Could This New Wearable Device Reduce Heat Stress in Construction Workers?

Architecture students at the University of Hong Kong invented a cooling apparatus that attaches to a construction helmet

Air Ring and parent sketches.jpg
Air Ring 48 attaches to the base of a construction helmet, providing crucial airflow to the sweatiest areas of the head and neck. Air Ring 48

In the summer after their first year studying architecture at the University of Hong Kong, Jeff Li and Joseph Wong were contemplating hats and climate change.

“We were basically thinking: ‘Huh, what are the big issues right now in this world?’” says Li. “And obviously it’s heat, right?”

Keeping cool during a Hong Kong summer is hard. Temperatures in the region often exceed 87 degrees Fahrenheit in July and August, and heat has risen year over year, with 2024 on track to be one of its hottest years on record, according to the Hong Kong Free Press.

The pair saw a need for a wearable item that cools construction workers on the job. Amid increasing temperatures, outdoor laborers in hot and humid climates like Hong Kong’s are at risk of severe heat stress, heat stroke and even death. “In the top of a half-finished building, it’s fully exposed,” says Li. “And in the covered areas, there’s no ventilation. It gets really, really hot.”

This was the origin of the Air Ring 48, a cooling device that attaches to the base of a construction helmet, providing crucial airflow to the sweatiest areas of the head and neck. Air Ring 48 was in the top 20 finalists for this year’s James Dyson Award, an international design competition with a cash prize to find the next generation of design engineers. With a fan balanced behind each ear, the device operates at the level of a whisper (30 decibels), and its battery can last for 17 hours, or the equivalent of two workdays.

Could This New Wearable Device Reduce Heat Stress in Construction Workers?
With a fan balanced behind each ear, the device operates at the level of a whisper (30 decibels), and its battery can last for 17 hours. Air Ring 48

“AR48’s practical application in tackling heat and noise issues, with potential uses beyond construction, makes it a versatile solution that significantly improves working conditions and safeguards workers’ health in challenging environments,” says Steve Yeung, a James Dyson Award judge in Hong Kong, in a press release.

Personal cooling devices for laborers take many forms. Specialized vests utilize freezable inserts or cold water within the lining of the garments to cool workers.

Meanwhile, other fan-cooled helmet systems are already on the market. The Tajima Seiryo 2 attaches to the back of a helmet with a maximum run time of 12 hours, and the Klein Cooling Fan attaches to the brim of Klein-specific helmets, ducting air through small tubes into the hard hats for up to 6 hours.

With similar devices on the market, the team behind Air Ring 48 developed 48 prototypes in order to achieve a scalable cooling system that is both functional and comfortable. At just over five ounces, the lightweight and ergonomic Air Ring 48 won’t weigh down a worker over the course of a workday.

“We focus a lot on the user’s perspective and how to maximize the user comfort, not only cooling, but also the weight perception when you wear it throughout the whole day,” says Wong.

Fabiano Amorim is an exercise physiologist at the University of New Mexico whose research includes studying heat stress in sugarcane workers in Brazil and construction workers in Missouri. When we talk about heat stress, Amorim explains we are referring to heat from two sources: our metabolism and our environment.

Consider a roofer working under the sun with no shade. Not only does the sun raise his body temperature, but each time he nails down a shingle, the roofer’s physical activity also causes reactions in the body to provide stored energy for the task at hand. The body can’t use all the energy that’s broken down from storage, so it raises the roofer’s body temperature. The body cools itself by circulating hot blood beneath the surface of our skin and secreting a layer of sweat on top. The blood heats the sweat, which evaporates, cooling the skin.

Humans are effective at cooling down in hot and dry environments, but in humid environments like Hong Kong, a high amount of water vapor in the air makes sweat evaporate more slowly, so the body has to work harder to cool itself.

“When the sweat drips on, you’re just dehydrating. You’re not cooling off. That’s a problem because you’re reducing the amount of water in your body, your temperature keeps going up, and then that's dangerous,” says Amorim.

For outdoor laborers, the combination of humid heat and physical activity without adequate cooling can create heat-stress-related illnesses like heat cramps, heat exhaustion, heat rash or heat stroke.

Air Ring 48 team
Li, Wong and their team developed 48 different prototypes. Air Ring 48

Li and Wong knew that fans could work in hot, humid environments because circulating air allows more sweat to evaporate than if the air remained stagnant. So fans figured into all 48 of the inventors’ prototypes, from the very first, consisting of a fan placed in a hole carved in the top of a fisherman’s hat, to the much more refined final product.

By the 40th prototype, the design featured a large circular fan at the back of the user’s head with a battery at the front to balance the load. The device was heavier than the Air Ring 48, with a short battery life of 3.5 to 6.3 hours. Workers with property development and construction companies in Hong Kong and Ghana who tested the prototype wanted more cooling behind the ears.

The second test trial brought the 43rd prototype closer to the Air Ring’s final shape: two smaller fans situated just above and behind the ears. The device weighed less than half a pound.

The 46th prototype inched the project closer to Air Ring 48’s current form, with a battery life of 15 hours and a five-ounce weight.

“If you add too much, the weight is going to add up. Battery life’s going to go down, all-around performance is going to shrink,” says Li. “So we, at this moment, right after 48 prototypes, we aim to optimize everything.”

The team reports a maximum skin cooling rate of 5.76 degrees Fahrenheit lower and a maximum core cooling rate of 1.21 degrees Fahrenheit lower. This data was tested by measuring the temperature difference between a wearer and non-wearer at the same time interval and location at three separately scheduled field tests.

Li’s and Wong’s educations in architecture shaped their design process, giving the team the disciplined passion to keep improving their device and the inventiveness to walk the fine line between efficiency and ergonomic design trial after trial. “[Architecture] gives you this design methodology that you can actually apply anywhere,” says Wong. “So as long as you are creative enough, you can actually do a lot of things with this skill set.”

Gig workers for app-delivery services, street vendors and outdoor cleaners are among the laborers experiencing heat stress in urban environments. While climate innovations like Air Ring 48 are critical, New York City’s Chief Climate Officer Louise Yeung says the way to mitigate the climate crisis is through policy.

“I think there’s a lot that we do to keep ourselves and each other safe, and that is really important, but that is no match for actual structural changes to labor standards,” says Yeung.

The chief climate officer says the best way to protect workers is by mandating that employers bear the responsibility of safeguarding their employees from extreme heat. Yeung prepared the recently released “Safeguarding Outdoor Workers in a Changing Climate” report, which outlines a twofold approach that addresses broader worker protections and public health initiatives that aid gig workers. The report recommends the creation of municipal heat standards to cover all New York City outdoor workers, reformation of the City Street Vending Code to allow street vendors to use awnings for shade coverage, expansion of public bathroom access, and passing the Temperature Extreme Mitigation Program (TEMP) Act.

That act is currently in committee in the New York State Senate. The law would provide workers with protections against extreme heat, such as water, shade and rest breaks.

Li and Wong have now graduated from the University of Hong Kong and currently work on Air Ring 48 full-time. They plan to continue to develop the product and possibly expand to the general market with hardware accessories, portable fans and other wearable devices.

“Our team is preparing for the worst,” says Wong, of climate change. In the years ahead, we could “encounter this really dreadful situation, where we really can’t go outdoors, and we really need something additional in our clothes to protect us.”

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