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Heat Hazard Assessment
potential for an employee who works in a hot environment to be affected
by heat stress depends on heat combined with physical labor, loss
of fluids and fatigue, in addition to the factors listed below.
An assessment of each job with these factors can assist in developing
a strategy to prevent heat related problems.
temperature and humidity levels must be taken into consideration
when assessing the potential for heat stress hazards. There are
several different ways to evaluate heat index based on temperature
and relative humidity. EHS has purchased a Wet Bulb Globe
Temperature (WBGT) index direct read out insturment. This temperature
accounts for the effects of ambient temperature, humidity and radiant
heat, and is an accepted measure of heat stress on an individual
in the monitored environement. EHS is compling data of WBGT
for commonly preformed hot jobs on campus, and will provide heat
stress monitoring as needed.
commonly used "quick and easy" approach to determining
heat stress index was developed by the National Weather Service
and is known as the "General Heat Stress Index". A copy
of this index is provided in Appendix B. This index can be used
to determine danger levels based on temperature and humidity.
ACGIH has established various Threshold Limit Values (TLVs) for
hot environments, as expressed in WBGT. A TLV is an average level
for an eight-hour work day and a 40-hour work week, to which it
is believed that nearly all workers may be repeatedly exposed, day
after day, without adverse effect (See Appendix C). These TLVs are
valid for workers dressed in light summer clothing only. Extra caution
must be exercised in establishing work practices for employees wearing
personal protective equipment (PPE) that poses as a barrier to heat
loss. (See Appendix C, table C2)
rate at which an employee works and the activities being performed
will have a direct effect on their potential to experience heat
stress. This work rate must be taken into consideration when establishing
safe work practices for employees working in hot environments. See
Appendix D for guidance in determining an employee's work rate based
on the activities they perform.
of Heat Sources
employee who works in an environment which is generally cool, but
in close proximity to hot objects may be at risk for heat stress.
Sources of heat must be identified and their location in relation
to the employee considered when assessing potential for heat stress.
Risk Factors for Heat Stress
factors can put employees at greater risk for heat stress. Employees
will be made aware of these risk factors, and given the opportunity
for medical consolation if those risk factors apply to them. Training
will consist of a video and review of this written program.
Barriers to Heat Loss
caution must be exercised in establishing work practices for employees
wearing personal protective equipment (PPE) that poses as a barrier
to heat loss. This equipment could include coveralls, gloves and
respirators, and chemical protective clothing. Guidelines for work-rest
regimens for employees wearing PPE is provided in Appendix E.
Heat Stress Manual Table of Contents