Page 207 - Safety Memo

A HEAT STRESS PROGRAM - WHEN TO IMPLEMENT

The incidence of heat stress is the result of a variety of factors. The following guidelines contain some of
the many factors which may require a heat stress program evaluation and/or program implementation:
 Ambient temperature.
 Humidity.

 Type of work required - the metabolic heat generated during heavy, moderate or light work.
 Required work clothing - the potential for heat stress increases as the impermeability of the work
clothing increases.
 Employee symptoms and/or complaints.
 Employee conditioning and/or acclimatization.

 Whenever it has been determined that a heat stress environment exists, then heat stress preventive
measures must be implemented. If the heat stress preventive measures are not successful, then
worker monitoring will commence. Worker monitoring will reduce heat stress related injuries by
adjusting the work/rest regimen to compensate for the hot environment.

HEAT STRESS PREVENTIVE MEASURES
Heat stress is the combination of environmental and physical work factors that constitute the total heat
load imposed on the body. One of the best ways to reduce heat stress on workers is to minimize the
amount of heat in the workplace. However, there are some work environments where heat production is
difficult to control, such as steam lines that cannot be shut down, high temperature or humidity work
sites, and radiant heat from the sun or a furnace. However, most heat related health problems can be
prevented or the risk of developing them reduced.

When unacceptable levels of heat stress occur, there are generally only six approaches to a solution:
 Modify the environment;
 Modify the clothing or equipment;

 Modify the work practices;
 Modify the worker by heat acclimatization;
 Modify production with a work/rest regimen; and

 Enhance the worker's knowledge of working in a hot environment.

Engineering Controls

A variety of engineering controls, including ventilation and spot cooling by local exhaust ventilation
at points of high heat production, may be helpful. Shielding may be required as protection from
radiant heat sources. Evaporative cooling and mechanical refrigeration are other ways to reduce heat
by engineering controls. The use of extra Air Filtration Devices (AFD) can be added to increase the
turnover rate of interior air and heat. Takeoff points at the top of the enclosure will also help in
removing heat. Cooling fans can also reduce heat in hot conditions. Shutting down hot steam lines or
eliminating steam leaks will also help, as will equipment modifications, such as the use of mechanical
equipment to reduce manual labor.

4 | P a g e