Empirical Approach to Outdoor WBGT from Meteorological Data and Performance of Two Different Instrument Designs

Abstract

Abstract. The wet bulb globe temperature index (WBGT) is a common method to assess the environmental contribution to heat stress as part of an occupational exposure assessment. The two purposes of this study were (1) to compare empirical relationships of some meteorological conditions to WBGT, and (2) to evaluate a smaller globe and alternative method to assess natural wet bulb using a relative humidity sensor. Data were collected in six West-central Florida locations over multiple days for a total of 14 measurement days. Multiple linear regression was used to explore relationships relevant to the two purposes. It was clear that estimating WBGT directly from meteorological data or through estimates of the components of WBGT can be accomplished with a 95% confidence of ± 2°C-WBGT. The 50 mm globe size is a reasonable approximation of the standard size (150 mm). The relative humidity method of the waterless natural wet bulb provides a very good estimation of natural wet bulb temperature. The determination of WBGT from the electronic instruments (small globe with or without the relative humidity method) provided a good estimate of the WBGT.

A Critical Review of OSHA Heat Enforcement Cases

“…1 Scientists have made important contributions to the understanding of heat illness and addressed methods to assess the environmental contribution to heat stress. [2][3][4][5][6] State governments have acted to prevent heat illness; for example, California and Washington have regulatory requirements addressing occupational heat stress. [7][8] The Occupational Safety and Health Administration (OSHA) does not have a specific heat-related regulation, but uses section 5(a)(1) of the OSH Act for enforcement action in heat illness cases.…”

Climate Change and Occupational Heat Problems

“…This special issue of Industrial Health presents papers on different aspects of occupational heat problems in relation to climate change. The papers present examples from different parts of the world, and highlight methods for heat exposure assessment 11) , standards for occupational heat exposures 12,13) , and the health and productivity risks of workplace heat in relation to climate conditions and climate change 14) . A small scientific conference on "Occupational heat exposure indicators for use in climate change impact assessments" was held in Lund, Sweden, in August 2012, and many of the papers in this collection are based on presentations in Lund.…”

Heat Exposure in Central Florida Fernery Workers: Results of a Feasibility Study

“…These data can be used to calculate estimated WBGT. 24 Quantitative documentation of the microclimate inside fernery operations is not available in the literature, but would be an important addition to future studies because workplace microclimates can deviate from the general climate of the surrounding area. 25 Plans for future studies include the use of the iButton (Maxim Integrated Products, Inc., San Jose, CA), which is a small personal temperature logger that can be worn attached participants’ clothing to collect environmental data at individual worksites.…”