Evaluating functional clothing in climatic chamber tests versus field tests: a comparison of quantitative and qualitative methods in product development

Abstract

For the evaluation of clothing by human beings, two different approaches can be identified- laboratory tests (i.e. climatic chamber tests) or field trials/wear trials. It has been suggested that the performance of clothing can be adequately predicted on the basis of the data obtained from climatic chamber tests and that field trials may be expendable altogether. From a product development perspective, this paper discusses the information provided by standard data collection methods and tools for the assessment of thermal comfort used in laboratory settings and compares this information with that acquired in field trials. When assessing the information provided in the laboratory test against those questions posed in a development process, the results highlight the insufficiency of objectively measurable criteria. Therefore, objective measurements alone cannot verify the adequacy of stated requirements for thermal comfort. The use of appropriate and sensitive tools for collecting subjective votes should also be noted, since small differences in thermal sensation affected the individual's preference for clothing. Exposed differences between subjects, in terms of thermophysiological as well as subjective responses, illustrate the importance of studying individual values and deviations as opposed to strict mean values for large populations in order to satisfy a potential user group. It is argued that complementary interviews form a basis for further understanding of ratings and preferences and that they should also be included in the climatic chamber evaluation 'tool box'. User satisfaction is based on a simultaneous assessment of partly opposing properties into a satisfying use value. Although laboratory test procedures can be developed and improved in relation to design issues, field evaluations must be regarded as an integrated part of an iterative development process. Only the actual use situation can provide the total spectrum of conditions on which basis requirements and/or properties can be prioritized or downgraded. This information forms the prerequisite for successful product development.