ahmadvand.org: راهنماي كار در محيط هاي داغ

راهنماي كار در محيط هاي داغ
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مدیرسایت در 2016-01-21

Guideline for work in HOT ENVIRONMENTS

Guideline for work in HOT ENVIRONMENTS0d0a  HOT ENVIRONMENTS AND THE HUMAN
BODY0d0a The human body functions best within a narrow internal  temperature
range of 36 to 38 degrees Celsius. Above or below this  range, the body's
temperature control center in the brain goes to work  and will cause shivering
to keep warm or perspiration to keep cool. As  the surrounding air warms, the
body pumps more blood to the skin and  increases sweat production. In this way
the body loses heat, to balance  the heat gain. When the heat gain becomes more
than the body can lose,  body temperature begins to rise and may lead to a
heat-related illness.0d0a 0d0aSOURCES OF HEAT GAIN AND HEAT
LOSS0d0a  Metabolic heat - the body's own internal heat,  generated by the
breakdown of food to form energy. The greatest energy  users, and therefore
internal heat producers, are muscles. Hard work in a  hot environment
contributes to the body's heat load.0d0a Conduction - the direct transfer of
heat to the body by  direct contact with a warm object. Generally, an almost
insignificant  source of heat when considering heat gain to the
body.0d0a Convection - the exchange of body heat with the  surrounding air that
comes into contact with the skin. If the moving air  is cooler than the body
temperature, it will cool the body; if warmer,  it will increase the heat load.
Air speed is an important factor in heat  loss or gain.0d0a Radiation - the
transfer of heat to the body through  air from a hot source, for example, a
furnace, an oven, or the sun. This  is an important factor as, again, heat is
lost from the body only if  the surrounding air is cooler than the body