Heat Stress Resource Page

Heat Index Chart

The Heat Index is a measure of how hot it really feels when relative humidity is factored in with the actual air temperature. To find the Heat Index temperature, look at the Heat Index Chart above or check our Heat Index Calculator. As an example, if the air temperature is 96°F and the relative humidity is 65%, the heat index--how hot it feels--is 121°F. The red area without numbers indicates extreme danger. The National Weather Service will initiate alert procedures when the Heat Index is expected to exceed 105°-110°F (depending on local climate) for at least 2 consecutive days.

Why humidity matters: Relative humidity is a measure of the amount of moisture in the air. Sweat does not evaporate as quickly when the air is moist as it does in a dry climate. Since evaporation of sweat from the skin is one of the ways the human body cools itself on a hot day, high humidity reduces our natural cooling potential and we feel hotter. Low humidity can also be a problem for outdoor workers in hot, desert-like climates. Sweat evaporates very rapidly in low humidity, which can lead to severe dehydration if a person does not drink enough water throughout the day.

IMPORTANT NOTE: The heat index values were devised for shady, light wind conditions, and exposure to full sunshine can increase heat index values by up to 15° Fahrenheit. To account for solar load, added precautions are recommended. See Protective Measures to Take at Each Risk Level.

NWS offers a slightly different Heat Index chart for area with high heat but low relative humidity. 

Download OSHA's Heat Index Chart here...

Source:OSHA: Using the Heat Index: A Guide for Employers and National Weather Service

How to Recognize the Symptoms of Heat Stress

Heat stroke, the most serious form of heat-related illness, happens when the body becomes unable to regulate its core temperature. Sweating stops and the body can no longer rid itself of excess heat. Signs include confusion, loss of consciousness, and seizures. Heat stroke is a medical emergency that may result in death! Call 911 immediately.

Heat exhaustion is the body's response to loss of water and salt from heavy sweating. Signs include headache, nausea, dizziness, weakness, irritability, thirst, and heavy sweating.

Heat cramps are caused by the loss of body salts and fluid during sweating. Low salt levels in muscles cause painful cramps. Tired muscles—those used for performing the work—are usually the ones most affected by cramps. Cramps may occur during or after working hours.

Heat rash, also known as prickly heat, is skin irritation caused by sweat that does not evaporate from the skin. Heat rash is the most common problem in hot work environments.

Source: OSHA

Infographics

Infographic: Heat-Related Illnesses

Source: CDC

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Infographic: Protect Your Workers from Heat Stress

Source: CDC and NIOSH

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Infographic: Dehydration Indicator Chart

Source: Ergodyne

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Infographic: Hydration Solutions

Source: Sqwincher

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OSHA/NIOSH Infosheet and NIOSH Fast Facts

OSHA / NIOSH: Protecting Workers from Heat Illness

Source: OSHA and NIOSH

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NIOSH Fast Facts: Heat Stress

Source: NIOSH

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NIOSH Fast Facts: Sun Exposure

Source: NIOSH

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NIOSH Fast Facts: Stinging Insects

Source: NIOSH

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NIOSH Fast Facts: Ticks and Mosquitoes

Source: NIOSH

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Printable Posters

Heat Illness Posters

Source: OSHA (Three posters in download)

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Heat Related Illness Poster

Source: NIOSH

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Ergodyne Toolbox Talks

Toolbox Talk: Heat Stress: Water, Rest and Shade

Source: Ergodyne

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Toolbox Talk: Heat Stress: Water, Rest and Shade: Shade

Source: Ergodyne

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Toolbox Talk: Heat Stress: Water, Rest and Shade: Water Wisdom

Source: Ergodyne

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Toolbox Talk: Heat Stress: Water, Rest and Shade: Rest

Source: Ergodyne

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OSHA Fact Sheets and Quick Card

OSHA Fact Sheet: Protecting Workers from the Effects of Heat

Source: OSHA

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OSHA Fact Sheet: Working Outdoors in Warm Climates

Source: OSHA

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OSHA Quick Card: Protecting Workers from Heat Stress

Source: OSHA

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Heat Stress Guides

Guide to Heat Stress

Source: Ergodyne

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Hot Weather Survival Guide

Source: SafetyNetwork.me and Safeopedia.com

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Using the Heat Index: A Guide for Employers

Source: OSHA

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Heat Training Guide

Source: OSHA

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Q&A: How Can You Encourage Employee Hydration?

Source: Sqwincher

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Heat Stress White Papers

Drink to Your Health

Source: Ergodyne

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Beyond Water, Rest and Shade

Source: Ergodyne

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Hydration: The Underappreciated Safety and Productivity Measure many Industrial Workplaces Miss

Source: Sqwincher and Safeopedia.com

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Dangers of On The Job Dehydration

Source: Sqwincher

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Products to Keep Workers Safe in Hot Weather

Hydration Products

Shade Products

Hi-Vis Safety Vests

Hi-Vis Safety Shirts

Traffic Safety Items

Additional Tools and Links

OSHA Heat Safety App

OSHA Occupational Heat Exposure Page

OSHA Heat Illness Prevention Campaign Page

National Weather Service: Heat Index Calculator

NWS Early Heat Index Forecasts Page

How can Quest help you and your team stay safe this summer?

Partnering with You to Protect Your Workers in Any Environment

Contact Quest for Summer Safety Solutions

Call 317-594-4500 or 800-878-4872