When temperatures rise, we think of workers on rooftops or black asphalt as being most vulnerable to heat stress problems, but indoor workers are not immune. Manufacturing companies that have workers inside buildings and/or outdoors need to be aware of the factors that contribute to heat stress, how to recognize heat-related physical symptoms, and how to prevent heat stress from escalating.
According to a Statistics Canada Health Report, “short- and long-term heat exposure can lead to a variety of heat-related illnesses and outcomes, including heatstroke, exhaustion, dehydration and hospitalization resulting from respiratory and cardiovascular diseases.”
Multiple factors contribute to indoor heat stress
Heat stress isn’t only a concern for people who are exposed to direct sunlight. Several contributors present at indoor manufacturing facilities can increase the risk of heat stress:
Heat-generating machinery
A machine doesn’t have to be a blast furnace to generate heat. Everything from computers to conveyors gives off radiant heat which can affect nearby workers.
Heavy or non-breathable extra clothing or protective equipment
The advice to prevent overheating often includes wearing loose, light, breathable clothing. However, in many industrial environments, safety regulations require that workers wear heavy clothing or protective gear like overalls, certain types of respirators, and hard hats. This additional clothing and equipment must be factored in when determining the risk of heat stress in a manufacturing environment.
Movement/exertion
Whether a person is sitting or standing, taking a few steps or moving quickly, carrying nothing or hauling heavy items all make a difference. Activity adds up to increase the effects of heat stress.
Lack of adequate ventilation and cooling
One problem with extreme temperatures is that they can stress a building’s HVAC (heating, ventilation and air conditioning) system to the point where it can’t keep up and maintain a comfortable indoor temperature.
In some cases, the indoor environment must be temperature controlled to suit a product. In these instances, additional measures need to be taken to prevent heat stress and ensure worker safety.
Acclimatization to heat
The human body is capable of adapting to heat to a certain extent, so the first week or two of hot conditions may result in more heat stress than after acclimatization has occurred.
Ideally, exposure to the hot environment would be gradual. Acclimatization is especially important for new workers who may not have experience adjusting to heat stress.
General health and recent illnesses
People who have underlying risk factors will be more susceptible to heat stress than other workers. Previous heat stress issues and illnesses may also leave a person less resilient to heat stress conditions.
Teamwork is needed to recognize signs and prevent heat stress escalation
One of the dangerous aspects of heat stress is that people can’t always recognize their own symptoms. Co-workers and managers need to be trained to look for and recognize signs and symptoms in order to keep everyone safe.
Identifying heat stress early, before it escalates to heat exhaustion or heat stroke is imperative.
Signs to look for include the following:
- Sweating is an effective way for the body to cool itself, but excessive sweating can cause dehydration. Resting in a cooler environment, along with fluid and electrolyte replacement can help prevent heat stress symptoms from escalating.
- Dizziness, headaches, and weakness are more serious signs that can signal heat exhaustion. Any signs of heat exhaustion must be taken very seriously, and treated immediately to prevent heat stroke.
- Lack of sweating, confusion and irrational behavior are serious signs of heat stroke that require urgent medical attention.
- Training, monitoring, and prevention are essential to avoid heat stress issues
Occupational Health and Safety agencies in the different jurisdictions in Canada have legislation that covers the duty of employers to ensure that the health and safety of their workers is protected while they are working.
Monitoring the actual temperature in areas where people will be working is an important step in preventing heat stress issues. To help reduce heat in the physical environment, the following tactics can be deployed where applicable:
- Increasing ventilation
- Using cooling fans
- Implementing misting fans
- Installing local exhaust ventilation at high heat points
- Placing reflective shields to redirect radiant heat
Ensuring that everyone is aware of the danger and seriousness of heat stress is also essential to provide a safe workplace. Providing daily reminders to workers about preventing heat stress issues, and the importance of health and safety during a heat wave is good practice.
Administrative controls recommended by the CCOHS include:
- allowing a sufficient acclimatization period;
- shortening exposure time and increasing the frequency of rest breaks as the risk of heat stress escalates
- providing cool (air-conditioned) rest areas and cool drinking water
- shifting work schedules and allowing workers to set their own pace where practical
- providing training and implementing heat stress safety measures are necessary for a safe working environment.
For more information about heat stress training, see the Heat Stress Awareness options offered by EMC.