The Effect of Cold Protective Clothing on Comfort and Perception of Performance

Human performance research for military operations in extreme cold environments

OBJECTIVES

Soldier performance in the Arctic depends on planning and training, protective equipment, and human physiological limits. The purpose of this review was to highlight the span of current research on enhancing soldier effectiveness in extreme cold and austere environments.

METHODS

The practices of seasoned soldiers who train in the Arctic and cold-dwelling natives inform performance strategies. We provide examples of research and technology that build on these concepts.

RESULTS

Examples of current performance research include evaluation of equipment and tactics such as the bioenergetics of load carriage over snow in Norwegian exercises; Canadian field monitoring of hand temperatures and freezing cold injuries for better protection of manual dexterity; and Dutch predictive modeling of cold-wet work tolerances. Healthy young men can respond to cold with a substantial thermogenic response based on US and Canadian studies on brown adipose tissue and other mechanisms of non-shivering thermogenesis; the potential advantage of greater fat insulation is offset in obese unfit subjects by a smaller thermogenic response. Current physiological studies are addressing previously unanswered problems of cold acclimation procedures, thermogenic enhancement and regulation, and modulation of sympathetic activation, all of which may further enhance cold survival and expand the performance envelope.

CONCLUSION

There is an inseparable behavioral component to soldier performance in the Arctic, and even the best equipment does not benefit soldiers who have not trained in the actual environment. Training inexperienced soldiers to performance limits may be helped with personal monitoring technologies and predictive models.

Design and evaluation of cooling workwear for miners in hot underground mines using PCMs with different temperatures

Cooling workwear using phase change materials (PCMs) was designed for miners in hot underground mines. A new arrangement of PCM packs was introduced that used 15 °C PCMs as the inner layer and 23 °C PCMs as the outer layer (15&23). Its performance was investigated using thermal manikin and human subject tests by comparison with clothing without PCMs (CON), with 15 °C PCMs (15&15) and with melted PCMs (mPCM) in a climate chamber (30 °C, 80% relative humidity). The PCM cooling workwear significantly increased the manikin heat loss, attenuated the rise of skin temperatures and improved thermal sensation and comfort. The cooling duration was extended in 15&23 as compared with 15&15. The added PCMs did not affect the perceptual exertion and body mobility. In summary, cooling workwear using PCMs with different temperatures can be an effective option for miners' personal cooling in a hot and humid environment.

Heating Characteristics of Films Prepared with Polymer-Graphite Composites

Heating films were prepared by using poly(methyl methacrylate) and polybutadiene composites containing graphite. The heating film was prepared by casting the as-made polymer composite on the PET film. Copper electrodes were attached to both ends of the as-prepared film, and the heating characteristics of the film were analyzed while applying the DC voltage. The electrical conductivity and the heating temperature of the heating films depended on the size, the structure, the content, and the dispersion characteristics of the graphite in the composite. The electrical resistance of the heating film was controlled to adjust the heating temperature of the film. The relationship between the physical/chemical structure and the heating characteristics of the composite film was studied by measuring the heating temperature as functions of film thickness and resistance by using an infrared thermal imaging camera. The lower the film resistance, the higher the heating temperature of the film. The surface temperature was uniform throughout the film.

A user-centred design process of new cold-protective clothing for offshore petroleum workers operating in the Barents Sea

Petroleum operations in the Barents Sea require personal protective clothing (PPC) to ensure the safety and performance of the workers. This paper describes the accomplishment of a user-centred design process of new PPC for offshore workers operating in this area. The user-centred design process was accomplished by mixed-methods. Insights into user needs and context of use were established by group interviews and on-the-job observations during a field-trip. The design was developed based on these insights, and refined by user feedback and participatory design. The new PPC was evaluated via field-tests and cold climate chamber tests. The insight into user needs and context of use provided useful input to the design process and contributed to tailored solutions. Providing users with clothing prototypes facilitated participatory design and iterations of design refinement. The group interviews following the final field test showed consensus of enhanced user satisfaction compared to PPC in current use. The final cold chamber test indicated that the new PPC provides sufficient thermal protection during the 60 min of simulated work in a wind-chill temperature of -25°C.

CONCLUSION

Accomplishing a user-centred design process contributed to new PPC with enhanced user satisfaction and included relevant functional solutions.

Assessment of the effectiveness of modular clothing protecting against the cold based on physiological tests

At many workstations in a cold environment, protective clothing provided for the workers is characterized by inadequate thermal insulation, which results in an adverse impact of the cold environment on the worker's body. The purpose of this article is to present developed new ergonomic modular cold protective clothing, which allows for easy adaptation of the thermal insulation of clothing to a worker's individual needs. This clothing was compared in a laboratory study with the clothing having so far been used by workers in a cold environment using physiological and physical measurements, subjective ratings of the thermal state as well as a questionnaire for subjective assessment of the used clothing. These measurements and ratings confirmed that the modular cold protective clothing is more effective in the process of ensuring thermal comfort to the wearer during work in a cold environment than the clothing having so far been used.