CTEH How-To: Scott Skelton on PPE in Extreme Heat

Employees who are exposed to hot weather, work in high-heat environments or wear personal protective equipment (PPE) may be at risk for heat-related illnesses such as stroke, exhaustion or cramps. So, what can employers do to minimize workers’ risk of heat stress while still keeping them safe on the job with PPE? Scott Skelton, CIH, CTEH’s senior industrial hygienist, is sharing his expertise below:

What are the benefits of PPE?

When used properly, PPE can help minimize or eliminate employees’ exposure to potentially hazardous chemicals and workplace hazards (i.e., physical, electrical, mechanical, etc.). It can include smaller protective items such as gloves and safety glasses to coveralls or full body suits.

Why does PPE increase the risk of heat stress?

As the National Institute for Occupational Safety and Health (NIOSH) has noted, PPE can “reduce the body’s normal way of getting rid of heat by sweat evaporation.” Because it’s often semi-permeable or impermeable, PPE retains excess heat and moisture. This can put additional strain on workers’ bodies by raising their core temperatures or increasing the physical effort needed to perform their duties.

Can fire-reflective clothing reduce the risk of heat stress?

Reflective clothing, which covers workers from the neck to feet, can reduce exposure to radiant heat. However, much like chemical protective garments, fire-reflective clothing can also prevent evaporative cooling. So it should always be worn as loosely as possible. If the level of radiant heat is too high, reflective clothing should be used in combination with an auxiliary cooling system (i.e., circulating air).

What cooling techniques should employers consider?

When deciding which cooling techniques to use, employers should ask questions such as, “How long will workers be exposed to heat?” or “How much mobility does this task require?” Here are a few options to consider:

Work/rest regimens are critical for reducing heat stress for continuous work activity in hot conditions. Workers need time to rest in a cool place, with PPE removed, while consuming cool water to combat the effects of metabolic heat increase and the lack evaporative cooling.

Auxiliary body cooling vests can hold dozens of frozen or dry ice packs. While they offer good mobility and are relatively inexpensive, they are only effective for short time periods (approximately 2-4 hours) in moderate to heavy heat.

Wetted clothing is a cost-effective solution for workplaces with high temperatures, low humidity and good airflow. It is often worn with reflective clothing or other impermeable PPE.

Water-cooled garments, which can offer semi or full body cooling, require a circulating pump, liquid-ice coolant and a container. Its heavy weight limits mobility and the amount of ice workers can carry, reducing its effective time of use.

  • According to the Occupational Health and Safety Administration (OSHA), circulating air is “the most highly effective, as well as the most complicated, personal cooling system.” It improves evaporative and convective cooling by providing a continual source of compressed air, but it can also be noisy and limit workers’ mobility.