What is the formula outdoor for WBGT?

What is the formula outdoor for WBGT?

• A. 0.7WB + 0.2GT + 0.1DB
• B. 0.6WB + 0.3GT + 0.1DB
• C. 0.8WB + 0.15GT + 0.05DB
• D. 0.5WB + 0.4GT + 0.1DB

Answer: (A)

Outdoor WBGT combines three measurements with weights that reflect how evaporative cooling, radiant heat, and ambient air temperature influence heat stress. The formula uses 0.7 times the natural wet-bulb temperature, 0.2 times the globe temperature, and 0.1 times the dry-bulb temperature, giving WBGT outdoor = 0.7 × WB + 0.2 × GT + 0.1 × DB. The dominant factor outdoors is humidity and the body's ability to cool itself, which the wet-bulb temperature captures, so it gets the largest weight. The globe temperature brings in radiant heat from the sun and surroundings, hence its smaller but significant weight. The dry-bulb temperature provides the baseline air temperature with the smallest weight. Altogether, this weighting reflects how heat stress tends to increase with higher humidity, more radiant heat, or higher air temperature, guiding safety decisions on heat exposure. Other weightings would misrepresent the relative influence of evaporative cooling and radiant heat and would not align with standard outdoor WBGT calculations.

Outdoor WBGT combines three measurements with weights that reflect how evaporative cooling, radiant heat, and ambient air temperature influence heat stress. The formula uses 0.7 times the natural wet-bulb temperature, 0.2 times the globe temperature, and 0.1 times the dry-bulb temperature, giving WBGT outdoor = 0.7 × WB + 0.2 × GT + 0.1 × DB.

The dominant factor outdoors is humidity and the body's ability to cool itself, which the wet-bulb temperature captures, so it gets the largest weight. The globe temperature brings in radiant heat from the sun and surroundings, hence its smaller but significant weight. The dry-bulb temperature provides the baseline air temperature with the smallest weight. Altogether, this weighting reflects how heat stress tends to increase with higher humidity, more radiant heat, or higher air temperature, guiding safety decisions on heat exposure.

Other weightings would misrepresent the relative influence of evaporative cooling and radiant heat and would not align with standard outdoor WBGT calculations.