When normalizing the allowable sound pressure on workplaces, the frequency spectrum of noise is broken by nine frequency bands.

The normalized parameters of constant noise are:

level sound pressure L., dB, in octave bands with medium megometric frequencies 31.5; 63; 125; 250; 500; 1000; 2000; 4000; 8000 Hz;

sound levelLA , dba.

The normalized parameters of non-permanent noise are:

- equivalent (Energy) Sound LevelLA ek, dB a,

-maximum sound levelLA Max, DB A. Excitement At least one of these indicators is qualified as a non-compliance with these sanitary standards.

In accordance with SanPiN 2.2.4 / 2.1.8.10-32-2002, the maximum permissible levels of noise are normalized in two categories of noise norms: the removal of noise in the workplace and the removal of noise in the premises of residential, public buildings and in the residential building.

For tonal and impulse noise, as well as noise created in the premises of air conditioning installations, ventilation and air heatingThe remote control should be accepted for 5 dB (dBA) fewer values \u200b\u200bspecified in Table. 8.4. of this paragraph and arr. 2 to SanPine 2.2.4 / 2.1.8.10-32-2002.

The maximum sound level for the oscillating and intermittent noise should not exceed 110 dBA. Even short-term stay in zones with sound level or sound pressure level in any octave strip over 135 dB A (dB) is prohibited.

Pow noise in the premises of residential, public buildings and on the territory of residential building.The permissible values \u200b\u200bof the sound pressure levels in the octave bands of the frequencies of the equivalent and maximum sound levels of the penetrating noise into the premises of residential and public buildings and noise on the territory of the residential building are established according to ad. 3 to Sanpin 2.2.4 / 2.1.8.10-32-2002.

Means and methods of protection against noise

The struggle against the noise in production is carried out comprehensively and includes measures of technological, sanitary and treatment-and-prophylactic nature.

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

(a) Soundproofing of enclosing structures, sealing of windows, doors, gates, etc., the device of soundproofed cabs for staff; shelter sources of noise into casing;

b) installation of the noise of sound-absorbing structures and screens;

c) the use of aerodynamic noise silencers in internal combustion engines and compressors; sound-absorbing cladding in airways of ventilation systems;

d) creating noise protection zones in various locations of people, using screens and green plantings.

The weakening of noise is achieved by using under the gender of elastic gaskets without tough communication with the supporting structures of buildings, installation of equipment on shock absorbers or special foundations. Sound absorption means are widely used - mineral wool, felt plates, perforated cardboard, wood-fiber plates, fiberglass, as well as active and jet silencers.

Silencersaerodynamic noise is absorption, reactive (reflex) and combined. In absorption

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

Soundproofingit is one of the most efficient and common methods for reducing production noise on the path of its distribution. With soundproof devices, it is easy to reduce the noise level by 30 ... 40 DB. Effective soundproofing materials are metals, concrete, wood, dense plastics, etc.

To reduce noise indoors, sound-absorbing materials are applied to the inner surfaces, and space-cutters are placed indoors.

Application of personal protection against noiseit is advisable in cases where collective protection means and other means do not provide noise reduction to permissible levels.

PPEs make it possible to reduce the level of perceived sound at 0 ... 45 dB, and the most significant fracture of noise is observed in the high frequency area that are most dangerous to humans.

The means of individual protection against noise are divided into anti-shirt headphones, covering the ear sink outside; antioxide liners overlapping an outer hearing pass or adjacent to it; antinoise helmets and helmets; Antinemic costumes. Antically liners are made of solid, elastic and fibrous materials. They are one-time and multiple use. Anti-shit helmets cover the entire head, they are used at very high noise levels in combination with headphones, as well as anti-co-costumes.

GOST 12.1.003-83

UDC534.835.46: 658.382.3: 006.354 Group T58

Interstate standard

Labor safety standards

General safety requirements

Occupational Safety Standards System

Noise. General Safety Requirements.

Date of introduction 01.07 84

Information details

1 Developed by the All-Union Central Council of Professional Unions by the USSR State Committee on Construction Affairs, Ministry of Railways, the Academy of Medical Sciences of the USSR, Ministry of Black Metallurgy of the USSR, Ministry agriculture USSR, Ministry of Health of the Ukrainian SSR, the Ministry of Health of the RSFSR, the USSR State Committee on Standards, Academy of Science of the USSR

Developers

B.A. Dvorianchikov; Yu.M. Vasilyev, Cand. tehn sciences; L.F. Lagunov, Cand. tehn Sciences: L.N. Pyatackova, Cand. tehn sciences; IN AND. Hoofs; G.L. Osipov, Dr. Tehn. Science; M.A. Porn; E.Ya. Yudin, Dr. Tehn. sciences; K.F. Calmabean, Cand. tehn Sciences; Yu.P. Chepulsky, Cand. tehn sciences; G.A. Suvorov, dr. Honey. sciences; L.N. Wakes, Dr. Med. sciences; E.I. Denisov, Cand. tehn sciences; L.N. Klyachko, Cand. tehn science; D.B. Chekhomova, Cand. tehn sciences; A.I. Ponomarev, Cand. tehn sciences; V.E.Kubinsky; V.Z. Claims, Cand. tehn sciences; V.V. Butcher; G.P. Savess; TA Kochinashvili, Cand. tehn sciences; A.M. Nicholasichvili; N.I. Borodin, Cand.tekhn. sciences; V.F. Drobyshevskaya; G.I. Varnahov; A.A. Menchov, Dr. Honey. sciences; V.N. Sog; Yu.P. Finger, Cand. honey. sciences; A.V. Kolesnikova, Cand. honey, sciences; Sh.L.zlotnik, Cand. tehn sciences; L.A. Potanina; N.P. Benevolenskaya, Dr. Honey. Science; V.A. Shcherbakov; Yu.N. Kamensky, Cand. honey. sciences; A.I. Tsysen, Cand. honey. science

2 Approved by Ivvedhen, the Resolution of the State Committee of the USSR according to standard: 06/06/83 No. 2473

3. Standard contains st seve 1930-79 in terms of valid values \u200b\u200bof sound boom levels and sound levels on workplaces manufacturing enterprises and their measles.

4. Instead of GOST12.1.003-76

5 References Industrial Technical Documents

6 limitedness of the action taken by Protocol No. 3-93 of the Interstate Council of Population, Metrology and Certification (IUS 5-6-93)

7 Reprint (September 1999) with change No. 1, approved in December 1988 (IUS 3-89)

Standards the classification of noise, characteristics and permissible levels of noise on working places, general requirements for protection against noise in workplaces, noise quality accuracy machines, mechanisms, means of transport and other equipment (hereinafter - machines) and noise measurements.

1. Classification

1.1. The noise of the spectrum of the spectrum should be divided into:

• broadband continuous spectrum of more than one octave width;
• tonal, which has pronounced discrete tones. The tonal nature of the hits of practical purposes (when controlling its parameters in the workplace) is set to measurement in the frequency bands in the exceedment of the levels of the pressure in one band above the adjacent no less than 10 dB.

1.2. Thoughtful noise challenges should be divided into:

• permanent, the sound level of which for an 8-hour working day (working shift) changes at the time of no more than 5 dB and the time-dimensions on the temporal characteristic of the "slow" noiseomer according to GOST 17187;
• the non-permanent, the sound level of which for an 8-hour working day (working shift) changes in time by more than 5 dB and the time-dimensions on the temporal characteristic of the "slowly" noiseomer according to GOST 17187.

1.3. Landworthy noise should be divided into:

• hesitable time, the sound level of which continuously changes in time;
• intermittent, the sound level of which stepwise changes (by 5 dB a and more), and the duration of the intervals, during which the level remains constant, is 1 s or more;
• a pulse consisting of one or more sound signals, each durability of 1 s, while the sound levels measured in dB AI and dB and, respectively, on the time characteristics of the "impulse" and "slowly" noiseomer according to GOST 17187, differ in more than 7 dB.

2. Characteristics and permissible levels of noise at workplaces

2.1. Characteristics of constant noise at workplaces are levels of sound booms L in dB in octave stripes with alternate meter frequencies 31.5, 63, 125, 250, 500, 1000, 2000, 4000, 8000 GG, defined by the formula

where P is the mid-mean value of sound pressure, pa;

p0 is the initial sound of sound pressure. In the air P0 \u003d 2? 10-5p.

Note. For indicative assessment (for example, when verifying the supervisory authorities, identifying the implementation of the measures for noise immunity, etc.) is allowed in the quality-acting of permanent broadband noise in the workplace

where RA is the average square of the sound pressure, taking into account the correction "A" of the noiseomer, PA.

(Modified edition, change No. 1)

2.2. Characteristics of non-permanent noise at workplaces is integralcriterion - equivalent (by energy) sound level in dB A, defined in accordance with the reference application 2.

Additional in time of the time and intermittent noise limit the maximum sounds of sound in DB · A, measured on time quality characteristics "Slowly", and for pulsed noise - the maximum level of sounding dB AI, measured on the temporal characteristic of the "pulse".

It is allowed to use the characteristics of non-permanent noise to use a noise dose or noise dose in accordance with the reference application 2.

2.3. Double sound pressure levels in octave frequency bands, sound levels Iequivalent sound levels on workplaces should be taken:

forms of permanent and non-permanent (except impulse) noise - Potablice;

for tonal pulse noise - 5 dB fewer values \u200b\u200bspecified in the table

Notes:

1 Allowed in industry documentation to establish more stringent norms for individual specimity activities, taking into account labor tensions in accordance with Annex3.

2 prohibits a short-term stay in areas with octave levels of audio pressing 135 dB in any octave strip.

for the noise generated in the rooms of air conditioning installations, ventilation of the i-heating heating - 5 dB less actual noise levels in these states (measured or defined by calculation), if the latter is not exceeded in the table (amendment for tonal and pulse noise in the industry should not be taken ), in other cases - 5 dB fewer the values \u200b\u200bspecified in the table.

(Modified edition, change No. 1).

2.4. Additionally to the requirements of Clause 2.3 The maximum sound level of non-permanent at workplaces on PP. 6 and 13 tables should not exceed 110 dB and during measurements on time quality characteristics "slowly", and the maximum sound level of pulse noise on working places according to clause 6 of the table should not exceed 125 dB ai when measuring at the impulse time quality characteristics.

3. Noise Protection

3.1. Arabestroperation of technological processes, design, manufacturing of the and exploitation of machines, production buildings and structures, as well as the priority of the workplace should be taken necessary measures By reducing a person acting on a person in workplaces, to the values \u200b\u200bthat are unraveling the permissible specified in the section. 2:

• developing bags-safe techniques;
• applications and collective protection methods according to GOST 12.1.029;
• application of personal protective protection according to GOST 12.4.051.

Note. Equipment and acoustic activities envisaged in designing enterprises, buildings and structures of various purposes - in the attractive and technical documents approved or agreed with the state system.

3.2. Zones with a level-abnormal or equivalent sound level above 80 dB and should be marked by security signs according to GOST 12.4.026. The administration is required to supply funds in these zones.

(Modified edition, change No. 1).

3.3. Alpoxy, in organizations and institutions should be provided with noise monitoring at workplaces at least once a year.

4. Requirements for noise characteristicsMashin

4.1. Instandals and (or) technical conditions on machines must be installed values \u200b\u200bof the noise characteristics of these machines.

4.2. Noise accuracy should be chosen from among the provided GOST 23941.

4.3. The values \u200b\u200bof the permissible noise characteristics of the machines should be established by the Output of the requirements of providing in the workplaces of permissible noise levels in accordance with the main purpose of the machine and the requirements of section. 2 inflamed. Methods of establishing extremely permissible noise characteristics of stationary machines - according to GOST 12.1.023.

4.4. If the noise characteristics of the machines corresponding to the best world-believers of similar techniques exceed the values \u200b\u200bestablished in accordance with the requirements of clause 4.3 of this standard, then in standards and (or) technical conditions on machines are allowed to establish the technically achievable noise characteristics of these changes.

Technicality values \u200b\u200bof noise characteristics of machines must be justified:

• the measurement of the noise characteristics of the representative number of machines is one of the methods of GOST 23941;
• data of ochum characteristics of the best models of similar machines manufactured by abroad;
• analyzes and means of reducing the noise used in the machine;
• the presence of acclaimed means of protection against noise to the levels established by paragraph 2.3, and their conversion to the regulatory and technical documentation for the machine;
• planometries to reduce noise to a level corresponding to the requirements of clause 4.3-standing standard.

4.5. Noise followers of the machines or limit values \u200b\u200bof noise characteristics should be specified in the passport on them, manual (instructions) for use or other documentation.

5. Noise measurement

5.1. Measurement at workplaces: enterprises and institutions - according to GOST 12.1.050 and GOST23941; agricultural self-propelled machines - according to GOST 12.4.095; tractors of suicide chassis - according to GOST 12.2.002; cars, road trains, buses, motorcycles, scooters, mopeds, motorbikes - according to GOST 27435 and GOST27436; transport aircraft and helicopters - according to GOST 20296; rolling stock-in-service transport - under sanitary standards to limit the noise by the adjustable composition of railway transport, approved by the USSR Ministry of Health; For marine river and lake courts - according to GOST 12.1.020, the sanitary standards of noise of the vessels of the river fleet vessels and the sanitary standards of noise on maritime courts approved by the USSR Ministry of Health.

(Modified edition, change No. 1).

5.2. Methods of measurements for certain noise characteristics of machines - according to GOST23941, GOST 12.1.024, GOST 12.1.025, GOST 12.1.026, GOST 12.1.027, GOST12.1.028.

ATTACHMENT 1

Reference

Information information GOST12.1.003-83

ST SEV 1930-79

(Modified edition, change No. 1).

Appendix 2.

Reference

Integral noise normalization criteria

1. Equivalent (by energy) The sound level in dB and of this non-permanent noise - the level of constant broadband noise, which has the same medium-mean-meaning sound pressure as this non-permanent noise for a working time interval and which is determined by the formula

- the current value of the average quadratic sound pressure, taking into account the correction "A" of the noiseomer, Pa;

p0 is the initial value of sound pressure (in the air P0 \u003d 2? 10-5 PA);

(Modified edition, change No. 1).

Appendix 3.

Reference

Noise levels for various types of laboribility, taking into account the degree of labor tension

* More than 50% of working time.

** According to normal and artificial lighting, approved by the USSR State Builder

The concept of noise

Noise - This is an indiscriminate fluctuations in various physical nature, characterized by the complexity of the time and spectral structure. From a physiological point of view, noise is every unfavorable perceived sound.

Sound - these are elastic waves that extend in the medium and create mechanical oscillations in it; In a narrow sense, the subjective perception of these oscillations by special human senses.

The impact of the factor on the human body

The prolonged effect of noise can lead to a deterioration of hearing, and in some cases - to deafness. The noise effect on the workplace is adversely affected by working and leads to:

decline in attention;

an increase in energy consumption with the same physical exertion;

• slowdown the speed of mental reactions, etc.

The concept of sound, as a rule, is associated with the auditory sensations of a person with normal hearing. Hearing sensations They are caused by oscillations of an elastic medium, which are mechanical oscillations propagating in a gaseous, liquid or solid medium and affecting human hearing organs. At the same time, medium fluctuations are perceived as sound only in a certain frequency domain (20 Hz - 20 kHz) and at sound pressures exceeding the human hearing threshold.

As a result, labor productivity and the quality of work performed is reduced.

Figure 1 shows the structure of the hearing organ.

Figure 1 - the structure of the organ of hearing

In the snail there is a primary analysis of sound. Each simple sound has its own plot on the basilar membrane. Low sounds cause oscillations of the site of the basilar membrane at the top of the snail, and the high - at the base of it.

The wave moves away from the tears of the tip of the snail. When the amplitude reaches its maximum, the wave quickly fades. In this area there are vortine-shaped currents of perilimphs, and maximum deflection of the basilar membrane occurs. Low-frequency sounds will pass throughout the snail and cause maximum deflection at the top. High-frequency sounds will scatter the basilar membrane only at the base of the snail. The nervous excitement in the auditory receptor auditory nerve It is transmitted to the hearing zone of the cerebral cortex, where the sound image is formed. Figure 2 shows the mechanism for the formation of audible sounds.

Figure 2 - The mechanism of formation of audible sounds

Areas of perception of sound intensity levels

I area - includes a level range from a hearing threshold of up to 40 dB and covers a limited number of signals, as a result of which a person does not have a daily training for the perception of such sounds; In this case, the ability to differentiate sounds is limited.

The II region - includes levels from 40 to 80 - 90 dB and covers the bulk of the useful signals, the levels of speech intensity from the whisper are stacked in this area until the loudest radio broadcasts, musical sounds, etc. It has the ability to the fine differentiation and the analysis of sound quality (and frequency and intensity). The person is most adapted to the perception of sounds of this area.

• III area - covers levels from 80 - 90 dB to the threshold of an unpleasant sensation - 120-130 dB. In this area, the function of the auditory analyzer has significant differences depending on the frequency, intensity and time of the impact of sound.

Classification of factor

The classification of the "Noise" factor is given in Table 1.

Table 1

Normated indicators of factors

Normated indicators for constant and non-permanent noise are shown in Table 2.

table 2

Standards

The maximum permissible levels of noise in the workplace are installed, taking into account the severity and tensions of labor activity. To determine the noise of noise corresponding to a specific workplace, it is necessary to conduct a quantitative assessment of the gravity and tensions of labor performed by the employee. Maximum permissible levels of sound and equivalent levels of sound at workplaces for labor activity of various categories of gravity and tension in the dBA are presented in Table 3.

Table 3. Maximum allowable sound levels and equivalent sound levels on workplaces for labor activity of different categories of gravity and tension in dba

The maximum permissible levels of sound pressure, sound levels and equivalent sound levels for the main most typical types of work and jobs are presented in Table 4.

Table 4. Maximum permissible sound pressure levels, sound levels and equivalent sound levels for the main most typical types of labor activity and jobs

Classes of labor conditions Depending on the noise levels are presented in Table 5

Table 5. Classes of working conditions depending on the noise levels in the workplace

Methodology for measuring

When measuring, in some reference time intervals, they are chosen so that they cover all the characteristic and repeating day-to-day noise situations [it is important to identify all significant changes in noise in the workplace, for example, 5 dB (dBA) and more]. In this case, the measurement results obtained in various shifts will not be contradictory.

Duration of measurements within each reference time interval

for constant noise at least 15 s;

for non-permanent, including intermittent, noise, it should be equal to the duration of at least one repeated working cycle or multiple to several working cycles. The duration of measurements may also be equal to the duration of a certain characteristic type of work or its part. The duration of measurements is considered sufficient if, with further increasing it, the equivalent sound level does not change by more than 0.5 dBA;

• for non-permanent noise, the causes of whose oscillations cannot be explicitly related to the nature of the work performed, 30 minutes (three measurement cycles of 10 minutes) or less, if the measurement results at a lower duration do not differ by more than 0.5 dB (dBA);

for impulse noise - no less time of passing 10 pulses (15 - 30 seconds recommended)

Noise measurements To monitor the correspondence of actual noise levels in the workplace, permissible levels on current standards should be carried out when operating at least 2/3 commonly used units of installed equipment in this room in the most common (characteristic) mode of its operation or otherwise, when typical Noise impact on the side of noise sources that are not at the workplace (in the working area). If it is known that the equipment far from the workplace creates a background noise on 15-20 dB on it lower than noise when equipped with equipment installed at this workplace, it should not be included.

Measurements should not be carried out when conversations of working, as well as when applying various sound signals (warning, information, telephone calls, etc.) and when working loud-speaking communication.

Measurements can be carried out in the presence or absence (last preferable) operator (working) in the workplace or in the working area. Measurements are carried out at fixed points or using a microphone fixed on the operator and moving with it, which provides a higher accuracy of determining the noise level and is preferable.

Measurements at a fixed point are carried out if the position of the operator's head is known exactly. In the absence of an operator, the microphone is installed at a specified measurement point located at the level of its head. If the position of the operator's head is not exactly known and measurements are carried out in the absence of an operator, the microphone is installed for a sedent workplace at a height (0.91 ± 0.05) m above the center of the seating surface during its average adjustment position for the operator's growth, and for standing working Places - at a height (1.550 ± 0.075) m above the support of the vertical passing through the center of the head of a straight person.

If the presence of the operator is necessary, then the microphone is set at a distance of approximately 0.1 m from the ear perceiving greater (equivalent) sound level, and orient in the direction of the operator's view, if possible, or in accordance with the manufacturer's instruction. If the microphone is fixed on the operator, it is installed on a helmet or shoulder using a frame, as well as on the collar at a distance of 0.1 - 0.3 m from the ear, but so as not to prevent the operation of the operator and do not create danger.

The microphone must be removed at least 0.5 m from the operator conductive.

Near the noise source, even minor changes in the position of the microphone can significantly affect the measurement results. If at the measurement point is well distinguishable, then there may be standing waves. The microphone is recommended to move several times in zone 0.1 - 0.5 m and as a measurement result, take the average value.

When the microphone is located close to the operator, a noticeable difference may be observed in the presence of an operator and without it (usually the measurement results in the presence of the operator above). This is especially manifested when measuring high-frequency tonal noise or noise of small sources close to them. To prevent coarse errors, it is recommended to compare the measurement results in the presence of an operator and without it and in case of their significant difference, calculate the average value.

Octave sound pressure levels, sound levels are measured by noiseomers of the 1st or 2nd accuracy class.

The equipment is calibrated before and after measuring noise in accordance with instructions for instructions.

Figure 3 shows the means of measuring the level of sound pressure.

Figure 3 - Means of measurement level of sound pressure

Actual sound pressure levels

Examples of actual soundproof levels are shown in Figure 4.

Figure 4 - actual sound pressure levels

Events to eliminate the harmful effects of noise

Events to protect against the noise of workplaces of industrial enterprises are primarily provided by the following construction and acoustic methods.

Rational from an acoustic point of view The decision of the objective plan of the object, the rational architectural and planning solution of buildings

The main principle of protection is the grouping of premises with an elevated level of noise and their separate location from other parts of the building. As for the equipment of these premises, the most favorable is considered to install it in the center of the room. In this case, there will be only one reflective surface - the floor. When installing equipment in the wall, it will also reflect sound waves, and the noise will be intensified. This principle acts to protect against structural noise, with the only difference that the equipment should not touch the walls of the room.

The use of enclosing structures of buildings with the required sound insulation

Fluent structures of buildings are walls, overlaps, partitions, and the like. They are divided into external and internal. External serve to protect against various climatic factors, and internal enclosing structures - for separation and redevelopment of the inner space of the building.

Elements of fences are recommended to be designed from materials with a dense structure that does not have through pores. Fencing made of through-porosity materials must have an outer layers of dense material, concrete or solution.

The inner walls and partitions of brick, ceramic and slag concrete blocks are recommended to be designed with the filling of the seams to the entire thickness (without PUS-Toshovka) and placed on both sides by a sauced solution.

Fencing structures need to be designed so that in the process of construction and operation in their joints there is no even minimal through slots and cracks. Arriving in the construction process of the gap and cracks after their clearing should be eliminated with constructive measures and sealing non-drying sealants and other materials for the entire depth.

Soundproofing of the building structures is carried out by covering them with sound-absorbing materials. The efficacy of sound insulation depends on the type of material used and from its thickness. Fibrous materials are most effective, which, due to their structure, are missing only a small percentage of noise. The thickness and material of the structures is determined on the basis of conducting acoustic calculations.

Application of sound-absorbing structures

The presence of reflections of sound waves from the surfaces of the closed space (room) and the objects that are in it usually increase the intensity of the sound compared to the levels created by the same sound source emitting to free (open) space. To eliminate the reflected part of the sound field, various sound-absorbing materials and structures based on them are used.

Sound-absorbing structures (suspended ceilings, wall cladding, snacks and piece absorbers) should be used to reduce noise levels at workplaces and in the areas of permanent stay of people in industrial and public buildings.

Sound-absorbing structures should be placed on the ceiling and on the upper parts of the walls. It is advisable to place sound-absorbing designs with individual sites or stripes. At frequencies below 250 Hz, the efficiency of sound-absorbing cladding increases when it is placed in the corners of the room.

Sound-absorbing facing area and the number of pieces of absorbers are determined by the calculation.

Pieces absorbers should be used if the facing is not enough to obtain the required reduction in noise, as well as instead of a sound-absorbing suspended ceiling, when its device is impossible or ineffectively (a large height of the production room, the presence of bridge cranes, the presence of light and aeration lamps). As mandatory measures to reduce noise and ensure optimal acoustic parameters of premises, sound-absorbing structures should be applied: in noisy shops of production enterprises; in the machine halls of computing centers; In soundproofing cabins, boxes and shelters.

The acoustic properties of materials substantially depend on their structural parameters, which determine the scope of application of these materials. So, if noise reduction in the low frequency range is required, then it is advisable to use cladding made of ultra-or super-thin fibrous materials with a density of 15-20 kg / m3. To reduce broadband noise in the middle and high frequency range, materials with larger fibers with a density of 20 - 30 kg / m3 and more should be selected.

It should be noted that in the area of \u200b\u200bdirect sound, sound-absorbing structures practically do not reduce noise levels.

Application of soundproofing and remote control cabins

Soundproofing cabins should be used in industrial shops and in the territories where permissible levels are exceeded, to protect the noise of workers and service personnel. In soundproofing cabins, the consoles of control and management of "noisy" technological processes and equipment, workplaces of masters and heads of workshops should be positioned.

Depending on the required sound insulation of the cabin can be designed from conventional building materials (bricks, reinforced concrete, etc.) or have a prefabricated structure collected from pre-made structures made of steel, aluminum, plastic, plywood and other sheet materials on the national or weld frame .

Soundproofing cabins should be installed on rubber vibration insulators to prevent the transmission of vibrations on the enclosing structures and the cab frame. The internal cabin volume should be at least 15 m3 per person. The height of the cabin (inside) is at least 2.5 m. The cabin should be equipped with a system of ventilation or air conditioning with the necessary silencers of noise. The inner surface of the cabin should be 50 - 70% lined with sound-absorbing materials.

Cabin doors must have sealing gaskets in the focus and locking devices that provide gaskets. In the cabins of the 1st and 2nd classes there must be double doors with a tambour.

The use of soundproof housings on noisy units

The use of soundproof housings is one of the most effective solutions to the problem of insulation of units with an elevated noise level. It is advisable to apply a soundproofing casing in cases where the noise created by the unit (machine) at the calculation point exceeds the allowable value by 5 dB and more at least in one octave strip, and the noise of the remaining technological equipment in the same octave strip (at the same calculated point ) 2 dB and more permissible.

Sound-insulating covers, as a rule, are made of fibrous materials, and the framework serves thin perforated metal panels. If the magnitude of the air noise sound insulation does not exceed 10 dB on medium and high frequencies, the casing can be made of elastic materials (vinyl, rubber, etc.), if more - the casing should be made from leaf structures. Casing elements must be attached on the frame.

The casing should be covered with vibration-absorbing material (sheet or in the form of mastic), while the thickness of the coating should be 2-3 times the thickness of the wall. From the inside, the casing should be placed a layer of sound-absorbing material with a thickness of 40 - 50 mm. For its protection against mechanical impacts, dust and other contaminants, you should use a metal mesh with a fiberglass or a thin film with a thickness of 20-30 μm.

The casing should not have direct contact with the unit and pipelines. Technological and ventilation holes should be equipped with silencers and seals. Installation of soundproof housings is one of the main activities to reduce the noise of ventilation equipment in buildings and rooms. They are installed on the supply, some exhaust installations and air conditioners. Sound-insulating housings are two metal sheets with sound-absorbing material between them. The acoustic efficiency of such housings can be up to 10 - 15 dB at low and up to 30 - 40 dB - at high frequencies.

Application of acoustic screens

The acoustic screen is some barrier between the workplace and the source of noise having high levels Soundproofing. Screens should be used to reduce sound pressure levels at workplaces in the area of \u200b\u200bdirect sound and in the intermediate zone. Install screens should be closer to the noise source.

Screens should be made of solid sheet materials or individual shields with mandatory cladding sound-absorbing surface materials facing the source of noise.

Constructively, the screens can be flat and p-shaped (in this case, their efficiency increases). If the screen surrounds the noise source, then it turns into a slurry and its effectiveness is approaching the efficiency of an infinite screen with a height H. The weiglock is advisable to apply noise for the source (sources) of noise, the levels of sound power of which are 15 dB and more higher than that of other noise sources.

Screen elements can be located vertically and under a specific slope to the horizontal (vertical) plane. The angle of inclination depends on the mutual location of the source of noise and the workplace.

The main parameters of the screen (height, shape, the thickness of the sound-absorbing cladding), under which a given acoustic efficiency is provided at a fixed distance to the noise source are determined by the estimated path. Linear screens sizes should be at least three times the linear dimensions of the noise source.

Without the noise of fans and the use of noise silencers in ventilation systems, air conditioning and in aerogazodynamic installations

To reduce the fan noise: select the unit with the lowest specific levels of sound power; ensure the operation of the fan in the maximum efficiency mode; reduce network resistance and not apply a fan that creates overpressure; Provide a smooth air supply to the inlet fan nozzle.

To reduce noise from the fan along the path of its propagation through the air ducts, it follows: to provide for the central (directly at the fan) and the end (in the air duct before the air distribution devices) noise silencers; Limit air movement speed in the networks of the amount of noise generated by regulating and air distribution devices within the allowable values \u200b\u200bin the served rooms.

A tubular, lamellar, channels, cylindrical, screen and chamber, and lined with sound-absorbing materials of the air ducts and their turns can be used as silencers of noise of ventilation systems.

The design of the muffler should be selected depending on the size of the duct, the required reduction in noise levels, the permissible air velocity based on the calculation of the corresponding draft of the rules.

Vibration Isolation of technological equipment

Air noise, especially vibration, spreading with small attenuation on the carrier and enclosing structures of buildings, as well as on pipelines and walls of channels and mines in buildings, emitted as a structural (shock) noise in rooms that are significantly remote from noise sources and vibrations. Protection against structural noise is carried out by the methods of acoustic vibration insulation of engineering equipment and its communications. These methods include the installation of flexible inserts and vibration insulators, facilities for the floors on the elastic base (floating floors).

In the first case, flexible inserts from linen cans are installed to reduce the structural noise of ventilation equipment on the sides of the discharge and suction of the fans. Inserts are manufactured in accordance with typical drawings and have a rectangular and round cross-section. For pumps and refrigeration machines, flexible inserts are used in the form of rubber sleeves.

Another way is to reduce noise through the use of vibration insulators. To achieve a goal in practice, two types of vibration insulators are often used: steel spring and rubber vibration insulators.

Rubber vibration insulators, the maximum allowable static deflection of which is 30% of their height, are used at speeds of more than 1800 rpm. These vibration insulators effectively reduce the transmission of vibration at high frequencies. However, their use does not significantly reduce the transmission of vibration at low frequencies. In addition, rubber vibration insulators have low wear resistance. The most effective is the use of combined vibration insulators consisting of spring vibration insulators, which are installed on rubber or cork pads with a thickness of 10 - 20 mm and fit to the support surface.

The third method is the use of floors on an elastic base (floating floors). Their effectiveness may be lower than in vibration insulators (in the calculated frequency band), but the damping ability of such floors is manifested in a wide frequency range.

In the designs of this type, as in general, when the soundproofing device, it is necessary to strictly monitor the lack of through holes and cracks in insulating structures, a dense adjuncing elements to each other. In the case of "floating floors", the elastic gaskets must go up onto the walls along their perimeter, preventing rigid mechanical contact of the floor (tie) with walls.

It is necessary to note the organizational ways of protection against noise (see below).

The choice of rational modes of operation of the equipment, restricting the time of finding staff in the zone of operation of aggregates (machines) with an increased level of noise (protection "time")

Protection "Time" provides for the premises in rooms with a high level of noise only for the official need for a clear regulation on the time of the actions committed; automation of work; Reducing the time of configuration work, etc.

The duration of additional regulated breaks is set to the level of noise, its spectrum and personal protective equipment. For those groups of workers, where, according to safety conditions, the use of contractions (listening to signals, etc.) is not allowed, only noise levels and its spectrum is taken into account.

Rest in the period of regulated breaks should be carried out in specially equipped facilities. During the lunch break, working when exposed increased levels Noise should also be in optimal acoustic conditions (when the sound level is not higher than 50 dBA).

Use of personal protection of hearing organs

Anti-liners, anti-checkered headphones and helmets include the means of individual protection of the organ of hearing. The effectiveness of PPE can be ensured by their correct selection depending on the levels and spectrum of noise, as well as to the control of the correct operation.

State system of sanitary and epidemiological rationing of the Russian Federation

Federal sanitary rules, norms and hygienic standards

2.2.4 Physical factors of the production environment

2.1.8 Physical environmental factors

Noise at workplaces,

in the premises of residential, public buildings

and on the territory of residential building

Sanitary norms

CH 2.2.4 / 2.1.8.562-96

Ministry of Health of Russia

Moscow

1. Developed by the Scientific Research Institute of Labor Medicine of the Russian Academy of Sciences (Suvorov G.A., Waisinov L.N., Prokopenko L.V., Kravchenko OK), Moscow Research Institute of Hygiene. F.F. Erisman (Karagodina I.L., Smirnova T.G).

2. Approved and put into effect by the Resolution of the State Committee for Public Administration of Russia of October 31, 1996 No. 36.

3. Instected instead of "sanitary standards of permissible noise levels at workplaces" No. 3223-85, "Sanitary standards permissible noise In the premises of residential and public buildings and on the territory of residential building "No. 3077-84," Hygienic Recommendations to establish noise levels at workplaces, taking into account the tensions and severity of labor "No. 2411-81.

· for the noise created in the premises of air conditioning installations, ventilation and air heating - 5 dBa less than the actual noise levels in the rooms (measured or calculated), if the latter do not exceed the values \u200b\u200bof the table. 1 (The correction for tonal and pulsed noise is not taken into account), otherwise - by 5 dBa less than the values \u200b\u200bspecified in Table. ;

· additionally, the maximum sound level should not exceed 110 dBA, and for pulsed noise - 125 dBA for pulsed noiseI.

5.3.1. Maximum permissible levels of sound pressure in octave bands, sound levels and equivalent sound levels for the main most typical types of labor activity and jobs developed taking into account categories of gravity and labor tensions are presented in Table. .

6. Normated parameters and permissible levels of noise in the premises of residential, public buildings and residential territory

6.1. The normalized parameters of permanent noise are the levels of sound pressure L, dB, in octave bands with medium meterometric frequencies: 31.5; 63; 125; 250; 500; 1000; 2000; 4000; 8000 Hz. For an indicative estimate, it is allowed to use the sound levels L A, DBA.

6.2. The normalized parameters of non-permanent noise are equivalent (energy) levels of sound L AEKV., DBA, and maximum sound levels L amax., DBA.

Evaluation of non-permanent noise for compliance with permissible levels should be carried out simultaneously on the equivalent and maximum sound levels. Exceeding one of the indicators should be considered as a non-compliance with these sanitary standards.

6.3. The permissible values \u200b\u200bof sound pressure levels in octave bands of frequencies, equivalent and maximum sound levels of penetrating noise in the premises of residential and public buildings and noise on the territory of the residential building should be taken in Table. .

Maximum permissible levels of sound pressure, sound levels and equivalent sound levels for the main most typical workshops and jobs

Permissible levels of sound pressure, sound levels, equivalent and maximum sound levels of penetrating noise in premises of residential and public buildings and noise on the territory of residential building

Note.

1. Permissible noise levels from external sources in the premises are established under the condition of providing regulatory ventilation of the premises (for residential premises, chambers, classes - with open versions, fraumugas, narrow windows).

2. Equivalent and maximum levels of sound in dBA for noise created in the territory of automobile, rail transport, 2 m from the enclosing structures of the first echelon of noise protection types of residential buildings, buildings of hotels, hostels facing the main streets of the citywide and district value, iron Roads, allowed to take 10 dba above (correction \u003d + 10 dBA) specified in positions 9 and 10 Table. .

3. Levels of sound pressure in octave frequency bands in dB, sound levels and equivalent sound levels in dBA for noise generated in rooms and in areas adjacent to buildings, air conditioning systems, air heating and ventilation, etc. engineering equipment, It should be taken by 5 dBa below (amendment \u003d - 5 dBA) specified in Table. (The amendment for tonal and impulse noise in this case should not be taken).

4. For a tonal and impulse noise, an amendment should be taken - 5 dBA.

Bibliography

1. Guide 2.2.4 / 2.1.8.000-95 "Hygienic Evaluation physical factors Industrial and Environment. "

2. Guidelines 2.2.013-94 "Hygienic criteria for evaluating working conditions in terms of harmfulness and danger of factors of the production environment, gravity, labor intensity."

3. Suvorov G. A., Denisov E. I., Waisins L. N. Hygienic rationing of production noise and vibrations. - M.: Medicine, 1984. - 240 s.

4. Suvorov G. A., Prokopenko L. V., Yakimova L. D. Noise and Health (Ecological and hygienic problems). - M: Union, 1996. - 150 s.

Noise rationing is carried out at the limiting noise spectrum and sound pressure level. With the first method, the maximum permissible levels of sound pressure are normalized in octave frequency bands with medium-generic frequencies 31.5, 63, 125, 250, 500, 1000, 2000. 4000, 8000 Hz. A combination of nine permissible sound pressure levels is called a limit spectrum.
The second rationing method general level Noise, measured on a scale of a noiseomer and called sound level in dBA, is used by ala orientative assessment of constant and non-permanent noise, since in this case the noise spectrum is unknown.
In production conditions, very often noise has a non-permanent character. Under these conditions, it is most convenient to use a certain average value called equivalent (by energy) LEX sound level and characterizing the average sound energy to dBA. This level is measured by special integrating noiseomers or calculated.
The standards of noise levels are governed by the "sanitary standards of permissible noise levels at workplaces" No. 3223-85, approved by the Ministry of Health, depending on their classification on spectral composition and temporary characteristics, type of work.
From the point of view of biological effects, the spectral composition and the duration of the noise is essential. Therefore, admissible levels of sound pressure are introduced corrections that take into account the spectral composition and the temporary structure of noise. The most adversely acting tonal and impulse noises. The tonal is the noise in which the sound of a certain frequency is listened. The impulse is the noise perceived as individual blows and consisting of one or more sound energy pulses with a duration of each less than 1 s. Broadband is considered to be noise in which sound energy is distributed throughout the spectrum of sound frequencies. Obviously, with an increase in noise exposure duration during shift, absolute values \u200b\u200bof the amendments are reduced. At the same time, they are greater for broadband than for tonal or impulse noise, at permanent workplaces, the allowable sound level is 80 dBA.
The hygiene norms of infrasound at workplaces approved by the Ministry of Health establish the permissible values \u200b\u200bof sound pressure levels in octave stripes with medium-meter frequencies 2, 4, 8 and 16 Hz not higher than 105 dB, and in the 32 Hz band - 102 dB.
The permissible ultrasound values \u200b\u200bin the workplace regulates GOST 12.1.001-83 "SSBT. Ultrasound. General security requirements. " The normalized characteristic of the ultrasound in the low-frequency range is the level of sound pressure in the third-party frequency bands with medium-meterometric frequencies from 12.5 to 100 kHz.

For a high-frequency range of ultrasound distributed only by contact path, the normalized characteristic is the peak value of the vibrationability (V M / s) or its logarithmic level (A.U dB), the permissible value of the ultrasound level in the contact zones and other parts of the operator body with the operator's working bodies should not exceed dB.
Methods of hygienic assessment of job vibration, normalized parameters and their permissible values \u200b\u200bare established by sanitary standards for vibration of workplaces CH 3044-84.
The hygienic okey of vibrations acting on a person in the workplace in production conditions, produce the following methods:

• frequency (spectral, analysis of the normalized parameter. It is the main method characterizing the vibrational impact on a person;
• integral assessment in the frequency of the normalized parameter used for the approximate estimate;
• the dose of vibration used to assess the vibration with the time of exposure.

With frequency analysis, the normalized parameters are the average quadratic values \u200b\u200bof Vibrousness V and Vibrating the LA (or their logarithmic levels of LV, LA), measured in octave or third-gravity frequency bands (for general narrow band vibrations only in third-party frequency bands).
In the integral frequency estimate, the normalized parameter is the corrected value of vibration and vibration and (or HX Logarithmic LU), measured by corrective filters or calculated by formulas.
With a dose vibration estimate by the normalized parameter, an equivalent value of the energy is equivalent to the energy (or its logarithmic level LUEKV), determined by the formula.