Three Instruments for Assessment of WBGT and a Comparison with WGT (BOTSBALL),
Abstract
Environmental heat stress, expressed as the ambient wet bulb globe temperature (WBGT), was measured using three different WBGT instruments: (a) the conventional shaded dry bulb, 15.2 cm black globe and naturally convected wet bulb thermometers; (b) a miniaturized thermometer kit; (c) a commercial WBGT instrument using thermistor sensors, and the WBGT was compared with (d) the ambient wet globe temperature (WGT) measured by a Botsball. Visual observations were made on the instruments at regular intervals and an automated data collection system was also used to obtain data from thermocouples attached to the instruments. Statistically significant differences in WBGT readings were found among the instruments; however, the difference for a given environment was usually less than 0.5 C. Readings taken by visual observations resulted in WBGT values which differed by less than 0.3 C from those calculated from the automated data collection system. By using an equation derived for the Botsball, WBGT = 1.044 WGT - 0.187 in degree C it is possible to convert the Botsball thermometer dial to indicate the conventional WBGT for outdoor environments; it then becomes a simple instrument for assessing environmental heat stress at the work site. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 14, 1979
- Accession Number
- ADA074979
Entities
People
- B. Onkaram
- L. A . Stroschein
- R. F. Goldman
Organizations
- United States Army Research Institute of Environmental Medicine