Carter & Carter heat stress prevention program involves four elements, which are:
1. Employee training
2. Assessing Job Heat Stress Risks
3. Assessing Employee Heat Stress Risks
4. Heat Stress Controls
1. Employee Training
The most important component of heat stress prevention program is employee training. In addition to reading this program document, employees shall be trained regarding the risks of heat stress and how it is reduced, as well as how to recognize heat illnesses and treat them. Specific components of the training include:
- The hazards of heat stress
- Personal precautions that can be taken to reduce heat stress
- Predisposing factors for, danger signs of, and symptoms of heat stress conditions and illnesses
- Dangers of using drugs, including therapeutic ones, and alcohol in hot work environments
- Awareness of first-aid procedures for, and the potential health effects of, heat stroke in themselves and others,
- Employee responsibilities in avoiding heat stress,
- Typical engineering and administrative controls implemented to reduce heat stress,
- Use of personal protective equipment, and
- Purpose and coverage of environmental and medical surveillance programs and the advantages of worker participation in such programs.
2. Assessing Job Heat Stress Risks
Supervisors are responsible for assessing every job/project to determine if it is likely to pose heat stress risks. Operations involving high air temperatures, radiant heat sources, high humidity, direct physical contact with hot objects, or strenuous physical activities have a high potential for inducing heat stress in employees. Indoor operations such as electrical utilities (particularly boiler or mechanical rooms) are examples of work locations where heat stress risks can exist. Outdoor operations conducted in hot weather, such as trenching, construction, and grounds maintenance/landscaping, and tasks requiring workers to wear semi-permeable or impermeable protective clothing, are also likely to cause heat stress among exposed workers. Supervisors are responsible for ensuring that appropriate heat stress reduction controls are instituted whenever significant heat stress is possible. Employees are empowered to request such controls if heat stress is expected or encountered.
3. Worker Heat Stress Risks
Supervisors are responsible for assessing their employee’s ability to perform jobs that might involve heat stress. Age, weight, degree of physical fitness, degree of acclimatization, metabolism, dehydration, use of alcohol or drugs, and a variety of medical conditions such as hypertension all affect a person’s sensitivity to heat. However, even the type of clothing worn must be considered. Prior heat injury predisposes an individual to additional injury. Individual susceptibility varies. In addition, environmental factors include more than the ambient air temperature. Radiant heat, air movement, conduction, and relative humidity all affect an individual’s response to heat.
Heat stress controls should be modified or the employee reassigned to a job without heat stress for employees identified as at risk for heat conditions or illness.
The 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.
Employee Risk Factors
Factors increasing an employee’s susceptibility to heat stress include:
- Being dehydrated
- Having recently consumed alcohol
- Having diarrhea or taking antidiarrheal medications
- Being exposed to high temperatures at night
- Fatigue
- Improper work procedures,
- Lack of acclimatization,
- Loss of sleep,
- Being obese,
- Being over age 40,
- Taking medications that inhibit sweating, such as antihistamines, cold medicines, diuretics, and some tranquilizers,
- Previous occurrence of heat stroke
- Poor physical conditioning,
- Recent immunizations (as they can cause a fever),
- Recent drug or alcohol use,
- Skin trauma, such as heat rash or sunburn),
- Use of respirators, and
- Wearing impermeable equipment, such as rubber gloves, rubber boots, or Tyvek® suits.
4. Heat Stress Controls
Heat stress controls can take the form of engineering controls, personal protective equipment (PPE), and administrative controls. The following examples of controls are appropriate for typical field conditions.
4.1 Personal Protective Equipment (PPE)
Reflective clothing, which can vary from aprons and jackets to suits that completely enclose the worker from neck to feet, can reduce the radiant heat reaching the worker. However, since most reflective clothing does not allow air exchange through the garment, the reduction of radiant heat must more than offset the corresponding loss in evaporative cooling. For this reason, reflective clothing should be worn as loosely as possible. In situations where radiant heat is high, auxiliary cooling systems can be used under reflective clothing.
Auxiliary body cooling ice vests, though heavy, may accommodate as many as 72 ice packets, which are usually filled with water. Carbon dioxide (dry ice) can also be used as a coolant. The cooling offered by ice packets lasts only 2 to 4 hours at moderate to heavy heat loads, and frequent replacement is necessary. However, ice vests do not tether the worker and thus permit maximum mobility. Cooling with ice is also relatively inexpensive.
4.2 Administrative Controls The two most important methods of preventing heat disorders are hydration and acclimatization because they increase the ability of the body to tolerate heat stress. Engineering and administrative controls are also important in reducing heat exposure.
Hydration- The most important factor in preventing heat illnesses is adequate water intake.
- Water must be available to employees who are working under heat stress risk conditions.
- Workers should drink at least five to seven ounces of cool water every 15 to 20 minutes.
- Under conditions of profuse sweating, a commercial electrolyte replacement drink may be appropriate. Some drinks are too concentrated and need to be diluted or consumed along with water.
Acclimatization A physiological adaptation will occur with repeated exposure to hot environments. The heart rate will decrease, sweating will increase, sweat will become more dilute and body temperature will be lower. The ability to acclimatize varies among workers. Generally, individuals in good physical condition acclimatize more rapidly than those in poor condition.
Approximately one week of gradually increasing the workload and time spent in the hot environment will usually lead to full acclimatization. On the first day, the individual performs 50 percent of the normal workload and spends 50 percent of the time in the hot environment. Each day an additional 10 percent of the normal workload and time is added so that by day six, the worker is performing the full workload for an entire day. The exposure time should be at least two hours a day for acclimatization to occur. Acclimatization is lost when exposed to hot environments does not occur for several days. After a one-week absence, a worker needs to reacclimatize by following a schedule similar to that for initial acclimatization. The acclimatization will occur more rapidly, so increases in workload and time can increase by approximately 20 percent each day after the first day, reaching normal work conditions by day four.Work Practices to Reduce Risk
Use the buddy system Ensure that co-workers watch one another for signs of heat stress. Reduce physical demands by reducing physical exertion such as excessive lifting, climbing, or digging with heavy objects. Spread the work over more individuals, use relief workers or assign extra workers. Provide external pacing to minimize overexertion.
Provide recovery areas, such as air-conditioned enclosures and rooms, and provide intermittent rest periods with water breaks. Establish provisions for a work/rest regimen so that exposure time to high temperatures and/or the work rate is decreased.
Reschedule hot jobs for the cooler part of the day. Routine maintenance and repair work in hot areas should be scheduled for the cooler seasons of the year. When possible, outdoor work areas should be provided with coverings, such as a tarp, to provide shade.
Monitor workers who are at risk of heat stress, such as those wearing semi-permeable or impermeable clothing when the temperature exceeds 70°F while performing strenuous tasks. Personal monitoring can be done by checking the heart rate, recovery heart rate, oral temperature, or extent of body water loss.
Personal precautions that employees should be aware of and institute precautions when exposed to heat stress include:
- Fluid intake: Drink 5 to 7 ounces of cool water every 15 to 20 minutes,
- Salt Supplements: Not recommended since too much salt can cause higher body temperature, increased thirst, and nausea * Dress to Increase Reflection and Convection: Wear light-colored, loose-fitting breathable clothing,
• Reduce Ultraviolet Radiation: Work in the shade,
• Stop the Heat Build-up: Take frequent short breaks in a cool shade.
• Reduce Metabolic Heat: Eat smaller meals before work activity.
• Avoid Dehydrating Liquids: Don’t drink caffeine and alcohol or large amounts of sugary drinks,
Post your comment on this topic.