When standardizing the permissible sound pressure at workplaces, the frequency spectrum of the noise is divided into nine frequency bands.

The normalized parameters of constant noise are:

sound pressure levelL, dB, in octave bands with geometric mean frequencies of 31.5; 63; 125; 250; 500; 1000; 2000; 4000; 8000 Hz;

sound levelLa , dBA.

The normalized parameters of non-constant noise are:

- equivalent (energy) sound levelLa eq, dB A,

-maximum sound levelLa max, dB A. Exceeding at least one of these indicators is qualified as non-compliance with these sanitary standards.

In accordance with SanPiN 2.2.4 / 2.1.8.10-32-2002, the maximum permissible noise levels are standardized for two categories of noise standards: remote control for noise at workplaces and remote control for noise in residential, public buildings and on the territory of residential buildings.

For tonal and impulse noise, as well as noise generated in rooms by air conditioning, ventilation and air heating, RCUs should be taken 5 dB (dBA) less than the values ​​indicated in table. 8.4. of this paragraph and app. 2 to SanPiN 2.2.4 / 2.1.8.10-32-2002.

The maximum sound level for oscillating and intermittent noise should not exceed 110 dBA. Even a short stay in areas with sound levels or sound pressure levels in any octave band exceeding 135 dB A (dB) is prohibited.

Remote control of noise in the premises of residential, public buildings and on the territory of residential buildings. The permissible values ​​of the sound pressure levels in the octave frequency bands of the equivalent and maximum sound levels of penetrating noise into the premises of residential and public buildings and of noise on the territory of residential buildings are established in accordance with Appendix. 3 to SanPiN 2.2.4 / 2.1.8.10-32-2002.

Means and methods of protection against noise

The fight against noise in production is carried out in a comprehensive manner and includes measures of a technological, sanitary and technical, therapeutic and prophylactic nature.

The classification of means and methods of protection against noise is given in GOST 12.1.029-80 SSBT “Means and methods of protection against noise. Classification ", SNiP II-12-77" Protection against noise ", which provide for protection against noise by the following construction-acoustic methods:

a) soundproofing of enclosing structures, sealing of porches of windows, doors, gates, etc., arrangement of soundproof cabins for personnel; by covering noise sources in enclosures;

b) installation of sound-absorbing structures and screens in rooms in the path of noise propagation;

c) the use of aerodynamic noise mufflers in internal combustion engines and compressors; sound-absorbing linings in the air ducts of ventilation systems;

d) the creation of noise protection zones in various places where people are located, the use of screens and green spaces.

Noise reduction is achieved by using elastic pads under the floor without their rigid connection with the supporting structures of buildings, installing equipment on shock absorbers or specially insulated foundations. Sound absorption means are widely used - mineral wool, felt boards, perforated cardboard, fiberboards, fiberglass, as well as active and reactive silencers.

Mufflers aerodynamic noise can be absorption, reactive (reflex) and combined. In absorption

In mufflers, noise attenuation occurs in the pores of the sound-absorbing material. The principle of operation of jet mufflers is based on the effect of sound reflection as a result of the formation of a "wave plug" in the elements of the muffler. Combined silencers both absorb and reflect sound.

Soundproofing is one of the most effective and common methods of reducing industrial noise on the way of its distribution. With the help of soundproofing devices, it is easy to reduce the noise level by 30 ... 40 dB. Effective sound insulating materials are metals, concrete, wood, dense plastics, etc.

To reduce noise in the room, sound-absorbing materials are applied to the internal surfaces, and piece sound absorbers are also placed in the room.

Use of personal protective equipment against noise it is advisable in cases where collective protective equipment and other means do not provide noise reduction to permissible levels.

PPE can reduce the level of perceived sound by 0 ... 45 dB, and the most significant noise suppression is observed in the high frequencies, which are most dangerous for humans.

Personal protective equipment against noise is subdivided into ear muffs that cover the auricle from the outside; anti-noise earmolds that block the external auditory canal or adjacent to it; anti-noise helmets and helmets; anti-noise suits. Anti-noise earbuds are made of hard, elastic and fibrous materials. They are single and multiple use. Anti-noise helmets cover the entire head, they are used at very high noise levels in combination with headphones and anti-noise suits.

Abstract on the topic:

"NORMALIZATION OF NOISE"

Noise measurement is carried out in two ways:

By the limiting noise spectrum (mainly for constant noise in standard octave bands with geometric mean frequencies - 63, 125, 250, 500, 1000, 2000, 8000 Hz);

According to the sound level in decibels "A" with a sound level meter (dBA), measured when the correction frequency response "A" is turned on (for a rough estimate of noise - medium-sensitive human hearing).

Sound pressure levels at workplaces in the standardized frequency range should not exceed the values ​​specified in GOST 12.1.003-83 (general noise level for assessing constant noise and integral-equivalent assessment for variable noise).

The normalized characteristic of constant noise at workplaces are the levels sound pressure L, dB in octave bands with geometric mean frequencies of 63, 125, 250, 1000, 2000, 4000 and 8000 Hz. The principle is also used, which is based on the sound level in dBA and is measured when the corrective frequency response "A" of the sound level meter is switched on. In this case, an integral assessment of the entire noise is carried out, in contrast to the spectral one. According to DSN 3.3.6-037-99, GOST 12.003-83, SSBT “Noise. General requirements safety "and SN 32.23-85" Sanitary standards of permissible noise at workplaces ", permissible sound pressure levels at workplaces should be taken for broadband noise according to table 2.5.1 .; for non-constant - 5 dB less than the values ​​given in table 2.5.1 .; for noise generated as a result of air conditioning or ventilation in rooms - 5 dB less than the values ​​indicated in table 2.5.1.

Table 2.5.1.

Acceptable noise levels

The sound level that is created by an enterprise or transport on the territory of residential buildings is determined by sanitary standards, and noise rationing in residential buildings and public buildings is determined by SNiP 2-12-77.

Taking into account the severity and intensity of labor, the permissible noise levels should correspond to the values ​​given in table 2.5.2.

Noise in classrooms, reading rooms should not exceed 55 dBA, and on the street more than 70 dBA. The permissible noise level on the street should not exceed 50 dBA during the day, and 40 dBA at night. The permissible noise level in residential premises should not exceed 40 dBA during the day, and 30 dBA at night.

A noise level of 110 dBA leads to impairment of the auditory organs, damage to the central nervous system, and weakening of the protective functions of the body. It is forbidden to approach without protective equipment to areas exposed to noise of 135 dBA. Noise level of 140 dBA causes pain, at 155 dBA causes burns, at 180 dBA - death.

Table 2.5.2.

Optimal sound levels at workplaces when performing work of various categories of severity and intensity

NOISE MEASURING INSTRUMENTS

Microphones and various sound level meters are used to measure noise. In sound level meters, the sound signal is converted into electrical impulses, which are amplified and, after filtering, are recorded on the scale by the device and the recorder.

The following devices are used to measure the levels of sound pressure and sound intensity: sound level meter of the Sh-71 type with octave filters OF-5 and OF-6; sound level meter PS 1-202 with octave filters OF-101 from RET (Germany); sound level meters of type 2203, 2209 with octave filters of type 1613 from Brüel, Ker (Denmark); noise and vibration meters IShV-1 and VShV-003.

The noise characteristics of the technological equipment are determined at a distance of 1 m from the contour of the machines. In the workplace, noise measurements should be made at ear level (at a distance of 5 cm from it) when the worker is in the main working position.

Modern sound level meters have correcting frequency characteristics "A" and "Lin". The linear objective characteristic (Lin) is used when measuring sound pressure levels in octave bands 63 ... 8000 Hz - over the entire frequency range.

In order for the indicators of the sound level meter to approach the subjective sensations of loudness, the characteristic of the sound level meter "A" is used, which approximately corresponds to the sensitivity of the hearing organ at different volume levels. The operating range of the sound level meter is 30-140 dB. Frequency analysis of noise is performed by a sound level meter with an attached spectrum analyzer (set of acoustic filters). Each filter passes a narrow band of sound frequencies defined by the high and low end of the octave bands. In this case, in production conditions, only the sound level in dBA is recorded, and spectral analysis conducted by tape recording of noise.

The fight against noise is carried out different methods and means:

1.reduction of the power of sound radiation of machines and assemblies;

2. localization of the effect of sound by constructive and planning solutions;

3. organizational and technical measures;

4. medical and preventive measures;

5. the use of personal protective equipment for workers.

Conventionally, all means of protection against noise are subdivided into collective and individual.

Collective remedies:

Means that reduce noise at the source;

Means that reduce noise on its way to the protected object.

Reducing noise at the source of occurrence is the most effective and economical (allows you to reduce noise by 5-10 dB):

Elimination of gaps in gear joints;

The use of globoid and chevron connections as less noisy;

Extensive use, whenever possible, of plastic parts;

Elimination of noise in bearings;

Replacement of metal cases with plastic ones;

Balancing of parts (elimination of imbalance);

Elimination of distortions in bearings;

Replacement gears on V-belt;

Replacement of rolling bearings for sliding (15 dB), etc.

To reduce noise in reinforcing shops, it is advisable to: use hard plastics to cover surfaces in contact with reinforcing wire; installation of elastic materials in places where reinforcement falls; the use of vibration-absorbing materials in the enclosing surfaces of machines.

Technological measures for reducing the noise level at the source include: reducing the amplitude of oscillations, speed, etc.

Collective protection means and methods that reduce noise on the way of its propagation are subdivided into:

Architectural planning;

Acoustic;

Organizational and technical.

Architectural and planning measures to reduce noise.

1.From the point of view of combating noise in urban planning, when designing cities, it is necessary to clearly divide the territory into zones: residential (residential), industrial, communal storage and external transport, in compliance with the standards of sanitary protection zones when developing the general plan.

2. The correct layout of industrial premises should be carried out taking into account the isolation of the premises from external noise and noisy industries. Industrial buildings with noisy technological processes should be located on the leeward side in relation to other buildings and a residential settlement, and always with end sides to them. (The mutual orientation of buildings is decided so that the sides of the buildings with windows and doors are against the blind sides of the buildings. The window openings of such workshops are filled with glass blocks, and the entrance is made with vestibules and sealing around the perimeter.

3. The most noisy and hazardous industries are recommended to be completed in separate complexes with the provision of gaps between individual nearby objects in accordance with sanitary standards. Indoors are also combined with noise technology, limiting the number of workers exposed to noise. There must be gaps (at least 100 m) between buildings with noisy technology and other buildings of the enterprise. Gaps between workshops with noisy technology and other buildings should be greened. The foliage of trees and shrubs is a good noise absorber. New railway lines and stations should be separated from residential buildings by a protection zone with a width of at least 200 m. When installing along the line of noise barriers, the minimum width of the protection zone is 50 m. Residential buildings should be located at a distance of at least 100 m from the edge of the highway.

Noiserefers to any unwanted sound or combination of such sounds. Sound is a wave-like oscillatory process propagating in an elastic medium in the form of alternating waves of condensation and rarefaction of particles of this medium - sound waves.

Any vibrating body can be the source of sound. When this body comes into contact with the environment, sound waves are generated. Concentration waves cause an increase in pressure in the elastic medium, and rarefaction waves - a decrease. This gives rise to the concept sound pressure is the alternating pressure that occurs when sound waves pass in addition to atmospheric pressure.

Sound pressure is measured in Pascals (1 Pa = 1 N / m 2). The human ear senses a sound pressure from 2-10 -5 to 2-10 2 N / m 2.

Sound waves are energy carriers. Sound energy per square meter of surface area perpendicular to the propagating sound waves, called the power of sound and is expressed in W / m 2. Since a sound wave is an oscillatory process, it is characterized by concepts such as oscillation period(T) is the time during which one complete oscillation occurs, and vibration frequency(Hz) - the number of complete oscillations in 1 s. The set of frequencies gives noise spectrum.

Noises contain sounds of different frequencies and differ among themselves by the distribution of levels at individual frequencies and the nature of the change general level in time. For the hygienic assessment of noise, the sound frequency range from 45 to 11,000 Hz is used, including 9 octave bands with geometric mean frequencies of 31.5; 63; 125; 250; 500; 1000; 2000; 4000 and 8000 Hz.

The organ of hearing distinguishes not the difference, but the multiplicity of changes in sound pressure, therefore, the intensity of sound is usually assessed not by the absolute value of the sound pressure, but by its level, those. the ratio of the generated pressure to the pressure taken as a unit

comparisons. In the range from the hearing threshold to the pain threshold, the sound pressure ratio changes by a factor of a million, therefore, to reduce the measurement scale, the sound pressure is expressed through its level in logarithmic units - decibels (dB).

Zero decibels corresponds to a sound pressure of 2-10 -5 Pa, which approximately corresponds to the threshold of audibility of a tone with a frequency of 1000 Hz.

Noise is classified according to the following criteria:

Depending on the the nature of the spectrum emit the following noises:

broadband, with a continuous spectrum more than one octave wide;

tonal, in the spectrum of which there are pronounced tones. The tonal nature of the noise is established by measuring in one-third octave frequency bands by the excess of the level in one band in comparison with the neighboring ones by at least 10 dB.

By timing characteristics distinguish between noises:

permanent, the sound level of which during an 8-hour working day changes in time by no more than 5 dBA;

fickle the noise level of which during an 8-hour working day changes in time by at least 5 dBA. Intermittent noises can be classified into the following types:

- hesitant in time, the sound level of which is continuously changing over time;

- intermittent, the sound level of which changes stepwise (by 5 dB-A or more), and the duration of the intervals during which the level remains constant is 1 s or more;

- pulse, consisting of one or more sound signals, each of which has a duration of less than 1 s; in this case, the sound levels measured, respectively, on the “impulse” and “slow” time characteristics of the sound level meter differ by at least 7 dB.

11.1. sources of NOISE

Noise is one of the most common adverse factors in the working environment, the impact of which on workers is accompanied by the development of premature fatigue, a decrease in labor productivity, an increase in general and occupational morbidity, as well as injuries.

At present, it is difficult to name a production that does not have elevated levels of noise in the workplace. The most noisy are the mining and coal, machine-building, metallurgical, petrochemical, forestry and pulp and paper, radio engineering, light and food, meat and dairy industries, etc.

So, in cold heading shops the noise reaches 101-105 dBA, in nail shops - 104-110 dBA, in braiding shops - 97-100 dBA, in seam polishing departments - 115-117 dBA. At the workplaces of turners, milling cutters, mechanics, blacksmiths-stampers, the noise level ranges from 80 to 115 dBA.

At factories of reinforced concrete structures, the noise reaches 105-120 dBA. Noise is one of the leading occupational hazards in the woodworking and logging industries. So, at the work place of a frame cutter and a cutter, the noise level ranges from 93 to 100 dBA with a maximum of sound energy in the region of medium and high frequencies. The noise in the carpentry shops fluctuates within the same limits, and logging operations (felling, skidding of timber) are accompanied by a noise level of 85 to 108 dBA due to the operation of skidding winches, tractors and other mechanisms.

The overwhelming majority of production processes in spinning and weaving mills are also accompanied by the formation of noise, the source of which is the striking mechanism of the weaving machine, blows of the shuttle drive. Most high level noise is observed in weaving shops - 94-110 dBA.

The study of working conditions in modern garment factories showed that the noise level at the workplaces of seamstresses-mechanics is 90-95 dBA with a maximum of sound energy at high frequencies.

The most noisy operations in mechanical engineering, including aircraft construction, automobile construction, car building, etc. should be considered cutting and riveting work using pneumatic tools, performance tests of engines and their units of various systems, bench tests for vibration strength of products, drum cooking, grinding and polishing parts, stamping blank.

The petrochemical industry is characterized by high-frequency noises of various levels due to the discharge of compressed air from a closed technological cycle of chemical production or

from compressed air equipment such as assembly machines and vulcanizing lines in tire factories.

At the same time, in mechanical engineering, as in no other industry, the largest volume of work falls on machine tool metalworking, which employs about 50% of all workers in the industry.

The metallurgical industry as a whole can be classified as an industry with a pronounced noise factor. Thus, intense noise is typical for smelting, rolling and pipe rolling industries. Of the industries related to this industry, hardware factories equipped with cold heading machines are characterized by noisy conditions.

The most noisy processes include noise from an open air jet (blowing) escaping from small diameter holes, noise from gas burners and noise generated when metals are sprayed onto various surfaces. The spectra from all these sources are very similar, typically high-frequency, without a noticeable drop in energy up to 8-10 kHz.

In the forestry and pulp and paper industries, woodworking workshops are the most noisy.

The building materials industry includes a number of noisy industries: machines and mechanisms for crushing and grinding raw materials and the production of precast concrete.

In the mining and coal industries, the most noisy operations are mechanized mining operations both with the use of hand-held machines (pneumatic perforators, jackhammers) and with the help of modern stationary and self-propelled machines (combines, drilling rigs, etc.).

The radio engineering industry is generally comparatively less noisy. Only its preparatory and procurement shops have equipment typical for the machine-building industry, but in much smaller quantities.

In light industry, both in terms of noise and the number of employed workers, spinning and weaving industries are the most unfavorable.

The food industry is the least noisy of all. Its characteristic noises are generated by flow units of confectionery and tobacco factories. However, some machines of these industries generate significant noise, for example, cocoa mills, some sorting machines.

Each branch of industry has workshops or separate compressor stations supplying the production with compressed air or pumping liquids or gaseous products. The latter are widely used in the gas industry as large independent farms. Compressor units generate intense noise.

Examples of noises typical for various industries, in the absolute majority of cases, have a common spectral shape: they are all broadband, with a slight drop in sound energy in the low (up to 250 Hz) and high (above 4000 Hz) frequencies with levels of 85-120 dBA. Exceptions are aerodynamic noises, where sound pressure levels rise from low to high frequencies, as well as low frequency noises, which are significantly less in industry than those described above.

All described noises characterize the most noisy industries and areas where physical labor predominates. At the same time, less intense noises are also widespread (60-80 dBA), which, however, are hygienically significant during work associated with nervous stress, for example, at control panels, during computer processing of information and other works that are becoming more widespread.

Noise is also the most common adverse factor in the working environment in the workplace of passenger, transport aircraft and helicopters; rolling stock of railway transport; sea, river, fishing and other vessels; buses, trucks, cars and special vehicles; agricultural machinery and equipment; road construction, land reclamation and other machines.

The noise levels in the cockpit of modern aircraft fluctuate in a wide range - 69-85 dBA (long-haul aircraft for medium and long-range airlines). In the cabs of medium-duty vehicles under various operating modes and operating conditions, the sound levels are 80-102 dBA, in the cabs of heavy vehicles - up to 101 dBA, in cars - 75-85 dBA.

Thus, for the hygienic assessment of noise, it is important to know not only its physical parameters, but also the nature of the work activity of the human operator, and, above all, the degree of his physical or nervous load.

11.2. biological effect of noise

Professor E.Ts. Andreeva-Galanina. She showed that noise is a general biological stimulus and affects not only the auditory analyzer, but, first of all, affects the structures of the brain, causing shifts in various body systems. Manifestations of noise impact on the human body can be conditionally subdivided into specific changes occurring in the organ of hearing, and nonspecific arising in other organs and systems.

Aural effects. Changes in the sound analyzer under the influence of noise constitute a specific reaction of the body to acoustic exposure.

It is generally accepted that the leading sign of the adverse effect of noise on the human body is a slowly progressive hearing loss of the type of cochlear neuritis (and, as a rule, both ears are equally affected).

Occupational hearing loss refers to sensorineural (perceptual) hearing loss. This term means hearing impairment.

Hearing loss under the influence of sufficiently intense and long-acting noise is associated with degenerative changes both in the hair cells of the organ of Corti and in the first neuron of the auditory tract - the spiral ganglion, as well as in the fibers of the cochlear nerve. However, there is no consensus on the pathogenesis of persistent and irreversible changes in the receptor region of the analyzer.

Occupational hearing loss usually develops after a more or less long period of work in noise. The timing of its occurrence depends on the intensity and frequency-time parameters of the noise, the duration of its exposure and the individual sensitivity of the hearing organ to noise.

Complaints about headache, increased fatigue, tinnitus, which can occur in the first years of work in a noise environment, are not specific to the lesion of the auditory analyzer, but rather characterize the reaction of the central nervous system to the effect of the noise factor. The feeling of hearing loss usually occurs much later than the appearance of the first audiological signs of damage to the auditory analyzer.

In order to detect the earliest signs of the effect of noise on the body and, in particular, on the sound analyzer, the most widely used method is to determine the temporal displacement of hearing thresholds (TSP) at different exposure times and the nature of the noise.

In addition, this indicator is used to predict hearing loss based on the ratio between constant shifts in the thresholds (losses) of hearing (HRL) from noise, acting during the entire time of work in noise, and temporary shifts in the thresholds (HRT) during daytime exposure. the same noise, measured two minutes after exposure to noise. For example, in weavers, the temporary displacements of hearing thresholds at a frequency of 4000 Hz for a daytime exposure to noise are numerically equal to constant hearing losses at this frequency for 10 years of work in the same noise. Based on this, it is possible to predict the resulting hearing loss by determining only the shift in the threshold for the daytime exposure to noise.

Noise accompanied by vibration is more harmful to the organ of hearing than isolated.

Extra-aural effects of noise. The concept of noise sickness took shape in the 1960s and 1970s. on the basis of works on the effect of noise on the cardiovascular, nervous and other systems. At present, it has been replaced by the concept of extra-aural effects as non-specific manifestations of the effect of noise.

Workers exposed to noise complain of headaches of varying intensity, often with localization in the forehead (more often they occur at the end of work and after it), dizziness associated with a change in body position, depending on the effect of noise on the vestibular apparatus, memory loss , drowsiness, increased fatigue, emotional instability, sleep disturbance (intermittent sleep, insomnia, less often drowsiness), pain in the heart, decreased appetite, increased sweating, etc. The frequency of complaints and their severity depend on the length of service, the intensity of noise and its nature ...

Noise can interfere with function of cardio-vascular system... Changes in the electrocardiogram were noted in the form of a shortening of the Q-T interval, lengthening of the P-Q interval, an increase in the duration and deformation of the P and S waves, displacement interval T-S, change in the voltage of the T wave.

The most unfavorable from the point of view of the development of hypertensive conditions is broadband noise with a predominance of high-frequency components and a level above 90 dBA, especially impulse noise. Broadband noise causes maximum shifts in peripheral circulation. It should be borne in mind that if there is addiction (adaptation) to the subjective perception of noise, then in relation to developing vegetative reactions, adaptation is not observed.

According to the data of an epidemiological study of the prevalence of major cardiovascular diseases and some risk factors (overweight, burdened anamnesis, etc.) in women working under conditions of constant occupational noise in the range from 90 to 110 dBA, it was shown that noise, as a separate factor (excluding common risk factors), may increase the frequency arterial hypertension(AH) in women under the age of 39 (with less than 19 years of experience) by only 1.1%, and in women over 40 - by 1.9%. However, when noise is combined with at least one of the "common" risk factors, an increase in hypertension can be expected by 15%.

When exposed to intense noise of 95 dBA and above, there may be a violation of vitamin, carbohydrate, protein, cholesterol and water-salt metabolism.

Despite the fact that noise affects the body as a whole, the main changes are noted on the part of the hearing organ, the central nervous and cardiovascular systems, and changes in the nervous system may precede disorders in the hearing organ.

Noise is one of the most powerful stressors in the workplace. As a result of exposure to high-intensity noise, changes occur simultaneously in both the neuroendocrine and immune systems. In this case, the anterior lobe of the pituitary gland is stimulated and the secretion of steroid hormones by the adrenal glands increases, and as a consequence, the development of acquired (secondary) immunodeficiency with involution of lymphoid organs and significant changes in the content and functional state T- and B-lymphocytes in the blood and bone marrow. Defects that arise immune system relate mainly to three main biological effects:

Decreased anti-infectious immunity;

Creation of favorable conditions for the development of autoimmune and allergic processes;

Decreased antitumor immunity.

The relationship between the incidence and the magnitude of hearing loss at speech frequencies of 500-2000 Hz has been proven, indicating that simultaneously with a decrease in hearing, changes occur that contribute to a decrease in the body's resistance. With an increase in industrial noise by 10 dBA, the indicators of the general morbidity of workers (both in cases and in days) increase by 1.2-1.3 times.

Analysis of the dynamics of specific and nonspecific disorders with an increase in work experience under noise exposure using the example of weavers showed that with an increase in work experience, a polymorphic symptom complex is formed in weavers, including pathological changes in the organ of hearing in combination with vegetative-vascular dysfunction. At the same time, the rate of increase in hearing loss is 3.5 times higher than the increase in functional disorders of the nervous system. With an experience of up to 5 years, transient vegetative-vascular disorders prevail, with an experience of more than 10 years - hearing loss. The relationship between the frequency of vegetative-vascular dysfunction and the magnitude of hearing loss was also revealed, which manifests itself in their growth with a decrease in hearing to 10 dB and in stabilization with the progression of hearing loss.

It was found that in industries with noise levels up to 90-95 dBA, vegetative-vascular disorders appear earlier and prevail over the frequency of cochlear neuritis. Their maximum development is observed with 10 years of work experience in noise conditions. Only at noise levels exceeding 95 dBA, by 15 years of work in a “noisy” profession, the extraaural effects stabilize, and hearing loss begins to prevail.

Comparison of the frequency of hearing loss and neurovascular disorders depending on the noise level showed that the growth rate of hearing loss is almost 3 times higher than the growth rate of neurovascular disorders (about 1.5 and 0.5% per 1 dBA, respectively), that is with an increase in the noise level by 1 dBA, hearing loss will increase by 1.5%, and neurovascular disorders - by 0.5%. At levels of 85 dBA and above, for each decibel of noise, neurovascular disorders occur six months earlier than at lower levels.

Against the background of the ongoing intellectualization of labor, an increase in the proportion of operator professions, an increase in the value of noise at medium levels (below 80 dBA) is noted. These levels do not cause hearing loss, but tend to be disruptive, annoying and fatiguing effects that add up to

such from strenuous work and with an increase in the length of service in the profession can lead to the development of extra-aural effects, manifested in general somatic disorders and diseases. In this regard, the biological equivalent of the effect of noise and stressful labor on the body was substantiated, equal to 10 dBA of noise per one category of intensity of the labor process (Suvorov G.A. et al., 1981). This principle is the basis of the current sanitary norms for noise, differentiated taking into account the intensity and severity of the labor process.

Currently, much attention is paid to the assessment of occupational health risks of workers, including those caused by the adverse effects of industrial noise.

In accordance with ISO 1999.2 “Acoustics. Determination of occupational exposure to noise and assessment of noise-induced hearing impairment ”can assess the risk of hearing impairment depending on the exposure and predict the likelihood of occupational diseases. On the basis of the mathematical model of the ISO standard, the risks of the development of occupational hearing loss are determined as a percentage, taking into account domestic criteria for occupational hearing loss (table 11.1). In Russia, the degree of occupational hearing loss is assessed by the average hearing loss at three speech frequencies (0.5-1-2 kHz); values ​​over 10, 20, 30 dB correspond to the 1st, IInd, II 1st degree hearing loss.

Given that the decline hearing I degree with a fairly high probability can develop without noise exposure as a result of age-related changes, it seems inappropriate to use the I-th degree of hearing loss to assess safe work experience. In this regard, the table shows the calculated values ​​of the work experience, during which hearing loss of the II and III degree may develop, depending on the noise level at workplaces. Data are given for different probabilities (in%).

V tab. 11.1 data for men are given. In women, due to a slower increase in age-related changes in hearing than in men, the data are slightly different: for more than 20 years of experience, women have 1 year more safe experience than men, and for more than 40 years, 2 years ...

Table 11.1.Work experience before the development of hearing loss exceeding

criterion values, depending on the noise level at the workplace (at 8-hour exposure)

Note. a dash means more than 45 years of work experience.

At the same time, it should be noted that the standard does not take into account the nature of labor activity, as provided for in the sanitary norms for noise, where the maximum permissible noise levels are differentiated by categories of severity and intensity of work and thereby cover the nonspecific effect of noise, which is important for maintaining health and working capacity. persons of camera professions.

11.3. noise rationing at workplaces

Prevention of the adverse effect of noise on the body of workers is based on its hygienic regulation, the purpose of which is to substantiate permissible levels and a set of hygienic requirements that provide prevention functional disorders or diseases. In hygienic practice, maximum permissible levels (MPL) for workplaces are used as a standardization criterion, allowing for deterioration and change in external performance indicators (efficiency

and performance) with a mandatory return to the previous system of homeostatic regulation of the initial functional state, taking into account adaptive changes.

Normalization of noise is carried out according to a set of indicators, taking into account their hygienic significance. The effect of noise on the body is assessed by reversible and irreversible, specific and nonspecific reactions, decreased performance or discomfort. To maintain health, performance and well-being of a person, optimal hygienic regulation should take into account the type labor activity, in particular, the physical and neuro-emotional components of labor.

The impact of the noise factor on a person consists of two components: the load on the hearing organ as a system that perceives sound energy, - aural effect, and the impact on the central links of the sound analyzer as a system for receiving information - extraaural effect. To assess the first component, there is a specific criterion - "fatigue of the organ of hearing", expressed in a shift in the thresholds of perception of tones, which is proportional to the magnitude of sound pressure and exposure time. The second component was named nonspecific influence, which can be objectively assessed by integral physiological indicators.

Noise can be considered as a factor involved in efferent synthesis. At this stage, all possible efferent influences (situational, reverse and search) are compared in the nervous system in order to develop the most adequate response. The effect of strong industrial noise is such an environmental factor that, by its nature, also affects the efferent system, i.e. affects the process of formation of a reflex reaction at the stage of efferent synthesis, but as a situational factor. In this case, the result of the impact of the situational and triggering influences depends on their strength.

In cases of an attitude towards activity, the situational information should be an element of the stereotype and, therefore, should not cause adverse changes in the body. At the same time, addiction to noise in the physiological sense is not observed, the severity of fatigue and the frequency of nonspecific disorders increase with the increase in the length of service in noise conditions. Consequently, the mechanism of action of noise cannot be limited by the factor of its participation in

situational afferentation. In both cases (noise and stress), we are talking about the load on the functional systems of higher nervous activity, and, therefore, the genesis of fatigue under such an effect will be of a similar nature.

The criterion for normalizing the optimal level for many factors, including noise, can be considered such a state physiological functions, at which a given noise level does not contribute its share to their voltage, and the latter is entirely determined by the work performed.

The tension of labor is made up of the elements that make up the biological system of reflex activity. Analysis of information, the amount of working memory, emotional stress, functional stress of analyzers - all these elements are loaded in the process of work, and it is natural that their active load causes the development of fatigue.

As in any case, the response to exposure consists of specific and non-specific components. What is the share of each of these elements in the process of fatigue is an unresolved question. However, there is no doubt that the effects of noise and labor intensity cannot be considered one without considering the other. In this regard, the effects mediated through nervous system(fatigue, decreased performance), both for noise and labor intensity have a qualitative similarity. Industrial and experimental studies using socio-hygienic, physiological and clinical methods and indicators have confirmed these theoretical propositions. On the example of studying different professions, the value of the physiological and hygienic equivalent of noise and intensity of neuro-emotional labor was established, which was within 7-13 dBA, ie. on average 10 dBA for one category of tension. Consequently, an assessment of the tension of the operator's labor process is necessary for a full hygienic assessment of the noise factor at workplaces.

The maximum permissible sound levels and equivalent sound levels at workplaces, taking into account the intensity and severity of work, are presented in tab. 11.2.

A quantitative assessment of the severity and intensity of the work process should be carried out in accordance with the criteria of Guideline 2.2.2006-05.

Table 11.2.Maximum permissible sound levels and equivalent sound levels at workplaces for work activities of different categories of severity and intensity, dBA

Note.

For tonal and impulse noise, the remote control is 5 dBA less than the values ​​indicated in the table;

For the noise generated in the premises by air conditioning, ventilation and air heating installations, the remote control is 5 dBA less than the actual noise levels in the premises (measured or calculated), if the latter do not exceed the valuestab. 11.1 (the correction for tonal and impulse noise is not taken into account), otherwise - 5 dBA less than the values ​​indicated in the table;

Additionally, for time-varying and intermittent noises, the maximum sound level should not exceed 110 dBA, and for impulse noise, 125 dBA.

Since the purpose of differentiated noise regulation is to optimize working conditions, the combinations of intense and very intense with heavy and very hard physical labor are not standardized on the basis of the need to eliminate them as unacceptable. However, for the practical use of new differentiated standards both in the design of enterprises and in the current monitoring of noise levels at operating enterprises, a serious problem is to bring the categories of the severity and intensity of labor into line with the types of work activities and work premises.

Impulse noise and its evaluation. Impulse noise is not strictly defined. So, in the current sanitary standards, impulse noise includes noises consisting of one or several sound signals, each with a duration of less than 1 s, while the sound levels in dBA, measured according to the characteristics "impulse" and "slow", differ by at least 7 dB.

One of the important factors determining the difference in responses to constant and impulse noise is the peak level. In accordance with the concept “ critical level»Noises with levels above a certain level, even very short-term, can cause direct trauma to the organ of hearing, which is confirmed by morphological data. Many authors indicate different values ​​of the critical level: from 100-105 dBA to 145 dBA. Such noise levels are found in production, for example, in forging shops, the noise from hammers reaches 146 and even 160 dBA.

Apparently, the danger of impulse noise is determined not only by high equivalent levels, but also by the additional contribution of temporal characteristics, probably due to the traumatic effect of high peak levels. Studies of the distribution of impulse noise levels have shown that, despite the small total duration of the action of peaks with levels above 110 dBA, their contribution to the total dose can reach 50%, and this value of 110 dBA was recommended as an additional criterion when assessing intermittent sanitary standards.

The above standards set the remote control for impulse noise by 5 dB lower than for constant noise (that is, they make a correction of minus 5 dBA for the equivalent level), and additionally limit the maximum sound level to 125 dBA "impulse", but do not regulate the peak values. Thus, the current regulations

are guided by the loudness effects of noise, since the characteristic "impulse" with t = 40 ms is adequate to the upper sections of the sound analyzer, and not to the possible traumatic effect of its peaks, which is generally recognized at the present time.

The noise impact on workers, as a rule, is variable in terms of noise level and (or) its duration. In this regard, the concept of equivalent sound level. Associated with an equivalent level is a noise dose that reflects the amount of energy transferred and can therefore serve as a measure of the noise load.

The presence in the current sanitary standards of noise at workplaces, in the premises of residential and public buildings and on the territory of residential buildings as a standardized parameter of an equivalent level and the absence of such as a noise dose are explained by a number of factors. First, the lack of domestic dosimeters in the country; secondly, when standardizing noise for residential premises and for some professions (workers whose hearing organ is a working organ), the energy concept requires amendments made to measuring instruments in order to express noise not in sound pressure levels, but in subjective loudness values.

Considering the emergence in recent years of a new direction in hygienic science to establish the degree of occupational risk from various factors of the working environment, including noise, it is necessary to take into account in the future the magnitude of the noise dose with different risk categories, not so much in terms of specific impact (auditory), but in terms of nonspecific manifestations (disorders) from other organs and systems of the body.

Until now, the effect of noise on a person has been studied in isolation: in particular, industrial noise - on workers of various industries, employees of the administrative and managerial apparatus; urban and residential noise - on the population of various categories in living conditions. These studies made it possible to substantiate the standards for constant and non-constant, industrial and household noise in various places and conditions of a person's stay.

However, for a hygienic assessment of the effect of noise on a person in industrial and non-industrial conditions, it is advisable to take into account the total noise effect on the body, which

possibly based on the concept daily dose noise, taking into account the types of human activity (work, rest, sleep), based on the possibility of cumulating their effects.

11.4. prevention of adverse effects of noise

Noise control measures can be technical, architectural and planning, organizational and medical and preventive.

Technical means of noise control:

Eliminate the causes of noise or reduce it at the source;

Attenuation of noise along transmission paths;

Immediate protection of a worker or group of workers from the effects of noise.

Most effective remedy noise reduction is the replacement of noisy technological operations with low-noise or completely silent ones. Reducing noise at the source is essential. This can be achieved by improving the design or layout of the installation that produces noise, changing the mode of its operation, equipping the noise source with additional soundproofing devices or enclosures located as close as possible to the source (within its near field). One of the simplest technical means noise reduction on transmission paths is a sound-insulating casing that can cover a separate noisy part of a machine (for example, a gearbox) or the entire unit as a whole. Sheet metal enclosures lined with sound-absorbing material can reduce noise by 20-30 dB. An increase in the sound insulation of the casing is achieved by applying a vibration-damping mastic to its surface, which reduces the vibration levels of the casing at resonant frequencies and a rapid attenuation of sound waves.

To attenuate aerodynamic noise generated by compressors, ventilation units, pneumatic transport systems, etc., mufflers of active and jet types are used. The most noisy equipment is placed in soundproof chambers. With large dimensions of machines or a large service area, special cabins are equipped for operators.

Acoustic decoration of rooms with noisy equipment can reduce noise in the area of ​​the reflected sound field by 10-12 dB and in the area of ​​direct sound up to 4-5 dB in octave frequency bands. The use of sound-absorbing linings for the ceiling and walls leads to a change in the noise spectrum towards lower frequencies, which, even with a relatively small decrease in the level, significantly improves working conditions.

In multi-storey industrial buildings, it is especially important to protect premises from structure-borne noise(spreading over the structure of the building). Its source can be production equipment, which has a rigid connection with the enclosing structures. The attenuation of the transmission of structure-borne noise is achieved by vibration isolation and vibration absorption.

Floating floors are a good protection against impact noise in buildings. Architectural and planning solutions in many cases predetermine the acoustic mode of industrial premises, making it easier or more difficult to solve problems of their acoustic improvement.

The noise regime of industrial premises is determined by the size, shape, density and types of arrangement of machines and equipment, the presence of a sound-absorbing background, etc. Planning measures should be aimed at sound localization and reduction of its propagation. Rooms with sources of high noise levels should, if possible, be grouped in one area of ​​the building adjacent to storage and auxiliary premises, and separated by corridors or utility rooms.

Considering that it is not always possible with the help of technical means to reduce noise levels at workplaces to standard values, it is necessary to use personal protective equipment for the hearing organ from noise (antiphones, plugs). The effectiveness of personal protective equipment can be ensured by the correct selection depending on the levels and spectrum of noise, as well as by monitoring the conditions of their use.

In the complex of measures to protect a person from the adverse effects of noise, a certain place is occupied by medical supplies prevention. Preliminary and periodic medical examinations are essential.

Contraindications for employment, accompanied by noise exposure, are:

Persistent hearing loss (at least in one ear) of any etiology;

Otosclerosis and others chronic diseases ear with a poor prognosis;

Dysfunction of the vestibular apparatus of any etiology, including Meniere's disease.

Taking into account the importance of individual sensitivity of the organism to noise, it is extremely important to monitor the workers of the first year of work in noise conditions.

One of the directions of individual prevention of noise pathology is to increase the resistance of the workers' organism to the adverse effects of noise. For this purpose, workers in noisy professions are advised to take 2 mg of B vitamins and 50 mg of vitamin C daily (course duration 2 weeks with a week break). The introduction of regulated additional breaks should also be recommended, taking into account the noise level, its spectrum and the availability of personal protective equipment.

Prevention of the harmful effect of noise on the human body begins with its regulation. Noise regulation consists in the establishment of safe sound levels, the excess of which is a threat to the life and health of the population, since it creates the risk of developing diseases associated with the adverse effect of noise.

Normalized according to the following indicators:

• sound level (for constant noise);
• equivalent sound level (this indicator equates the sound level of inconsistent noise over a certain period of time to a certain sound level of constant broadband noise);
• maximum sound level (for intermittent noise);
• sound pressure levels in octave bands with geometric mean frequencies of 31.5 Hz, 63 Hz, 125 Hz, 250 Hz, 500 Hz, 1000 Hz, 2000 Hz, 4000 Hz, 8000 Hz.

Principles of noise regulation in residential and public areas and workplaces differ from each other.

Normalization of noise in residential and public buildings and in the adjacent territory

For residential premises and premises in public buildings and institutions, permissible noise levels have been established.

The permissible noise level is a level that does not cause significant anxiety in a person and does not cause significant changes in the indicators of the functional state of systems and analyzers that are sensitive to noise.

In other words, such noise is not only invisible to humans, but also will not cause absolutely any physiological effects on the part of the body. To such a noise the human body you do not have to adapt, which means that it is not a stress factor.

Let me remind you that the criterion for the "noticeability" of noise, i.e. its subjective perception, in itself cannot determine any norms of noise, since a person gets used to the subjective perception of even sufficiently high noise levels, but getting used to noise in a physiological sense does not occur. Fatigue and physiological effects caused by noise accumulate over time and can result in various functional disorders and diseases, which is why the ability of noise at known levels to cause the appearance of such effects determines the norms of noise along with its subjective perception.

If the permissible noise level is not exceeded, then it does not bother people in such an environment, it creates a comfortable atmosphere for doing everyday activities, does not cause fatigue, and contributes to active or peaceful rest.

When normalizing noise, both various states a person, both physiological and caused by various diseases, for example, noise that is invisible to a waking person, especially if he is having fun or is engaged in active rest, will interfere with a person who is trying to fall asleep, and therefore interfere with the normal course of sleep and rest of the body , which is fraught with his health. Therefore, for premises in which people can be around the clock, various standards have been established for the daytime (from 7 to 23 hours) and for the night time (from 23 hours to 7 hours).

Likewise, noise that does not interfere healthy person, can cause discomfort for a sick person. Therefore, for residential premises, and for premises equated to them, the noise standards are slightly higher than for the wards of hospitals and sanatoriums.

In classrooms, the permissible noise levels are commensurate with the norms for living quarters, since in order to focus on the educational process, any distractions are completely unnecessary.

For public institutions in which people have fun, make purchases, receive any services, the noise levels are higher than for residential premises, educational and treatment-and-prophylactic institutions.

Permissible noise levels have also been established for public areas.

Where are noise standards for residential and public spaces established?

The permissible noise levels are established in special regulatory documents that regulate the criteria for safety and harmlessness to human health of various environmental factors and requirements that provide favorable conditions for human life. These documents are: sanitary rules (SP), sanitary and epidemiological rules and regulations (SanPiN), sanitary standards (SN).

All of the listed types of documents are mandatory for the fulfillment of their requirements by citizens, individual entrepreneurs, legal entities regardless of their affiliation and type of property.

Failure to comply with the mandatory requirements of the above regulatory documents provides for civil, administrative and criminal liability.

The main document establishing permissible noise levels is SN 2.2.4 / 2.1.8.562-96 "Noise at workplaces, in residential, public buildings and on the territory of residential development."

In addition to it, noise standards are regulated in specialized SP and SanPiN, for example, SanPiN 2.1.2.2645-10 "Sanitary and epidemiological requirements for living conditions in residential buildings and premises", SP 2.1.2.2844-11 "Sanitary and epidemiological requirements for a device, equipment and maintenance of hostels for employees of organizations and students educational institutions" etc.

There are different levels of noise and its permissible limits, the excess of which poses a great danger to human hearing.

How is noise measured?

Noise, like sounds, is measured in decibels (dB). According to the law of the Russian Federation, there are established norms that cannot be exceeded. In the daytime - no more than 55 decibels, at night - no more than 45 dB. These are the maximum permissible values, since their increase has a negative impact on human health. Basically, the nervous system suffers, headaches occur.

Why are high sounds dangerous?

Noise levels can vary. Some do not exceed the norms established by law and do not interfere with human life. In the daytime, a higher level of sounds is allowed, but it also has its own limits in decibels. If the norm is exceeded, then the person may feel nervousness, irritability. Reactions are inhibited, productivity and intelligence are reduced.

Noise over 70 decibels can impair hearing. Especially loud sounds have a strong effect on the health of babies, disabled people and the elderly. According to studies of the effect of noise on humans, the reaction of the nervous system to an increase in the permissible norms of the sound background starts from 40 decibels. Sleep is disturbed already at 35 dB.

Strong changes in the nervous system occur with a noise of 70 decibels. In this case, a person may experience mental illness, hearing and vision deteriorate and even change in negative side blood composition.

For example, in Germany, almost twenty percent of workers work in a noise environment of 85 to 90 decibels. And this led to an increasing number of cases of hearing loss. Constant noise exceeding the norm, at least leads to drowsiness, fatigue and irritation.

What happens to hearing when exposed to noise?

Long-term or excessively loud background sounds can damage a person's hearing aid. The most dangerous thing is rupture of the eardrums. Accordingly, hearing decreases or complete deafness occurs. In the worst case, with a loud explosion, the sound level of which reaches 200 decibels, the person dies.

Norms

The maximum noise level in a residential building (at any time of the day) is set in accordance with sanitary requirements. Sound over 70 decibels and above is harmful not only for the psychological, but also for the physical condition of a person. At enterprises, the noise level is regulated in accordance with the sanitary standards and hygienic requirements established in the Russian Federation.

The optimal background noise is considered to be 20 decibels. For comparison: city noise averages between 30 and 40 dB. And the maximum allowable for airliners is 50 dB above the ground. Today, noise levels on many city streets reach 65 to 85 decibels. But the most common indicators are from 70 to 75 dB. And this is at a rate of 70 dB.

A high noise level (dB) is 90. It causes headaches, increases blood pressure, etc. To areas with elevated level noise includes residential areas near airports, industrial enterprises, etc. In construction sites, the permitted level of heightened sounds should not exceed 45 decibels.

The main sources of noise are automobiles, aviation and railway transport, industrial production, etc. The average background noise on the roads of large cities is from 73 to 83 decibels. And the maximum is from 90 to 95 dB. In houses located along highways, noise can reach 62 to 77 decibels.

Although according to sanitary standards, the sound background should not exceed 40 dB during the day, and 30 dB at night. According to the Ministry of Transport, approximately thirty percent of the population lives in areas of noise discomfort in the Russian Federation. And from three to four percent of the townspeople are under the aviation sound background.

Low-intensity noise levels from urban traffic that are heard in residential areas are approximately 35 decibels. This does not cause physiological changes in people. At sound level at 40 decibels after ten minutes, a change in hearing sensitivity begins. Under the influence of constant noise for fifteen minutes, the sensations return to normal. At 40 dB, the duration of restful sleep is slightly disturbed.

At the factories where the press works, a special muffler is installed on it. As a result, the noise is reduced from 95 to 83 decibels. And it becomes below the established sanitary standards for production.

But mostly people suffer from car noise. In cities with busy traffic, the sound background is slightly higher than the norm. During the passage of powerful trucks, the noise reaches its maximum value - from 85 to 95 decibels. But on average in big cities, the excess permissible norm ranges from 5 to 7 decibels. And only in private sectors does the noise load meet the accepted standards.

Technological progress causes an increase in artificial sound background, which in this case becomes harmful to humans. In some industries, the noise level in the room reaches 60 to 70 decibels and higher. Although the norm should be 40 dB. All operating mechanisms create a lot of noise, spread over a long distance.

This is especially noticeable in the mining and metallurgical industries. In such industries, the noise reaches 75 to 80 decibels. From explosions and operation of turbojet engines - from 110 to 130 dB.

What do sanitary noise standards include?

Sanitary noise standards include many factors. The frequency characteristics, the duration and time of exposure to a loud sound background, and its nature are measured. Measurements are taken in decibels.

The norms are based on the characteristics, which noise level, acting even for a long time, does not cause negative changes in the human body. During the day it is no more than 40 decibels, and at night - no more than 30 dB. The admissible limit of traffic noise is from 84 to 92 dB. And over time, the established norms of the sound background are planned to be reduced further.

How to determine the noise level?

It is quite easy to get rid of loud noise at night. You can call the district or police squad. But in the daytime, determining the noise level is much more problematic. Therefore, there is a special expertise. A special sanitary and epidemiological commission from Rospotrebnadzor is called. And the outgoing noise is recorded in decibels. After the measurements, an act is drawn up.

Construction noise standards

During the construction of residential buildings, developers are obliged to provide the premises with good sound insulation. The noise should not exceed 50 decibels. This applies to sounds transmitted through the air (a working TV, conversations of neighbors, etc.).

Comparative indicators of permissible noise

A short-term exposure to loud sounds up to 60 decibels is not dangerous for a person. Unlike systematic noise, which disrupts the nervous system. The noise levels (in dB) from various sources are described below:

• human whisper - from 30 to 40;
• refrigerator operation - 42;
• lift car movement - from 35 to 43;
• ventilation "Breezer" - from 30 to 40;
• air conditioner - 45;
• the noise of a passing airliner - 140;
• playing the piano - 80;
• forest noise - from 10 to 24;
• flowing water - from 38 to 58;
• the noise of a working vacuum cleaner - 80;
• colloquial speech - from 45 to 60;
• supermarket noise - 60;
• car horn - 120;
• cooking food on the stove - 40;
• motorcycle or train noise - from 90;
• repair work - 100;
• dance music in nightclubs - 110;
• baby crying - from 70 to 80;
• the lethal noise level for humans is 200.

The list shows that many of the sounds that a person encounters on a daily basis exceed the permissible noise level. Moreover, only natural sounds are listed above, which are almost impossible to avoid. And if additional decibels are added, then the sound threshold established by sanitary standards is sharply exceeded.

Therefore, rest is important. After working in industries where the noise level is off scale, it is necessary to restore hearing. To do this, it is enough to visit as much time as possible in relaxing, calm places. Outdoor trips are well suited for this.

How to measure noise in decibels?

The permissible noise level can be measured independently using special items - noise meters. But they are very expensive. And the fixation of the level of sounds is carried out only by specialists, without the conclusion of which the acts will be invalid.

As mentioned above, harsh noise sometimes leads to rupture tympanic membranes... For this reason, hearing deteriorates, sometimes to complete deafness. Although the eardrum can heal, the process is very long and depends on the severity of the injury.

For this reason, it is recommended to avoid prolonged exposure to noise. From time to time you need to give your ears a rest: to be in complete silence, to go to the village (to the country house), not to listen to music, to turn off the TV. But first of all, it is advisable to abandon all kinds of portable music players with headphones.

All this will help preserve our precious ear, which will always serve faithfully. In addition, silence helps the eardrums to heal after injury.