How do cooling towels work?
How do cooling towels work?
Working in hot environments presents its challenges, one of which heat exhaustion and heat stroke. According to OSHA, heat stroke was the likely cause of 18 workplace fatalities in 2018 and 13 in 2017. For this reason, heat stress and heat stroke should be assessed and controlled in the same serious manner as other critical hazards, like falls or being struck by equipment.
We can’t control the weather, and removing employees from hot environments is not always a viable option. So, we are often left relying mainly on administrative controls and PPE to mitigate hot weather hazards.
Cooling towels are specialty PPE for hot weather work that are designed to help workers regulate their body temperature to a comfortable level so they can work longer without suffering the effects of heat stress. Let's go over how they work.
Why a Towel?
While it seems strange for a piece of PPE and it doesn’t look like it offers any substantial physical protection, a towel makes total sense when talking about heat stress.
Our neck and shoulders are not only directly exposed to sun and implicitly to warming, they are also big muscles that generate large amounts of heat that needs to be dissipated in order to keep our body cool and not overheat.
A towel is also versatile. Besides being worn over the shoulders, it can be placed over the head or any other part of the body that needs cooling.
How Does It Work?
Cooling towels sold as PPE are no different than those used by runners, bikers, or hikers and serve the same purpose. Towels work through evaporative cooling. Just like sweating, it directs the heat away from the body.
The towel is immersed in cold water and then pressed to leave it wet, but not dripping. Not only does the wet towel feel pleasant because it is cool, but the temperature differential between the user’s body and the towel will help transfer heat from the body to the towel. The heat is then lost through evaporation, providing a cooling effect.
The cooling effect is more potent in low to medium humidity environments, since the drier the environmental air, the faster the rate of evaporation and the stronger the cooling effect.
In humid environments, the towel will still absorb heat from the body, but since the air is saturated with humidity, the water from the towel will not evaporate, effectively storing the heat. So, the cooling effect will be short lived. In these environments, you will have to soak the towels in cold water more frequently to "recharge" it when it warms or dries up.
The towel also acts as a physical barrier against the sun, preventing its rays from reaching and heating the skin. For this reason, a light colored towel is preferable, since it absorbs less radiation (heat) than dark colors. A towel with a higher UPF is also preferable since it will provide additional UV protection, which is important for people working for extended periods outdoors.
(Learn more about UV Risk in the Workplace.)
More Than Just Towels
Although cooling towels are a common and simple option, many other versions of this product exist, including cooling bands, bandanas and hard hat pads, which can be placed under a hard hat for all-day cooling relief. These other types of products work the same way, but the way they are worn may be more comfortable or practical for certain types of workers or conditions.
Despite its modest look, a cooling towel is an important piece of personal protective equipment for anyone working in hot environments.
More Q&As from our experts
- What questions should you ask before buying a cooling towel?
- What questions should I ask before buying a cooling vest?
- What is the difference between absorptive and evaporative cooling products?