Calculate the WBGT outdoors using WB 90°F, GT 98°F, and DB 94°F.

Calculate the WBGT outdoors using WB 90°F, GT 98°F, and DB 94°F.

• A. 85
• B. 92
• C. 96
• D. 90

Answer: (B)

Outdoor WBGT combines how hot the air is, how radiant heat from the sun adds to the heat, and how much evaporative cooling can occur. The formula is WBGT_outdoors = 0.7 × Wet-Bulb + 0.2 × Globe + 0.1 × Dry-Bulb. Plugging in the numbers: 0.7 × 90 = 63; 0.2 × 98 = 19.6; 0.1 × 94 = 9.4. Add them up: 63 + 19.6 + 9.4 = 92.0°F. So the outdoor WBGT is 92°F. This value indicates the heat stress risk under sun exposure. (If there were no solar load, the formula would be different: 0.7 × Wet-Bulb + 0.3 × Globe.)

Outdoor WBGT combines how hot the air is, how radiant heat from the sun adds to the heat, and how much evaporative cooling can occur. The formula is WBGT_outdoors = 0.7 × Wet-Bulb + 0.2 × Globe + 0.1 × Dry-Bulb.

Plugging in the numbers: 0.7 × 90 = 63; 0.2 × 98 = 19.6; 0.1 × 94 = 9.4. Add them up: 63 + 19.6 + 9.4 = 92.0°F.

So the outdoor WBGT is 92°F. This value indicates the heat stress risk under sun exposure. (If there were no solar load, the formula would be different: 0.7 × Wet-Bulb + 0.3 × Globe.)