As the temperature rises, the safety of workers exposed to extreme heat becomes a major concern. In Belgium, heatwaves have been linked to severe incidents in various sectors, particularly in industries like construction and infrastructure. These incidents often lead to fatigue, dehydration, and even heatstroke.
This article summarizes the key factors influencing workplace conditions during heatwaves in Belgium.
The Impact of Extreme Heat on Work Conditions
Heatwaves and Their Effect on Workers
In Belgium, heatwaves have become more frequent and intense, particularly during the summer months. These extreme conditions significantly impact workers, especially in fields like construction, where workers are often exposed to direct sunlight and extreme temperatures. Prolonged exposure to high heat can lead to:
Fatigue
Dehydration, and
Heatstroke.
These health risks not only reduce worker efficiency but also increase the chances of workplace accidents. Managing heat stress isn’t just about compliance—it’s about creating an environment where workers can do their best without risking their health.
The Role of Employers in Managing Heat Stress
Employers have a duty to act when temperatures reach dangerous levels, and this usually means implementing measures based on the guidance of occupational health professionals. Some of these protective measures include:
Shielding workers from direct radiation,
Ensuring proper ventilation in work areas, and
Providing sufficient breaks to avoid heat-related illnesses.
Understanding the Wet Bulb Globe Temperature (WBGT)
What is the Wet Bulb Globe Temperature?
When discussing heat-related concerns with the HSE officer (Health, Safety, and Environment), it is critical to reference heat measurement using a wet bulb globe thermometer, which is not a standard thermometer. This device considers humidity and thermal radiation, because HSE assessments are based on the WBGT index rather than air temperature. The WBGT index evaluates an individual's ability to work safely in a given environment over an 8-hour period.
How is WBGT Calculated?
To calculate WBGT, we use a combination of temperature readings that change depending on whether or not solar radiation is present. The formula is as follows:
Without solar radiation: WBGT = 0.7 × thn + 0.3 × tg
With solar radiation: WBGT = 0.7 × thn + 0.2 × tg + 0.1 × ta
Where:
thn is the natural wet bulb temperature,
tg is the black globe temperature, which is measured with a thermometer housed in a matte black copper sphere designed to capture radiative heat,
ta is the air temperature.
Humidity also plays a significant role in determining WBGT values. The higher the humidity, the more heat stress is felt by workers, even if the air temperature is the same. For example, at an air temperature of 35°C:
At 35% humidity, the WBGT is 26.8,
At 55% humidity, the WBGT rises to 29.8,
At 80% humidity, the WBGT reaches 32.9.
WBGT can be estimated using specialized websites or tables from the SPF Emploi (Federal Public Service Employment, Labour and Social Dialogue) website. If you’re looking for a more hands-on approach, WBGT measurement devices are available for purchase, even on platforms like Amazon.
Managing Breaks and Workload Based on WBGT
Workload categories based on WBGT help determine when breaks are necessary.
For example, at 60% relative humidity and 30°C (WBGT = 26), breaks are necessary only for heavy or very heavy work. If no prior arrangements are in place, employers can rely on predefined rest-work schedules from standards like NBN EN ISO 7243 or follow physician recommendations.
Light work: Office tasks, driving.
Moderately heavy work: Carpentry, tractor operation.
Heavy work: Digging, sawing, pushing or pulling heavy equipment.
Very heavy work: Excavation, climbing ladders, stair ascent.
Heat Stress Protection and Safety Measures
Protecting workers from heat stress goes beyond just implementing rest periods. Other safety measures include:
Ventilation: Making sure that air circulates properly in work areas to help cool things down.
Hydration: Encouraging workers to drink enough water to stay hydrated.
Cooling measures: Using cooling devices or providing shaded areas for breaks.
These strategies help reduce the risk of heatstroke and other heat-related illnesses.
Ozone Peaks and Their Impact on Outdoor Workers
The Role of Ozone in Heatwaves
Ozone levels tend to rise during heatwaves, which presents an added risk for outdoor workers. Ozone can irritate the respiratory system and worsen heat stress, especially for workers who are already struggling with high temperatures.
Mitigating Ozone Risks
To protect outdoor workers from ozone exposure, employers can:
Plan physical tasks for early mornings, when ozone levels are lower,
Limit overtime, reducing prolonged exposure to ozone,
Ensure regular indoor breaks to minimize exposure.
Temporary Unemployment for Safety
In some cases, the working environment may remain unsafe despite all efforts to mitigate risks. If that happens, employers may have no choice but to place workers on temporary unemployment for their own safety. While this decision can be disruptive, it’s ultimately in the workers' best interests.
Conclusion
As temperatures keep rising, managing heat stress in the workplace becomes even more critical. By understandingnthe WBGT, adjusting workloads, and accounting for factors like ozone, team leaders can help reduce the risk of heat-related illnesses and create safer, more efficient work environments.
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