PPE

Harm and prevention of noise in workplace

The concept and occupational exposure limits of noise are analyzed from the perspective of environment and physiology. All the sounds that make people bored, unpleasant and unnecessary are collectively referred to as noise. 1t includes the sound that endangers people’s health, the sound that interferes with people’s study, work and rest, and other unnecessary sounds

according to the requirements of occupational health standard “physical factors of occupational exposure limits of hazardous factors in the workplace” (gbz2.2-2007), if workers work 5 days a week and 8 hours a day, the occupational exposure limit of steady-state noise is 85 dB (a); 1n case of unsteady noise, the limit of equivalent sound level is also 85 dB (a)< (1) there are many kinds of noise sources in enterprises. Air flow noise caused by sudden change of gas pressure, such as compressed air, high pressure steam venting, heating furnace, etc; There are mechanical noise caused by mechanical friction, vibration, impact or high-speed rotation, such as ball mill, pulverizer, mechanical conveyor belt, etc; There is electromagnetic noise caused by the vibration of electrical components caused by alternating and pulsating magnetic field, such as transformer< (2) there are many high-noise equipment, and the noise hazard is serious the main influencing factors of the harmful effects of noise on human body are as follows: 1) noise intensity; 22. Contact time; 3. The spectrum of noise; 4. Noise type and contact mode; 5. 1ndividual differences; â‘?Other factors, such as vibration, cold and toxic substances, will enhance the adverse effects of noise the harm of noise to human health the influence of noise on human health is multifaceted. The greater the noise intensity, the higher the frequency, the longer the action time and the smaller the individual endurance, the more serious the harm. The main harm of noise to human body is as follows: (1) auditory system: long term exposure to strong noise mainly causes hearing loss. The development of hearing loss is first physiological reaction, then pathological changes until deafness. Physiological hearing loss is characterized by recovery after a period of time away from the noise environment, while pathological hearing loss can not be completely recovered. According to statistical data, noise below 80 dB (a) will not cause noise induced deafness in the case of long-term exposure; 80 ~ 85 dB (a) noise can cause slight hearing loss; 85 ~ 100 dB (a) noise can cause a certain amount of noise induced deafness; When noise is above 100dB (A), the incidence rate of noise induced hearing loss will increase significantly. When people are unprepared, high-intensity explosive noise (such as sudden blasting and explosion) can cause permanent hearing loss in a moment, that is, explosive deafness. At this time, people’s hearing organs will suffer serious trauma< (2) nervous system: after long-term exposure to strong noise, neuroids appeared, mainly including headache, dizziness, tinnitus, palpitation, sleep disorder, memory loss, etc; There are emotional and behavioral changes, such as anxiety, excitement, tension, irritability, mental fatigue, etc< (3) cardiovascular system: under the effect of noise, autonomic nerve regulation function changes, showing heart rate accelerated or slowed down, blood pressure instability (tend to increase), serious cases lead to coronary heart disease and arteriosclerosis (4) digestive system: gastrointestinal dysfunction, loss of appetite, wasting, gastric secretion reduction, gastrointestinal motility slowed down, leading to an increase in the incidence rate of stomach diseases and gastric ulcer diseases. (5) female menstruation and reproductive function: women exposed to noise may have menstrual cycle disorder, dysmenorrhea, etc; The rate of spontaneous abortion increased; The incidence rate of pregnancy induced hypertension has an increasing trend. Br / >
prevention of noise hazards

noise control should consider the three elements of sound, namely noise source, transmission medium and receiver, and the prevention of hazards should also be combined with occupational health examination< (1) transform the sound source and reduce the noise. Through technological innovation, we can transform the sound producing object into non sound producing or low sound producing object? This is the fundamental measure. For example, by using new materials, improving the structure of mechanical equipment, reforming the process and operation methods, improving the machining accuracy and assembly quality of parts to reduce noise< (2) reasonable planning and design to control noise propagation and reflection. For example, the high noise area and the office area are arranged separately, the high noise machines and the low noise machines are arranged separately, and the greening is used to reduce the noise. The ways to control the transmission and reflection of noise include: (1) sound absorption. The porous material is applied on the surface of the wall and roof to absorb the radiated or reflected sound energy, so as to reduce the noise. The commonly used sound-absorbing materials include glass wool, slag cotton, foam plastic, felt, cotton wool and so on2. Silence. Noise elimination is the main measure to prevent aerodynamic noise, which is used in air duct and exhaust pipe. By using the principle of filtering, the direction or shape of sound wave can be changed in the process of propagation, so as to consume sound energy and reduce noise. Commonly used Resistance Muffler, resistance muffler, impedance compound muffler. 3. Sound insulation. Closed noise source; The sound insulation room shall be established, and the staff shall operate in the sound insulation room. 4. Vibration isolation< (3) strengthen personal protection. Personal protection is an economic and effective measure. The commonly used anti noise devices include earplug, earmuff, anti noise cotton, anti noise helmet, etc. They mainly use the sound insulation principle to block the noise into the eardrum< (4) occupational health examination. Through the pre job occupational health examination, the occupational contraindication patients were controlled to engage in noise work; Through regular health monitoring and examination during the post, the noise sensitive or early hearing loss can be found as early as possible, and corresponding measures can be taken to prevent further hearing loss China labor insurance net

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