The Wet Bulb Globe Temperature (WBGT) is a composite temperature used to estimate the effect of temperature, humidity, wind speed (wind chill), and visible and infrared radiation (usually sunlight) 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:
Where
- Tw = Natural wet-bulb temperature (combined with dry-bulb temperature indicates humidity)
- Tg = Globe thermometer temperature (measured with a globe thermometer, also known as a black globe thermometer)
- Td = Dry-bulb temperature (actual air temperature)
- Temperatures may be in either Celsius or Fahrenheit
Indoors, or when solar radiation is negligible, the following formula is often used:
The WBGT index was developed in 1956 by the United States Marine Corps at Parris Island to reduce heat stress injuries in recruits; it has been revised several times.
Read more about Wet Bulb Globe Temperature: Uses
Famous quotes containing the words wet, bulb, globe and/or temperature:
“A bone,
polished in wet and sun,
worried of wild beaks,
and of the whelps’ teeth
worried of flesh,
left to bleach under the sun.”
—Hilda Doolittle (1886–1961)
“... until the shopkeeper plants his boot in our eyes,
and unties our bone and is finished with the case,
and turns to the next customer, forgetting our face
or how we knelt at the yellow bulb with sighs
like moth wings for a short while in a small place.”
—Anne Sexton (1928–1974)
“Where on the globe can there be found an area of equal extent with that occupied by the bulk of our States, so fertile and so rich and varied in its productions, and at the same time so habitable by the European, as this is?”
—Henry David Thoreau (1817–1862)
“The siren south is well enough, but New York, at the beginning of March, is a hoyden we would not care to miss—a drafty wench, her temperature up and down, full of bold promises and dust in the eye.”
—E.B. (Elwyn Brooks)