Outdoor operation shall be stopped when the maximu

2022-10-18
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The State Administration of work safety: outdoor work should be stopped when the maximum temperature is above 40 ℃

the State Administration of work safety, the Ministry of health, the Ministry of human security, the all China Federation of trade unions and others recently jointly formulated a new version of the Interim Measures for heatstroke prevention and cooling measures, which defines the daily maximum temperature above 35 ℃ as "high temperature weather", and includes heatstroke caused by high temperature weather work into the category of industrial injury

the exposure draft stipulates that if the daily maximum temperature reaches above 40 ℃, outdoor operations on that day should be stopped; When the temperature is above 37 ℃ and below 40 ℃, the outdoor operation time of workers shall not exceed 5 hours, and outdoor operation shall not be arranged from 12:00 to 15:00; When the temperature is above 35 ℃ and below 37 ℃, shift breaks should be taken to shorten the continuous working time of workers, and outdoor workers should not be arranged to work overtime; Pregnant female workers shall not be arranged to work in high temperature weather above 35 ℃ and in workplaces with indoor temperature above 33 ℃

workers engaged in high-temperature operations and high-temperature weather operations shall enjoy post allowance according to law. The employer shall provide sufficient cool drinks and heatstroke prevention and cooling drugs that meet the health standards for workers working in high temperature and high temperature weather, and shall be equipped with heatstroke first aiders and sufficient first-aid drugs

temperature, air humidity, airflow radiation

how does the human body dissipate heat

heat and cold affect the human body under the comprehensive action of four meteorological factors: temperature, air humidity, air flow and radiation. Among the four meteorological factors, temperature plays a major role in the heat dissipation of the human body

● coping with temperature: when the temperature is lower than 15 ℃, human metabolism will increase. When the temperature is between 15 ℃ and 25 ℃, metabolism will maintain a basic level. When the temperature is higher than 25 ℃, metabolism will decrease slightly, and when the temperature is higher than 35 ℃, metabolism will increase with the temperature

● heat dissipation of human body: when the temperature is below 20 ℃, it dissipates heat in the form of conduction, convection and radiation; When the temperature reaches 26 ℃, the evaporation heat dissipation increases significantly; When the temperature rises to 32 ℃, evaporative heat dissipation has become the main form; When the temperature rises to 38 ℃, evaporative heat dissipation becomes the only form of heat dissipation. For example, when the temperature is 25 ℃, people who rest naked account for 10% of the total heat dissipation by conduction convection, 67% by radiation and 23% by evaporation; When the temperature rises to 34.7 ℃, it is 7%, 5% and 88% respectively

heat resistance exercise is very effective

what kind of thermal adaptability do people have

the human body has great adaptability to the changes of external temperature, especially after exercise or acclimatization

● naked people can still maintain their body temperature at 36.7 ℃ to 37.8 ℃ when the temperature is in the range of 15.6 ℃ to 54.5 ℃

● in the room, the difference between the vertical temperature difference (the temperature difference between 0.05m and 1.5m above the floor) and the horizontal temperature difference is too large, which can make people's temperature regulation nervous and continue for a long time, which is not conducive to health, especially for the elderly, the weak and children. Cold in the lower limbs can reflexively cause changes in other parts of the body, such as nasal and respiratory mucosal swelling. Generally, the temperature difference between vertical and horizontal should be within 3 ℃

● factors related to temperature change, such as temperature, air humidity, airflow, radiant heat, labor intensity and time, among which only temperature is significantly related to temperature change, and others can only strengthen or weaken temperature

● the role of other factors cannot be ignored. For example, at a high temperature of 45 ℃, the relative humidity is very low (less than 15%), and the body temperature can still maintain a constant level. When the temperature is 33 ℃, the relative humidity reaches 100%, it can cause the human body to overheat. For another example, when the temperature is between 20 ℃ and 25 ℃ in a quiet state, the heat balance can be maintained, while in moderate physical labor, the temperature will drop to 10 ℃. During the test, the data will be recorded from ℃ to 15 ℃, so as to improve the efficiency of tire product development and the accuracy of new products. In physical labor, it will fall to 5 ℃ to 10 ℃, so as to maintain the same heat balance

air humidity determines air evaporation and perspiration and heat dissipation

how does air humidity affect people

Qi dampness plays an important role in the heat balance and warm sensation of the human body

● when the temperature is appropriate, the heat dissipation of human body mainly depends on conduction convection and radiation, which is less affected by air humidity. For example, when the temperature is 20 ℃ to 25 ℃, the change of relative humidity between 30% and 80% is almost imperceptible

● when the temperature is 15.5 ℃, the influence of 50% change in relative humidity on human body is only equivalent to 1 ℃ change in temperature

● at high temperature, if the relative humidity increases, sweat is not easy to evaporate into large drops, so it cannot play the role of heat dissipation, and the efficiency of evaporation and heat dissipation is also reduced. Under extremely hot conditions, small changes in humidity will have a great impact on sweating rate, pulse, rectal temperature and tolerance time

airflow speed affects heat dissipation and air evaporation

what are the benefits of blowing in high temperature and humidity

● when the temperature is lower than the skin temperature, the heat dissipation is directly proportional to a certain air velocity. If the air velocity is 0.1 to 0.18 M/s, the heat dissipation can be increased by 20%, while at 0.6 m/s, it can be increased to 100%

when the temperature is higher than the skin temperature, air flow has two functions: one is to promote the evaporation of sweat and help dissipate heat; The other is that the human body can also obtain heat from the environment due to convection. At high temperature and low humidity, for example, when the temperature is 48.9 ℃, the relative humidity is 28% and the air velocity is 0.26 M/s in the past few years, people wearing coats can only work for 2.9 to 3.5 hours, but when the air velocity is increased to 0.51 M/s, they can complete the work for 4 hours

● when the skin and clothes are wet, increasing the air velocity has a greater impact on sweating, evaporation and heat dissipation than convective heating, which is beneficial. However, after the skin and clothes are dry, the increase of air velocity is detrimental to the human body. The hot and dry wind will evaporate the juice from the skin quickly, and the sweat can't keep up with it. The skin is dry and the skin temperature rises quickly, which is more likely to cause overheating

● at high temperature and high humidity, no matter the size of the air flow, it is always good for heat dissipation

radiation affects heat dissipation

what is the relationship between people and radiation sources

all objects with a temperature above 0 ° K (-273.2 ℃) have infrared radiation, so all objects in nature can be regarded as infrared radiation sources, and so can the human body. The human body often radiates outward, while surrounding objects such as walls, ceilings, tank walls, and policy supporting left and right bow decks can also radiate to the human body

the radiation sources existing in the environment can heat the surrounding objects into secondary radiation sources, and the heated objects can heat the air through conduction convection and radiation to raise the temperature. For example, marching in summer is not only affected by high temperature and solar radiation, but also affected by secondary radiation on four sides, such as roads and rock walls, so it is very difficult to dissipate heat. However, at high temperature, the temperature of surrounding objects is low, which can greatly increase the heat dissipation of the human body

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