Limits of permissible noise level in an apartment in 2021 - standards in decibels, what to compare 40, 70 dB and other values ​​with, methods of self-measurement, liability for violation

The state has established a period during which it is prohibited to make noise, listen to loud music and carry out repair work in residential buildings. Silence is guarded during the day and at night. If you plan to carry out any actions that may disturb the peace of other citizens, it is worth finding out permissible noise level in the apartment according to the law.

The value of the indicator is especially relevant for people who live in apartment buildings in large cities. It's not just the neighbors who can make loud noises here. If the noise level causes concern even at acceptable times, citizens of the Russian Federation have the right to initiate an examination and bring the offender to justice. The rule applies equally in a situation in which neighbors were listening to music too loudly through amplifiers, or there was construction going on under the windows. We will talk further about the norms enshrined in the law, the specifics of conducting an examination in the event of a violation, and other nuances that must be observed.

Current legislature

The permissible noise level is measured in decibels. In residential premises, the volume allowed does not exceed 55 decibels during the day and 45 decibels at night. The permissible standard is established because exposure to higher noise levels can negatively affect human health. First of all, the nervous system suffers. Headaches may occur.

The maximum permissible noise level in a residential building is established by the codes of the Russian Federation and standards adopted by other bodies. Regardless of how many decibels the outgoing sound is, what its source is, a level above 70 decibels is considered harmful to the physical and psychological state of citizens. At night, violations can be dealt with by calling the local police officer. This is possible if neighbors listen to music loudly. It is more difficult to correct the situation during the daytime. To force neighbors to stop, a special examination or the involvement of a commission from Rospotrebnadzor will be required. In any situation, it is necessary to write a statement of complaint. It will be officially recorded. After the appropriate measurements have been completed, a report will be drawn up.

In addition to the reproduction of noise from neighbors, there is the concept of “compliance with standards by the developer during the construction of residential buildings and premises.” In accordance with the current legislation of the Russian Federation, the sound insulation of an apartment building should not exceed 50 decibels. Airborne noise is taken into account.

It can be:

• conversations between neighbors in a residential building;
• operation of a TV behind the wall of an apartment building;
• other noise exceeding the maximum permissible DCB level.

If the maximum permissible norms are violated, and this fact is proven, a fine will be collected from the developer. The proceedings begin after residents file a complaint and conduct various examinations.

What happens to hearing when exposed to noise?

First of all, the organs that perceive and process sounds are affected by strong noise waves. The disease develops in different ways:

1. Gradually. This is the case when the ear first adapts to a strong background sound, then becomes exhausted and finally atrophies.
2. Swiftly. Sound perception disappears abruptly with short-term but very strong sound exposure.

All people are different and they can even perceive the same sound in completely different ways. It depends on the characteristics of the person’s nervous system, physical and mental state, age, living conditions, profession and much more. It is also surprising that he tolerates the sounds that a person reproduces himself much more easily than similar sounds from the outside. If a person is constantly exposed to increased background noise, the following hearing problems may occur:

1. Complete hearing loss or deafness. The cause of this condition is most often a short-term, but very strong sound. An example of this is a blast or sound wave. But the fact that a person simply does not pay attention to constant exposure to noise also leads to similar consequences.
2. Hearing loss develops gradually and goes through several stages. The first sign is a short-term hearing loss in a quiet room. Over time, hearing returns to normal more and more slowly, resulting in permanent hearing loss.
3. Noise disease is a whole complex of ear dysfunctions combined with disorders in the nervous system.
4. Noise intoxication is, in most cases, voluntary exposure to loud sounds. Usually this condition is a reaction of the nervous system, but sometimes it can cause physical damage to the ear.
5. Stunning is a sharp and sudden impact of very loud noise. There is no hearing immediately after this or it is very weak. All this is temporary, but hearing is not always fully restored.

Any pathology depends on the volume level and the duration of exposure to noise.

A person should pay attention if they have one or more of these symptoms:

1. Dull tinnitus, constant or periodically recurring, is especially noticeable when a person is in a quiet room.
2. Ringing in the ears - in one or two at once.
3. It feels like someone is constantly whistling quietly. This indicates the presence of microtraumas in the eardrum.
4. Constant questioning of the interlocutor, misunderstanding of individual sounds or letters. Very often such sounds include “f”.

What is the danger of noise that exceeds permissible standards?

Whatever the reason for exceeding permissible standards, it interferes with rest, study and work.

The human body reacts negatively to noise. Prolonged repair work or other actions that disturb the silence lead to a decrease in reaction, absent-mindedness, irritability, nervousness and hinder intelligence.

The citizen's productivity decreases. Exposure to sounds exceeding 70 decibels increases the risk of accidents and causes hearing loss. This especially affects pensioners, young children, disabled people and women.

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If a person on the street or at home is exposed to noise up to 60 decibels for a short period of time, this is not dangerous. However, exceeding the value of the indicator can provoke the development of nervous system disorders.

Noise produced by various activities
Sound source	Indicator value
Human whisper	30-40 dB
Baby crying	70 db
Elevator movement	35-43 dB
Working air conditioner	45 dB
Refrigerator operation	42 dB

Impact on the human body

The sounds that surround every person every day sometimes significantly exceed possible parameters. For example, the sound of a normal vacuum cleaner running reaches 80 decibels. The screams of an adult can be estimated at 90 decibels, the signal of a car - at 120 decibels. The fact is that they are unsystematic.

For a person to feel bad as a result of sound exposure, its consistency is necessary. High and loud sounds have a special impact on children, the elderly, and women. Frequent exposure to noise of various types has a negative impact on the human condition:

1. diseases of the nervous system (nervousness, irritability, aggression);
2. headache;
3. high blood pressure.;
4. hearing loss, up to hearing loss.

Children exposed to constant noise attacks experience problems with their studies. Their intelligence, speed of thinking, and level of concentration decrease. The danger of the consequences is expressed in the fact that they do not appear immediately, but after some time.

ATTENTION! A sound of 200 decibels is fatal.

How to measure noise level?

Having found out what noise standard in decibels in an apartment during the day and night is established by current legislation, it is worth familiarizing yourself with the specifics of the measurement. You can perform the action yourself. To do this you will need to purchase a special device. It is called a noise meter. However, such devices are expensive and are not essential. Therefore, their use at home is practically not carried out. There is no point in purchasing the device. The authorized bodies will not take into account measurements made by the citizen independently. Specialists should be involved in drawing up the act.

The need to measure noise levels after 23 hours in practice can arise quite often. The source of sound can be not only neighbors, but also organizations located nearby. In this situation, it is necessary to contact specialists from government or private structures of the Russian Federation who measure the sound level in a residential building. In this case, the procedure is performed several times. Ideally, it is recommended to do it twice during the day and twice at night. The process is performed with a window open and closed in a residential building. You can contact specialists if ordinary sounds from the street penetrate into your apartment and cause discomfort.

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Measurements are taken to ensure that all building regulations have been met. If it can be proven that there is a violation, repairs to soundproof the premises will fall on the shoulders of the developer.

Regardless of who conducts the examination in residential premises, after the measurements a document is drawn up that has legal force. It records all the results obtained. The document is used when filing a lawsuit.

When renovating an apartment

Time frames have been established for construction and finishing work. In most regions of the Russian Federation the following standards have been adopted:

• Repairs to the apartment are possible only from 9.00 to 19.00.
• It is unacceptable to carry out construction work on days that fall on holidays and weekends.
• It is prohibited to conduct noisy activities continuously for 6 hours. If there is a need for longer work, an hour break should be taken.
• The mandatory break must be between 13.00 and 15.00.
• Repair and finishing work in the residential premises of an apartment building should not be carried out for more than three months.

If you want to finish the repairs faster, you can try to negotiate with your neighbors. Obtain written permission from them to carry out work outside the hours established by law. The document is drawn up in any form with the signature of the residents of the apartment building. If an agreement is not reached, generally established rules should be followed.

Why is expertise required?

Having found out how many decibels are allowed in an apartment during the day, you need to take into account that exceeding the permissible noise level is one of the main factors of environmental pollution. This indicator must be constantly monitored in order to prevent deterioration in health.

SES workers have created a number of regulatory documents, in accordance with which the degree of danger of noise in residential premises, on the street, in production, in medical and educational institutions is determined. Their meaning may vary depending on the time of day. Monitoring compliance with permissible noise levels in various areas of human life is carried out by authorized services. Thus, the State Inspectorate is responsible for measurements in production. The Labor Inspectorate monitors the indicator in workplaces. Compliance with acceptable standards in residential premises is monitored by the sanitary and epidemiological service.

Who measures and where to go

In order for noise measurements to have legal force and be used in court, they must be carried out by authorized persons. These may be judicial officials (if noise measurements are ordered during the trial), employees of Rospotrebnadzor or organizations with similar licenses.

In order to call an employee who will measure the noise level, you need to submit an application. Then the expert who made the measurements may be invited to the court to provide explanations.

What to consider?

If the permissible noise level in a residential apartment is regularly exceeded, this cannot be ignored. Sooner or later, this will affect human health. In this case, it does not matter at all what provokes the increase in the indicator.

Before hiring a specialist to measure the permissible noise level in a residential building, you need to find out whether he has a license to carry out such activities. Even if you plan only short-term interaction with a specialist, it is necessary to conclude an agreement.

When measurements have been taken, it is important to check that the documents contain all the necessary information specified in accordance with established rules. Only after the document on the results of the examination has been received, you need to contact Rospotrebnadzor directly. If their visit does not produce results, you will need to draw up a statement of claim and submit it to the court. If neighbors in a residential building often listen to music loudly or make noise at prohibited times, you need to contact the local police officer. Violation of the permissible level must be recorded. Then you will need to write a statement and draw up an act of violation. If you have to go to court in the future, these documents will be required.

What do sanitary standards for noise in a populated area include?

According to sanitary standards, according to the nature of the noise there are:

1. Broadband noise. Its continuous spectrum is more than 1 octave wide.
2. Tonal noise contains tones in its spectrum.

The following noise characteristics are also present:

1. Constant noise. Over the course of an 8-hour working day, it does not change in one direction or another by more than 5 dB.
2. Intermittent noise. It changes by more than 5 dB during a work shift.

An intermittent noise may be:

1. Fluctuating, its level changes over time constantly.
2. Intermittent noise, it changes in steps of 5 dB or more. The duration of continuous intervals is no more than 1 s.
3. Impulsive noise, it can consist of either one or several sounds lasting at least 1 s.

Norms

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

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

High noise level (dB) is 90. It causes headaches, increases blood pressure, etc. Areas with high noise levels include residential areas near airports, industrial enterprises, etc. In construction sites, the permitted level of increased noise is not must exceed 45 decibels.

The main sources of noise are cars, 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 from 62 to 77 decibels.

Although, according to sanitary standards, background noise 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 noise discomfort zones in the Russian Federation. And from three to four percent of citizens are under the aviation sound background.

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

In factory production where the press operates, a special muffler is installed on it. As a result, 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 where there is heavy traffic, the sound background is slightly higher than normal. When powerful trucks pass, the noise reaches its maximum value - from 85 to 95 decibels. But on average in large cities the excess of the permissible norm ranges from 5 to 7 decibels. And only in private sectors does the noise level meet 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 or higher. Although the norm should be a value of 40 dB. All operating mechanisms create a lot of noise, spreading 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 the operation of turbojet engines - from 110 to 130 dB.

2021 Directories

Sound volume. Noise level and its sources

The physical characteristic of sound volume is the sound pressure level, in decibels (dB). “Noise” is a disorderly mixture of sounds.

Low and high frequency sounds seem quieter than mid frequency sounds of the same intensity. Taking this into account, the uneven sensitivity of the human ear to sounds of different frequencies is modulated using a special electronic frequency filter, obtaining, as a result of normalization of measurements, the so-called equivalent (energy-weighted) sound level with the dimension dBA (dB(A), then Yes – with filter “A”).

A person, in the daytime, can hear sounds with a volume of 10-15 dB and higher. The maximum frequency range for the human ear, on average, is from 20 to 20,000 Hz (possible range of values: from 12-24 to 18,000-24,000 hertz). In youth, mid-frequency sound with a frequency of 3 KHz is better heard, in middle age - 2-3 KHz, in old age - 1 KHz. Such frequencies, in the first kilohertz (up to 1000-3000 Hz - the zone of speech communication) - are common in telephones and on radios in the MF and LW bands. With age, the perceptible sound range narrows: for high-frequency sounds - decreasing to 18 kilohertz or less (in older people, every ten years - by about 1000 Hz), and for low-frequency sounds - increasing from 20 Hz or more.

In a sleeping person, the main source of sensory information about the environment is the ears (“sensitive sleep”). Hearing sensitivity at night and with eyes closed increases by 10-14 dB (up to the first decibels, on the dBA scale), compared to the daytime, therefore, loud, sharp noise with large jumps in volume can wake up sleeping people.

If there are no sound-absorbing materials (carpets, special coverings) on the walls of the premises, the sound will be louder due to multiple reflections (reverberation, that is, echo from the walls, ceiling and furniture), which will increase the noise level by several decibels.

Noise scale (sound levels, decibels), in the table

Decibel dBA	Characteristic	Sound sources
0	Can not hear anything
5	Almost inaudible
10	Almost inaudible	quiet rustle of leaves
15	Barely audible	rustle of leaves
20	Barely audible	human whisper (at a distance of 1 meter).
25	Quiet	human whisper (1m)
30	Quiet	whispering, ticking of the wall clock. The permissible maximum according to the standards for residential premises at night, from 11 pm to 7 am (SNiP 23-03-2003 “Noise Protection”).
35	Quite audible	muffled conversation
40	Quite audible	ordinary human speech. The norm for residential premises during the day, from 7 a.m. to 11 p.m. Read more in Rossiyskaya Gazeta. A forty-decibel sound level is established as acceptable by standards (SP 51.13330... PROTECTION AGAINST NOISE, SNiP 23-03...) for auditoriums of educational organizations, classrooms, classrooms, libraries and conference rooms.
45	Quite audible	normal, calm conversation. The norm for gyms.
50	Clearly audible	conversation, typewriter. The norm for offices in administrative buildings, office and work premises.
55	Clearly audible	Upper standard for class A office premises (according to European standards)
60	Noisy	Norm for offices
65	Noisy	loud conversation (1m)
70	Noisy	loud conversations (1m)
75	Noisy	scream, laugh (1m)
80	Very noisy	a scream, a motorcycle with a muffler, the noise of a vacuum cleaner (with a high engine power - 2 kilowatts).
85	Very noisy	loud human scream, motorcycle with muffler
90	Very noisy	loud screams, freight railway car (seven meters away)
95	Very noisy	subway car (7 meters outside or inside the moving car)
100	Extremely noisy	orchestra, subway car (intermittently), thunder, the screech of a running chainsaw, the noise of a gasoline lawn mower Maximum permissible sound pressure for the player's headphones (according to European standards)
105	Extremely noisy	noise in the aircraft cabin (until the 80s of the twentieth century) and the maximum sound pressure level (in dBA) for low-power gasoline-powered chain saws at their maximum operating modes.
110	Extremely noisy	helicopter
115	Extremely noisy	sandblasting machine (1m) and similar mechanisms
120	Almost unbearable	jackhammer (1m)
125	Almost unbearable
130	Pain threshold	plane at the start
135	Contusion
140	the sound of a jet plane taking off, at the edge of the runway
145	Contusion	rocket launch.
150	the sound at the moment of firing from an “unsuppressed” (without a silencer), medium-caliber gun, near the muzzle of the barrel.
155	Concussion, injuries
160	Shock, injuries	shock wave from a supersonic aircraft
At sound levels above 160 decibels - rupture of eardrums and lungs is possible, more than 200 - death (noise weapon)

* In regions, in large cities, at the local level, their own restrictive norms and rules may apply, based on legislative amendments to the Law on Silence, adopted by regional legislators, the implementation of which is controlled by local authorities.

The maximum permissible sound levels (LAmax, dBA) are 15 decibels more than “normal”. For example, for living rooms of apartments, the permissible constant sound level during the daytime is 40 decibels, and the temporary maximum is 55. With constantly operating engineering equipment, an amendment of minus 5 is taken into account.

Inaudible noise is sounds that are not perceived by the ear, with frequencies less than 16-20 Hz (infrasound) and more than 20 KHz (ultrasound). Low-frequency vibrations of 5-10 hertz can cause resonance, vibration of internal organs and affect brain function. Low-frequency acoustic vibrations increase aching pain in bones and joints in sick people. Infrasound sources: cars, carriages, thunder from lightning, etc.

In workplaces, the maximum permissible equivalent sound levels by law for intermittent noise are: the maximum sound level should not exceed 110 dBAI, and for impulsive noise - 125 dBAI. It is prohibited to stay even for a short time in areas with deafening sound pressure levels - over 135 dB, in any octave band.

The noise emitted by a computer, printer and fax in a room without sound-absorbing materials can exceed a level of 70 db. Therefore, it is not recommended to place a lot of office equipment in one room where people may be. Equipment that is too noisy should be moved outside the premises where the staff workstations are located. You can reduce the noise level if you use noise-absorbing materials as room decoration and curtains made of thick fabric. Soft (foam, sold in pharmacies) anti-noise earplugs will also help if their sound reduction parameter (SNR) is at least 30 decibels. Explosive sounds are dampened using special mechanical membranes. High-quality insulating headphones (acceptable in terms of price and quality, can be found, for example, in hardware stores) - provide maximum hearing protection, reliably covering not only the ear canal, but also the adjacent temporal bone of the skull.

The crying of a child, compared to other sounds of the same volume, has a much stronger effect on the human psyche, as an irritant and incentive for active physical actions (calming, feeding, etc.) They are unlikely to be fined for noisy children or neighbors above , if the cause of the noise is not related to domestic violence or family dysfunction. Not too loud, the clatter of ordinary steps, too, is unlikely to be grounds for prosecution.

When constructing buildings and structures in accordance with modern, more stringent sound insulation requirements, technologies and materials must be used that can provide reliable protection from noise.

For fire alarms: the sound pressure level of the useful audio signal provided by the siren must be at least 75 dBA at a distance of 3 m from the siren and no more than 120 dBA at any point in the protected premises (clause 3.14 NPB 104-03).

A high-power siren and a ship's howler - the pressure is more than 120-130 decibels.

Special signals (sirens and “quacks” - Air Horn) installed on official vehicles are regulated by GOST R 50574-2002. The sound pressure level of the signaling device, when a special sound signal is given, at a distance of 2 meters along the horn axis, must be not lower than: 116 dB(A) – when installing a sound emitter on the roof of a vehicle; 122 dBA – when installing the radiator in the engine compartment of a vehicle. Fundamental frequency changes should be from 150 to 2000 Hz. Cycle duration is from 0.5 to 6.0 s.

The horn of a civilian vehicle, according to GOST R 41.28-99 and UNECE Rules No. 28, must produce a continuous and monotonous sound with an acoustic pressure level of no more than 118 decibels. This is the same order of magnitude as the maximum permissible values ​​for car alarms.

If a city dweller, accustomed to constant noise, finds himself in complete silence for some time (in a dry cave, for example, where the noise level is less than 20 db), then he may well experience depression instead of rest.

Sound meter device for measuring sound level, noise

To measure the noise level, a sound level meter is used (pictured), which is produced in different modifications: household (estimated price - 3-4 tr, gradation of measurement ranges: 30-130 dB, 31.5 Hz - 8 kHz, filters A and C), industrial (integrating, etc.) Of the most common models, we can distinguish: SL, octave, svan. On the dial indicators of sound level meters, the needle can, due to inertia (at a certain dynamics of increase in the sound level), fly further than the peak value of the signal itself. Therefore, the final values ​​(already processed by the chip, according to the algorithm of the selected filter) are taken from the digital display of the device.

To measure infrasonic and ultrasonic noise, professional wide-range noise meters are used. If constant monitoring of “acoustic smog” is not required, then they are limited to single, estimated measurements. Devices are rented for a period of time, or a specialist with certified equipment is invited.

Also, there are many different special applications for mobile devices (smartphones and tablet computers) that allow you to approximately determine the noise level in decibel units. These programs, including their free versions, can be downloaded from Google Play, Android Market or App Store. In order for the measurement results to be correct, it is necessary to pre-calibrate the device, checking it against a reference sound level meter or, at least approximately, against a control sound source with a known sound pressure level. Other settings before taking measurements: direction of the microphone, its sensitivity to the desired frequencies of the spectrum of acoustic vibrations, etc. When working outdoors, you may need a wind shield on the microphone to prevent sound interference from the wind. Video instructions on how to use the devices and reviews of the results of experiments and tests can be found on YouTube.

Sound frequency ranges

Subranges of the audio frequency spectrum to which the filters of two- or three-way speaker systems are tuned: low-frequency - fluctuations up to 400 hertz; mid-frequency – 400-5000 Hz; high frequency – 5000-20000Hz

Musical classification, names of singing voices by frequency range, taking into account the gender of performers

Men's:

Bass profundo (super low, contractave) – 44-262 Hz Bass (low) – 82-349 Hz Baritone (middle) – 110-392 Hz Tenor (high) – 132-532 Hz Tenor altino (super high) – 131- 700 Hz

Women's:

Contralto (low) – 165-692 Hz Mezzosoprano (middle) – 220-880 Hz Soprano (high) – 262-1046 Hz Coloratura soprano (the highest female voice, up to the “F” note of the third octave) – 260-1400 Hz.

Frequency ranges of sounds produced when playing musical instruments:

Acoustic guitar – 82-1175 Hz Electric guitar – 82-1570 Hz Bass guitar – 41-250 Hz Trumpet – 160-1200 Hz Violin – 200-2800 Hz Grand piano – 27-4200 Hz

Symphony orchestra - 31-15000 Hz Variety orchestra - 25-16000 Hz Brass band - 50-10000 Hz
Speed ​​of sound and its range
The approximate speed of audible, mid-frequency sound (frequency of about 1-2 kHz) and the maximum range of its propagation in various environments: in the air - 344.4 meters per second (at a temperature of 21.1 Celsius) and approximately 332 m/s - at zero degrees; in water - approximately 1.5 kilometers per second; in hard wood - about 4-5 km/s along the fibers and one and a half times less - across.

At 20 °C, the speed of sound in fresh water is 1484 m/s (at 17 ° - 1430), in sea water - 1490 m/s.

The speed of sound in metals and other solids (the values ​​of only the fastest, longitudinal elastic waves are given): in stainless steel - 5.8 kilometers per second. Cast iron – 4.5 Ice – 3-4 km/s Copper – 4.7 km/s Aluminum – 6.3 km/s Polystyrene – 2.4 kilometers per second.

With increasing temperature and pressure, the speed of sound in air increases. In liquids there is an inverse relationship with temperature.

Velocity of propagation of elastic longitudinal waves in rock masses, m/s: soil – 200-800 sand dry / wet – 300-1000 / 700-1300 clay – 1800-2400 limestone – 3200-5500

They reduce the range of sound propagation along the surface of the earth - high obstacles (mountains, buildings and structures), the opposite direction of the wind and its speed, as well as other factors (low atmospheric pressure, high temperature and low air humidity). Distances at which the source of loud noise is almost inaudible - usually from 100 meters (in the presence of high obstacles or in a dense forest), to 300-800 m - in open areas (with a fair average wind - the range increases to a kilometer or more) . With distance, higher frequencies are “lost” (attenuated and dissipated faster) and low-frequency sounds remain. The maximum propagation range of medium-intensity infrasound (a person cannot hear it, but there is an effect on the body) is tens and hundreds of kilometers from the source.

The attenuation intensity (absorption coefficient) of mid-frequency sound (about 1-8 kHz), at normal atmospheric pressure and temperature, above the ground with short grass, in the steppe, is approximately 10-20 dB for every 100 meters. Absorption is proportional to the square of the frequency of the acoustic waves.

To calculate the approximate distance at which sound from a point source will still be heard (to the level accepted, in the calculated “ideal” model, the threshold of audibility for the human ear or a microphone of electronic recording equipment), its level is successively reduced by 6 decibels, with each increase double the distance. For example, if the sound pressure at two meters is 40 dB, then at four meters it is 34 dB.

// comment by the author of the site KAKRAS.RU If during a thunderstorm you saw strong lightning and after 12 seconds heard the first rumbles of thunder, this means that lightning struck four kilometers from you (340 * 12 = 4080 m.) In rough calculations, it is accepted – three seconds per kilometer of distance (in airspace) to the sound source.

The line of propagation of sound waves deviates in the direction of decreasing the speed of sound (refraction on a temperature gradient), that is, on a sunny day, when the air at the surface of the earth is warmer than the air above it - the line of propagation of sound waves bends upward, but if the upper layer of the atmosphere turns out to be warmer than the ground layer, then the sound will go back down from there and will be heard better.

Sound diffraction is the bending of waves around an obstacle when its dimensions are comparable to or less than the wavelength. If it is much longer than the wavelength, then the sound is reflected (the angle of reflection is equal to the angle of incidence), and an acoustic shadow zone is formed behind the obstacles.

Reflections of a sound wave, its refraction and diffraction - cause multiple echoes (reverberation), which has a significant impact on the audibility of speech and music indoors or outside, which is taken into account during sound recording to obtain live sound (by placing small-sized stereo images in optimally close areas of the stereo image). microphones with a sharp directivity characteristic, for recording direct sound, followed by mixing and mixing the “dry” recording with a processor into digital or using long-distance, well-tuned ambient microphones, with additional recording of reflected sounds).

Conventional sound insulation does not protect against infrasound.

The noisiest cities in Russia are many regional and district centers of the country, almost all areas of major transport hubs and urban residential areas along avenues and near airports. This category includes: Moscow, St. Petersburg, Krasnoyarsk, Rostov-on-Don, Chelyabinsk, Yekaterinburg, Perm, Irkutsk, Yaroslavl, Voronezh, Novokuznetsk, Nizhny Tagil, Magnitogorsk, Omsk, Ufa, Samara, Nizhny Novgorod, Novosibirsk, Murmansk , Perm, Tula, Ulyanovsk, Kemerovo and others.

The main sources of noise in the city are trams, cars, trucks, operating industrial enterprises, construction sites and airliners flying at low altitude. Even realtors adjust real estate prices depending on the local level of noise pollution in a house with apartments for sale or rent.

The trend is that the intensity of urban noise, due to the increasing number of cars on the roads, is only growing. The general situation is aggravated by the low-frequency screaming of car radios from cars, the speakers of sound systems and the screams of television shows sounding from the open windows of high-rise buildings built along the roads.

If, according to the decision of the municipal authorities, heavy transport flows are pushed onto long-distance bypass roads, beyond the boundaries of populated areas, and intra-city cargo transportation is allowed only at strictly defined hours of the day and only on streets permitted for this purpose - the listed measures can significantly improve the environmental situation and increase the comfort of living.

A separate story is the noise made by birds, insects, and pets. These are, for example, barking dogs and meowing cats. In the garden plots of private houses, there can be a lot of all sorts of noisy living creatures - pigs squealing from hunger, crowing roosters, loudly cackling geese, mooing cows. Therefore, the private sector on the outskirts of cities often resembles a large village, due to the characteristic sounds of rural discord.

In large cities, in industrial centers, the level of background noise is higher than in small settlements. A different rhythm of life. Therefore, in megacities and industrial centers, their own standards for permissible noise levels and time restrictions may apply.

Noise from air conditioners and refrigerators

Modern split air conditioning systems operating in quiet mode (designed specifically to be turned on at night) usually do not exceed the sound level allowed by standards for residential premises. But this condition is really only feasible for indoor (room) air conditioner units. External (street, window) units with a compressor and an exhaust fan, placed outside the premises, are much louder and, as they say, “along the entire street.” In the instructions for external units, decibel values ​​are indicated, but these are significant values. For the closest neighbors, whose windows face the same side of the wall of a multi-story building, this is a real problem that causes inconvenience.

Malfunctions in the operation of the refrigerator electric motor (poor rotor alignment, poor-quality assembly and defective components) can cause severe vibration and excessive noise. If, moreover, there are no damping rubber pads under the legs, then the vibration is transmitted to the floor and further into the floor slab.

Acoustic repellers

Loud sound and ultrasound with a frequency of 20-50 kilohertz, reproduced with modulation of several hertz, are used to scare away birds from airfields, animals (dogs, animals of prey) and insects (mosquitoes, midges), unless they are deaf. Infrasonic repellers (at a frequency that causes an uncontrollable feeling of fear and a state of panic), of sufficient power, can even act at the level of the internal organs of a living organism, causing their vibrations to resonate. The most compact and wide-range emitters include piezo sound emitters.

The toxicity of sound depends on the shape of the signal, which has a stepped (for example, rectangular) or smooth (for example, sinusoidal) graph, and on the difference in the phases of the oscillations when mixing them. Ready-made sound files and tuning presets can be found and downloaded on the Internet.

Acoustic scares and noise shockers are not an absolutely reliable means of protection, since the degree of their impact depends on many factors - individual characteristics, direction and power of the emitter, working conditions, etc. In professional equipment, standard means of combined action are used. For example, if it is necessary to completely clear a protected area of ​​moles, mice and rats, not only acoustic, but also seismic emitters (periodically transmitting mechanical vibrations into the ground) are used.

When working with equipment, you should follow the precautions specified in the instructions for each device and not violate safety regulations.

Faster than the waves

After the plane overcomes the speed of sound (Mach = 1), the moment it passes the front of the Mach cone is accompanied by a sharp, loud bang, like an explosion. Overcoming each subsequent sound barrier (M = 2,3,4... Mach numbers) narrows the cone of the shock wave (shock wave) and makes the “boom” even louder.

The observer hears a roar when a very fast moving body (an airplane, a shell or a bullet) has already flown past. For example, when shooting from a Mosin rifle with a standard cartridge at a kilometer distance, the sound of the shot arrives approximately two seconds after the bullet arrives and hits the conditional target. At subsonic speeds, on the contrary, first the noise approaches (rustle, whistle, howl of a mine or shell), and then its source.

Hypersound – movement faster than Mach 5.

At takeoff, mines or projectiles fired at maximum range follow a flat ballistic trajectory - their speed is usually already subsonic.

Binaural Beat Frequency

When the right and left ears hear sounds (for example, from the player’s headphones, f < 1000 hertz, f1 – f2 < 25 Hz) of two different frequencies, the brain, as a result of processing these signals, receives a third, difference beat frequency (binaural rhythm, which is equal to arithmetic difference between their frequencies), “audible” as low-frequency vibrations that coincide with the range of normal brain waves (delta - up to 4 Hz, theta - 4-8 Hz, alpha - 8-13 Hz, beta - 13-30 Hz). This biological effect is taken into account and used in recording studios - to transmit low frequencies that are not directly reproduced by the speakers of conventional stereo systems (due to design limitations), but these methods and methods, if used ineptly, can negatively affect the psychological state and mood of the listener, since they differ from the natural (almost “symmetrical”), natural perception of noises and sounds by the human ear.

// with the binaural effect, not three, but two sounds are “heard”: the first is the arithmetic mean, in frequency, from two real ones, and the second is a clock sound, simulated by the brain. As the frequency difference increases (>20-30 hertz), the sounds decompose, in perception, into their original ones, with their actual frequency, and the binary effect disappears. The difference in the phases of sound waves arriving at the right and left ear - allows you to determine the direction to the source of sound / noise, its volume and timbre - the distance to it.

International standardization of physical parameters

The development and dissemination of standards, since the beginning of the 20th century, has been promoted by the International Electrotechnical Commission (IEC, the organization’s website is located at https://www.iec.ch/). The Russian Federal Agency for Technical Regulation (Rosstandart) is a full member of this organization. The IEC published the International Electrotechnical Vocabulary (IEV) to unify electrical terminology. There are several domestic Internet resources from which you can, in whole or in parts, download this document translated into Russian.

National standards of IEC member countries are identical or modified in relation to international ISO standards. As an example, “GOST R 52797.1-2007 Acoustics. Recommended methods for designing low-noise workplaces in industrial premises. Part 1. Principles of noise protection" and other regulatory documents.

Information in the universal Internet encyclopedia: https:// ru.wikipedia.org/wiki/Sound_volume

Schumann resonance

In those places of the ionosphere where electromagnetic waves of sufficient power hit, with a well-established (with high signal quality) Schumann resonance, especially at the frequencies of its first harmonics, the resulting plasma clots begin to emit infrasonic acoustic (sound) waves.
Specific ionospheric emitters exist as long as lightning discharges continue in the initiating thunderstorm source - approximately up to the first tens of minutes. For the eight-hertz frequency, these emitting points are located on the opposite side of the globe from the electromagnetic source. waves On 14 Hz - in a triangle. Local, highly ionized regions in the lower layers of the ionosphere (sporadic Es layer) and plasma reflectors can be interconnected or spatially coincide. How to preserve your hearing
Long-term exposure to noise levels of more than 80-90 decibels can lead to partial or complete hearing loss (at concerts, the power of speaker systems can reach tens of kilowatts). Also, pathological changes in the cardiovascular and nervous systems can occur. Absolutely safe for the human ear - only sounds with a volume of up to 35 dB.

The reaction to prolonged and strong noise exposure is “tinnitus” - ringing in the ears, “noise in the head”, which can develop into progressive hearing loss. It is typical for people over 30 years old, with a weakened body, stress, alcohol abuse and smoking. In the simplest case, the cause of ear noise or hearing loss may be a wax plug in the ear, which can be easily removed by a medical specialist (by rinsing or extraction). If the auditory nerve is inflamed, this can be cured, also relatively simply (with medications, acupuncture). Pulsating noise is a more difficult case to treat (possible causes: narrowing of blood vessels due to atherosclerosis or tumors, as well as subluxation of the cervical vertebrae).

To protect your hearing: • do not increase the sound volume in the player's headphones, trying to drown out external noise (in the subway or on the street). At the same time, electromagnetic radiation to the brain from the headphone speaker also increases; • in a noisy place, to protect your hearing - use anti-noise soft earplugs, earbuds or headphones (noise reduction is more effective at high sound frequencies). They must be adjusted individually to the ear. In field conditions, they also use flashlight bulbs (they are not for everyone, but they are the right size). In shooting sports, individually molded “active earplugs” with electronic filling are used, at the same price as a telephone. They must be stored in packaging. It is better to choose earplugs made from hypoallergenic polymer that have good SNR (noise reduction) of 30 dB or more. In case of sudden changes in pressure (on an airplane), to equalize it and reduce pain, you need to use special earplugs with micro holes; • use noise-insulating, environmentally friendly materials in the premises to reduce noise; • when underwater diving, to prevent the eardrum from rupturing, blow in time (blow through the ears by holding your nose or swallowing). Immediately after diving, you cannot board a plane. When jumping with a parachute, you also need to equalize the pressure in a timely manner so as not to get barotrauma. Consequences of barotrauma: noise and ringing in the ears (subjective “tinnitus”), hearing loss, ear pain, nausea and dizziness, and in severe cases, loss of consciousness. • with a cold and runny nose, when the nose and maxillary sinuses are blocked, sudden changes in pressure are unacceptable: diving (hydrostatic pressure - 1 atmosphere per 10 meters of immersion depth in water, that is: two - at ten, three - at around 20 m. etc.), parachute jumping (0.01 atm per 100 m altitude, increases rapidly, with acceleration). // approximately seven and a half millimeters of mercury barometer - for every hundred meters, in height. • give your ears a break from loud noise.

Techniques usually used to equalize pressure on both sides of the eardrum: swallowing, yawning, blowing with a closed nose. The Frenzel method is to hold your nostrils and forcefully move your tongue back along the roof of your mouth (when the muscles contract, the nasal cavities and Eustachian tubes will open). When firing a shot, artillerymen open their mouths or cover their ears with the palms of their hands.

Common causes of hearing loss: water getting into the ears, infections (including those of the respiratory system), trauma and tumors, the formation of cerumen and its swelling upon contact with water, prolonged stay in a noisy environment, barotrauma due to a sudden change in pressure, inflammation of the middle ear – otitis (accumulation of fluid behind the eardrum).

Ear diseases are treated by an otolaryngologist.

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Ways to protect yourself from noise pollution

photo from Noyabrsk-inform website

• In urban development, means of isolation from highways and railways are provided: non-residential buildings, garages, and plantings are erected.
• At home, you should be careful when choosing household appliances. Having your refrigerator, washing machine, and air conditioner on can give you migraines and irritability. With a careful examination of equipment indicators, you can reduce 50 dB in an apartment by 25, for example, by replacing a monoblock air conditioner with a split system.
• Pay attention to the most vulnerable places in the apartment - window and door openings, cracks. A regular PVC double glazed window reduces the sound coming from the street by 25 - 28 dB on average. If there is a source of particular volume near the apartment (motorway, airport), you can install windows with increased sound insulation.
• During repairs, pay attention to the gaps between the wall and ceiling. They should be filled with foam or other material so that sounds from the neighboring apartment do not complicate your life. Wallpaper can also improve the situation - heavy vinyl ones will create another barrier. The same applies to the floor: an additional layer between the concrete and the final coating will allow you to forget about your neighbors below.

Finally, a piece of advice to maintain your peace of mind and health: after a hard and noisy day at work, after a fun but loud holiday, take time for silence. Sounds up to 35 dB are optimal. Time in nature or soft classical music will calm your nerves and prepare you for another day in the city.

How to prevent hearing loss?

Now that we know the causes of hearing impairment, we can easily say that if we avoid prolonged aggressive exposure to noise on the hearing aid, then this alone will be enough to prevent hearing impairment. However, it is necessary to give our ears a rest: be in silence, go to places where the noise level is reduced, do not listen to loud music, TV, etc. As a result, the more time we can spend in calm, relaxing places, the more we can restore our hearing, which will serve us faithfully for a long time.

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