Directory. 01 Basic concepts of hot work.
02 The impact of high temperature on human health
03 Probability and type of heat stroke
04 Technical measures for high-temperature work.
05 Health care measures for hot work.
06 First aid for heat stroke.
1 What is hot work?
It refers to the operation in which the average WBGT index of the work place is not less than 25 in the process of production and labor.
Wet bulb globe temperature is a basic parameter for comprehensively evaluating the heat load of human contact with the working environment. The International Organization for Standardization adopts the ISO7243 standard, which uses the heat pressure index to reflect the degree of heat exposure to the human body.
Feel the same meteorological conditions.
Summer heat pressure index.
tw = natural wet-bulb temperature.
Wrap the thermometer in a damp cloth and measure the temperature in an unsheltered external environment to reflect whether sweat is volatile.
tg = black ball temperature.
In the specified black non-reflective copper ball, the temperature measured by temperature is used to reflect the effect of solar radiation.
td = dry-bulb humidity.
In a sheltered environment, the temperature measured by thermometer is not affected by humidity and solar radiation, and reflects the effect of pure air.
Types of hot work.
High temperature and strong radiation operation, high temperature and high humidity operation, summer open-air operation.
High-temperature and high-radiation operation is characterized by high temperature, high thermal radiation intensity, and low relative humidity, forming a dry and hot environment. It mainly refers to the operation in the place where there is a productive heat source.
High temperature, high air and humidity operation It is characterized by high temperature, high air humidity, and low heat radiation intensity. The formation of high humidity is mainly caused by the production process of a large amount of water vapor or the production requirements to maintain a high relative humidity in the workshop.
Summer open-air operation In addition to the direct radiation of the sun, the summer open-air operation is also subject to the additional thermal action of the secondary radiation source of the heated ground and surrounding objects. The temperature is high around noon, forming a working environment with a combined effect of high temperature and radiant heat.
2 The effects of high temperatures on human health.
When working at high temperatures, the human body will have a series of physiological function changes, which are adaptive reactions within a certain limit, but if they exceed the range, they will have adverse effects and even cause lesions.
The effects of high temperatures on the human body.
The way the human body dissipates heat.
Radiative convection evaporates.
Thermoregulation. However, when working in a high temperature, strong radiation and high humidity environment, the heat production and heat of the human body obviously exceed the heat dissipation, and the heat storage in the body exceeds the ability to regulate body temperature, resulting in heat stroke.
Water-salt metabolism. Heavy sweating during high-temperature work can lead to a large loss of water and salt, water and electrolyte disorders, metabolic disorders, and heat cramps.
Digestive system. Loss of appetite, indigestion, and gastrointestinal disorders increase during high temperatures.
Circulatory system delivers blood to the ** vascular network - heat dissipation.
Sufficient blood in the working muscles - to maintain blood pressure.
Profuse sweating – decreased effective blood volume.
Heart rate increases during high temperatures — heat exhaustion.
Long-term high temperature – compensatory cardiac hypertrophy.
Nervous system. People are slow to respond to the outside world, lack of concentration, muscle ability, accuracy and coordination of movements, and reduced brain reaction speed and concentration. Prone to work-related accidents.
Protective response of the nervous system to high temperatures.
Middle nerve excitation.
degree increase. Central nervous system excitation.
degree increases. Urinary system.
Most of the body fluids of the human body are discharged by the sweat glands, and the amount of water and salt excreted by the kidneys is greatly reduced, which concentrates the urine and increases the burden on the kidneys, which can lead to renal insufficiency and renal failure in severe cases.
3 Probability and type of heat stroke.
Occupational heat stroke.
Acute diseases with central nervous system and/or cardiovascular disorders as the main manifestations caused by thermal balance and/or water and salt metabolism disorders in high-temperature working environments.
Causes of heat stroke. The ambient temperature is too high, the humidity is too high, the wind speed is small, the labor intensity is too large, the working time is too long, fatigue, lack of sleep, obesity, frailty, and has not yet adapted to heat.
Type of heat stroke. Precursor to heat stroke.
Heavy sweating, thirst, dizziness, tinnitus, chest tightness, palpitations, nausea, increased body temperature, general weakness.
Mild heat stroke. Body temperature above 38, flushing or pale, clammy cold, blood pressure drop and other severe heat stroke.
Fainting and cramping, **dry and sweatless, body temperature above 40, etc.
Heatstroke is caused by the blockage of heat dissipation pathways and the disorder of body temperature regulation mechanism in a hot environment. The clinical characteristics are that the onset of the disease is sudden in a high temperature environment, the body temperature can reach more than 40, the beginning of profuse sweating, and then the appearance of "no sweat", accompanied by dry heat and impaired consciousness, drowsiness, coma and other central nervous system symptoms.
heatstroke
Heat cramps occur during labor in hot and dry conditions, excessive sweating, excretion of a lot of NACL, and spasms of the muscles of the limbs and abdominal wall. The patient's temperature is not elevated. Heat cramps are usually the first warning of collapse due to heat, and can occur in muscles in the arms, legs, and abdomen after overexertion, usually due to a lack of salt in the body (because of excessive sweating, especially if there is not enough salt).
heatcramp
Heat exhaustion Most people believe that in high temperature and high humidity environment, the increase in blood flow is not accompanied by splanchnic vasoconstriction or increase in blood volume, which cannot meet the effective compensation, resulting in a temporary decrease in blood supply to the brain and syncope.
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4. Technical measures for high-temperature work.
Rational design of the process.
Improving production equipment and operating methods is a fundamental measure to improve the working conditions of hot work. For example, keep workers away from heat sources to reduce labor intensity.
Arrangement of heat sources.
Arrange it outside the workshop as much as possible;
When using natural ventilation based on hot pressing, try to arrange it under the skylight;
When natural ventilation is mainly used through the hall, try to arrange it on the downwind side of the dominant wind direction in summer;
To make it easy to take cooling measures at the work site, a wall (board) can be set between the heat sources, so that the air rises along the wall and is excluded through the skylight, so as not to spread to the entire workshop.
Heat insulation. Thermal insulation is an important measure to protect against radiation. Water or materials with low thermal conductivity can be used for thermal insulation, especially water has the best thermal insulation effect, and the specific heat of water is large, which can absorb radiant heat to the greatest extent. When the radiation intensity is high, heat insulation measures such as water curtains, hot water insulation tanks, and heat insulation screens should be taken.
Ventilation and cooling. Natural ventilation: any house can be through doors and windows, gaps for natural ventilation, high temperature workshop is not enough in this way, must be the air inlet and exhaust outlet configuration reasonably, make full use of the comprehensive effect of hot pressure and wind pressure, so that natural ventilation to maximize the efficiency.
Mechanical ventilation: When natural ventilation cannot meet the needs of cooling or when production requires a certain temperature and humidity to be maintained in the workshop, mechanical ventilation or air conditioning facilities can be used.
5. Health care measures for high-temperature work.
Refreshing drinks and heatstroke medicines.
Employees who work in the open air in high temperature and in summer should provide tea, mung bean soup, salted soda and other cool drinks at the job site in accordance with relevant regulations, and prepare heatstroke prevention and cooling drugs such as Feng Youjing, Huoxiang Zhengqi Water and Rendan.
Heatstroke prevention and cooling medicine.
A Huoxiang Zhengqi Oral Liquid (Water, Pills, Capsules) b, 10 drops of water, N, Rendan, c, Guangdong herbal tea granules, d, Qingliang oil, e, Feng Youjing.
Personal protection. The work clothes of high-temperature workers should be made of fabrics with heat resistance, low thermal conductivity and good air permeability, and personal protective equipment such as work hats, protective glasses, face shields, gloves, shoe covers, leg guards, sun hats, etc., should also be distributed according to the needs of different types of work.
Medical prevention. Employees engaged in high-temperature work should be subject to occupational health examinations before starting work and before entering the summer, and the cycle of health examinations during the period of employment is one year. Those who have occupational contraindications are not allowed to engage in high-temperature work. Employees who have not recovered for a long time and those who are infirm should avoid working in hot temperatures as much as possible.
Occupational contraindications to hot work.
Stage A and stage hypertension.
bActive peptic ulcer.
c Chronic nephritis.
dUncontrolled hyperthyroidism, diabetes mellitus.
e large area ** scar.
Organizational measures for hot work.
1) Formulate a high-temperature protection plan for high-temperature production, take comprehensive measures to ensure the health of employees, and supervise and inspect the high-temperature protection work.
2) Conduct regular monitoring of high-temperature work sites in accordance with the "Measurement of Physical Factors in the Workplace".
3) Special high-temperature operations, such as the crane cab of the high-temperature workshop, the monitoring room in the workshop, the operation room, etc., should have good heat insulation measures or effective cooling measures, so that the indoor heat radiation intensity is less than 700w m2, and the temperature does not exceed 28.
4) Set up a lounge.
In the vicinity of the high temperature as a business site, a workshop rest room with a suitable temperature should be set up, and a temporary awning should be built for employees to rest in the open air in summer.
Establish a reasonable labor rest system.
For employees engaged in high-temperature work, a reasonable labor rest system is formulated, and the work and rest time is adjusted in a timely manner according to the change of temperature. For positions that exceed the occupational exposure limit for high-temperature work in the "Occupational Exposure Limit for Harmful Factors in the Workplace", methods such as rotation operation should be adopted to shorten the continuous operation time of employees as much as possible.
6 First aid for heat stroke.
First aid for heat stroke.
For patients with mild symptoms.
The patient should be asked to leave the hot work environment quickly, go to a well-ventilated and cool place to rest quietly, and drink some light salt water or salty cool drinks.