Accession Number:



Biophysical assessment of the US Army Improved Hot Weather Combat Uniform (IHWCU) and a comparison to the currently fielded Fire Resistant Army Combat Uniform (FRACU)

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Technical Report,01 Jan 2018,31 Dec 2019

Corporate Author:

Biophysics and Biomedical Modeling Division, U.S. Army Research Institute of Environmental Medicine Natick United States

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New uniforms have been developed specifically for hot and humid environments. Methods Standard tests for the thermal and evaporative resistances Rt and Ret were conducted ASTM F1291-16 and ASTM F2370-16 for two US Army uniforms, the new Improved Hot Weather Combat Uniform IHWCU and the currently fielded Fire Resistant Army Combat Uniform FRACU. Results Standard biophysical test values were similar between the two ensembles IHWCU, FRACU for thermal insulation 1.44 and 1.40 clo, vapor permeability im 0.40 and 0.43, and evaporative potential imclo 0.29 and 0.32 in near-still air conditions 0.4 ms-1 wind velocity. The modeling values for these measures 1.0 ms-1 wind velocity were nearly identical 1.11 and 1.11 clo, 0.41 and 0.45 im, and 0.37 and 0.37 imclo. Conclusion This work provides some quantitative evidence that the thermal properties of these two ensembles are similar and that from a biophysical perspective there are negligible differences between them.

Subject Categories:

  • Protective Equipment

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