Heat stress | What is heat stress | Heat stress causes

         HEAT STRESS | WHAT IS HEAT STRESS | HEAT STRESS CAUSES

Heat stress

HEAT STRESS | WHAT IS HEAT STRESS | HEAT STRESS CAUSES

Working in hot environments, whether these are man-made e.g. working near hot surfaces or natural i.e. summer climate, sunshine, hot winds, or desert conditions puts people under extreme thermal stresses that can have serious consequences on their health and safety.

The human body is at optimum comfort when its core temperature is maintained between 36°C-37.5°C.

Temperature increases by more than 1°C, the body is either suffering from an infection that is causing a fever; or else it is unable to deal with the heat in the surrounding environment.

The elements balance out, the body does not store heat but if they do not the body either loses i.e. feels cold or gains heat (i.e. feels hot). Either situation can potentially have serious health effects on the human body.

Tiredness, dehydration, overweight, physical fitness, and the calorific content of the diet can all affect the body’s ability to exchange heat. However, the physical demands of activities being carried out, whether these are work-related or leisure, rest periods, and general acclimatization to the conditions also play important roles in the body’s ability to exchange heat.

 HEAT & HUMAN HEALTH

The amount of heat in any environment is dependent on four critical parameters, these are ambient air temperature, Humidity, Air Movement, and the Presence of Radiant or Conducting Objects in the immediate vicinity.

When the body cannot balance its temperature between 36°C - 37.5°C, one of the following progressive symptoms can occur unless adequate controls are in place.

What is Heat Stress?

Heat stress occurs when the body builds up more heat than it can handle. The early signs of employee heat illness are mild dizziness, fatigue, irritability, decreased concentration, and impaired judgment. The employee may also be experiencing heat cramps, painful spasms of the leg, arm, or abdominal muscles, heavy sweating, and thirst. Other common heat-related illnesses include heat strain, heat exhaustion, and heatstroke. Heat strain is a general term for how the body responds to heat stress.

 CONTROL OF RISKS

The risk of heat-related illnesses can be reduced by application of one or more of the following control strategies:

·         Engineering controls that provide a cooler working environment.

·         Administrative safe working practices aimed at reducing exposure.

·         Ample awareness, training, and information to enable workers to recognize hazardous conditions, and potential symptoms and apply the controls that have been provided to them.

 Engineering Controls

These are the most effective means of reducing excessive heat exposure, and the examples listed below illustrate some engineering approaches that can be investigated and implemented for reducing exposure to thermal environments:

1.       Reducing Metabolic Heat Production (i.e. heat produced by the body): by automation and mechanization of tasks to minimize the need for heavy physical work and the resulting buildup of body heat.

2.       Reducing Radiant Heat Emissions from Hot Surfaces: covering hot surfaces with sheets of low emissivity material such as aluminum or paint reduces the amount of heat radiated from the hot surface into the workplace.

3.       Insulating Hot Surfaces: the insulation reduces the heat exchange between the source of heat and the work environment.

4.       Shielding: this is to block radiated heat from reaching workstations. The types of shields that can be used include stainless steel, aluminum, or other bright metal surfaces which reflect heat to the source. Absorbent shields, such as water-cooled jackets made of black-surfaced aluminum, also can effectively absorb and carry away heat.

5.       Ventilation and Air Conditioning: by the use of dilution ventilation or localized air conditioning in the Operator Shelter or Control Room. These allow workers to cool down after periods of intense heat exposure.

6.       Reducing the Humidity: by application of air conditioning, dehumidification, and elimination of open hot water baths, drains, and leaky steam valves help reduce humidity.

Acclimatization

This is the body’s mechanism of coping with a new thermal environment. Complete heat acclimatization generally takes about 7 days, but some people may require a slightly longer period. Loss of acclimatization occurs gradually when a person has moved permanently away from a hot environment, but a decrease in heat tolerance occurs even after a long weekend. As a result of reduced heat tolerance, it is not advisable for anyone to work under very hot conditions on the first day back to a working week.

New employees shall acclimatize before assuming a full workload. For experienced employees, it is advisable to assign about half of the normal workload on the first day of work and gradually increase the work period on subsequent days. Well-trained, physically fit workers can tolerate heat better than people in poor physical conditions. However, fitness and training do not substitute the acclimatization regime.

Some medications can interfere with acclimatization. For example, blood pressure tablets, diuretics, antispasmodics, sedatives, and tranquilizers decrease the body's ability to cope with the heat. Workers shall always seek advice from the medical practitioner on the suitability of a medication for them if they work in hot environments.

Urine Color Charts

Effective hydration is reflected in the color of the urine or its specific gravity. The company beat the Heat Urine Charts for monitoring the effectiveness of hydration programs, and as educational tools to encourage workers to drink fluids during the working day to avoid heat-related illness.

 MONITORING OF PERSONNEL

Monitoring of personnel is essential to ensure the timely identification of potential heat stress cases. All supervisors/managers shall visually monitor employees to note signs of heat stress. Employees shall be instructed to observe for symptoms of heat stress and methods on how to control it. The company heat stress site assessment checklist shall be used for monitoring as provided.

Any pregnant employee shall not be allowed to work in temperatures higher than 32°C, medical advice shall be sought from a concerned doctor of the pregnant employee.

Affected employees shall be treated by first aider Emergency Medical Technician and medical provider by company, so in all cases, medical assistance shall be summoned immediately.

To treat heat stress cramps, remove the victim from the hot environment to a cool area ambulance or vehicle ideally with 25°C (77°F) temperature, and loosen tight clothing. Rest the cramping muscles by having the victim sit or lie down. Replace fluids by mouth using water or approved rehydration fluids. Do not give salt or high sodium solutions.