Clothing Physiological Properties of Cold Protective Clothing and Their Effects on Human Experience

Abstract

Approximately one third of the Finnish working population is exposed to cold ambient temperatures (<+10 °C) at their work due to natural or artificial environments. The longest cold exposure times are experienced in construction and maintenance work, agriculture and forest industry, process industry, traffic and military personnel. Climatic changes in the Arctic are expected to take place in the future and thus the activity of several industries will be increased in the region. Without sufficient protection against cold, windy and moist ambient conditions, cooling of the workers causes discomfort and moreover will impair physical and mental performance. Cold protective clothing creates a microclimate around the worker, and it is required to prevent detrimental cooling and to enable the worker to maintain the thermal balance.<br/><br/>This thesis aimed to contribute new scientific information based on effects of clothing size, moderate wind and moisture on heat loss mechanisms through the layered cold protective clothing and how these affect the user’s experience on thermal comfort, coping and performance. Finally, the thesis aimed to gather the obtained information and the most significant findings from holistic points of view to determine recommendations for future design and development of cold protective clothing.<br/><br/>The effects of layered cold protective clothing were examined from a multi-disciplinary perspective using textile technological and clothing physiological methods combined with thermophysiological and usability evaluation methods both in laboratory and in authentic field conditions. The measured materials consisted of layered fabric and clothing combinations, as well as different types of casualty coverings and protective gloves. The measurements were performed in the air temperature between −20 °C and +27 °C. Convective heat loss was studied in wind speeds of calm (0.3 m/s), moderate (4.0 m/s) and high (8.0 m/s). Effects of moisture from internal and external sources on clothing thermal insulation and heat loss were studied.<br/><br/>The study found that the inner layer influenced the most on moisture handling properties, such as heat content for evaporation, drying time, and decrease in thermal insulation when wet. Garment fit and size was shown to affect the thermal insulation by about 20% and it should be considered in standardisation for clothing size and testing of the cold protective clothing. Moisture transfer mechanisms and their effects on the clothing insulation in the cold differed whether the moisture appeared from internal or external sources of the clothing. Wind decreased the intrinsic insulation by up to 33% depending on material air permeability, body position and wind speed and direction. The study also showed that development of the cold protective clothing during several decades provided improved human experiences such as thermal comfort, coping and performance during long-term cold exposure. Well-being at work is supported also by comfort, which is emphasized by thermal and sensorial sensations in the cold climate. Therefore, the findings are significant for improving occupational safety, health, and well-being as well as productivity in outdoor processes.