JOINT BASE MYER-HENDERSON HALL, Va. - For years, the Army has used Wet Bulb Globe Temperature as an index to measure air temperature and humidity. This device has been a valuable tool to indicate heat stress and prevent heat casualties.

"The wet bulb is used to give soldiers a work-rest ratio whenever heat conditions are extreme," said Sgt. William Butusov, of the Directorate of Plans, Training Mobilization and Security on Joint Base Myer-Henderson Hall.

DPTMS employees have been using a WBGT device to monitor heat conditions over the summer. They take daily readings and pass on the information to command leadership. "The base commander and command sergeant major make appropriate calls [about working conditions], and then we'll disseminate the information," Butisov said.

"You fill up the wet bulb with water and the machine calculates everything. The dry bulb is telling the temperature as it sits and the wet bulb is telling you if it was saturated with moisture in the air what it would be," he explained.

"On a hot day [for example], we'll come out and pull up the wet bulb index, and it will tell us which heat category we're in, and more importantly, the work-rest amounts - for example, you need to work for 40 minutes, then take a 20-minute break."

He said the chart, which comes with the device, also indicates factors for work and rest. An example of this might be you can still work, but we'd like you to be working in the shade ... nothing too strenuous, Butisov pointed out.

"If the temperature is above 90 degrees, it's recommended you work 10 minutes and rest 50," he explained. He said the chart has color-coded sections for working conditions, used at command levels to indicate the working conditions in different heat conditions.