This work is devoted to the assessment of noise pollution of the territory of a residential area located in the Leningrad region, Tosnensky district, village. Fedorovskoe, st. Pochtovaya, 1, from the workflow for the construction of a sports hall adjacent to the existing school building. The authors carried out a quantitative and qualitative assessment of the acoustic characteristics of noisy equipment during the construction work indicated above, by theoretical calculations and by computer modeling and optimization, in accordance with the sanitary noise standardization in force in Russia. The assessment of the existing sound levels in the objects of protection has been carried out. It was revealed that the normatively permissible values were exceeded by the expected sound levels in the objects of protection. A scientifically substantiated list of measures has been developed to protect the surveyed objects from noise, taking into account the effectiveness of noise protection.

noise characteristic

noise source

construction site

computer modelling

noise protection

1. All-Union norms of technological design of road transport enterprises ONTP-01-91 / Rosavtotrans. Approved by the protocol of the concern "Rosavtotrans" dated August 07, 1991 No. 3.

2. LLC "CEB GA". Estimated and instrumental zoning of the territory of the "residential area with developed infrastructure", with a total land area of 38,177 hectares, located at the address: Moscow, Voskresenskoye settlement, Yazovo village, located in the area of responsibility of the Ostafyevo airfield (aircraft noise), Moscow , 2015 .-- 52 p.

3. Sanitary and Epidemiological Rules and Regulations “Hygienic Requirements for the Organization of Construction Production and Construction Works. SanPiN 2.2.3.1384-03 ", approved by the Chief State Sanitary Doctor of the Russian Federation on June 11, 2003.

4. СН 2.2.4 / 2.1.8.562-96 Noise at workplaces, in premises of residential, public buildings and on the territory of residential buildings.

5. SNiP 23-03-2003. Noise protection.

Purpose of the study

Establishing compliance with the norms of acoustic conditions for people staying in areas adjacent to residential buildings and on recreation sites located in the noise impact zone from the construction process of reconstruction of the school building.

Materials and research methods

The tasks of creating acoustically safe living conditions for the population in residential areas by noise protection measures were solved on the basis of a systematic approach. Analytical studies were carried out using the methods of applied acoustics, mathematical statistics and computer modeling.

Research results and their discussion

According to SN 2.2.4 / 2.1.8.562-96 "Noise at workplaces, in the premises of residential, public buildings and on the territory of residential development" and SNiP 23-03-2003 "Protection against noise" in the updated edition of 2011 calculation and assessment both the maximum sound levels L Amax (in dBA) and the equivalent sound levels L Aeq (in dBA), created in our case by the operation of construction equipment near the residential area, are subject to transport noise.

Rationing is established for regulated intervals of daytime and nighttime. Regulated time intervals are 16 hours of daytime (from 7-00 to 23-00) and 8 hours of night time (from 23-00 to 7-00). The main sources of noise at the construction site are single trucks (MAZ 333702 truck crane and KamAZ trucks) that move at low speeds.

Table 1

Standardized levels according to SN 2.2.4 / 2.1.8.562-96 (Table 3) for protected areas of recreation areas

When assessing noise on the ground, sanitary and hygienic requirements regulate the maximum permissible noise levels both in the premises of the objects of protection, in the territories adjacent to residential buildings, and at recreation sites. Table 1.Criteria for standardizing noise in the territory and recreation areas are given.

In accordance with note 2 of table. 1 SNiP 23-03-2003 "Protection against noise", the permissible noise levels from external sources in residential premises are established subject to the provision of standard air exchange and must be performed subject to open vents or other devices that provide air inflow and exhaust. It is known that a window in ventilation mode has a sound insulation of 10 dBA.

The development of measures to protect the territory of a residential area from external noise is associated with the need for preliminary special acoustic calculations. Installed:

1. The noise regime of the investigated territory and the premises of residential and other buildings located on it is determined by the separate action of the linear source (access roads for vehicles at the construction site), as well as single point sound emitters (parking of the truck crane by grab). The determined values of the indicators of such noise are numerically presented for the calculated point on the ground (Fig. 2-3).

2. There may also be various local (point) sources, such as resistance welding installations, household noise, etc.

3. We have chosen three as the locations of the calculated points (Fig. 2-3):

RT1 - the territory of a preschool institution;

PT2 - territory adjacent to the nearest residential building;

RT3 - the territory of the school itself (closest to the construction site).

Let us consider the methods for determining the noise characteristics of a working truck crane and moving trucks.

1. It is customary to determine the noise characteristic of a working truck crane based on the results of field measurements (see item 1 of Table 2).

2. Equivalent noise level of traffic flow L Aeq, dBA is determined by the formula

L Aeq = 10 lgQ + 8.41gP + 13.3 lgV + 9.2, (1)

where Q is the intensity of the traffic flow, auto / h;

Р - the share of freight transport in the flow,%;

V is the average speed of the car flow, km / h.

To calculate the equivalent sound level generated by a car when driving through the territory of an enterprise (in accordance with the requirements of ONTP 01-91), it is accepted:

For vehicles: Q = 1 vehicle / h, P = 100%, V = 10 km / h. Thus, the equivalent sound level will be L Aeq ~ 39, ZdBA.

The maximum sound level at a speed of 60 km / h is characteristic of KamAZ trucks - 89dBA.

When driving through the territory at a speed not exceeding 10 km / h, the maximum sound level will be:

L Amax = L Amax 60 + 30 lgV / Vo, (2)

where L Amax60 is the tabular value of the maximum sound level at a speed of 60 km / h, 89 dBA;

V - real (permissible) speed of vehicles on the construction site - 10 km / h. Then the maximum sound level will be:

L Amax = 89 + 30 lg 10/60 = 66 dBA.

The equivalent and maximum sound pressure levels at the construction site when vehicles are moving will be L Amax = 66dBA and L Aeqv = 39, ZdBA, respectively.

Table 2 shows the noise characteristics of the sources taken in the calculation.

table 2

Noise characteristics of sources

Noise source	Sound pressure levels, dB, in octave bands of geometric mean frequencies, Hz	L A eq, dBA
Noise source		L A eq, dBA
The noise of a working truck crane based on MAZ
Noise when driving for construction site

Rice. 1. Scheme for determining sound levels in objects of protection by theoretical calculation

Methodology for assessing the noise mode of the objects under study by cartographic methods

The sound level (dBA), or sound pressure (dB), created by a single point radiator in a homogeneous environment for a free sound field L R, at design points located at a distance R i (m) from its acoustic center, can be determined by the ratio:

L Ri = L pi + 10lgФ - 20lgR i / R 0 - - 10lgΩ + L neg. - ΔL screen. (3)

Here Ф and Ω are, respectively, the directivity factor of the emitter, which for equally directional sources is taken Ф = 1, and the total spatial angle of acoustic radiation into the open space bounded by the earth's surface is Ω = 2π, R 0 = 7.5 m.

In this computational model, we used the assumption that the diffraction pattern (Fig. 1), obtained by the computational method near flat surfaces (facades) of residential buildings for a radiator with a fixed sound frequency of 1.0 KHz, corresponds to that obtained in the assumptions of geometric acoustics of the energy theory of sound. Thus, in the calculation model used in this study, the value of λ is taken equal to 0.34 m for f = 1.0 KHz, 0.17 m for f = 2.0 KHz, etc.

The energy summation of the sound levels of all sources of external noise at the design points on the territory of the adjacent building is carried out using the relation

L Σ = 10lg Σ10 0.1LRi. (4)

Here L Σ is the total value of the added sound pressure levels (dB) or sound levels (dBA) at the design point;

L Ri - the magnitude of the absolute values of each of the added sound pressure levels (dB), or sound levels (dBA), created at the calculated point (RT) by real (IS) and imaginary (IS /, IS //, ...) sources.

The above ratios are implemented in the form of a special program for a PC "AcousticLab". With its help, an assessment was made, a forecast was made and visualization of the noise regime of the investigated objects of protection was carried out. Evaluation models are presented in the form of sound field maps, respectively, taking into account the action of an automobile source of external noise as follows. This program is used when zoning areas around Moscow airports.

Table 3 shows the analysis of noise pollution of the residential area under consideration, taking into account the cartographic assessment of the noise regime of the construction site, shown in Fig. 2 and fig. 3.

Analysis of the results table. 3 made it possible to draw the following conclusions:

At the computational point (PT1) closest to the noise source (ИШ1) before noise protection, the value of exceeding the sanitary standard is 2.5 dBA;

The greatest excess of the norm before noise protection is observed at the design point PT3 and is 9.2 dBA.

Rice. 2. Evaluation of the noise regime of a residential area by equivalent sound levels when performing installation work with a MAZ 333702 truck crane in the daytime (before noise protection). Crane parking in the center of the construction site

Table 3

Analysis of the noise mode at design points (PT1-PT2) before and after noise protection

Note. The values of exceeding the sanitary standard (55 dBA) with a "-" sign are shown in brackets.

Rice. 3. Evaluation of the noise regime of a residential area by equivalent sound levels when performing installation work with a MAZ 333702 truck crane in the daytime (after noise protection - installation of a fence with a height of 5 meters). The crane stand is as far away from the school building as possible

Development of special noise protection measures

Consider the following two as noise protection measures:

1) the device of a noise protection screen around the construction site;

2) the establishment of strict regulations for the production of noisy work.

1. To eliminate the established excess of the normative levels of equivalent noise, it is proposed to install a noise shield instead of a temporary fence of the construction site with a height of 2.0 m. Structurally, the noise barrier can be made of sheet metal with a thickness of at least 1 mm with lining of the inner surfaces with a porous material (foam, polyurethane foam, etc.), as well as from wooden structures with a board thickness of at least 25 mm (in the absence of gaps between the boards, lining porous material is not required).

Using a computer model, it was established:

a) the minimum height of the screen during the operation of the truck crane during the entire work shift will be 5.0 meters;

b) the most unfavorable position of the crane at the point indicated in Fig. 3 by the ISH symbol 3.

Additional noise protection measures.

2. For the second group of noise protection measures in order to reduce noise impact in the process of performing work, it is necessary:

Reduce the duration of work in the daytime of noisy equipment (when the crane is operating for 40 minutes during each hour of the work shift, the equivalent noise level can be reduced to 1.2 dBA); in more detail and with calculations, this event is discussed below in the text;

Reduce the transmission of vibration through the soil by the presence of acoustic seams at the construction site with filling them with elastic material (such an acoustic seam can be arranged under the proposed soundproof screen in the form of a trench under the foundation of the screen);

With the help of organizational and technical measures, exclude the work of construction equipment at night ( necessarily);

Use sound-insulating casings for machines that are easy to implement during operation;

Use wooden deck decks under which air cushion shock absorbers are installed (usually a car camera). To fix the position, the platform is attached to the floor with straps;

Place storage and other functional premises on the construction site, taking into account acoustic zoning for quiet areas;

Place rubber mats (dimensions 21x350x350 mm) under reinforced concrete foundations and under the paws of construction machines as far as possible and appropriate.

With a reduction in the duration of the truck crane (organization of work without installation and unloading), i.e. work no more than 40 minutes during each hour of the entire work shift (for an 8-hour work shift, work no more than 320 minutes, i.e. 5 hours and 20 minutes), the height of the screen can be reduced to 4.0 meters, since the total equivalent the noise level from the crane operation will decrease by 1.2 dBA, and the acoustic efficiency of the screen for RT 2 when the noise source is placed in the worst position - ISh 3 (Fig. 3) will decrease by an average of 4.0 dBA. The results of these calculations are presented in table. 4.

Conclusion

The results obtained made it possible to determine the influence of the construction process on the noise pollution of the specified object of protection.

The analysis of the obtained results of such a study made it possible to establish the following:

1. The noise regime of the investigated territory and the premises of residential and other buildings located on it is determined by the separate action of a linear source - access roads for vehicles at the construction site, as well as single point sound emitters (parking of a truck crane by grab). There may also be various local (point) sources, such as resistance welding installations, household noise, etc.

2. The initial boundary conditions adopted in the work made it necessary to assess the adverse external impact of noise sources on the objects of protection located on the territory of the investigated residential complex.

3. As a result of the forecast, the following was established:

Equivalent and maximum sound pressure levels at the construction site when vehicles are moving will be L Amax = 66 dBA and L Aeq = 39, З dBA, respectively;

The equivalent and maximum sound pressure levels at the construction site during the operation of the truck crane will be L Amax = 79.0 dBA and L Aeqv = 78.0 dBA, respectively;

As the main noise protection measure, it is recommended to install a noise protection screen along the contour of the construction site fencing made of Paroc slabs 100 mm thick and 5.0 m high with constant crane operation, and 4.0 m high with a reduction of up to 45 minutes per hour throughout the entire work shift. mounting or unloading (screen design options are indicated below in the text);

It should be especially noted that the presence of a noise shield will protect the adjacent development area from all internal local sources of noise, including biogenic noise caused by household processes during breaks in the work of all construction personnel.

Table 4

Analysis of the noise regime at the design points (RT1-RT3) after the noise protection measure - the regulations for the production of noisy work

Note. The calculation takes into account a decrease in the equivalent sound level by 1.2 dBA with a decrease in the operation of a truck crane to 40 minutes during each hour of a work shift and a decrease in the acoustic efficiency of a noise shield by 4.0 dBA with a decrease in height from 5 to 4 meters.

Taking into account the fact that the sound insulation of obstacles (acoustic screens) should be more than 20 dBA (so that the noise transmitted through the obstacle does not add up energetically to the noise that has passed around the edge of the screen - the diffraction effect), we recommend using Paroc plates with a thickness of 100 mm.

Structurally, the noise barrier can be made of sheet metal with a thickness of at least 1 mm with lining of the inner surfaces with a porous material (foam, polyurethane foam, etc.), as well as from wooden structures with a board thickness of at least 25 mm (in the absence of gaps between the boards, lining porous material is not required).

The requirement of clause 6.5 that "machines and assemblies that create noise during operation should be operated in such a way that sound levels at workplaces, on sites and on the territory of the construction site do not exceed the permissible values specified in sanitary standards" : if at the workplaces of the construction site there will be no noise levels higher than 80 dBA, in the adjacent residential area there will be no excess noise levels when installing a fence with a height of 4 meters around the entire perimeter.

Bibliographic reference

Zakharov Yu.I., Sankov P.N., Zakharov V.Yu., Tkach N.A. ACCOUNTING THE FACTOR OF NOISE POLLUTION WHEN ORGANIZING A CONSTRUCTION SITE // Modern science-intensive technologies. - 2015. - No. 10. - P. 32-38;
URL: http://top-technologies.ru/ru/article/view?id=35153 (date accessed: 12/30/2019). We bring to your attention the journals published by the "Academy of Natural Sciences"

Attenuation of noise on the way of its propagation is provided by a complex of construction and acoustic measures. These include rational planning solutions (first of all, removing noise sources at an appropriate distance from objects), sound insulation, sound absorption and sound reflection of noise.

Noise mitigation measures should be envisaged already at the stage of designing master plans for cities, industrial enterprises and planning premises in individual buildings. Thus, it is unacceptable to place objects that require protection from noise (residential buildings, laboratory and design buildings, computer centers, office buildings, etc.), in the immediate vicinity of noisy workshops and units (test boxes of aircraft engines, gas turbine plants, compressor stations etc.). The noisiest objects should be combined into separate complexes. When planning rooms inside buildings, the maximum possible distance between quiet rooms and rooms with intense noise sources is provided.

To attenuate the noise penetrating into isolated rooms, it is necessary: to use materials and structures that provide adequate sound insulation for floors, walls, partitions, solid and glazed doors and windows; use sound-absorbing ceiling and wall cladding or artificial sound absorbers in isolated rooms; provide acoustic vibration isolation for units located in the same building; apply soundproof and vibration-damping coatings on the surface of pipelines passing through the room; use mufflers in mechanical ventilation and air conditioning systems.

The machine room of the elevators must not be located directly above and below the living quarters, as well as next to them. Elevator shafts should not be adjacent to the walls of living rooms. Kitchens, bathrooms, toilets should be combined into separate blocks adjacent to the walls of stairwells or to the same blocks of adjacent rooms, and separated from living quarters by a corridor, vestibule or hallway.

The installation of pipelines and sanitary devices on the enclosing structures of living rooms, as well as the placement of bathrooms and sewer risers next to them, is prohibited.

In all public, and sometimes in residential buildings, ventilation systems are used, sometimes air conditioning and air heating systems with mechanical equipment can create significant noise.

To attenuate the noise propagating through the channels of ventilation, air conditioning and air heating systems, special silencers (tubular, honeycomb, plate and chamber with sound-absorbing material) should be used, as well as air ducts and squeegees lined from the inside with sound-absorbing material (Figure 1). The type and size of the muffler is selected depending on the required noise level, permissible air flow rate and local conditions.

Sound insulation of premises from airborne noise is the attenuation of sound energy in the process of its transmission through the fence. Most often, soundproof fences are walls, partitions, windows, doors, ceilings.

Currently, multilayer structures are used in construction practice more and more often. In some cases, they make it possible to obtain significant additional insulation compared to single-layer structures of the same mass (up to 12-15 dB).

In ceilings, to ensure the standard insulation of impact and airborne noise, a floor is made on an elastic basis (floating floor) or soft roll coverings are used. The joints between internal enclosing structures, as well as between them and other adjoining structures, must be equipped in such a way that cracks and cracks that weaken the insulation do not appear during operation (Figure 2).

Figure 1. Ventilation mufflers (diagrams):

a --- tubular; b - lamellar; в - cellular;

d - cylindrical.

To increase sound insulation, double doors with a vestibule are also used. Doors are provided with elastic gaskets. Walls in the vestibule should be lined with sound-absorbing material. Doors should open in different directions.

Double windows insulate better from airborne noise (up to 30 dB) than twin windows (20-22 dB).

Rice. 2.

a - floating floors on a continuous flexible basis (1 - floor covering; 2 - prefabricated or monolithic screed plate; 3 - soundproof flexible gasket; 4 - load-bearing part of the floor; 5 - plinth; b - floating floor on tape or artificial gaskets; c - overlap with soundproof materials (1 - soft roll floor; 2 - overlap; 3 - plinth)

Recently, "soundproof ventilation windows" have been widely used, which provide high sound insulation and at the same time allow ventilation of the room. These are two blind frames, located at a distance of 100 mm or more from one another, with soundproofing lining along the contour. Glasses of different thickness are used or in one frame a package of two glasses. A hole is installed in the wall under the window, in which a box is installed in the form of a muffler with a small fan that provides air flow into the room.

Sound absorbing structures are designed to absorb sound. These include sound-absorbing wall cladding and artificial sound absorbers. Sound absorbing structures are widely used.

Most often, sound-absorbing cladding is used: in educational, sports, entertainment and other buildings to create the best acoustic conditions for the perception of speech and music; in production workshops, offices and other public premises (typing bureaus, computer counting stations, administrative premises, restaurants, waiting rooms of railway stations and air terminals, shops, canteens, banks, post offices, etc.); in corridor-type premises (schools, hospitals, hotels, etc.) to prevent the spread of noise.

The sanitary and hygienic requirements for sound-absorbing structures are, first of all, that they should not worsen hygienic conditions due to shedding of fibers or material particles, or contribute to the accumulation of dust. The ease of dust cleaning of sound-absorbing structures is of particular importance in buildings with increased sanitary and hygienic requirements (hospitals) and with increased dust emission (most industrial enterprises).

The effectiveness of sound-absorbing cladding in noisy rooms depends on the acoustic characteristics of the room, the characteristics of the selected structures, the way they are placed, the location of noise sources, the size of the room and the location of the design points. Usually it does not exceed 6-8 dB.

Measures to combat urban noise can be divided into two groups: architectural planning and construction acoustic.

Reducing noise along the path of its propagation from the source to the residential area implies rational design of the road plan, cross-sections and the use of the right-of-way.

In this case, if it is impossible to provide a buffer zone from highways to development, taking into account the requirements of sanitary standards, the following options for reducing traffic noise can be distinguished (Figure 3, a-j):

Figure 3. Schemes for the protection of residential buildings from traffic noise.

a - noise barrier on the highway right-of-way;

b - a combination of a noise barrier on the right-of-way and a barrier located on the dividing strip (with a small width of the dividing strip, it is combined with the fences);

c - retaining wall from the side located close to the building;

d - green spaces within the buffer zone;

d - protective earth shafts;

e - road in a notch within settlements;

g - a road on an overpass with a device on the dividing strip and along the edges of noise protection barriers made of transparent plastic. The space under the flyover can be used for parking. For better protection, a low ground shaft can be erected;

h - gallery with natural light;

and - a gallery open to the area opposite to the building area with the use of the space above the gallery for parking and additional protection from noise by green spaces;

к - tunnel with complete isolation from traffic noise and use of the space above the tunnel for local traffic.

Various administrative measures can be used. These include: redistribution of traffic flows by city streets; restriction of movement at different times of the day in one direction or another; changes in the composition of vehicles (for example, a ban on the use of trucks and buses with diesel engines on some streets of the city), etc.

When developing projects for the planning and development of cities for noise protection, both natural conditions (terrain and green spaces) and special structures (screens near highways) can be used. It is also possible to apply rational methods of zoning the territory according to the conditions of the noise regime for certain types of buildings, plots and areas for recreation, household needs, etc. noise transport reduction of the population

Consider possible options for noise protection in cities. First of all, in order to protect against noise when designing cities and other settlements, it is necessary to clearly divide the territory according to its functional use into zones: residential, industrial (production), communal storage and external transport. Industrial (production) and communal storage areas, designed for large traffic flows along transport routes, are located so that they do not cross the residential area and do not wedge into it.

To protect against noise when designing an external transport system, it is necessary to provide for bypass railway lines in cities (for passing transit trains outside the city), place marshalling yards outside settlements, and technical stations and parks of reserve rolling stock, railway lines for freight traffic and access paths - outside the residential area; to separate new railway lines and stations during new construction from residential buildings in cities and other settlements of the SPZ; maintain a proper distance from the borders of airports, factory, military airfields to the boundaries of residential buildings

When designing the road network, the maximum possible enlargement of the Inter-highway territories, a decrease in the number of intersections and other transport hubs, and the device of smooth curved road connections should be envisaged. On the territory of residential areas, it is necessary to limit through traffic.

Functional zoning of microdistrict territories should be carried out taking into account the need to locate residential buildings and preschool institutions in areas farthest from noise sources, transport highways, parking lots, garages, transformer substations, etc. which allow higher sound levels. These are consumer services, trade, catering, utilities, administrative and public institutions. Shopping centers and service blocks are usually built on the border of microdistricts along transport routes as a single complex.

If residential buildings need to be located on the border of microdistricts along transport routes, it is advisable to use special types of noise-proof residential buildings. Depending on the insolation conditions, it is recommended to build: noise-proof residential buildings, the architectural and planning solutions of which are characterized by an orientation towards the noise sources of the windows of auxiliary rooms and no more than one living room without sleeping places for multi-room apartments; noise-proof residential buildings with increased soundproofing properties of external enclosing structures, oriented towards noise sources and with built-in ventilation systems.

To ensure sanitary standards in apartments and on the territory of microdistricts, it is necessary to use compositional techniques for grouping noise-protected buildings, based on the creation of a closed space. When locating residential buildings along transport routes, one should not resort to compositional methods of grouping residential buildings, which are based on the disclosure of space towards the roadway.

If the architectural and planning measures (gaps, construction methods, etc.) do not provide the proper noise regime in buildings and on the territory of a residential neighborhood, as well as in order to save the territory necessary to comply with territorial gaps with transport highways, it is advisable to use construction and acoustic methods: noise-protective structures and devices, screens, noise-protective greening strips, and for residential buildings also structures of window openings with increased sound insulation.

Various buildings and structures can be used as screens: buildings with reduced noise requirements; noise-proof residential buildings; artificial or natural relief elements (excavations, ravines, earthen ramparts, embankments, barrows) and walls (roadside retaining, fencing and soundproofing). It is advisable to place noise shields as close as possible to the noise source.

Buildings with reduced noise requirements (consumer services, trade, catering, utilities; public and cultural and educational, administrative and economic institutions) and noise-proof residential buildings should be placed along noise sources in the form of a frontal, if possible continuous, development. Premises of administrative, public and cultural and educational institutions with increased requirements for acoustic comfort (conference room, reading rooms, auditoriums of theaters, cinemas, clubs, etc.) should be erected on the side opposite to noise sources. They are separated from the highway by corridors, foyers, halls, cafes and buffets, auxiliary rooms.

As an additional means of protection against noise, you can use special noise protection strips of green spaces. Several strips are formed with gaps between them equal to the height of the trees. The width of the strip should be at least 5 m, and the height of the trees should be at least 5-8 m.On the noise protection strips, the crowns of the trees should be tightly joined together.

Noise regulation

Noise regulation is carried out in two directions: hygienic regulation and regulation of noise characteristics of machines and equipment (technological).

The current noise standards at workplaces are regulated by SanPiN 2.2.4 / 2.1.8.10-32-2002 "Noise at workplaces, in residential, public buildings and in residential areas" and GOST 12.1.003. "SSBT. Noise. General safety requirements ".

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

Maximum permissible sound levels and equivalent sound levels in the workplace

For a rough estimate of the noise, the sound level is taken, determined according to the so-called A scale of the sound level meter in decibels - dBA.

These documents establish the permissible noise levels in working rooms for various purposes. At the same time, zones with a sound level above 80 dBA are considered dangerous, they must be marked with special signs, and those working in these zones must be provided with personal protective equipment.

The maximum sound level for oscillating and intermittent noise should not exceed 110 dBA. In areas with a sound pressure level above 135 dBA, even a short stay of people is prohibited.

For various production equipment and machines, the standards set the limit levels of noise characteristics (machine tools, compressors, weaving and other equipment).

There are also standards that establish methods for determining noise performance.

The standards establish that the noise characteristics of the machines are indicated in the technical documentation.

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

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

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

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

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

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

Workers can be protected from noise both by collective means and methods, and by individual means.

Basic methods of noise protection:

1. Reducing noise at source

Reasons: mechanical, aerodynamic, hydrodynamic and electromagnetic phenomena due to the design and nature of the machines, inaccuracies in manufacturing, etc.

To reduce noise in the source, the following is used:

Replacement of shock mechanisms with shockless ones;

Using low noise connections;

Replacement of metal parts with plastic ones;

Replacing rolling bearings with plain bearings

Change of operating modes;

Lubrication, etc.

These are the most effective measures because post-noise control is more expensive and often ineffective.

2.changing the directivity of noise emission

Appropriate orientation of installations in relation to workplaces or residential buildings.

This method is used when a working device (machine, unit, installation) radiates noise in a directed manner. An example of such a device is a pipe for discharging compressed air into the atmosphere in the direction opposite to the workplace.

To maintain the standard noise regime in residential areas, noise control should be carried out in three main areas:

At the source of noise - by engineering and technical and organizational and administrative methods;

Along the path of noise propagation - by urban planning and construction-acoustic methods;

In the object of noise protection - by constructive and construction methods.
External in relation to the residential area of Nyagan are railway transport, air transport and transit traffic flows.

Noise from railway transport occurs when trains move and handle them at marshalling yards. Noise levels depend on the speed of movement, the load of the cars, the general technical condition of the trains, the track, etc.

Taking into account the branching in the station area, the equivalent level of generated noise (taking into account the number of train pairs) is 80 dBA. Reducing the noise level to the standard value is achieved at a distance of 180-200 m.

In order to reduce the noise level, it is planned to create a sanitary protection zone along the railway track with noise-proof landscaping, and eliminate a number of access roads.

The airport located 10 km away from the city does not affect the general background noise.

Transit cargo flows are mainly directed to the bypass road, and also do not affect the overall background noise.

The main source of intracity noise is the city's main network.

The calculation of the noise characteristics of traffic flows must be carried out in accordance with SNiP 11-12-77 "Protection against noise".

The sound level Later, in dBA at the calculated point on the territory of the object protected from noise, is determined by the formula:

LAther = LAeqv - Laras - L-Aecr - L-Azel

(in accordance with SNiP 11-12-77 "Protection against noise" clause 10.7) The project provides for the following urban planning measures:

Functional division of transport routes;

Assigning the width of streets in accordance with the accepted classification of the road network;

Redistribution of traffic flows due to the creation of one-way streets, alternate streets, a bypass highway;

Greening of adjacent areas, creation of noise-proof green strips and others.

Consolidation of inter-highway areas and rational distribution of traffic loads on the road network can reduce noise by an average of 8 dBA.

The arrangement of streets-alternatives leads to a reduction in noise on the tracks by 5-10 dBA, and at intersections by 8-25 dBA.

The organization of traffic allows to reduce the level of traffic noise by 2-10 dBA, and regulation of the composition of traffic flows and the use of automatic control systems by 10-15 dBA.

Depending on the design of the planting of green spaces, the efficiency of noise protection is 3-15 dBA, and the use of noise barriers is 5-25 dBA.

Residential buildings used as noise barriers must have high sound insulation qualities of external fencing

structures and, first of all, windows, which can reduce the sound level by 18-45 dBA.

The dimensions of the sanitary protection zones from transformers to residential buildings are calculated taking into account the number and capacity of transformers at a substation voltage of 110-220 kV. (200-250 m).

The use of a complex of noise protection measures allows you to improve the acoustic regime in residential premises.

ELECTROMAGNETIC FIELD PROTECTION

To protect the population from the adverse effects of the electromagnetic field created by the overhead line, it is necessary to organize a sanitary protection zone. The size of the zone for 110 kV transmission lines coincides with the size of the technical zone, i.e. equal to 5 m, for overhead lines - 330 kV -20 m.

Taking into account that the field strength in buildings can be reduced due to planning solutions, the use of special building structures, it seems possible for the rational use of the sanitary protection zone from the TV and radio center to divide its territory into a zone of strict "construction" regime and a zone of "restriction".

The "strict" regime zone includes the technical territory of the radio transmitting facility.

The zone of "restrictions" can be used for urban development, provided that a set of measures aimed at reducing the level of field strength (rational planning, the use of special building structures, radio engineering methods) will provide the recommended maximum permissible field strength in residential and other premises.

Noise protection fences

For all settlements that are located close to highways or railway lines, the problem of high noise levels is common. In this situation, the owners of the estates are forced to escape from the loud noise using all possible means. Most often, a high blank fence is still not enough to protect your house and site, for this reason you have to resort to additional measures - to attract special structures and materials. One of the options for creating a soundproof fence is multilayer panels. Their outer surfaces are represented by metal corrugated sheets, and between them there is foam insulation or mineral wool slabs. Such a panel simultaneously performs two functions - reflects and simultaneously absorbs sound, that is, it is a full-fledged noise protection system. The finished panel is not for sale; it is assembled on the spot by representatives of firms that specialize in the construction of fences. The height of the fence is calculated according to a certain scheme: an imaginary line is drawn between the point of the top of the roof ridge, as well as the supposed highest point of the location of trucks on the road, which should be covered by a fence. The upper part of the structure must be equipped with a sound absorber.

In the second version, a sound-reflecting stone surface is created. In this case, the base of the stone fence can be made of foam concrete, but the cladding is made of stone - either artificial or natural. The stone is laid unevenly with an imitation of slate surfaces. The more small and frequent irregularities near the wall, the more it dissipates noise.

In the latter version, a polycarbonate sheet with a thickness of more than eight millimeters is used. In addition to strength, this material is characterized by a fairly good sound-absorbing property. If you want to create a more decorative design, you can combine polycarbonate with wood.

Noise protection measures

A solution should be sought through a preliminary analysis of the acoustic regime of the main areas, assessing the existing and predicted noise characteristics of the highway and the acoustic impact on the buildings of the first development front, as well as the development of noise protection measures that ensure the standard acoustic regime. In real conditions of reconstruction of main streets, it is almost impossible to ensure the permissible noise levels on the adjacent territory of multi-storey residential buildings, therefore, the main emphasis should be placed on noise protection of residential premises and preservation of the housing stock. At the same time, noise protection measures can make up a very significant share in the estimate of the project for the reconstruction of the city highway.

Acoustic calculation of the territories of the planned highways at the design stage allows you to minimize the cost of noise protection measures. The well-known methods of acoustic calculation of territories according to SNiP II-12-77 "Protection against noise" and "Guidelines for accounting in urban development planning projects for noise reduction requirements" imply a graphic-analytical calculation of the noise characteristics of the highway with the construction of noise maps. Modern computer technologies make it possible to use effective methods for the numerical calculation of noise pollution in urban buildings. They involve numerical modeling of the process of noise propagation, which is a computationally laborious task. An alternative is the approach based on the sampling of the study area and the energy summation of the noise at the points of interest using GIS. For some selected point on the territory, energy is summed up from discrete point sources. The highway is a line noise source and is represented as a collection of point sources. The calculation of the propagation of noise energy takes into account the effect of attenuation as a function of distance, as well as diffraction and reflection of sound, i.e. the influence of sources that are not in the line of sight. This approach potentially leads to some decrease in the accuracy of calculations due to sampling. However, this disadvantage is compensated by the fact that all calculations can be carried out by means of the GIS itself, and this makes it possible to combine the solution of transport and planning problems with the assessment of the effect of noise pollution.