Post #10 : WBGT

Because i'm a procrastinator who procrastinates:
I have no idea what happened but i don't have Tuesdays blogging topic. I was there but somehow i didn't write it down i don't know how that happened, could you please tell me it? I just realized i didn't have last Tuesdays (blog 10 topic) so sorry its so close to the deadline. I have Thursdays (penetration vs permeation) though.
- Sent Sun 4/19/2015 8:48 PM to Samuel Moss

-Update:

Blog #10 = WBGT

“Wet Bulb Globe Temperature (WBGT) is a measure of the heat stress in direct sunlight, which takes into account: temperature, humidity, wind speed, sun angle and cloud cover (solar radiation). This differs from the heat index, which takes into consideration temperature and humidity and is calculated for shady areas. If you work or exercise in direct sunlight, this is a good element to monitor. Military agencies, OSHA and many nations use the WBGT as a guide to managing workload in direct sunlight.”
- http://www.srh.noaa.gov/tsa/?n=wbgt

“Body temperature increases not only when the temperature is high, but also when there is high humidity, which makes it difficult for sweat to evaporate. Also, the temperature felt by the body changes just by avoiding direct and reflected sunlight. -- Since it is easy to develop heat disorders when the WBGT is high, this index is used to prevent heat disorders at work sites, sporting activities, and in everyday life.”
- https://www.otsuka.co.jp/en/health_illness/heatdisorder/care_12/

In the late 1950s, at the US Marine Corps Recruit Depot on Parris Island in South Carolina, there was a significant number of casualties due to heat stroke from the high heat and humidity of the training locations. Consequentially the Department of the Navy commissioned a series of studies on the effects of heat on work and exercise performance. The result was a heat index called the “Wet Bulb Globe Temperature” (WBGT). Later it was used by researchers as an easily measured general heat-stress index, and over time has become used in workplaces and sporting situations.

The WBGT is measured by a three-temperature element device:

The natural wet-bulb temperature abbreviated, ‘Tw’ includes a thermometer with a bulb covered by a wet cotton wick, and the distilled water is supplied from a reservoir. The cotton wick will always be wet, allowing for continuous cooling of the thermometer's bulb due to evaporation, simulating the process of human sweat. The natural wet-bulb thermometer is not protected from wind or radiation. Representing the effects of radiation, wind and humidity.

The black globe temperature abbreviated, ‘Tg’ usually consists of a six inch black globe with a thermometer located at the center. The black globe temperature represents the effects of radiation and wind.

The (shade) air temperature abbreviated, ‘Ta’ which is mainly a thermometer which is shielded from radiation - usually by being placed in a weather screen. This the standard temperature that is generally quoted in weather observations and forecasts.

When calculating the three elements Tw, Tg, and Ta are combined into a weighted average to produce the WBGT.

Two different methods are used to calculate WBGT in the workplace: one for workplaces with direct sunlight, and the other for workplaces without direct sunlight. When conditions of an area fluctuate widely, a time-weighted WBGT is often used.

WBGT = (0.7 × Tw) + (0.2 × Tg) + (0.1 × Ta)
Indoors, or when solar radiation is negligible:
WBGT = (0.7 x Tw) + (0.3 x Tg)