Wet Bulb Globe Temperature

Wet Bulb Globe Temperature

The Wet Bulb Globe Temperature (WBGT) is a composite temperature used to estimate the effect of temperature, humidity, and solar radiation on humans. It is used by industrial hygienists, athletes, and the military to determine appropriate exposure levels to high temperatures. It is derived from the following formula:

WBGT=0.7T_w + 0.2T_g + 0.1T_d

Where
* Tw= Natural wet-bulb temperature (humidity indicator)
* Tg=Globe thermometer temperature (measured with a globe thermometer, also known as a black globe thermometer, to measure solar radiation)
* Td=Dry-bulb temperature (normal air temperature)
* Temperatures may be in either Celsius or Fahrenheit

Indoors, or when solar radiation is negligible, the following formula is used:

WBGT=0.7T_w + 0.3T_g

The American Conference of Governmental Industrial Hygienists publishes threshold limit values (TLVs) that have been adopted by many governments for use in the workplace. The process for determining the WBGT is also described in ISO 7243, Hot Environments - Estimation of the Heat Stress on Working Man, Based on the WBGT Index.

In hot areas, some US military installations display a flag to indicate the heat category based on the WBGT. The military publishes guidelines for water intake and physical activity level for acclimated and unacclimated individuals in different uniforms based on the heat category.

The WBGT index was developed by the United States Marine Corps at Parris Island in 1956 to reduce heat stress injuries in recruits and has been revised several times.

The heat index used by the National Weather Service and the humidex used by the Meteorological Service of Canada are also measures of perceived heat, but they do not account for solar radiation.

References

* [http://www.e-publishing.af.mil/shared/media/epubs/AFPAM48-151.pdf Air Force Pamphlet 48-151]
* [http://chppm-www.apgea.army.mil/documents/TBMEDS/tbmed507.pdf U.S. Army Technical Bulletin Medical 507/Air Force Pamphlet 48-152]
* [http://www.zunis.org/how_hot_is_hot_how_safe_is_safe.htm Zunis Foundation background article]

ee also

*Hygrometer
*Meteorology

External links

* http://www.wetglobe.com
* [https://www.wbgt.drum.army.mil/wbgt.asp Fort Drum implementation]
* [http://www.ccohs.ca/oshanswers/phys_agents/hot_cold.html Canadian Centre for Occupational Health and Safety guidelines]
* [http://www.osha.gov/dts/osta/otm/otm_iii/otm_iii_4.html Occupational Safety and Health Administration guidelines]
* [http://www.bom.gov.au/info/thermal_stress/ "About the WBGT and Apparent Temperature Indices"] from Australian Bureau of Meteorology (includes a formula to approximate WBGT from dry bulb temperature and relative humidity)


Wikimedia Foundation. 2010.

Игры ⚽ Нужна курсовая?

Look at other dictionaries:

  • Wet Bulb Globe Temperature — Température au thermomètre globe mouillé L indice de Température au thermomètre globe mouillé, de son nom originel Wet Bulb Globe Temperature (WBGT), est un indice composite de température utilisé pour estimer les effets de la température, de l… …   Wikipédia en Français

  • WBGT (Wet-Bulb Globe Temperature) — WBGT (Wet Bulb Globe Temperature)  комплексный индекс который учитывает и радиационный и конвективный теплообмен, но также и влажность воздуха. Первые попытки выработки единого индекса для характеристики среды ограничивались минимальными… …   Википедия

  • Wet-bulb temperature — The wet bulb temperature is a type of temperature measurement that reflects the physical properties of a system with a mixture of a gas and a vapor, usually air and water vapor. Wet bulb temperature can have several technical meanings:… …   Wikipedia

  • Température au thermomètre-globe mouillé — L indice de Température au thermomètre globe mouillé, de son nom originel Wet Bulb Globe Temperature (WBGT), est un indice composite de température utilisé pour estimer les effets de la température, de l humidité, et du rayonnement solaire sur l… …   Wikipédia en Français

  • Temperature — This article is about the thermodynamic property. For other uses, see Temperature (disambiguation). A map of global long term monthly average surface air temperatures i …   Wikipedia

  • WBGT — Température au thermomètre globe mouillé L indice de Température au thermomètre globe mouillé, de son nom originel Wet Bulb Globe Temperature (WBGT), est un indice composite de température utilisé pour estimer les effets de la température, de l… …   Wikipédia en Français

  • WBGT — Wet Bulb Globe Temperature (Academic & Science » Meteorology) * LPTV 18, Rochester, New York (Community » TV Stations) …   Abbreviations dictionary

  • WBGT — Wet Bulb Globe Temperature Contributor: CASI …   NASA Acronyms

  • Thermal comfort — Human thermal comfort is defined by ASHRAE as the state of mind that expresses satisfaction with the surrounding environment (ASHRAE Standard 55). Maintaining thermal comfort for occupants of buildings or other enclosures is one of the important… …   Wikipedia

  • Hyperthermia — An analog medical thermometer showing a temperature of 38.7 °C (101.7 °F) ICD 9 …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”