces, as well as for the design of new workplaces (for example building climate control systems) and thus affect the issue of health and efficiency in the workplace. As determination of CVR is currently quite complex, very time consuming and costly, alternative methods need to be developed. Deduction of CVR from clothing microclimate ventilation measurements is such an alternative (1). Two methods for the measurement of clothing ventilation have been developed: one by Lotens and Havenith (2) in the Netherlands and one by Crockford et al (3,4), which was further developed in Loughborough for the UK Ministry of Defence by Bouskill (5). Both methods for measuring clothing ventilation are currently in use in different laboratories, however without ever being directly compared. For this paper, it was chosen to start with a practical comparison of these methods to each other and a validation of both.