Heat stress hazards and control measures

Heat stress hazards and control measures: the climatic conditions (Temperature, humidity, movement of air, and radiant temperature of surrounding), amount and type of clothing and who works or engages in strenuous physical exertion in hot and humid environments are at high risk for heat stress. In addition, their factors that increase the risk of an accident, for example, workers may suffer from previous ailments (cardiovascular or respiratory diseases, diabetes, etc.). In this blog follow the standard of SABIC SHEM 12.06

It is difficult to predict just who will be affected and when, because individual susceptibility varies. Each person is different. People who are in good health and physically fit tend to adjust faster and more easily. However, some individuals may not be able to fully acclimatize regardless of their health or physical condition.

Exposure to heat can cause various health effects including systemic disorders such as:

1. Heat rash,
2. Syncope,
3. Heat cramps,
4. Heat exhaustion,
5. Transient heat fatigue,
6. Rhabdomyolysis
7. Heat stroke and hyperpyrexia etc.

Heat exposure

It is a discomfort, usually experienced when staying in an excessively hot environment that requires excessive efforts by the mechanisms available to the body to maintain the internal temperature at 37 degrees Celsius.

Heat rash are tiny red spot on the skin. The spots are the result of inflammation caused when sweat glands become plugged.

Symptoms: skin itching and feeling prickling.

First aid: practice good personal hygiene, and keep the skin clean and the pores unclogged. Allow skin to dry. Wear loose clothing. See a doctor if the rash persists.

Syncope

Syncope means ‘fainting’. The first signs are dizziness, feeling light-headed and perhaps nauseous, and the person may faint. Usually occurs at the beginning of heat stress season before the circulation system is adapted

Symptoms: Fainting (short duration), dizziness, light headache, 

First aid: lay the victim in a cool location horizontally with feet elevated. If conscious give fluids. Call for medical care.

Heat cramps

Cramping of active muscles (arms, legs), involuntary (usually abdominal) muscles, or both. The cause is the salt imbalance resulting from the failure to replace salt lost with sweat. Cramps most often occur when people drink a large amount of water without sufficient salt (electrolyte) replacement.

Symptoms: Muscle cramps, pain or spasms in the abdomen, arms or legs.

First aid: replenish electrolytes through drinking fluids. Rest in a cool environment. Avoid salt tablets. Call for medical care.

Transient heat fatigue

Symptoms: General feeling of tiredness or fatigue

First aid: Fluid replacement and frequent rest.

Rhabdomyolysis

It is a medical condition associated with heat stress and prolonged physical exertion, resulting in the rapid breakdown, rupture and death of muscle. When muscle tissue dies, electrolytes and large proteins are released into the bloodstream which can cause irregular heart rhythm and seizure and damage kidneys.

Symptoms: Muscle cramps, pain, abnormally cola-coloured urine, weakness, exercise tolerance, asymptomatic.

First aid:

Stop activity, call for medical care (medical team to check for rhabdomyolysis signs), increase oral hydration (water preferred), 

Heat stress hazards and control measures – Heat exhaustion

The severity and intensity of these syndromes range from mild to life-threatening. Other types of heat-related illnesses are heat rash, heat cramps, heat syncope, and heat stroke.

Heat exhaustion can occur when the body loses too much water or salt, usually as a result of excessive sweating or dehydration. It can start suddenly or over time, usually after working or playing in the heat.

Heat exhaustion symptoms:

• Cold, clammy, bristly skin when in the heat
• Heavy sweating
• Weakness
• Irritability
• Elevated body temperature
• Fainting
• Dizziness
• Fatigue
• Weak and rapid pulse
• Low blood pressure when standing up
• Muscle cramps
• Nausea or vomiting
• Headache
• Extreme thirst
• Mild disorientation
• Less urine output

If you suspect heat exhaustion and are left untreated, heat exhaustion can lead to heat stroke, a life-threatening condition. If you suspect heat exhaustion, take these steps right away:

• Move the person away from the heat to a shaded or air-conditioned place.
• Lay the person down and raise their legs and feet slightly.
• Take off tight or thick clothing.
• Give them a drink of fresh water, a non-caffeinated sports drink with electrolytes, or another non-alcoholic and non-caffeinated beverage.
• Cool the person with cold water, using a spray bottle or sponge, and fan them.
• Monitor the person carefully.
• Call for medical care.

Contact a health care provider if signs or symptoms worsen or if the person does not improve after taking first aid measures. Call your local emergency number if the person’s condition worsens, especially if they:

• Fainting
• Agitation
• Confusion
• Seizures
• Inability to drink
• Core body temperature (measured with a rectal thermometer) of 104°F (40°C)

Heat stress hazards and control measures – Heatstroke

Heat stroke occurs when your body temperature rises rapidly and you cannot lower it. It can be life-threatening. It causes damage to the brain and other vital organs. Heat stroke can occur without any other pre-existing heat-related conditions, such as heat exhaustion. Signs and symptoms of heat stroke include:

• Fever over 104 degrees Fahrenheit (40 degrees Celsius)
• Changes in mental status or behaviour, such as confusion, agitation, and slurred speech
• Hot, dry skin or sweating may stop
• Nausea and vomiting
• Rapid pulse
• Fast breathing
• Fainting
• Seizures
• Breathlessness (having trouble catching your breath)
• Severe muscle cramps
• Severe dehydration
• Loss of consciousness (coma)
• Fatal if treatment delay

Then move the person out of the heat right away. Try to cool the person down. For example:

• Put her in a bathtub with cold water or give her a cold shower.
• Wet the person with cool water, using a sponge.
• Fan it while you spray it with cold water.
• Put ice packs or cold wet towels on your neck, armpits, and groin.
• Cover the person with cool, wet sheets.
• If the person is conscious, offer cool water, a sports drink with electrolytes, or another non-alcoholic, non-caffeinated beverage.
• Start CPR if the person loses consciousness and shows no signs of circulation, such as breathing, coughing, or movement
• Call for medical care immediately

Heat stress hazards and control measures against high temperatures

For this reason, specialists advise employers to inform and train workers about the risks involved in heat. Take care of acclimatization, ventilation and temperature of the workspace. Facilitate the hydration of workers.

Encourage the use of clothing that prevents the accumulation of heat. Adapt the pace and work schedules and establish breaks during the day when dealing with a lot of physical activity. More in detail, these are some of the explanations for heat stress, hazards and control measures.

What is heat stress in safety?

Heat stress can cause health damage such as skin rash, syncope, skin burns, muscle cramps, dehydration, exhaustion, heat stroke etc.  The latter is especially serious and can lead to death. Heat stress is the excess heat that workers receive and accumulate in their bodies. Sometimes it is due to the physical activity that they carry out, since some jobs may require great physical effort.

Although this is not the only factor, it also influences the clothing that employees wear. Inadequate clothing can cause a rise in the worker’s body temperature.

In addition, we must take into account the environmental conditions in the place where they carry out their work activity. This means that we have to be aware that the temperature may be too high for the development of certain activities. It may be necessary to implement specific prevention measures for heat stress to correct this situation.

Therefore, heat stress is caused by different factors that produce heat accumulation in the body. The body’s core temperature exceeds 37 º C, and different health damages can be produced.

Acclimatization is a process by which the body adapts to exposure to elevated temperatures. The body needs time to adjust when working in hotter environments. Employees are more likely to develop heat illness when they are not allowed or encouraged to relax when a heat wave or when they start a new job that exposes them to heat.

What type of hazard is heat stress?

Correctly identifying and evaluating these risk factors for heat stress will be the first step in designing an adequate prevention plan. Some of the risk factors that most affect the worker susceptible to occupational heat stress are:

• Prolonged exposure to high temperatures.
• Carrying out intense physical work, for example, loading and unloading activities.
• Use of personal protective equipment that prevents the evaporation of sweat (garments that are not cotton or breathable).
• Lack of rotating shifts and few breaks.
• Consumption of toxic substances, such as alcohol or caffeine.
• Intake of certain medications, for example, antihistamines, diuretics or antidepressants is harmful.
• The personal physical condition of the worker.
• The lack of training in the execution of intense physical tasks constitutes a risk factor, leading to “heat stroke”.

Above mentioned hazards can cause serious consequences for workers. To avoid reaching serious cases, it is important to keep in mind that there are a series of symptoms or signs that alert you to possible heat stress:

• Headache
• Weakness
• Fatigue
• Muscle cramps
• Nausea
• Profuse sweating
• Confusion

How do you prevent heat stress at work?

Inform and train workers about the risks related to heat, its effects and the preventive measures to be adopted. For this reason, people who work in these conditions must be aware of the risks. And employers must take preventive measures available to workers to guarantee their health. As you already know, in summer, the risk of human beings suffering heat stress illness is more frequent due to the high temperatures that summer presents. OSHA standard

• Provide heat stress rest shelter, as well as cool and shaded environments.
• Provide drinking water in the vicinity of the workplace.
• Provide adequate personal protective equipment to workers (loose, breathable, light fabric and colours).
• Avoid manual handling. Provide mechanical handling aids and work equipment for handling loads.
• Organize rotating shifts to reduce the time of exposure to heat whenever possible.
• Avoid heavy activities in the central hours of the day (between 12 and 15) and take frequent breaks.
• Consider that a period of 7 to 15 days of adaptation is necessary for the worker to acclimatize to the heat.
• Avoid isolated work, favouring teamwork to facilitate the mutual supervision of workers.

When someone shows signs of heat stress you should?

Symptoms of heat injury appear when the body produces and retains more heat than it loses, raising its internal temperature. Exposure to heat increases the probability of accidents at work as the worker finds himself uncomfortable.

You have to observe the first symptoms to act early and thus avoid major, irreversible and fatal damage. If an employee shows any signs or symptoms of heat illness or complains of such symptoms, first aid procedures should be performed immediately.

Progression to more serious illness can be rapid and may include impaired speech and coordination, confusion, unusual behaviour, nausea, vomiting, hot dry skin, unusually excessive perspiration, loss of consciousness, and seizures. The affected employee may not be able to self-diagnose these problems.

No employee with signs or symptoms of heat illness shall be left unattended or sent home without on-site first aid.

In body	In mind	In behaviour
Headache	anxiety	Eating too much or less than normal
muscle tension or pain	Concern	outbursts of anger
Chest pain	Lack of motivation or focus	drug addiction or alcoholism
Fatigue	feeling overwhelmed	tobacco use
Stomach ache	Irritability or anger	Social isolation
Sleeping problems	sadness or depression	Exercise less often
dizziness	Confusion
Nausea	loss of coordination
exhaustion
seizures
Fainting
Pale, cool, clammy skin
Dry, red, hot skin

During periods of high temperatures, employees must be monitored for early signs and symptoms of heat illness to ensure that ill employees receive prompt treatment and that progression to serious illness is halted. If an employee experiences fainting, disorientation, loss of consciousness, or other symptoms of heat illness while working unobserved, initial medical treatment may be delayed, resulting in serious or fatal injury.

• Advice to stop physical activity and rest by sitting in a cool place.
• Advice to drink water, juices and sports drinks diluted in water, or another non-alcoholic drink to replace fluids that have been lost through sweating.
• Advice to wear light clothing.
• Advice to cool the body with cool water and a fan to minimize body temperature.
• Advice to seek medical attention if notice symptoms of heat exhaustion or heat stroke.

Safety tips for working in hot weather

Adequate water is required at all times, regardless of outdoor temperature, and must be made available to employees at no charge. Companies must take measures to prevent heat stress. Both the management team and the workers must become aware of the importance of having good acclimatization.

Frequent breaks are taken or each worker stays hydrated throughout the work day. To carry out compliance with these measures, we must implement additional protection measures, such as:

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Provision of pure and cool drinking water

Water is the body’s best defence against heat, aside from eliminating heat exposure. Under conditions of high temperatures and strenuous work, the human body can lose more than a quart of fluid per hour through perspiration alone. Continual replacement of this lost fluid is critical to allowing the body to maintain the life-sustaining cooling benefits of perspiration. For this reason, it is essential to guarantee the availability, easy access and consumption of pure, potable and cold water.

Provision of heat stress shelter

Employers must allow and encourage employees to take a cool-down break in the shade for no less than five minutes at a time when they feel the need to do so to avoid overheating. It is critical that workers are not rushed when taking cool-down breaks, as the purpose of this shaded break is to reduce employee heat stress. 

Waiting until symptoms appear before seeking shade and recovering poses a significant risk of developing heat illness. Shade eliminates sunlight as a direct source of heat, and since people produce more metabolic heat while working,

Monitoring the heat stress symptoms

Because every workplace is unique, the new provisions give employers options and flexibility to monitor and monitor employees. When employees work in small groups of no more than 20 workers, direct observation by a supervisor or designated employee may be sufficient. 

When there are too many employees for direct observation, the employer may use a buddy system and group employees into pairs. With the buddy system, the employer must train employees to keep in touch, observe each other throughout the day, and immediately report any signs or symptoms of heat illness. 

In the case of employees who must work alone, the employer can communicate with the employee by radio or cell phone as long as the coverage is adequate.

Heat stress campaign

To prevent heat stress and its effects, the health and safety officer launched a specific campaign just before summer to intensify prevention work to avoid victims of heat stroke during the remainder of the summer.

The actions are designed to raise awareness among workers to protect those people who carry out their work in conditions that can end up causing heat stroke, when the body registers an increase in body temperature, either due to physical effort in a hot or poorly ventilated environment.

Provision of training

Employers must train all employees. The training must be provided before starting a job that involves a risk of heart illness. This means that at a minimum, training must be provided when an employee is hired and refresher training as needed. 

Training provided close to the hot season is more effective than training provided during cold seasons without refresher and follow-up training. As a best practice, some employers use the technique of daily “safety meetings,”

What is the WBGT index today?

The WBGT index is based on the combination of environmental heat loads and metabolic heat loads. It is used, due to its simplicity, to quickly discriminate whether or not a heat stress risk situation is admissible. Although its calculation often allows taking decisions, regarding the possible preventive measures to be applied.

The higher the WBGT, the greater the risk of heat stress. When WBGT reaches a certain level, it can be dangerous to work or exercise in hot weather. The specific WBGT levels that pose a risk vary depending on the individual’s activity level, acclimatization to heat, and other factors.
There is a strong relationship between WBGT and heat stress.

Studies have shown that WBGT is a good predictor of physiological changes that occur in response to heat stress, such as an increase in heart rate and core body temperature.

The use of WBGT can help reduce the risk of heat-related illness by allowing people to assess the level of heat stress and take steps to protect themselves. For example, if the WBGT is high, people may choose to work or exercise in the shade, drink plenty of fluids, and wear light-coloured, loose-fitting clothing. Here is a table that shows the relationship between WBGT and the risk of heat stress:

WBGT?

Normal thermometer (dry bulb)

Wet-bulb thermometer – (humidity)

Globe temperature – (radiant heat)

Also read: WBGT VS heat index

General heat stress categories and work schedules

Here are some heat stress categories and work schedules or work frequencies:

Light work: This type of work requires a moderate amount of physical activity, such as walking, standing, or light lifting. For light work, the NIOSH work/rest schedule recommends a work period of 30 minutes followed by a rest period of 15 minutes.

Moderate work: This type of work requires a significant amount of physical activity, such as carrying heavy objects or doing strenuous labour. For moderate work, the NIOSH work/rest schedule recommends a work period of 20 minutes followed by a rest period of 40 minutes.

Heavy work: This type of work requires a very high level of physical activity, such as doing construction work or firefighting. For heavy work, the NIOSH work/rest schedule recommends a work period of 10 minutes followed by a rest period of 50 minutes.

In SABIC Saudi Arabia work schedule and rest frequency during heat stress

• Category 1 – (25-27 WBGT) – 45m work, 15m rest
• Category 2 – (28-29 WBGT) – 30m work, 30m rest
• Category 3 – (29-31 WBGT) – 15m work, 45m rest
• Category 4 – (32 WBGT) – Stop activities

These are just general guidelines, and the specific work schedule or work frequency that is right for you will depend on several factors, including the ambient temperature, the humidity, the type of work you are doing, and your level of fitness.

Heat stress work/rest category matrix – WBGT (ºC)
Continuous work	75% work, 25% rest	50% work, 50% rest	25% work, 75% rest
24	25 – 27	28 -29	29 – 31

What and when to drink

Being dehydrated is a serious issue. Un-acclimatized workers can lose up to 5 or 6 litres of fluid in an 8-hour shift. While working, drink 250 ml (1 cup) of water every 15-20 minutes. Make sure plenty of cool (10-15 degrees centigrade) drinking water with supplementary salt is available at the worksite.

Conclusion:

• Drink plenty of water or liquids, without waiting to feel thirsty.
• Stay in cool places, in the shade or if possible in heated places.
• Take frequent breaks to rest when the heat and humidity are high.
• If you have to stay outside, wear light, loose clothing and light colours.
• Wear cool, comfortable and breathable shoes.
• You should cover your head if you are in the sun. A wide-brimmed hat significantly reduces exposure to solar radiation. You should use sun protection creams in areas where your skin may be uncovered.
• Be on the lookout for heat-related symptoms. If you work together with other colleagues, it is necessary to monitor their status and ask someone to do the same for you. Heat stroke can cause someone to lose consciousness.
• Avoid copious meals. It would be a good option to choose salads, fruits and foods rich in liquids.