Wearing heavy duty industrial clothing and personal protective equipment (PPE) increases heat stress in workers by trapping air against the skin, increasing its humidity and reducing evaporation.
The effects of heat stress on workers can include reduced operational capacity and cognitive function, leading to increased safety dangers.
However the solution is not to stop wearing PPE or protective clothing – which could be far more dangerous – but rather to implement effective workplace cooling strategies.
Why heat stress is increased
Industrial and blue collar workers are often required to wear full-body clothing as well as personal protection equipment (PPE) such as safety gloves, glasses and breathing masks.
2014 research into the physiological impact of wearing military clothing suggests that wearing PPE and heavy duty clothing increases heat stress on the human body.
The study, titled “Military Clothing and Protective Material: Protection at the Limits of Physiological Regulation,” discusses the ways in which PPE and clothing can increase heat stress.
One of these ways is by trapping air between the clothing and skin. PPE and industrial clothing is often thick and heavy and typically covers the entire body, leaving air little room to escape and for cool air to move into.
As the study states: “When more completely clothed …air becomes trapped and it increases in thickness, forming an insulated microclimate above the skin.”
This means the trapped air becomes hotter and also becomes more humid, impeding the evaporation of moisture and exacerbating heat stress.
“This obstructs, and eventually prevents, evaporative heat loss,” the study says.
Furthermore, sweat produced by the body to facilitate that evaporative cooling is absorbed by the PPE or clothing material which the study says results in less effective cooling than evaporation of sweat from the skin.
The result is an increase in deep body temperature, heart rate and skin temperature, while operational capacity is reduced.
Impacts of heat stress
The resulting heat stress can lead to physical discomfort and dangerous physical illnesses such as heat exhaustion and heat stroke.
Cognitive function and productivity is also impaired. When workers become too hot, they may become irritable, have a reduced attention span and diminished work capacity.
Should PPE removed?
Although PPE and industrial clothing increases heat stress risks, they are also a critical last line of defence against safety hazards and it is vital workers wear them, even in the heat.
While heat stress might be unpleasant, the consequences of working without safety gear could be far worse.
Instead, employers can help mitigate the effects of heat on workers by emphasising hydration and providing a range of heat stress management training and procedures, outlined below and in more detail here.
- Work Rate
- Heat acclimatisation and fitness
- Ice Ingestion
- Cooling apparel
- Environmental Monitoring
- Heat Stress Management Policy