Black Globe Temperature Estimate for the WBGT Index
The wet bulb globe temperature (WBGT) index is used in industry, sports and other areas to indicate the heat stress level for humans and animals. One of the values needed to calculate the WBGT Index is the black globe temperature. The black globe temperature is measured using a Black Globe Temperature Sensor which includes a black globe with a thermometer inserted in the center. However, the Black Globe Temperature Sensor can be costly and many of these instruments may be needed to get measurements in many locations. The lead author has derived a formula to estimate the black globe temperature using readily available data collected by the National Weather Service (NWS). The formula was derived from a formula suggested by Kuehn, which was based on heat transfer theory. The resulting equation was a fourth degree polynomial in terms of the black globe temperature. It was determined that the black globe temperature can be very accurately approximated by taking a fourth degree polynomial in terms of the black globe temperature to create a linear approximation for black globe temperature. Some preliminary tests indicate accuracy within 0.5 °F.
KeywordsBlack globe Heat index Heat safety Heat stress Temperature measurement Wet bulb globe temperature
The authors would like to thank Bruce Sherbon of NOAA for his construction of an inexpensive Black Globe Temperature Sensor. The authors would also like to thank Jamie Frederick of NOAA for programming the web page to calculate the WBGT Index. Finally, V. E. Dimiceli would like to thank Glenn Wiley of NOAA for helping V. E. Dimiceli to get a research sabbatical at NOAA/NWS in the fall of 2010.
- 1.Keuhn LA et al (1970) Theory of the globe thermometer. J Appl Physiol 25(5):750–757Google Scholar
- 2.Committee on Sports Medicine and Fitness (1991) Sports medicine: health care for young athletes, 2nd edn. Elk Grove Village IL, American Academy of Pediatrics, 1991:98Google Scholar
- 3.Helen MB, Joseph B, Douglas JC, Douglas MK, Paul EP (2002) National athletic trainers’ association positional statement: exertional heat illnesses. J Athl Train 37(3):329–343Google Scholar
- 4.OSHA Technical Manual, TED 01-00-015 [TED 1-0.15A], updated June 2008. Available http://www.osha.gov/dts/osta/otm/otm_iii/otm_iii_4.html
- 6.Dimiceli VE, Amburn SA, Piltz SF (2011) Estimation of black globe temperature for calculation of the wet bulb globe temperature index. Lecture Notes in Engineering and Computer Science: Proceedings of the world congress on engineering and computer science 2011, WCECS 2011, 19–21 Oct 2011, San Francisco, pp 591–599Google Scholar
- 7.J Wakefield (2007) Information Generation Section, National Oceanic and Atmospheric Administration Earth System Research Laboratory. Available http://gfesuite.noaa.gov/EFTHome.html
- 8.Purswell JL, Davis JD (2008) Construction of a low cost black globe thermometer. Applied Engineering in Agriculture. ASABE 24(3):379–381Google Scholar
- 9.Hunter CH, Minyard CO (1999) Estimating wet bulb globe temperature using standard meteorological measurements. Department of Energy, Office of Scientific and Technical Information, U S A, WSRC-MS-99-00757, 2.7Google Scholar
- 10.Commonwealth of Australia (2010). Thermal comfort observations. Bureau of Meteorology, ABN 92 637 533.532Google Scholar
- 11.Campbell Scientific Corporation (2010) Black globe instruction manual. Campbell Scientific Corporation, Canada. Available http://www.osha.gov/dts/osta/otm/otm_iii/otm_iii_4.html
- 13.Turco SHN, da Silva TGF, de Oliveira GM, Leitão MMVBR, de Moura MSB, Pinheiro C, da Silva Padilha CV (2008). Livestock Environment VIII, 31 Aug–4 Sept 2008, Iguassa Falls, Brazil 701PO408Google Scholar