1. What is WBGT?

Definition: Wet Bulb Globe Temperature (WBGT) is a measure of heat stress in direct sunlight that accounts for temperature, humidity, wind speed, sun angle, and cloud cover.

Purpose: OSHA uses WBGT to assess heat stress risk for workers and determine appropriate work/rest schedules.

2. How Does the WBGT Calculator Work?

The calculator uses the OSHA formula:

Where:

• \( T_w \) — Wet bulb temperature (measures humidity)
• \( T_g \) — Globe temperature (measures radiant heat)
• \( T_d \) — Dry bulb temperature (ambient air temperature)

Explanation: The formula weights the wet bulb temperature most heavily (70%) because humidity is the most significant factor in heat stress.

3. Importance of WBGT Monitoring

Details: WBGT is critical for preventing heat-related illnesses in outdoor workers, athletes, and military personnel. OSHA recommends monitoring when temperatures exceed 77°F (25°C).

4. Using the Calculator

Tips: Enter all three temperature measurements in Celsius. Use proper instruments (wet bulb thermometer, globe thermometer, and standard thermometer).

5. Frequently Asked Questions (FAQ)

Q1: What's a dangerous WBGT level?
A: OSHA considers WBGT above 30°C (86°F) as high risk, requiring work/rest cycles and other precautions.

Q2: How is this different from heat index?
A: WBGT accounts for solar radiation and wind, while heat index only considers temperature and humidity in shade.

Q3: Where should measurements be taken?
A: At the work area height, not in shade, representative of worker exposure.

Q4: What's the OSHA action level?
A: At WBGT ≥ 26.7°C (80°F), OSHA recommends increased water intake and awareness training.

Q5: Can I use regular thermometer readings?
A: No, specialized wet bulb and globe thermometers are required for accurate WBGT calculation.