1. What is the OSHA Heat Index?

Definition: The heat index is a measure of how hot it feels when relative humidity is factored in with the actual air temperature.

Purpose: OSHA uses this index to assess heat-related risks in the workplace and recommend protective measures.

2. How Does the Calculator Work?

The calculator uses the NOAA heat index formula:

Where:

• \( HI \) — Heat Index (°F)
• \( T \) — Temperature (°F)
• \( RH \) — Relative Humidity (%)

Explanation: The formula accounts for how humidity affects the body's ability to cool itself through perspiration.

3. Importance of Heat Index Calculation

Details: OSHA uses heat index values to determine risk levels and required protective measures for workers:

• Less than 91°F: Lower (Caution)
• 91°F to 103°F: Moderate
• 103°F to 115°F: High
• Greater than 115°F: Very High to Extreme

4. Using the Calculator

Tips: Enter the temperature (°F) and relative humidity (%). Values must be between -40°F to 140°F for temperature and 0% to 100% for humidity.

5. Frequently Asked Questions (FAQ)

Q1: Why does OSHA use heat index instead of just temperature?
A: Humidity significantly affects how the body experiences heat. High humidity reduces sweat evaporation, making it harder for the body to cool itself.

Q2: What are OSHA's recommendations based on heat index?
A: OSHA recommends increasing water breaks, providing shade, adjusting work schedules, and implementing acclimatization programs as heat index rises.

Q3: How accurate is this calculator?
A: It uses the official NOAA formula that OSHA references, providing results accurate to within ±1.3°F under normal conditions.

Q4: Does this account for direct sunlight?
A: No, the heat index is for shade conditions. In direct sunlight, it can feel up to 15°F hotter.

Q5: What precautions should be taken at different heat index levels?
A: OSHA provides specific guidelines for each risk category, including mandatory rest breaks, hydration requirements, and work/rest cycles.