Module 1: Occupational Hygiene - Section 5: Instrumentation

OH5.11: Evaluation of Heat Stress - Preventing Heat Disorder

Preventing heat disorders:

The risk of heat-related illnesses can be reduced by:

• Engineering controls to provide a cooler environment;
• Safe work practices to reduce worker exposure; and
• Training employees to recognise and prevent heat-related illnesses.

Engineering controls:

• Ventilation and air conditioning are commonly used to provide cool workstations;
• Introduce evaporative or mechanical cooling;
• Optimise air velocity near workers by strategically locating air supply and extractor fans;
• Use of shielding to stop radiated heat from reaching workstation;
• Reduce humidity by eliminating hot water baths, drains, and leaky steam valves;
• Isolate, relocate or redesign hot processes;
• Use work saving devices (automation or mechanisation) to reduce metabolic heat production.

Administrative control:

• Schedule heavy work during cool parts of the day;
• Spread job across more workers;
• Train workers to recognise signs and symptoms of heat disorders (first aid training);
• Provide adequate water supply;
• Acclimatization;
• Work-rest schedules and illness records;
• Assess WBGT at the work site in cases of heat illness.

Personal protective equipment:

• Specifically designed heat-protection clothing is available for working in extremely hot conditions;
• Light clothing allows maximum skin exposure and efficient body cooling through sweat evaporation;
• Work that requires wearing of impermeable clothing presents an added heat burden as clothing reduces the body's ability to dissipate heat.