Wet Bulb Globe Temperature kit can help prevent heat injuries
July 3, 2008
FORT SAM HOUSTON, Tx --- With an already scorching summer under way, post safety officials recommend units purchase a Wet Bulb Globe Temperature kit to help determine work-rest cycles and water consumption.
The kit is particularly important for Soldiers in training, both on post and at Camp Bullis, since it can help prevent heat injuries, said Mary Lloyd, Army Medical Department Center and School safety specialist at Camp Bullis.
"A Wet Bulb Globe Temperature allows Soldiers to train and work safely within weather of that day," she said.
The WBGT is derived from a combination of temperatures from three thermometers - wet globe for humidity, black globe for solar factor, and dry bulb for the ambient temperature.
The kit contains all three thermometers as well as a calculator for determining the WBGT, which is used to calculate the heat category. The heat category determines the recommended water consumption and work-rest cycle.
Unlike the heat index on television, which is based only on temperature and humidity, the WBGT also accounts for strength of the wind and sun. As a result, the WBGT may read much lower than the heat index, Lloyd said.
"You should put the kit as close as possible to where you're training," Lloyd said. "If you're in the shade, move the kit in the shade. That way you'll get the most accurate reading for the training involved and won't limit training unnecessarily."
Along with the kit, post personnel can also access a general WBGT reading for Fort Sam Houston, which is posted on the Environmental Health link of the Preventive Medicine Web page at http://www.gprmc.amedd.army.mil/pmo/pm_index.htm.
Environmental Health uses an automated WBGT system so the readings are updated continually. While accurate, "The WBGT is in full sun most of the day, so the reading may not be applicable to your specific training area. That's why it is so important to take independent readings," said Capt. Naomi Skinner, chief of Environmental Health, Brooke Army Medical Center.
"It's important to keep in mind that WBGT readings vary depending on location and environment," Lloyd said, adding that amount of shade, wind, direct sunlight and presence of water factor into a reading.
Lloyd recommends people use the readings from the Web site as a general guideline and use a unit WBGT device to determine the index in their specific location.
"If you use someone else's temperature, you may be taking more time for rest than needed or not drink enough water," Lloyd said. "So it's important to derive a local reading."
Lloyd recommends unit personnel take a WBGT reading every hour and keep a written record.
"The WBGT is an excellent tool to help ensure the safety of Soldiers during the heat of summer," she said.