Employees who feel uncomfortably hot or cold are more likely to behave unsafely. Their ability to make decisions and/or perform manual tasks deteriorates. For example:
- They may take shortcuts to get out of cold environments.
- They might not wear personal protective equipment (PPE) properly in hot environments, which increases the risks.
- A worker’s ability to concentrate may start to decrease, which increases the risk of them making errors.
Employers should be aware of these risks and make sure the underlying reasons for these unsafe behaviours are understood and actively discouraged and prevented.
Thermal discomfort can seriously impact a worker’s overall morale and work performance. Prolonged exposure can lead to fatigue, lowered concentration and productivity. In addition, worker complaints and absenteeism can increase.
Feeling hot or cold depends on:
- Air temperature.
- Relative humidity of the air.
- Presence of hot or cold objects in the surrounding area.
- Presence of air movement (breeze, ventilation).
- Physical exertion.
- Clothing.
Various methods of measuring occupational heat exposure combine these environmental factors to obtain a single number as a measure of overall heat load. The most used measure in the workplace is the wet bulb globe temperature (WBGT) index.
Heat stress can lead to dehydration, heat rash, increased in blood pressure, fainting or exhaustion and heat stroke. In severe cases, there is also a risk of loss of life.
Some workers regularly deal with warm temperatures because of their working environments, such as boiler rooms, foundries, smelting operations, bakeries and catering kitchens. Some workers may be at risk of heat stress due to working in small spaces or wearing protective equipment.
The following temperature ranges should provide thermal comfort for most people in an indoor environment.*
| Summer | Winter | |
| Sedentary work | 19-24°C | 18-22°C |
| Physical work | 16-21°C | 16-19°C |
*These values assume:
- Workers are wearing seasonally appropriate clothing.
- The air speed is about 0.1–0.2 metres per second (without creating a draught where sedentary work is carried out).
- Humidity levels are normal (40-70%).
- Workers are not directly exposed to any radiant heat sources.
To avoid heat stress and ill-health effects, workplace exposure assessments need to be carried out.
Thermal comfort in the workplace in South Africa is governed by the Machinery and Occupational Safety Act, 1983 (Act 6 of 1983), updated on 7 March 2003.
A lighting assessment is a careful examination of the lighting conditions in a work environment. It aims to:
- Identify potential hazards due to the current lighting conditions, such as insufficient illumination, excessive contrast glare or flicker.
- Decide which employees are affected by these issues.
- Evaluate the risks and decide whether improvement measures are required to protect employees.
During a thermal assessment, assigned certified specialists from Strat Environment will come and assess your workplace environment. At this point, the specialist will highlight problems that could be preventing the capabilities of your employees, and describe how to properly fix them.
Learn more about some general thermal problems you can fix, by signing up for an official assessment from Strat Environment.
Sources:
https://www.hse.gov.uk/temperature/thermal/
https://www.ccohs.ca/oshanswers/phys_agents/heat/heat_control.html
http://www.saflii.org/za/legis/consol_reg/erfw428.pdf