KOROYD-Integrated Industrial Safety Helmets Show Heat Index Reduction of up to 8° F / 4.5° C

KOROYD Heat Stress Reduction

Recent testing has shown KOROYD integrated industrial safety helmets have a significant heat index reduction. These helmets are poised to answer the demands of a warming world and protect workers by reducing heat stress risk. 

Against the backdrop of another summer of shocking and sometimes devastating climate news – including the hottest July on record – KOROYD has unveiled stunning test data poised to answer the growing need for PPE that protects workers not only from injuries and accidents, but also from soaring temperatures. 

As heat stress becomes an increasingly salient topic within industrial safety, head protection must advance to not only protect the wearer from impacts but also reduce heat stress risk. According to researchers at Williams College, heat shocks significantly increase accident rates, while another study found a link between heat stress and decrease of cognitive performance. It is vital, particularly as average temperatures rise, to protect workers from the impacts of heat stress by improving the breathability of their head protection.


The body works hard to regulate temperature, primarily through evaporation of sweat. Thermoregulation keeps deep body temperature at safe levels of between 37°C ± 1°C. Heat stress is a state that occurs when the body is unable to cool itself effectively.


Answering the call for innovative solutions, KOROYD has completed a rigorous test protocol to evaluate the thermal comfort of industrial helmets with significant results. KOROYD’s study results identify which type of helmet construction is less likely to contribute to heat stress, and drive recommendations for helmet design prioritizing heat stress reduction. The findings indicate that KOROYD integrated helmets show a reduction of up to 8 degrees Fahrenheit or 4.5 degrees Celsius on the heat index. 

Why Does Heat Stress Matter?

According to the Centers for Disease Control and Prevention, millions of workers are exposed to extreme heat at work in the US each year, too often leading to preventable injuries, accidents, and fatalities. This crucial reality of heat-related worker protection is not lost on regulatory bodies and industry leaders. With OSHA considering a federal heat standard in the US, and several states already enforcing OSHA-approved state policies, employers and regulating bodies alike are making strides toward protecting workers from heat-related injuries and fatalities. An average of 702 heat-related deaths occur each year in the US alone, while the Bureau of Labor Statistics reports that 528 work-related deaths due to environmental heat exposure occurred between 2011 and 2021 in the United States.

About the Study

KOROYD developed a test method to evaluate the thermal comfort of industrial helmets, using a head form replicating human sweat. Using a head form with a semipermeable membrane passable only by water vapor, the KOROYD team was able to simulate human thermoregulation in a controlled and reproducible way. In the test, a water basin was heated to 37°C, allowing the team to mimic skin temperature and humidity buildup.

The helmets were tested at room temperature, the head form temperature was set at 37˚C. Both the humidity and temperature were tracked over one hour. Using sensors across the head form, the team measured temperature, relative humidity, and absolute humidity, and used the data to calculate the heat index (HI).


The heat index (HI), also called “apparent temperature,” is a measure of how a temperature feels to the human body, more accurately representing when air temperature and relative humidity combine to exponentially increase the perceived temperature and related dangerous heat levels.

According to the test results, there is a significant reduction of the heat index in KOROYD integrated safety helmets compared to helmets with traditional EPS constructions: up to 8 degrees Fahrenheit / 4.5 degrees Celsius. 

As demonstrated by the test results, using KOROYD construction in a helmet better supports the body’s ability to thermoregulate, unlike traditional insulating EPS foams used in many high performance safety helmets. Heat and humidity rise and evaporate through KOROYD’s unique tubular structure, which is 95% air, improving the feeling of comfort during long periods of usage and reducing the risk of heat-related injuries and fatalities. In hot and humid environments, KOROYD can improve the release of heat by allowing air circulation and sweat evaporation. Crucially, this can also help prevent the temptation of short term removal of PPE, another open door to injuries and fatalities.

Protection Without Compromise

KOROYD-integrated safety helmets are poised to answer the demands of a warming world and protect workers by reducing heat stress risk. To learn more about the study and results, visit koroyd.com/heatstress.

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