WBGT index

The ISO philosophy for the assessment of hot environments is to use a simple, fast method of monitoring the environment, based on the wet bulb globe temperature (WBGT) index (ISO 7243). If the WBGT value exceeds the provided reference value, or if a more detailed analysis is required, then ISO 7933 provides an analytical method of assessment. 

A computer program is provided for ease of calculation and efficient use of the standard. This rational method of assessing hot environments allows identification of the relative importance of different components of the thermal environment, and hence can be used in environmental design. The WBGT index is an empirical index, and it cannot be used to analyze the influence of the individual parameters. The required sweat rate (SW. ) has this capability, but lack of data may make it difficult to estimate the benefits of protective clothing. 

Heat Condition/ Color Code WBGT Index (°F) Water Intake (Qt/h) Work/Rest Cycles for Acclimatized Soldiers Unacclimatized Soldiers and Trainees... 

Wearing mission oriented protective posture (MOPP) gear or body armor adds 10°F to the wet bulb globe thermometer (WBGT) index. 

Wet-Bulb Globe Temperature Index Researchers developed the WBGT index as a simple-to-use method for determining if military troops were likely to suffer from heat illnesses in hot environments. The WBGT index requires only two or three measurements wet-bulb (static) temperature (WB), dry-bulb temperature (DB), and globe temperature (GT). One can compute WBGT values from one of two equations, depending on the presence of a solar load. 

Compute the WBGT index for the following and recommend appropriate controls ... 

Internahonal Standards Organization. (1982). International Standard 7243. Hot environments - Estimation of the heat stress on working man, based on the WBGT index (Wet bulb globe temperature). Geneva, ISO. Instrumentation and measurement see IS07726. 

Although the WBGT index considers the portion of heat stress that results from the net effects of dry air temperature, radiant heat transfer, and humidity, it does not sufficiently reflect the air move-... 

The WBGT heat stress index is calculated inside buildings and outside buildings without solar load as... 

Stafford Country Public Schools, Office of Safety Security (unknown year) Wet Bulb Globe Temperature Index (WBGT). Available at www.pen.kl2.va.us/Div/Stafford/Safety/wetbulb.html (accessed 13 April 2006). 

A more complex and well-known climatic index is the Wet Bulb Globe Temperature (WBGT), used as a heat stress indicator. The 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 ... 

An index discussed later is the wet-bulb globe temperature (WBGT). When making wet-bulb readings for WBGT, the wet-bulb thermometer must be stationary and not involve moving air. 

The Wet Bulb Globe Temperature index (WBGT) can be calculated from the formula ... 

The WBGT, see Table 10.5, is the most favoured in Australia, although with outdoor workers, some unions work simply on a temperature of 37.5°C as a basis for walking off the job. The Belding and Hatch index has the value that predictions can be made of what will happen to the index when humidity, temperature or airflow are altered. 

WBGT = web-bulb globe temperature index NWBT = natural wet-bulb temperature DBT = dry-bulb temperature GT = globe temperature. 

WBGT=Wet Bulb Globe Temperature Index NWB=Nature Wet-Bulb Temperature DB=Dry-Bulb Temperature GT=Globe Temperature... 

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