Heat Stress
INTRODUCTION
Many Orange County employees are exposed
to hot environments when they perform their
everyday jobs and recreational activities. Hot
environments cannot only make the worker
uncomfortable, but they can also lead to heat
related injuries and illnesses. The following is
a list of occupations and activities that have the
potential to expose individuals to heat stress:
* Outdoor work, including construction,
roadwork, part maintenance, etc.
* Heavy maintenance
* Welding operations
* Working in confined spaces
* Bakeries or restaurant kitchens
* Workers in boiler rooms
* Laundries
* Recreation complexes
The following equation is frequently used to
determine if heat stress could be a hazard:
H=M+R+C-E
H = Heat Storage, gain or loss
M = Metabolic heat gain
R = Radiant heat gain or loss
C = Convection heat gain or loss
E = Evaporative heat loss
When the body is exposed to extreme
temperatures, it responds to the environment by
attempting to regulate itself. When the body’s
temperature starts to rise, blood vessels near the
skin surface expand. This expansion, known as
vasodilatation, allows the body to release heat
through the surface of the skin.
It is the duty of Orange County managers/
supervisors to ensure that their workplace is
safe as possible. In order to prevent heatrelated illnesses from occurring in the
workplace, managers/ supervisors shall first,
anticipate situations that could lead to heat
stress, and second, educate their employees on
the hazards of hot environments and preventive
measures for heat stress. Before implementing
a heat stress prevention plan in the workplace,
it is necessary to understand how the body
handles heat and the consequences of heat
exposure.
If this method is not sufficient enough for
regulating body temperature, the body’s next
response is sweating. When the body sweats, it is
not the sweat that cools the body off; rather it is
evaporation of sweat into the air that cools the
body. In some situations sweating may not
always cool the body. In conditions where there
is high humidity, the air contains too much water
to absorb sweat; this sweat stays on the body.
One should be aware of humidity conditions when
working in a hot environment and take extra
precautions to reduce heat stress when humidity is
high. To further understand the relationship
between temperature and humidity, a heat stress
index chart is contained in Appendix A.
How the Body Handles Heat
Health and Safety Problems
The human body must maintain a temperature
of around 98.6F in order to function properly.
Body temperature is maintained by balancing
net heat produced by the body and the heat
exchanged with the environment. The body
produces heat by metabolism and loses heat by
radiation,
convection,
conduction,
or
evaporation. However, the body may also gain
heat by radiation, convection or conduction.
When the body’s cooling system is not effective,
the increase in body temperatures can cause a
variety of disorders that range from non-serious to
extremely serious. Even minor heat related
disorders can increase to rate of accidents in the
workplace. Slipperiness of hands, dizziness,
fatigue, irrational reasoning, and fogging of safety
glasses are some results due to a hot environment.
Safety and Health Manual
Effective Date:
Revised Date:
September 19, 1997
December 16, 2016
Exhibit K
Page 1
Gently massaging the affected muscles may
relieve pain and cramps.
Sunburn
Symptoms:
Red, painful, swollen skin.
Blistering and peeling of skin if severe. Chills
and fever can occur.
Risk Associated: Skin cancer, decreased ability
of body to release heat.
Treatment: Apply cold compresses and skin
lotions or bathe is cool water. Consume fluids.
Heat Rash/Prickly Heat
Symptoms: Itchy red skin rash. Likely to occur
in humid environments, where sweat does not
readily evaporate.
Sweat glands become
plugged causing rash.
Risk Associated:
Heat rash can be
uncomfortable, which decreases worker(s)
performance.
Treatment: Ointment designed to treat heat
rash. Bathe regularly. Keep skin dry.
Heat Exhaustion
Symptoms:
Extreme weakness or fatigue,
dizziness, intense thirst, cool clammy skin,
giddiness, weak rapid pulse, nausea, or headache,
complexion may be flushed or pale, and/or body
temperature may be slightly elevated. Victim
may vomit or lose consciousness in more severe
cases.
Risk Associated: Increased injury due to fatigue,
victim has high risk to continue on to a state of
heat stroke.
Treatment: Have victim rest in a cool place and
drink plenty of fluids. Call for medical help.
Apply cool, damp cloth to body, usually a water
dampened towel works best. Do not leave victim
unattended until help arrives.
Heat Stroke
Heat Syncope (Fainting)
Symptoms: Victim faints as a result of blood
pooling to other parts of the body to control
temperature. Usually occurs in victims who
are not acclimatized to hot environments.
Risk Associated: Injuries from falling while
fainting.
Treatment: Upon lying down, victim usually
recovers. Victim should lie in a cool place,
consume a cool fluid, and a physician should
be consulted. Do not give victim water if they
are unconscious.
Heat Cramps
Symptoms: Sudden painful muscle spasms that
occur when individuals sweat profusely and do
not adequately replace the body’s salt loss.
Risk Associated: Fall-related injuries. Workers
at elevated levels are especially susceptible to
falling.
Treatment: Move victim to shade, loosen
clothing give victim lightly salted liquids.
Symptoms: A body temperature of 105o F or
higher, dry hot flushed skin, rapid pulse,
unconsciousness, lack of perspiration, mental
confusion, nausea, vomiting, difficulty breathing,
headache or dizziness. Advanced Symptoms:
convulsions, collapse, loss of consciousness, no
detectable pulse.
Risk Associated: Can be fatal if victim is not
treated promptly.
Treatment:
Immediate cooling is necessary.
Immerse victim in water, massage body with ice,
call ambulance.
** To prevent any of these conditions from
getting worse, recognition of symptoms and early
treatment are the key factors to alleviating these
illnesses.
Factors Affecting Heat Stress
The following are a list of factors that may
decrease the ability of the body to withstand hot
environments:
Safety and Health Manual
Effective Date:
Revised Date:
September 19, 1997
December 16, 2016
Exhibit K
Page 2
♦ Loss of sleep
♦ Consumption of alcohol with in the past 24
hours. Alcohol is a known diuretic (causes
dehydration)
♦ Dehydration
♦ Diarrhea and anti-diarriahal medications
♦ Exposure to high temperatures at night
♦ Lack of acclimatization
♦ Older age (over 40)
♦ Medications to inhibit sweating, such as
antihistamines, cold medicine
♦ Improper clothing, too heavy, too tight
♦ Poor physical conditioning
♦ Obesity
♦ Improper work procedures
♦ Previous occurrences of heat stroke
Prevention of Heat Stress
Managers/supervisors and employees shall
implement the following ideas of this section in
order to reduce the chance of their employees
from suffering heat-related disorders.
There are many types of preventive measures
that Orange County employees and employers
shall tame to eliminate the incidence of heatrelated illness.
Managers/Supervisors:
To reduce heat stress on workers,
managers/supervisors
shall
consider
implementing these following measures:
1. Supply potable water from a sanitary
dispensing system. Water supply should be
adequate enough to provide 1.5 gallons per
person per day. Drinking water must be
readily available for all workers.
2. For indoor environments, ventilation, (a
portable fan or cross ventilation) may be
necessary. Other indoor environments may
require air conditioning.
3. Outdoor working environments are harder to
control. If possible, rotate light and hard work
tasks among employees.
4. Assess the physical capability of all employees
before placing them in a hot environment. It
has been proven that heat acclimatized
employees are better able to handle hot
environments. Acclimatization usually takes
about 7 days.
It is done by gradually
increasing exposure of the worker to a hot
environment.
5. Train employees on the dangers of extreme
environments, symptoms, and treatment for
heat-related illnesses.
6. Allow employees to take frequent work/rest
cycles. Work/rest cycles do not necessarily
mean breaks, but rather a light duty task out of
the sun.
7. If possible, managers/supervisors are to have
employees perform the most stressful tasks
during cooler parts of the day, early morning or
at night.
8. Never allow a worker, who is suffering from
any form of heat stress to leave work alone,
unless a physician approves.
9. Have employees
System.”
implement
the
“Buddy
The Buddy System
1. Never allow an employee to work alone in a
hot environment.
2. Know the signs of heat stress and teach your
workers to recognize heat stress too.
3. Teach employees who work together to be on
the look out for telltale signs of heat stress in
their coworkers.
Safety and Health Manual
Effective Date:
Revised Date:
September 19, 1997
December 16, 2016
Exhibit K
Page 3
Employees
Employees also have the duty and
responsibility to prevent heat-related injuries in
the workplace. Employees are required to
follow these items:
Take immediate action if it’s hot and you feel
weak, dizzy, sweaty, or nauseous. Pay attention
to cramps and to anyone who tells you that you
look pale. Don’t let heat illness progress too far!
1. Know when to know when to stop. Take a
break when feeling too hot/tired. Over
exertion can quickly lead to a heat-related
illness in a hot environment.
2. Avoid eating heavy meals before and during
work shifts. Digesting heavy meals reduces
the efficiency of the body’s cooling systems.
3. Consume 5 to 7 ounces of water every 20
minutes, when working in a hot
environments, even if not thirsty. (Thirst is
not a reliable indicator for dehydration.)
4. Avoid the use of drugs and consumption of
alcoholic beverages and caffeine during
prolonged periods of heat. Employees are to
inform their managers/ supervisors if they
are taking any type of medication with side
effects that may increase the chance(s) of
suffering from a heat related illness.
5. Learn and retain information that the
manager/ supervisor provides on heat stress.
Employees must learn to recognize
symptoms of heat stress either on
themselves or other co-workers.
1.
2.
3.
4.
5.
6.
7.
8.
9.
Symptoms to look for:
Abnormal behavior
Pale and dry skin (not always)
Seizures
Excessive sweating or cessation of sweating
(not always)
Chest pain
Dizziness, headaches
Nausea
Cramps
Loss of consciousness
Safety and Health Manual
Effective Date:
Revised Date:
September 19, 1997
December 16, 2016
Exhibit K
Page 4
APPENDIX A
HEAT INDEX CHART
ACTUAL TEMPERATURE (F)
75
Relative
Humidity
0%
69
80
85
90
95
100
105
110
115
120
125
73
78
83
87
91
95
99
103
107
111
10%
70
75
80
85
90
95
100
105
111
116
128
20%
72
77
82
87
93
99
105
112
120
130
145
30%
73
78
84
90
96
104
113
123
135
148
40%
74
79
86
93
101
110
123
137
151
50%
75
81
88
96
107
120
135
150
60%
76
82
90
100
114
132
149
70%
77
85
93
106
124
144
80%
78
86
97
113
136
90%
79
88
102
122
138
100%
80
91
108
136
•
NOTE: Exposure to full sunlight increases the numbers by 5%.
90 – 104 Heat related illness possible
105-131
Heat related illness probable
Heat stroke possible
>130 Heat stroke probable
Section 7
Safety and Health Manual
Effective Date:
Revised Date:
September 19, 1997
December 16, 2016
Exhibit K
Page 5