Employers have an obligation to provide a safe working environment for all workers on their sites. There are limits to directly addressing environmental factors, but control measures must be employed.

Heat is a hazard in many workplaces, whether the work takes place outside or indoors around sweltering boilers, vessels, pipes, and machinery.

On top of that, many workers have to don flame-resistant, hi-vis clothing and other types of PPE, not all of which is very breathable. And in all that heat, under the weight of all that equipment, they have to perform physically demanding tasks.

If unchecked, heat stress can contribute to heat exhaustion, heat stroke, heat syncope (fainting), heat cramps, and hyperthermia. Employers must, therefore, assess the work environment and processes in order to determine whether they need to implement appropriate control measures.

(Learn about The Hierarchy of Hazard Controls.)

In this article, we'll discuss some of the things that need to go into your heat stress protocol. If any of your workers are exposed to extreme heat, or exposed to heat for a prolonged period, you need to implement engineering controls, administrative controls, and promote awareness among your workforce.

Signs and Symptoms of Heat Stress

  • Confused thinking
  • Dizziness
  • Headache
  • Cramping in muscles
  • Pale skin
  • Profuse sweating or no sweating whatsoever
  • Rapid heart rate

Workers who have medical conditions, are overweight, or taking certain medications can be more prone to the serious effects of heat stress. Depending on how those factors interact with the expected work environment, it can be prudent to decide that particular workers are not fit for a particular job or task and provided with alternative working arrangements.

(Learn more in Workers and Heat Stress: What You Need to Know.)

Engineering Controls for Heat Stress

Creating Ventilation

Our body sweats to help us stay cool. The heat around us causes the sweat to evaporate. That evaporation causes the sweaty skin to cool down.

When the air moves quickly, the water vapor moves from the body's surface more quickly. That increases the rate of cooling. Conversely, if the air is still or the humidity levels in the air are high, this cooling process isn't as effective.

In work environments with stagnant air, air movers might help facilitate the body's natural sweating process by constantly moving the shell of air around a worker. Air movers and fans may not change the temperature, but they do help create the conditions under which the body's natural cooling mechanisms can do their job.

In short, if the air is not moving and it is safe to do so, consider creating some artificial ventilation to to slow the onset of heat stress and reduce its impact.

(Learn more in Proper Ventilation to Improve Indoor Air Quality.)

Providing Shade

Working under direct sunlight dramatically increases a worker's exposure to heat. The best and easiest way to control for this is to create shade in areas where the work is taking place.

In principle, creating shade is as simple as erecting a large enough structure between the sun and the work area. In practice, however, that is often easier said than done. If it isn't practicable to have the work carried out in the shade, make sure that workers at least have a shaded area to rest in during their breaks.

Administrative Controls for Heat Stress

Acclimating Workers

Whenever I travel to warmer places like Mexico, I'm always astonished to see people walking around in long pants, long sleeves, and layers of clothing. "How can they tolerate this heat?" I wondered, as I sweat profusely despite only wearing shorts and a t-shirt.

The answer is simple: they're acclimated to the heat.

When there is a dramatic swing in the temperature, your body's ability to cool itself down experiences a bit of lag time. It's the same with the cold – lots of us shiver and complain when temperatures first drop in the fall but we get used to the chill by the time winter settles in.

You can use this to your advantage by cycling in workers who will be subject to excessively hot work environments. You might, for instance, start by giving employees who work in the heat a short break every 30 minutes, then gradually moving it to every 60 minutes and then 90 minutes as they adapt to the temperature.

Schedule Frequent Breaks

It's not enough to say "If you feel hot, take a break." It's a mistake to put the onus on the workers to self-monitor while they're trying to focus on their task. Many employees will just push past the symptoms or fail to notice them at all.

Even if a worker does notice some early symptoms of heat stress setting in, a fast-paced work environment might make them feel like they can't sit down for a break when they need one.

It should go without saying, but ignoring the symptoms is a bad idea. Once dehydration or significant heat exhaustion set in, recovery is much more difficult. When it comes to heat stress, an ounce of prevention really does equal a pound of cure.

For that reason, it's much more effective to assign frequent breaks to worker, rather than just allowing them to take breaks as needed.

(See Reducing Environmental Risks: Indoor Temperature Control for related reading.)

Awareness

Looking Out for Each Other

Workers who are made aware of the issue can anticipate heat hazards, know when they're at increased risk, recognize the signs of dehydration and heat stress, and monitor their coworkers.

That last point is worth stressing. It can be difficult to recognize the signs of heat stress in ourselves, especially once confusion sets in. Because of that, it's often coworkers or supervisors who identify heat stress, not the person suffering from it One of the main tenets of an effective heat stress protocol, then, is encouraging workers to look out for each other and to know what to look out for.

Hydration

It's important for the employer to have an awareness of the risks associated with heat, too. When they're aware, they can ensure that workers take care of themselves.

Employers and supervisors should remind workers to keep plenty of water on hand and to drink frequently throughout the workday.

Drinks with added electrolytes can be consumed periodically. This is especially beneficial for workers who sweat a lot and lose lots of fluid and salts in the process.

Posting reminders on the job site is one way to remind workers that they should hydrate, but it's no substitute for direct reminders from supervisors or management.

Conclusion

You can't control the weather and usually can't do much about how hot it gets in your workplace. But by thoughtfully implementing a heat stress protocol, you can make sure your workers are protected even when the heat is turned up.