WBGT Heat Stress
Calculate Wet Bulb Globe Temperature (WBGT) to assess heat stress risks.
What is WBGT (Wet Bulb Globe Temperature)?
WBGT is a composite temperature index that measures heat stress on the human body. It combines air temperature, humidity, wind speed, and radiant heat to provide a single value indicating the risk of heat-related illness. Our calculator helps determine safe work/rest cycles based on WBGT readings.
How to Calculate WBGT
Select Environment
Choose whether you're calculating for indoor or outdoor conditions.
Enter Temperatures
Input wet bulb, dry bulb, and globe temperatures (outdoor also needs solar load).
Select Work Intensity
Choose the metabolic workload level (light, moderate, heavy).
Review Recommendations
Get work/rest cycle recommendations and safety alerts.
Features & Benefits
Indoor/Outdoor Modes
Different formulas for environments with and without solar radiation.
Work-Rest Guidelines
Automatic recommendations based on workload intensity.
Risk Indicators
Color-coded alerts for different heat stress levels.
Unit Conversion
Support for Celsius and Fahrenheit inputs.
ACGIH Standards
Based on American Conference of Governmental Industrial Hygienists guidelines.
Save Calculations
Record readings for compliance documentation.
Who Uses This Tool?
HSE Officers
Pre-shift heat stress assessment
HSE officers use the WBGT calculator before outdoor work shifts to determine if environmental conditions are safe, implementing appropriate work-rest cycles and hydration schedules. This ensures compliance with ACGIH threshold limit values and protects workers from heat-related illness.
Athletic Trainers
Outdoor sports practice safety
Athletic trainers calculate WBGT before and during outdoor practices to decide whether training should be modified, moved indoors, or cancelled. Many athletic governing bodies mandate specific WBGT thresholds for practice intensity, making this calculation essential for player safety.
Construction Site Managers
Managing heat exposure on active job sites
Construction site managers monitor WBGT throughout the day to adjust crew schedules as conditions change. When WBGT readings climb during midday hours, they can proactively shift heavy labor to cooler periods and rotate crews through shaded rest areas.
Military Training Officers
Setting flag conditions for field exercises
Military training officers use WBGT to determine heat condition flag categories (green through black) that govern physical training intensity, water intake requirements, and mandatory rest intervals. Accurate WBGT calculation prevents heat casualties during field exercises and physical fitness testing.
Pro Tips
- 1.
Always measure WBGT at the actual work location, as conditions can vary significantly even within a short distance due to shade, reflected heat from surfaces, and localized airflow.
- 2.
Recalculate WBGT at least every hour during the workday since conditions change rapidly - a reading taken at 7 AM may be dangerously inaccurate by 10 AM.
- 3.
When selecting work intensity level, account for personal protective equipment such as coveralls or chemical suits, which can effectively raise the perceived WBGT by several degrees.
- 4.
Keep a log of WBGT readings alongside work-rest schedules to build historical data that helps you predict high-risk days and plan ahead based on weather forecasts.