northeastern part of the United States we typically encounter hot temperatures between the months of June and September. On some
days outside temperatures can approach 100.0 Fahrenheit (F). On
days in which the relative humidity is high the outside environment can
be an undesirable place to be. If your job entails vigorous
activity in a hot climate, heat stress can be a major occupational
the human body is pretty efficient at keeping our body temperatures
constant. In order to maintain our body temperatures at a
constant temperature, the body must release the heat. This is
carried out through blood circulation and sweating. Once your body
temperature reaches 98.6F, your heart begins to pump more blood through
the circulatory system. Blood vessels expand and allow more blood
flow to the skin surface where the excess heat can be released through
process is not enough to cool the body, your brain tells your sweat
glands in the skin to release large quantities of sweat onto the skin
surface. As the sweat evaporates it cools the skin by eliminating
heat from the body. In environments with high humidities this
process is hindered because the evaporative process is decreased and it
is harder for the body to cool itself.
resulting from this situation can range from being uncomfortable to
death. With so much blood being pumped to the skin it is hard for
the body to maintain its normal functions. Increased body temperature
and physical discomfort promote irritability, anger, and other
emotional states, that can cause workers to bypass safety procedures or
to lose concentration while performing hazardous job functions.
many occupations that require workers to be in hot and humid
environments. Outdoor jobs may include; construction, roofing,
groundskeeping, or farming. Hot indoor occupations can include;
bakery and restaurant kitchen workers, brick firing and ceramic
processes, foundries, mines, boiler rooms, laundries, and glass
manufacturing to name a few.
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following is a description of the potential harmful effects of heat
(listed from the most dangerous to the least) courtesy of the
Occupational Safety and Health Administration (OSHA)
Heat stroke occurs when the body's system of
temperature regulation fails and body temperature rises to critical
levels. This condition is caused by a combination of highly variable
factors, and its occurrence is difficult to predict. Heat stroke is a
medical emergency. The primary signs and symptoms of heat stroke are
confusion; irrational behavior; loss of consciousness; convulsions; a
lack of sweating (usually); hot, dry skin; and an abnormally high body
temperature, e.g., a rectal temperature of 41°C (105.8°F). If
body temperature is too high, it causes death. The elevated metabolic
temperatures caused by a combination of workload and environmental heat
load, both of which contribute to heat stroke, are also highly variable
and difficult to predict.
shows signs of possible heat stroke, professional medical treatment
should be obtained immediately. The worker should be placed in a shady
area and the outer clothing should be removed. The worker's skin should
be wetted and air movement around the worker should be increased to
improve evaporative cooling until professional methods of cooling are
initiated and the seriousness of the condition can be assessed. Fluids
should be replaced as soon as possible. The medical outcome of an
episode of heat stroke depends on the victim's physical fitness and the
timing and effectiveness of first aid treatment.
campus employees should call x99 (on campus) or 212)854-5555 (off campus)
immediately if he/she suspects that an employee is experiencing heat
of the worker's protests, no employee suspected of being ill from heat
stroke should be sent home or left unattended unless a physician has
specifically approved such an order.
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Exhaustion - The signs and
symptoms of heat exhaustion are headache, nausea, vertigo, weakness,
thirst, and giddiness. Fortunately, this condition responds readily to
prompt treatment. Heat exhaustion should not be dismissed lightly,
however, for several reasons. One is that the fainting associated with
heat exhaustion can be dangerous because the victim may be operating
machinery or controlling an operation that should not be left
unattended; moreover, the victim may be injured when he or she faints.
Also, the signs and symptoms seen in heat exhaustion are similar to
those of heat stroke, a medical emergency.
suffering from heat exhaustion should be removed from the hot
environment and given fluid replacement. They should also be encouraged
to get adequate rest.
Heat Cramps are usually caused by
performing hard physical labor in a hot environment. These cramps have
been attributed to an electrolyte imbalance caused by sweating. It is
important to understand that cramps can be caused by both too much and
too little salt. Cramps appear to be caused by the lack of water
replenishment. Because sweat is a hypotonic solution (±0.3%
NaCl), excess salt can build up in the body if the water lost through
sweating is not replaced. Thirst cannot be relied on as a guide to the
need for water; instead, water must be taken every 15 to 20 minutes in
extreme conditions, such as working for 6 to 8 hours in heavy
protective gear, a loss of sodium may occur. Recent studies have shown
that drinking commercially available carbohydrate-electrolyte
replacement liquids is effective in minimizing physiological
disturbances during recovery.
Collapse ("Fainting"). In heat
collapse, the brain does not receive enough oxygen because blood pools
in the extremities. As a result, the exposed individual may lose
consciousness. This reaction is similar to that of heat exhaustion and
does not affect the body's heat balance. However, the onset of heat
collapse is rapid and unpredictable.
heat collapse, the worker should gradually become acclimatized to the
Heat Rashes are the most common problem
in hot work environments. Prickly heat is manifested as red papules and
usually appears in areas where the clothing is restrictive.
increases, these papules give rise to a prickling sensation. Prickly
heat occurs in skin that is persistently wetted by unevaporated sweat,
and heat rash papules may become infected if they are not treated. In
most cases, heat rashes will disappear when the affected individual
returns to a cool environment.
Heat Fatigue - A factor that predisposes
an individual to heat fatigue is lack of acclimatization. The use of a
program of acclimatization and training for work in hot environments is
advisable. The signs and symptoms of heat fatigue include impaired
performance of skilled sensorimotor, mental, or vigilance jobs. There
is no treatment for heat fatigue except to remove the heat stress
before a more serious heat-related condition develops.
What can we do to stay cool?
of the National Institute of Occupational Safety and Health NIOSH.
best ways to reduce heat stress is to minimize heat in the workplace.
However, there are some work environments where heat production is
difficult to control, such as when furnaces or sources of steam or
water are present in the work area or when the workplace itself is
outdoors and exposed to varying warm weather conditions.
to a large extent, capable of adjusting to the heat. This adjustment to
heat, under normal circumstances, usually takes about 5 to 7 days,
during which time the body will undergo a series of changes that will
make continued exposure to heat more endurable.
day of work in a hot environment, the body temperature, pulse rate, and
general discomfort will be higher. With each succeeding daily exposure,
all of these responses will gradually decrease, while the sweat rate
will increase. When the body becomes acclimated to the heat, the worker
will find it possible to perform work with less strain and distress.
exposure to heat gives the body time to become accustomed to higher
environmental temperatures. Heat disorders in general are more likely
to occur among workers who have not been given time to adjust to
working in the heat or among workers who have been away from hot
environments and who have gotten accustomed to lower temperatures. Hot
weather conditions of the summer are likely to affect the worker who is
not acclimatized to heat. Likewise, workers who return to work after a
leisurely vacation or extended illness may be affected by the heat in
the work environment. Whenever such circumstances occur, the worker
should be gradually reacclimatized to the hot environment.
course of a day's work in the heat, a worker may produce as much as 2
to 3 gallons of sweat. Because so many heat disorders involve excessive
dehydration of the body, it is essential that water intake during the
workday be about equal to the amount of sweat produced. Most workers
exposed to hot conditions drink less fluids than needed because of an
insufficient thirst drive. A worker, therefore, should not depend on
thirst to signal when and how much to drink. Instead, the worker should
drink 5 to 7 ounces of fluids every 15 to 20 minutes to replenish the
necessary fluids in the body. There is no optimum temperature of
drinking water, but most people tend not to drink warm or very cold
fluids as readily as they will cool ones.
temperature of the water, it must be palatable and readily available to
the worker. Individual drinking cups should be provided--never use a
common drinking cup.
acclimatized workers lose much less salt in their sweat than do workers
who are not adjusted to the heat. The average American diet contains
sufficient salt for acclimatized workers even when sweat production is
high. If, for some reason, salt replacement is required, the best way
to compensate for the loss is to add a little extra salt to the food.
Salt tablets should not be used.
Tips for staying cool when working on hot days
lot of cool water all day, before you feel thirsty. Every 15 minutes,
you may need a cup of water (5 to 7 ounces).
rest breaks. Rest in a cool, shady spot. Use fans.
light-colored clothing, made of cotton.
work in hot areas, take turns with other workers, so some can rest.
travel to a warm area for a new job, you need time for your body to get
used to the heat. Be extra careful the first 2 weeks on the job.
in protective clothing, you need more rest breaks. You may also need to
check your temperature and heart rate.
University policy for hot working conditions
from time to time, the air-conditioning units servicing the Morningside
Campus buildings breakdown. For employees who work indoors, this
situation can be an uncomfortable experience. If the air
conditioning unit in your work area is not functioning properly, your
Area Manager should be notified. Your supervisor can contact your
building area manager and place a request to the University's HVAC shop
to make the necessary repairs to your unit.
HVAC system is being repaired supervisors should allow employees to
take breaks in cool areas. In addition, there should be an
adequate supply of drinking water available.
EH&RS office possesses instrumentation that can measure ambient
temperatures, relative humidity, and heat stress. Work/rest regimens
can be provided to employees who must work outdoors on hot days (ex.
grounds staff), in hot indoor environments (ex. boiler room mechanics),
or in protective clothing. The EH&S office utilizes the
guidelines set forth by the American Society of Heating, Refrigerating,
and Air-Conditioning Engineers, Inc. (ASHRAE) and the American
Conference of Governmental Industrial Hygienists (ACGIH) when assessing
the conditions associated with working in environments with elevated
temperatures and relative humidities.
recommends that indoor office temperatures during the summer months
should be between 73F to 79F with a relative humidity between 40 to 60
percent. If indoor temperatures and/or relative humidities rise above
these recommended ranges, your supervisor should notify your area
manager who can arrange for an investigation into the situation.
a job that requires you to work in a hot environment, and you have
questions regarding heat stress, please contact the EH&S office.
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