Question (1) : In a chemical processing plant, the Industrial Hygienist is assessing the heat stress conditions for the plant operators. These operators work in different areas of the plant, each with varying temperature conditions. The following temperature data has been determined:

Reactor area:

Wet bulb temperature = 120F

Globe temperature = 160F

Control room:

Wet bulb temperature = 85F

Globe temperature = 90F

Storage area:

Wet bulb temperature = 75F

Globe temperature = 80F An operator spends four 30-minute periods of each workday in the Reactor area, two corresponding 45-minute periods in the Control room, and the remaining time in the Storage area. Calculate the Time Weighted Average (TWA) WBGT Index for a typical operator.