D S Moran1, K B Pandolf. 1. U.S. Army Research Institute of Environmental Medicine, Natick, MA 01760-5007, USA.
Abstract
BACKGROUND: Industrial and military safety personnel often require an easy, quick and accurate assessment of heat stress as a potential risk. The widely used WBGT index to evaluate heat stress is cumbersome and suited for a fixed site station rather than a mobile situation. Recently, a modified discomfort index (MDI) compiled from ambient temperature (Ta) and wet bulb temperature (Tw) was suggested to evaluate heat stress. HYPOTHESIS: Validation of the simple and easy-to-operate MDI on an independent database can determine whether this index is able to serve as a reliable and valid alternative to WBGT. METHODS: Four separate database sets obtained from the Marine Corps Training Site on Parris Island, SC, served to validate this index. Hourly weather measurements were collected daily during 4 yr, representing a wide range of environmental conditions. RESULTS: The MDI validity was tested vs. the WBGT index. A highly significant correlation coefficient (r) greater than 0.95 (p < 0.001) was found in each of the four database sets. CONCLUSIONS: The simply constructed and user friendly MDI is easier to calculate and use than WBGT, and it has the potential to serve as an attractive alternative to the WBGT index in assessing heat stress.
BACKGROUND: Industrial and military safety personnel often require an easy, quick and accurate assessment of heat stress as a potential risk. The widely used WBGT index to evaluate heat stress is cumbersome and suited for a fixed site station rather than a mobile situation. Recently, a modified discomfort index (MDI) compiled from ambient temperature (Ta) and wet bulb temperature (Tw) was suggested to evaluate heat stress. HYPOTHESIS: Validation of the simple and easy-to-operate MDI on an independent database can determine whether this index is able to serve as a reliable and valid alternative to WBGT. METHODS: Four separate database sets obtained from the Marine Corps Training Site on Parris Island, SC, served to validate this index. Hourly weather measurements were collected daily during 4 yr, representing a wide range of environmental conditions. RESULTS: The MDI validity was tested vs. the WBGT index. A highly significant correlation coefficient (r) greater than 0.95 (p < 0.001) was found in each of the four database sets. CONCLUSIONS: The simply constructed and user friendly MDI is easier to calculate and use than WBGT, and it has the potential to serve as an attractive alternative to the WBGT index in assessing heat stress.