Harm and Prevention of Workplace Noise

The concept of noise and occupational exposure limits are analyzed from an environmental and physiological point of view. All noises that make people bored, unpleasant, and unwanted are collectively referred to as noise. They include sounds that endanger people’s health, interfere with people’s learning, work, and The sound of rest, and other unwanted sounds.

According to the requirements of the National Occupational Health Standard “Physical Factors for Occupational Exposure Limits of Harmful Factors in the Workplace” (GBZ2.2-2007), if workers work 5 days a week and work 8 hours a day, the occupational exposure limit for steady-state noise is 85 dB(A); For non-stationary noise, the equivalent sound level limit is also 85 dB(A).

Corporate workplace noise characteristics

(1) There are many kinds of noise and the sources are wide. There are noises of air flow due to abrupt changes in gas pressure, such as compressed air, high-pressure steam venting, heating furnaces, etc.; mechanical noise due to mechanical friction, vibration, impact, or high-speed rotation, such as ball mills, crushers, mechanical conveyor belts, etc. There are electromagnetic noises generated by the vibration of electric devices caused by alternating magnetic fields and pulsation, such as transformers.

(2) There are many high-noise equipment and serious noise damage.

Influence factors of noise on human body

The main influencing factors for the harmful effects of noise on the human body are: 1 noise intensity; 2 contact time; 3 spectrum of noise; 4 noise types and contact patterns; 5 individual differences; 6 other factors such as vibration, cold and toxic substances coexist , will enhance the adverse effects of noise.

The harm of noise to human health

The impact of noise on human health is manifold. The greater the intensity of noise, the higher the frequency, the longer the duration of action, and the smaller the personal endurance, the more serious the damage. The harm of noise to the human body is mainly manifested in:

(1) Auditory system: Long-term exposure to strong noise mainly causes hearing impairment. The development process of hearing impairment is primarily a physiological reaction, followed by pathological changes until deafness. Physiological hearing loss is characterized by recovery from a noisy environment for a period of time, whereas pathological hearing loss cannot be completely restored. According to statistics, in the case of long-term exposure, noise below 80 dB(A) will not cause noise deafness; 80~85 dB(A) noise will cause slight hearing loss; 85~100 dB(A) The noise will produce a certain amount of noise deafness; when the noise is above 100dB(A), the incidence of noise deafness will increase significantly. In the absence of ideological preparation, high-intensity detonation noise (such as sudden blasting, explosion) can cause permanent hearing loss in a moment, that is, detonation deafness, and human hearing organs will suffer serious trauma.

(2) Nervous system: After a long-term exposure to strong noise, there is neurosis, mainly headache, dizziness, tinnitus, palpitations, sleep disorders, memory loss, etc.; there is a change in mood and behavior, such as anxiety, excitement, tension, irritability, Mental fatigue and so on.

(3) Cardiovascular system: Under the effect of noise, the autonomic regulatory function changes, showing a faster or slower heart rate, unstable blood pressure (increased trend), and severe coronary heart disease and arteriosclerosis.

(4) Digestive system: Gastrointestinal disorders, loss of appetite, weight loss, decreased secretion of gastric juice, slowing of gastrointestinal motility, resulting in increased incidence of stomach diseases and gastric ulcer diseases.

(5) Women's menstruation and reproductive function: women exposed to noise may have menstrual cycle disorders, dysmenorrhea, etc.; spontaneous abortion rate is increased; the incidence of pregnancy-induced hypertension has an increasing trend.

Prevention of noise hazards

The control of noise should take into account the three elements of sound: the source of noise, the medium of propagation, and the recipient. At the same time, hazard prevention should also be combined with occupational health checks.

(1) Transform sound sources and reduce noise. Through technological innovations, the transformation of vocal objects into objects that do not sound or whisper is a fundamental measure. For example, by adopting new materials, improving the structure of mechanical equipment, reforming processes and methods of operation, and improving component processing accuracy and assembly quality to reduce noise.

(2) Reasonable planning and design to control noise propagation and reflection. If the high-noise area and the office area are arranged separately, the high-noise machine and the low-noise machine are arranged separately, and greening is used to reduce the noise. Ways to control noise propagation and reflection include: 1 Sound absorption. Porous materials are applied to the surfaces of walls and roofs to absorb radiation or reflected acoustic energy to reduce noise. Commonly used sound-absorbing materials are glass wool, slag wool, foam plastic, felt, cotton wool and so on. 2 silencer. Silencing is the main measure to prevent aerodynamic noise. It is used in wind tunnels and exhaust pipes. The principle of filtering is used to change the direction or shape of the sound wave during propagation so as to achieve the purpose of reducing acoustic noise by using sound energy. Commonly used resistance muffler, resistance muffler, impedance composite muffler. 3 sound insulation. Confined noise sources; establishment of soundproof rooms, employees operating in the sound insulation room. 4 vibration isolation.

(3) Strengthen personal protection. Personal protection is an economic and effective measure. Commonly used anti-sound use has earplugs, earmuffs, soundproof cotton, soundproof helmets, etc. They mainly use the principle of sound insulation to block the noise from being introduced into the eardrum.

(4) Conduct occupational health examinations. Through pre-employment occupational health examinations, patients with occupational contraindications are controlled to engage in noise operations; health monitoring is performed regularly during the post, early detection of people who are sensitive to noise or early hearing impairment, and corresponding measures are taken to prevent further hearing loss.

China Labor Insurance Network

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