Protective Garment Design and Testing

High-tech specialized garments, such as those utilized in professional sports, alpine mountaineering, and chem-bio defense for our armed forces, must provide advanced thermal and/or chemical barrier protection without hindering performance of the wearer. Meeting these goals requires garment designers to balance tradeoffs between protection, comfort, durability, weight, and cost. While seemingly simple, advanced garment design and evaluation must account for complex underlying physical, chemical, environmental, and physiological phenomena. For example, impermeable garments are inexpensive and provide high barrier protection against chem-bio agents, but their lack of breathability restricts any significant physical activity and also makes them more prone to hazardous leakage at garment closures.

Testing of Protective Garment Performance in Creare’s Wind Tunnel Facility.

Creare is developing advanced modeling and experimental test facilities and procedures to evaluate the physical, thermal, and chemical performance of advanced garments and materials. Targeted users of these tools range from high-performance outdoor apparel manufacturers to government agencies seeking next-generation protective garments for our armed forces. Our methodology is based on a first principles characterization of the underlying physical, thermal, and chemical phenomena, and involves both analytical modeling and experimental testing.

Modeling chem-bio protective garment performance requires an understanding of the coupling effects of environmental wind, bodily motion, and garment fit on airflow patterns around and underneath the garment; aerosolized chem-bio agent droplet dispersion, wicking, and evaporation; the interaction of chem-bio agents with protective materials doped with micro porous adsorbents and self-detoxifying catalysts; selective agent and water vapor transport through permselective breathable membranes; physiological heating and sweating in response to exertion; and performance endpoint characterization in terms of comfort and toxicological response. Our modeling approaches range from computational fluid dynamics simulations providing the highest accuracy and detail, to simplified lumped parameter approximations for highly efficient screening of large numbers of garment design alternatives.

Creare’s experimental test facilities for evaluating protective garment performance provide highly repeatable test conditions and include a 30' wind tunnel with up to 100 mph wind speeds; an anatomically correct, mechanized “clothed arm” body simulator; aerodynamic injectors for introducing simulated agent challenges that impinge on the “clothed arm” apparatus; and real-time data monitoring of airflow and agent transport around, through, and underneath the protective garments. We use these facilities to study garment performance under different environmental and agent threat conditions, while accounting for additional highly relevant effects such as bodily motion, garment fit, and closure leakage.

The immediate objective of our work is to improve the lives of the soldiers who serve in our armed forces. Current garments use an activated carbon liner for protection, but they are heavy, hot, and uncomfortable. Our tools may help protective garment designers to integrate constant “built-in” chem-bio protection as part of standard uniforms, thus making our soldiers safer while allowing them to perform their duties. In other applications, our tools may help improve high performance outdoor and sportswear apparel designs, and eventually may enable customers to custom order garments optimized to their specific anatomy, intended physical activity, and climate.

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