Heat Stress
• International Paper
– Cedar River Mill
– Curt Krambeer, Process Team Member
– Leon Hospodarsky, Manufacturing Support
Team Member
What is Heat Stress
• Heat stress is defined as a condition in
which the total net heat load on your body
from internal heat production and external
sources exceeds your body’s capacity to
cool itself.
Why worry about Heat Stress
• A report from the U.S. Department of
Commerce, states that a conservative
estimate of the number of workers in
industries where heat stress is a potential
safety and health hazard would be 5 to 10
million workers.
• The CDC reported that during the 19992003 period a total of 3442 deaths
resulted from exposure to extreme heat.
Levels of Heat Stress
• Mild or moderate heat stress may be uncomfortable and
may affect performance and safety, but it is not usually
harmful to your health. When heat stress is more
extreme, the possible health effects or heat-related
illnesses include:
– Heat edema: swelling.
– Heat rashes: tiny red spots on the skin, which cause a
prickling sensation.
– Heat cramps: sharp pains in the muscles.
– Heat exhaustion: excessive loss of water and salt.
– Heat syncope: fainting.
– Heat stroke: the most serious level of heat stress.
Heat Exhaustion vs. Heat Stroke
• Heat Exhaustion: is caused by excessive loss of water and salt.
Symptoms include:
– Heavy sweating (Eventually sweating may stop)
– Weakness
– Dizziness
– Nausea
– Headache
– Muscle cramps
• Heat Stroke: (elevated body temperature) is the most serious type
of heat illness – life threatening and requires immediate medical
attention. It is the worsening of all the heat exhaustion symptoms
plus:
– Elevated body temperature greater than 41°C (106°F).
– Complete or partial loss of consciousness.
Personal Factors
• Tolerance to heat stress will vary from
person to person (think: age, gender, body
mass, medical conditions).
• An individual’s tolerance to heat will vary
from day to day (think: food and liquid
intake, sleep, clothing, drug/alcohol use).
• At a minimum, heat stress will generally
decrease an employee’s judgment and
workmanship.
Other Factors Affecting Heat Stress
• Air Temperatures
– What can be measured by a thermometer.
• Other sources of heat
– Direct sunlight, machinery that generates heat.
• Relative Humidity
– Moisture in the air. The more moisture in the air the less your
body is able to sweat and cool itself.
• Moving air (speed) usually cools a person.
– Moving air will cool a person as long as the air moving is cooler
than the person. (less than 37°C (98.6°F)
• Physical Exertion
– Moving around or working generates heat.
The Body’s Response to Heat
• Body works best when it has an internal
“core” temperature of 37°C (98.6°F).
• During regular day, your body may vary by
about 1°C (2°F).
• When you work in extreme hot
temperatures, your body has to adapt.
– Sweat – evaporating sweat cools the body
– Increase blood flow to the skin – (radiate
away excess heat)
Acclimatization
• People can adapt to hotter temperatures through a
process called “acclimatization.” Acclimatization allows
you to work more safely and efficiently. However,
becoming acclimated takes time. (4 to 7 working days)
• Your body will learn to adapt, sweat more, conserve
body salt, and reduce cardiovascular stress.
• Work schedules should consider acclimatization needs.
Developing a Heat Stress
Program
• Prevention is your best defense against
heat stress.
• Planning should include an analysis of
work environments and job duties.
• Identify methods to limit employees’
exposure to heat.
• Education and training of employees.
• Evaluate effectiveness of program.
Analysis
• Various ways to measure heat.
– Thermometer: Air temperature
– Heat Index: Temperature + Humidity
– WBGT (Wet Bulb Globe Temperature) Index
WBGT
• Our Heat Stress Team chose to work with
the WBGT (Wet Bulb Globe Temperature)
– This device monitors a dry bulb sensor that
measures ambient temperature; a wet bulb
sensor takes into account evaporative
cooling, giving an indication of the effects of
humidity on an individual; and a globe sensor
provides an indication of the radiant heat
exposure on an individual due to either direct
light or hot objects in an environment.
WBGT continued
• The team performed studies in each mill during
the summer of 2008, gathering information to
determine potentially hot locations.
• In addition, the team worked with maintenance
personnel to study the affects of moving and
cooling the air for scheduled jobs.
• Data from the studies along with feedback from
those working on the jobs was collected.
What did we determine?
• There are definite hot spots in the mill
regardless of the time of year.
• Both maintenance and process have jobs that
are more susceptible to heat stress regardless of
the time of the year.
Red Zones
• A “Red Zone” was defined as having the capability of being a
hot area regardless of the time of year. Those areas marked
were:
•
•
•
•
•
•
•
#1 PM
Pulpers – Op. Floor
Saveall
Dryer section (All)
All of OCC Mezzanine from
North Hatchway North.
Top side of Machine
#2 PM
Pulpers – Op. Floor
Saveall
Dryer section (All)
All of OCC Mezzanine from
North Hatchway North.
Top side of Machine
Possible Control Methods
• Pre-work planning can decrease the
chance of heat stress.
• Engineering controls (such as AC units).
• By using fans, misters, air horn, etc., we
can control the environment.
• Using cooling PPE can help control body
core temperature.
• Limiting the amount of exposure time will
help.
Decision Tree
Heat Stress Decision Tree
Note: Red Zone defined
as Red Zone regardless of
time of year.
Start
Is Heat Stress Expected?
No
Stop
Yes
Complete JPSA for Heat
Stress Guidelines.
Planned
Complete International
Paper Risk Assessment
Card for Heat Stress
Guidelines.
Is this a planned job or a
day-to-day job?
Heavy
Day-to-day
Stop
Is work to be performed in
a Red Zone?
No
Is work heavy or light?
Yes
Is General Access Allowed?
(or is this a normal work
area?)
No
Light
Yes
Complete International
Paper Risk Assessment
Card for Heat Stress
Guidelines.
No
Can work be completed in
15 minutes or less?
Stop
Yes
Light work may be
performed without
additional heat stress
controls.
Risk Assessment Card
JPSA
Fan Maintenance
• Exhaust and Cooling Fans are critical to
help cool these warm environments
• Team members are responsible to write
work notifications for any permanent fan
that requires attention
• Portable fans should be transported to the
Shop for repair as necessary
• Area Process Owners will maintain fans
PPE Options
•
•
•
•
•
Safety cooling vests
Chill cap
Chill It bandana
Terry cloth tori band
Sponge tori band
Hydration Options
•
•
•
•
•
•
Additional water fountains
Portable water coolers
Extra bottled water when needed
Gatorade stations
Electrolyte packets
Popsicles
Policy Development
• Heat stress policy updated to incorporate
identified process improvements.
• Education and training required for all
employees.
Education
•
•
•
•
Symptoms
Recognition
Treatment
Prevention is the key.
Training
•
•
•
•
New hire orientation training
Yearly refresher training
First responder training
Leadership training
Preventing Heat Stress
• Know signs/symptoms of heat-related illnesses;
monitor yourself and coworkers.
• Block out direct sun or other heat sources.
• Use cooling fans/air-conditioning; rest regularly.
• Drink lots of water; about 1 cup every 15
minutes and electrolyte drinks in moderation.
• Wear lightweight, light colored, loose-fitting
clothes.
• Avoid alcohol, caffeinated drinks, or heavy
meals.
Scenario – OCC Sump Pump Belt
Replacement (in July)
•
•
•
•
Review Heat Stress Decision Tree
Unplanned job in non - Red Zone
Complete JPSA or Risk Assessment Card
Per the JPSA or Risk Assessment Card
consider whether any Heat Stress controls
or PPE are necessary
• Stay hydrated!
Scenario – Removing Dryer
Section Pileup (in August)
•
•
•
•
Review Heat Stress Decision Tree
Unplanned job in Red Zone
Complete Risk Assessment Card
Per the Risk Assessment Card use
appropriate Engineering Controls and PPE
for Heat Stress
• Examples of PPE include cooling vests
• Stay hydrated!
TIP!
• Intense thirst is not a good warning sign of
heat stress, an unacclimatized worker may
not experience thirst.
• If you experience thirst you are already
becoming dehydrated!
• Prevention is your best defense against
heat stress.