HSE و بهداشت حرفه ای

Control of Heat Stress for Workers & Heat Stress

 

What is Heat Illnes

Heat stsress is the effect that the thermal environment has on a person’s ability to maintain a normal body temperature. Physical work generates heat in the body which must be lost to the environment through sweating and evaporation. A hot or humid environment makes this more difficult and this can affect both mental and physical performance. Inability to get rid of body heat adequately may result in heat illness.

Heat-related disorders and diseases

Prickly heat rash: Heat rashes exhibit as red spots on the skin that cause a prickling sensation during heat exposure.

Heat cramps are often the first indicator of a heat-related problem. Symptoms are sharp and painful spasms in the muscles that are being stressed in hot environments, mostly calves, arms, abdominal wall and back. Heat cramps usually occur in unacclimatised workers who have replaced water lost through sweating but who have not replaced salt at the same time.

Heat exhaustion often begins suddenly, sometimes after excessive exercise or work, heavy sweating (with fluid and salt loss) and inadequate fluid and electrolyte intake. It can precede heat stroke and is characterized by heavy sweating but with cool, moist and pale skin. Dizziness, blurred vision and unconsciousness may accompany a rapid but weak pulse and low blood pressure. Low-grade fever, headache, confusion, fatigue, nausea, heat cramps, rapid breathing and dark-colored urine may also be present.

Heat stroke is the most serious heat illness, often resulting from exercise or heavy or prolonged work in hot environments with inadequate fluid intake. What makes heatstroke severe and potentially life-threatening is that the body's normal mechanisms for dealing with heat stress, such as sweating and temperature control, are lost. Main symptoms of heat stroke are elevated body temperature (> 40 °C), hot and dry skin (sweating stops), and central nervous system dysfunction, ranging from headache, Irritability, dizziness, confusion, personality changes to partial or complete loss of consciousness (coma). A rapid heartbeat, rapid shallow breathing and nausea can also be present. Heat stroke can be fatal and requires prompt medical attention.

Hydration Maintenance

The fluid intake required to maintain hydration is determined by the sweat rate which in turn is determined by the work rate and the conditions. Sweat rates vary considerably and increase with acclimatisation. The following recommendations are for the average acclimatised worker.

Required fluid intake to maintain hydration during work

The table below shows the fluid intake required to replace sweat at different workloads and conditions.
As a general guide, work in hot weather requires an intake of 2 litres every 2-3 hours..

In these situations the workload exceeds TWL and even with adequate fluid replacement heat storage will limit work time as other factors prevent achievement of heat balance.

Choice of Fluid Replacement Drinks

Replacement of the fluid lost in sweat requires intake of adequate quantities of water and salt. Drinking at mealtimes replaces both and is essential. Remember to encourage workers to:

• Add a little extra salt to their meals during hot weather, salt tablets are not recommended
• Drink water with meals
• Limit consumption of soft drinks as the sugar content is high
• Limit consumption of caffeinated drinks (coffee, tea, cola) and ‘energy drinks’, as the caffeine may reduce fluid retention

If workers are sweating heavily between meals, an electrolyte replacement drink is recommended. Replacing salt as it is lost helps the body absorb and retain the water consumed:

• Sports drinks are high in sugar and often quite acidic which can damage teeth. They are not designed for prolonged consumption at work
• For prolonged consumption, a fluid with 4% or less sugar is recommended
• Appropriate products designed for industrial use are available commercially
• The suggested schedule is to drink the electrolyte replacement fluid at every second drink (i.e. one for one with water)
• For diabetics or those on sugar restricted diets, medical advice is required on the
• preferred fluids for rehydration

Control of Heat Stress for Workers

Working in extreme heat without proper controls can be fatal! Look out for yourself and your friends at work.:

Recommendations for Workers:

1. Read, understand and follow the employer’s occupational health and safety procedures and instructions regarding work in hot environments.
2. Report all signs of heat illness to the supervisor (feeling faint, dizziness, fatigue, headache, nausea, vomiting, cramps).
3. Drink enough water during the day and maintain proper hydration status
   1. Come to work fully hydrated (drink plenty of water before you get to work).
   2. Drink plenty of water during the shift at least 2 litres every 2-3 hours in summer (or rehydration fluid approved by the employer).
   3. Drink water regularly and make it a way of life.
   4. If you drink water only when you are thirsty it is too late-drink even when you are not thirsty in the heat.
4. Wear appropriate clothing (lightweight, light-colored, loose-fitting, cotton) and carry a water container with you of at least 1-2 litres to fill regularly.
5. Self-pace your work – do not push your body beyond its limits.
6. Report non-acclimatization to supervisor (if you have been away from work for more than 14 days) and try to acclimatize for 5-7 days before starting hard work in a hot environment.
7. Look out for signs of heat illness in the people you work with and take them to a shady area and cool them down – call for help.

Control of Heat Stress for Employers

Preventing Heat Related Illness in the Workplace

Heat exposure and heat stroke can be fatal if proper controls are not implemented. Employers have a legal responsibility to protect the health of their workers as stipulated by the UAE Labour Law (Federal Law No. 8 of 1980).

For workers working in hot environments this includes protecting the worker from heat related illness and to control heat-related risks. Employers are expected to take appropriate necessary actions, e.g. establishing occupational health and safety procedures for work in hot environments, instructing and training workers and supervisors to prevent, recognize and deal with heat related illness and provide controls, including appropriate amounts of drinking water and electrolyte replacement drinks, appropriate clothing and personal protective equipment where applicable or necessary.

Recommendations for Employers:

Heat Stroke

Heat stroke is the most serious heat-related disorder. It occurs when the body becomes unable to control its temperature: the body's temperature rises rapidly, the sweating mechanism fails, and the body is unable to cool down. When heat stroke occurs, the body temperature can rise to 106 degrees Fahrenheit or higher within 10 to 15 minutes. Heat stroke can cause death or permanent disability if emergency treatment is not given.

Symptoms

Symptoms of heat stroke include:

• Hot, dry skin or profuse sweating
• Hallucinations
• Chills
• Throbbing headache
• High body temperature
• Confusion/dizziness
• Slurred speech

First Aid

Take the following steps to treat a worker with heat stroke:

• Call 911 and notify their supervisor.
• Move the sick worker to a cool shaded area.
• Cool the worker using methods such as:
  • Soaking their clothes with water.
  • Spraying, sponging, or showering them with water.
  • Fanning their body.

Heat Exhaustion

Heat exhaustion is the body's response to an excessive loss of the water and salt, usually through excessive sweating. Workers most prone to heat exhaustion are those that are elderly, have high blood pressure, and those working in a hot environment.

Symptoms

Symptoms of heat exhaustion include:

• Heavy sweating
• Extreme weakness or fatigue
• Dizziness, confusion
• Nausea
• Clammy, moist skin
• Pale or flushed complexion
• Muscle cramps
• Slightly elevated body temperature
• Fast and shallow breathing

First Aid

Treat a worker suffering from heat exhaustion with the following:

• Have them rest in a cool, shaded or air-conditioned area.
• Have them drink plenty of water or other cool, nonalcoholic beverages.
• Have them take a cool shower, bath, or sponge bath.

Heat Syncope

Heat syncope is a fainting (syncope) episode or dizziness that usually occurs with prolonged standing or sudden rising from a sitting or lying position. Factors that may contribute to heat syncope include dehydration and lack of acclimatization.

Symptoms

Symptoms of heat syncope include:

• Light-headedness
• Dizziness
• Fainting

First Aid

Workers with heat syncope should:

• Sit or lie down in a cool place when they begin to feel symptoms.
• Slowly drink water, clear juice, or a sports beverage.

Heat Cramps

Heat cramps usually affect workers who sweat a lot during strenuous activity. This sweating depletes the body's salt and moisture levels. Low salt levels in muscles causes painful cramps. Heat cramps may also be a symptom of heat exhaustion.

Symptoms

Muscle pain or spasms usually in the abdomen, arms, or legs.

First Aid

Workers with heat cramps should:

• Stop all activity, and sit in a cool place.
• Drink clear juice or a sports beverage.
• Do not return to strenuous work for a few hours after the cramps subside because further exertion may lead to heat exhaustion or heat stroke.
• Seek medical attention if any of the following apply:
• The worker has heart problems.
• The worker is on a low-sodium diet.
• The cramps do not subside within one hour.

Heat Rash

Heat rash is a skin irritation caused by excessive sweating during hot, humid weather.

Symptoms

Symptoms of heat rash include:

• Heat rash looks like a red cluster of pimples or small blisters.
• It is more likely to occur on the neck and upper chest, in the groin, under the breasts, and in elbow creases.

First Aid

Workers experiencing heat rash should:

• Try to work in a cooler, less humid environment when possible.
• Keep the affected area dry.
• Dusting powder may be used to increase comfort.

Recommendations for Employers

Employers should take the following steps to protect workers from heat stress:

• Schedule maintenance and repair jobs in hot areas for cooler months.
• Schedule hot jobs for the cooler part of the day.
• Acclimatize workers by exposing them for progressively longer periods to hot work environments.
• Reduce the physical demands of workers.
• Use relief workers or assign extra workers for physically demanding jobs.
• Provide cool water or liquids to workers.
• Avoid drinks with caffeine, alcohol, or large amounts of sugar.
• Provide rest periods with water breaks.
• Provide cool areas for use during break periods.
• Monitor workers who are at risk of heat stress.
• Provide heat stress training that includes information about:
  • Worker risk
  • Prevention
  • Symptoms
  • The importance of monitoring yourself and coworkers for symptoms
  • Treatment
  • Personal protective equipment

Recommendations for Workers

Workers should avoid exposure to extreme heat, sun exposure, and high humidity when possible. When these exposures cannot be avoided, workers should take the following steps to prevent heat stress:

• Wear light-colored, loose-fitting, breathable clothing such as cotton.
• Avoid non-breathing synthetic clothing.
• Gradually build up to heavy work.
• Schedule heavy work during the coolest parts of day.
• Take more breaks in extreme heat and humidity.
• Take breaks in the shade or a cool area when possible.
• Drink water frequently. Drink enough water that you never become thirsty.
• Avoid drinks with caffeine, alcohol, and large amounts of sugar.
• Be aware that protective clothing or personal protective equipment may increase the risk of heat stress.
• Monitor your physical condition and that of your coworkers.