3.14 – Heat & Cold Stress
How workers are exposed
There are three main causes of heat stress. They are:
|Environment||Radiant heat from direct or indirect sunlight (reflection from pavement or kilns)
Air temperature hotter than skin temperature (warms a worker up)
High humidity (makes it harder for a worker to cool down)
|Work||The more active you are, the more heat you will produce|
|Worker||Conditioning (regular work in hot environments makes workers less prone to heat stress)
Poor health, including obesity, advanced age, and medical conditions (the body responds poorly to overheating)
Not staying hydrated
Excess clothing or inappropriate personal protective equipment (they trap heat and prevent cooling)
The dangers to workers
As a worker’s body heats up it loses fluids and salt through sweat. As workers dehydrate they are less able to cool themselves down. Workers in a hot environment should be aware of these warning signs of heat stress:
- Excessive sweating
If heat stress is not recognized and treated early, it can lead to heat disorders, which have serious effects on the body. These include:
|Heat cramps||Painful muscle cramps
Can lead to heat exhaustion if left untreated
|Heat exhaustion||Shallow breathing
Increased heart rate
Weak, rapid pulse
Cool, pale, clammy skin
Weakness, fatigue, dizziness
Headache and nausea
Can lead to heat stroke if left untreated
|Heat stroke||Hot, dry, flushed skin
No longer sweating
Agitation and confusion
Decreased level of consciousness and awareness
Nausea and vomiting
Increase in breathing rate
How to protect workers
The most effective way to reduce the risk of heat stress is to eliminate the source of exposure. If that’s not possible, there are other risk controls to use. When choosing risk controls, start by asking yourself the questions in the following steps, which are listed in order of effectiveness.
Elimination or substitution
Eliminating the hazard by substituting a safer process or material, where possible, is the most effective control. A question to consider:
- Can the job be done in a cooler environment?
Making physical modifications to facilities, equipment and processes can reduce exposure. Some questions to consider:
- Can ventilation be improved?
- Can hot surfaces be insulated or covered to reduce radiant heat?
- Can shields and barriers be installed to protect workers from heat?
- Can humidity be reduced?
Changing work practices and work policies, awareness tools, and training can limit the risk of heat stress. Some questions to consider:
- Can warning signs be posted in the work area?
- Can cool-down rooms be provided?
- Can workers be acclimated to heat?
- Can water be provided?
Personal protective equipment
This is the least effective control. It must always be used in addition to at least one other control. Some questions to consider:
- Do workers have heat-reflective clothing or water-cooled suits?
- Has personal protective equipment been tested to make sure it is working properly?