Apparent evaporative resistance at critical conditions for five clothing ensembles.

A limiting factor for clothing ensembles inherent during heat stress exposures is the evaporative resistance, which can be used to compare candidate ensembles and in rational models of heat exchange. In this study, the apparent total evaporative resistance of five clothing ensembles (cotton work clothes, cotton coveralls, and coveralls made of Tyvek 1424 and 1427, NexGen and Tychem QC was estimated empirically from wear trials using a progressive heat stress protocol and from clothing insulation adjustments based on ISO 9920 (2007) and wetness. The metabolic rate was moderate at 165 W m(-2) and relative humidity was held at 50%.

WBGT clothing adjustment factors for four clothing ensembles and the effects of metabolic demands.

This study measured the clothing adjustment factors (CAFs) for four clothing ensembles (Cotton Coveralls, Tyvek 1427 Coveralls, NexGen Coveralls, and Tychem QC Coveralls; all coveralls were worn without hoods) against a baseline of cotton work clothes to determine whether the CAFs would be affected by the metabolic rate. Fifteen participants wore one of the five ensembles while walking on a treadmill at low, moderate, and high rates of work in an environment maintained at 50% relative humidity. A climatic chamber was used to slowly increase the level of heat stress by increasing air temperature.