Vibration protection in the boiler room. How to reduce the noise of a boiler room: at the design stage and with special means

The number of requests from citizens received by the Office of Rospotrebnadzor in the Tyumen Region about the deterioration of living conditions due to exposure to excess noise levels increases every year.

In 2013, 362 complaints were received (in total regarding violations of peace and quiet, accommodation and noise), in 2014 - 416 complaints, and in 2015, 80 complaints were already received.

According to established practice, after residents apply, the Department orders measurements of noise and vibration levels in residential premises. If necessary, measurements are carried out in organizations located near apartments, where, for example, “noisy” equipment is operated - a source of noise (restaurant, cafe, store, etc.). If noise and vibration levels exceed permissible values, according to SN 2.2.4/2.1.8.562-96 “Noise in workplaces, residential premises, public buildings and in residential areas”, addressed to the owners of noise sources - legal entities, individual entrepreneurs - the Department issues an order to eliminate identified violations of sanitary legislation.

How can you reduce the noise from the equipment listed above so that during its operation there are no complaints from the residents of the house? Of course, the ideal option is to provide the necessary measures at the design stage of a residential building, then the development of noise-reducing measures is always possible, and their implementation during construction is tens of times cheaper than in those houses that have already been built.

The situation is completely different if the building has already been built and there are noise sources in it that exceed current standards. Then, most often, noisy units are replaced with less noisy ones and measures are taken to isolate the units and the communications leading to them from vibration. Next, we will consider specific sources of noise and measures for vibration isolation of equipment.

NOISE FROM THE AIR CONDITIONER

The use of three-link vibration isolation, when the air conditioner is installed on the frame through a vibration isolator, and the frame on a reinforced concrete slab through rubber gaskets (in this case, the reinforced concrete slab is installed on spring vibration isolators on the roof of the building), leads to a reduction in penetrating structural noise to levels acceptable in residential premises.

To reduce noise, it is necessary, in addition to strengthening the noise and vibration insulation of the air duct walls and installing a muffler on the air duct of the ventilation unit (from the premises), to attach the expansion chamber and air ducts to the ceiling through vibration-isolating hangers or gaskets.

NOISE FROM THE BOILER ROOM ON THE ROOF

To protect the boiler room located on the roof of the house from noise, the foundation slab of the roof boiler room is installed on spring vibration isolators or a vibration isolating mat made of a special material. Pumps and boiler units equipped in the boiler room are installed on vibration isolators and soft inserts are used.

Pumps in the boiler room must not be installed with the engine facing down! They must be installed in such a way that the load from the pipelines is not transferred to the pump housing. In addition, the noise level is higher with a higher power pump or if several pumps are installed. To reduce noise, the boiler room foundation slab can also be placed on spring shock absorbers or high-strength multilayer rubber and rubber-metal vibration isolators.

Current standards It is not allowed to place a roof boiler room directly on the ceiling of residential premises (the ceiling of a residential premises cannot serve as the basis for the floor of the boiler room), as well as adjacent to residential premises. It is not allowed to design rooftop boiler houses on buildings of preschool and school institutions, medical buildings of clinics and hospitals with 24-hour stay of patients, on dormitory buildings of sanatoriums and recreational facilities. When installing equipment on the roof and ceilings, it is advisable to place it in places farthest from the protected objects.

NOISE FROM INTERNET EQUIPMENT

According to recommendations for the design of communication systems, informatization and dispatching of housing construction projects, antenna amplifiers cellular communications It is recommended to install in a metal cabinet with a locking device on technical floors, attics or staircases on upper floors. If it is necessary to install house amplifiers on different floors of multi-story buildings, they should be installed in metal cabinets in close proximity to the riser under the ceiling, usually at a height of at least 2 m from the bottom of the cabinet to the floor.

When installing amplifiers on technical floors and attics, to eliminate the transmission of vibration from a metal cabinet with a locking device, the latter must be installed on vibration isolators.

EXIT - VIBRATION ISOLATORS AND “FLOATING” FLOORS

For ventilation, refrigeration equipment on the upper, lower and intermediate technical floors of residential buildings, hotels, multifunctional complexes or in the vicinity of noise-regulated premises where people are constantly present, the units can be installed on factory-made vibration isolators on a reinforced concrete slab. This slab is mounted on a vibration-isolating layer or springs on a “floating” floor (an additional reinforced concrete slab on a vibration-isolating layer) in a technical room. It should be noted that fans and external condenser units, which are currently produced, are equipped with vibration isolators only at the request of the customer.

“Floating” floors without special vibration isolators can only be used with equipment having operating frequencies of more than 45-50 Hz. These are, as a rule, small machines, the vibration isolation of which can be ensured in other ways. The effectiveness of floors on an elastic base at such low frequencies is low, so they are used exclusively in combination with other types of vibration isolators, which provides high vibration isolation at low frequencies (due to vibration isolators), as well as at medium and high frequencies (due to vibration isolators and a “floating” floor ).

The floating floor screed must be carefully isolated from the walls and the load-bearing floor slab, since the formation of even small rigid bridges between them can significantly worsen its vibration-isolating properties. Where the “floating” floor adjoins the walls there must be a seam made of non-hardening materials that does not allow water to pass through.

NOISE FROM THE GARBAGE CHIP

To reduce noise, it is necessary to comply with the requirements of the standards and not design the waste chute adjacent to residential premises. The garbage chute should not be adjacent to or located in walls enclosing residential or office premises with regulated noise levels.

The most common measures to reduce noise from garbage chutes are:

• “floating” floors are provided in waste collection rooms;
• with the consent of the residents of all apartments at the entrance, the garbage chute is sealed (or eliminated) with the placement of a garbage chamber for wheelchairs, a concierge room, etc. in the premises. (the positive thing is that in addition to noise, odors disappear, the possibility of rats and insects, the likelihood of fires, dirt, etc. is eliminated);
• ladle loading valve mounted framed with rubber or magnetic seals;
• decorative heat and noise insulating lining of the garbage chute trunk made of building materials separated from the building structures by soundproofing gaskets.

Today many construction companies offer their services various designs to increase the sound insulation of walls and promise complete silence. It should be noted that in fact, no structures can remove the structural noise transmitted through the floors, ceilings and walls when disposing of solid household waste into a garbage chute.

NOISE FROM ELEVATORS

In SP 51.13330.2011 “Noise protection. The updated version of SNiP 03/23/2003 states that it is advisable to locate elevator shafts in the stairwell between flights of stairs (clause 11.8). When making an architectural and planning decision for a residential building, it should be provided that the built-in elevator shaft is adjacent to rooms that do not require increased protection from noise and vibration (halls, corridors, kitchens, sanitary facilities). All elevator shafts, regardless of the planning solution, must be self-supporting and have an independent foundation.

The shafts must be separated from other building structures with an acoustic seam of 40-50 mm or vibration-isolating pads. Acoustic mineral wool slabs on a basalt or fiberglass base and various foamed polymer roll materials are recommended as the material for the elastic layer.

To protect an elevator installation from structural noise, its drive motor with gearbox and winch, usually installed on one common frame, are vibration-isolated from the supporting surface. Modern elevator drive units are equipped with appropriate vibration isolators installed under metal frames on which motors, gearboxes and winches are rigidly mounted, and therefore additional vibration isolation of the drive unit is usually not required. In this case, it is additionally recommended to make a two-stage (two-link) vibration isolation system by installing a support frame through vibration isolators on a reinforced concrete slab, which is also separated from the floor by vibration isolators.

The operation of elevator winches installed on two-stage vibration isolation systems has shown that noise levels from them do not exceed standard values ​​in the nearest residential premises (through 1-2 walls). For practical purposes, care must be taken to ensure that vibration isolation is not compromised by occasional rigid bridges between the metal frame and the supporting surface. Electrical supply cables must have sufficiently long flexible loops. However, the operation of other elements of elevator installations (control panels, transformers, cabin and counterweight shoes, etc.) may be accompanied by noise above standard values.

It is prohibited to design the elevator engine room floor as a continuation of the ceiling slab of the upper floor living room.

NOISE FROM TRANSFORMERSSUBSTATIONSON THE GROUND FLOORS

To protect residential and other premises with regulated noise levels from noise from transformer substations, the following conditions must be observed:

• premises of built-in transformer substations;
• should not be adjacent to noise-protected premises;
• built-in transformer substations should
• located in basements or on the first floors of buildings;
• transformers must be installed on vibration isolators designed accordingly;
• electrical panels, containing electromagnetic communication devices, and separately installed oil switches with an electric drive must be mounted on rubber vibration isolators (air disconnectors do not require vibration insulation);
• ventilation devices in the premises of built-in transformer substations must be equipped with noise suppressors.

To further reduce noise from the built-in transformer substation, it is advisable to treat its ceilings and internal walls with sound-absorbing cladding.

Built-in transformer substations must be protected from electromagnetic radiation (a mesh made of a special material with grounding to reduce the level of radiation from the electrical component and a steel sheet for the magnetic component).

NOISE FROM ATTACHED BOILER ROOMS,BASEMENT PUMPS AND PIPES

Boiler room equipment (pumps and pipelines, ventilation units, air ducts, gas boilers etc.) must be vibration-isolated using vibration foundations and soft inserts. Ventilation units are equipped with silencers.

To vibration-isolate pumps located in basements, elevator units in individual heating units (IHP), ventilation units, refrigeration chambers, and the above equipment are installed on vibration foundations. Pipelines and air ducts are vibration-insulated from the house structures, since the predominant noise in apartments located above may not be the basic noise from equipment in the basement, but that which is transmitted to the enclosing structures through vibration of pipelines and equipment foundations. It is prohibited to install built-in boiler rooms in residential buildings.

In piping systems connected to the pump, it is necessary to use flexible inserts - rubber-fabric hoses or rubber-fabric hoses reinforced with metal spirals, depending on the hydraulic pressure in a network, 700-900 mm long. If there are pipe sections between the pump and the flexible insert, the sections should be attached to the walls and ceilings of the room on vibration-isolating supports, suspensions or through shock-absorbing pads. Flexible inserts should be located as close as possible to the pumping unit, both on the discharge and suction lines.

To reduce noise and vibration levels in residential buildings from the operation of heat and water supply systems, it is necessary to isolate the distribution pipelines of all systems from the building structures at the points where they pass through the load-bearing structures (entering and exiting residential buildings). The gap between the pipeline and the foundation at the inlet and outlet must be at least 30 mm.

Prepared based on materials from the journal Sanitary-Epidemiological Interlocutor (No. 1(149), 2015

Ph.D. L.V. Rodionov, head of the support department scientific research; Ph.D. S.A. Gafurov, senior Researcher; Ph.D. V.S. Melentyev, senior researcher; Ph.D. A.S. Gvozdev, Samara National Research University named after Academician S.P. Koroleva", Samara

To provide hot water and heating to modern apartment buildings(MKD) projects sometimes include roof boiler houses. This decision in some cases it is cost-effective. At the same time, often when installing boilers on foundations, proper vibration insulation is not provided. As a result, residents of the upper floors are subject to constant noise exposure.

According to the sanitary standards in force in Russia, the sound pressure level in residential premises should not exceed 40 dBA during the day and 30 dBA at night (dBA is an acoustic decibel, a unit of measurement of noise level taking into account human perception of sound. - Ed.).

Specialists from the Institute of Machine Acoustics at Samara State Aerospace University (IAM at SSAU) measured the sound pressure level in the living space of an apartment located under the roof boiler room of a residential building. It turned out that the source of the noise was the roof boiler room equipment. Despite the fact that this apartment is separated from the roof boiler room by a technical floor, according to the measurement results, an excess of daily sanitary standards was recorded, both at the equivalent level and at an octave frequency of 63 Hz (Fig. 1).

The measurements were performed during the daytime. At night, the operating mode of the boiler room remains virtually unchanged, and the background noise level may be lower. Since it turned out that the “problem” was already present during the day, it was decided not to carry out measurements at night.

Picture 1 . Sound pressure level in the apartment in comparison with sanitary standards.

Localizing the source of noise and vibration

To more accurately determine the “problem” frequency, measurements of the sound pressure level in the apartment, boiler room and on the technical floor were carried out in different operating modes of the equipment.

The most typical mode of equipment operation, in which a tonal frequency appears in the low-frequency region, is the simultaneous operation of three boilers (Fig. 2). It is known that the frequency of boiler operating processes (combustion inside) is quite low and falls in the range of 30-70 Hz.

Figure 2. Sound pressure level in various rooms when three boilers are operating simultaneously

From Fig. 2 shows that the frequency of 50 Hz prevails in all measured spectra. Thus, the main contribution to the spectra of sound pressure levels in the rooms under study is made by boilers.

The level of background noise in the apartment does not change much when the boiler equipment is turned on (except for the frequency of 50 Hz), so we can conclude that the sound insulation of the two floors separating the boiler room from the living rooms is sufficient to reduce the level airborne noise produced by boiler equipment to sanitary standards. Therefore, you should look for other (not direct) ways of spreading noise (vibration). The high sound pressure level at 50 Hz is likely due to structure-borne noise.

To localize the source of structural noise in residential premises, as well as to identify vibration propagation paths, vibration acceleration measurements were additionally carried out in the boiler room, on the technical floor, as well as in the living space of the apartment on the top floor.

The measurements were carried out at various operating modes of boiler equipment. In Fig. Figure 3 shows the vibration acceleration spectra for the mode in which all three boilers operate.

Based on the results of the measurements, the following conclusions were made:

– in the apartment on the top floor under the boiler room, sanitary standards are not met;

– the main source of increased noise in residential premises is the combustion process in boilers. The prevailing harmonic in the noise and vibration spectra is the frequency of 50 Hz.

– lack of proper vibration isolation of the boiler from the foundation leads to the transfer of structural noise to the floor and walls of the boiler room. Vibration spreads both through the boiler supports and through the pipes with transmission from them to the walls, as well as the floor, i.e. in places where they are rigidly connected.

– measures should be developed to combat noise and vibration along the path of their propagation from the boiler.

A) b)
V)

Figure 3 . Vibration acceleration spectra: a – on the support and foundation of the boiler, on the floor of the boiler room; b – on the support of the boiler exhaust pipe and on the floor near the boiler exhaust pipe; c – on the wall of the boiler room, on the wall of the technical floor and in the living area of ​​the apartment.

Development of a vibration protection system

Based on a preliminary analysis of the mass distribution of the gas boiler structure and equipment, cable vibration isolators VMT-120 and VMT-60 with a rated load on one vibration isolator (VI) of 120 and 60 kg, respectively, were selected for the project. The vibration isolator diagram is shown in Fig. 4.

Figure 4. 3D model of a cable vibration isolator of the VMT model range.

Figure 5. Vibration isolator fastening schemes: a) support; b) hanging; c) lateral.

Three variants of the vibration isolator fastening scheme have been developed: support, suspended and lateral (Fig. 5).

Calculations have shown that the lateral installation scheme can be implemented using 33 vibration isolators VMT-120 (for each boiler), which is not economically feasible. In addition, very serious welding work is expected.

When implementing a suspended scheme, the entire structure becomes more complicated, since wide and fairly long corners must be welded to the boiler frame, which will also be welded from several profiles (to provide the necessary mounting surface).

In addition, the technology for installing the boiler frame on these skids with VIs is complex (it is inconvenient to attach the VIs, it is inconvenient to position and center the boiler, etc.). Another disadvantage of this scheme is the free movement of the boiler in lateral directions (swinging in the transverse plane on the VI). The number of vibration isolators VMT-120 for this scheme is 14.

The frequency of the vibration protection system (VPS) is about 8.2 Hz.

The third, most promising and technologically simpler option is with a standard support circuit. It will require 18 vibration isolators VMT-120.

The calculated frequency of the VZS is 4.3 Hz. In addition, the design of the VIs themselves (part of the cable rings are located at an angle) and their proper placement around the perimeter (Fig. 6) allows such a design to accommodate a lateral load, the value of which will be about 60 kgf for each VI, while the vertical load on each VI is about 160 kgf.

Figure 6. Placement of vibration isolators on the frame with a support diagram.

Design of a vibration protection system

Based on data from static tests and dynamic calculations of VI parameters, a vibration protection system for a boiler room in a residential building was developed (Fig. 7).

The vibration protection facility includes three boilers of the same design 1 installed on concrete foundations with metal ties; piping system 2 for the supply of cold water and the removal of heated water, as well as the removal of combustion products; pipe system 3 for supplying gas to the boiler burners.

The created vibration protection system includes external vibration protection supports for boilers 4 designed to support pipelines 2 ; internal vibration protection belt of boilers 5 , designed to isolate vibration of boilers from the floor; external anti-vibration mounts 6 For gas pipes 3.

Figure 7. General form boiler room with installed vibration protection system.

Main design parameters of the vibration protection system:

1. The height from the floor to which it is necessary to raise the load-bearing frames of the boilers is 2 cm (installation tolerance minus 5 mm).

2. Number of vibration isolators per boiler: 19 VMT-120 (18 - in the internal belt bearing the weight of the boiler, and 1 - on the external support to dampen vibrations of the water pipeline), as well as 2 vibration isolators VMT-60 on external supports - for vibration protection of the gas pipeline.

3. The “support” type loading scheme works in compression, providing good vibration isolation. The natural frequency of the system is in the range of 5.1-7.9 Hz, which provides effective vibration protection in the region above 10 Hz.

4. The damping coefficient of the vibration protection system is 0.4-0.5, which provides a gain at resonance of no more than 2.6 (oscillation amplitude no more than 1 mm with an input signal amplitude of 0.4 mm).

5. To adjust the horizontality of boilers, nine seats for vibration isolators of a similar type are provided on the sides of the boiler in the U-shaped profiles. Only five are nominally installed.

During installation, it is possible to place vibration isolators in any order in any of the nine places provided to achieve alignment of the center of mass of the boiler and the center of rigidity of the vibration protection system.

6. Advantages of the developed vibration protection system: simplicity of design and installation, insignificant rise of boilers above the floor, good damping characteristics of the system, possibility of adjustment.

The effect of using the developed vibration protection system

With the introduction of the developed vibration protection system, the sound pressure level in the residential premises of the upper floor apartments decreased to an acceptable level (Fig. 8). The measurements were also carried out at night.

From the graph in Fig. 8 it can be seen that in the normalized frequency range and at the equivalent sound level, sanitary standards in residential premises are met.

The effectiveness of the developed vibration protection system when measured in a residential area at a frequency of 50 Hz is 26.5 dB, and at an equivalent sound level of 15 dBA (Fig. 9).

Figure 8 . Sound pressure level in the apartment in comparison with sanitary standards, taking into account developed vibration protection system.

Figure 9. Sound pressure level in one-third octave frequency bands in a living room when three boilers are operating simultaneously.

Conclusion

The created vibration protection system makes it possible to protect a residential building equipped with a roof boiler room from vibrations created by the operation of gas boilers, as well as to ensure normal vibration operating conditions for the most gas equipment together with the pipeline system, increasing the service life and reducing the likelihood of accidents.

The main advantages of the developed vibration protection system are simplicity of design and installation, low cost in comparison with other types of vibration isolators, resistance to temperatures and pollution, insignificant rise of boilers above the floor, good damping characteristics of the system, and the possibility of adjustment.

The vibration protection system prevents the propagation of structural noise from the roof boiler room equipment throughout the building structure, thereby reducing the sound pressure level in residential premises to an acceptable level.

Literature

1. Igolkin, A.A. Reducing noise in residential premises through the use of vibration isolators [Text] / A.A. Igolkin, L.V. Rodionov, E.V. Shakhmatov // Security in the technosphere. No. 4. 2008. pp. 40-43.

2. SN 2.2.4/2.1.8.562-96 “Noise in workplaces, in residential and public buildings and in residential areas”, 1996, 8 p.

3. GOST 23337-78 “Noise. Methods for measuring noise in residential areas and in residential and public buildings”, 1978, 18 p.

4. Shakhmatov, E.V. A comprehensive solution to the problems of vibroacoustics of mechanical engineering and aerospace engineering products [Text] / E.V. Shakhmatov // LAP LAMBERT Academic Publishing GmbH&CO.KG. 2012. 81 p.

From the editor. On October 27, 2017, Rospotrebnadzor published information on its official website “On the impact of physical factors, including noise, on public health”, which notes that in the structure of citizens’ complaints about various physical factors, the largest specific gravity(over 60%) are complaints about noise. The main ones are complaints from residents, including acoustic discomfort from ventilation systems and refrigeration equipment, noise and vibration during operation of heating equipment.

The reasons for the increased noise level generated by these sources are the insufficiency of noise protection measures at the design stage, installation of equipment with deviations from design solutions without assessing the generated levels of noise and vibration, unsatisfactory implementation of noise protection measures at the commissioning stage, placement of equipment not provided for by the design, and also unsatisfactory control over the operation of equipment.

The Federal Service for Supervision of Consumer Rights Protection and Human Welfare draws the attention of citizens that in the event of adverse effects of physical factors, incl. noise, you should contact the territorial Office of Rospotrebnadzor for the constituent entity of the Russian Federation.

Ministry of Health of Russia

Moscow

1. Developed by the Research Institute of Occupational Medicine Russian Academy Sciences (Suvorov G.A., Shkarinov L.N., Prokopenko L.V., Kravchenko O.K.), Moscow Research Institute of Hygiene named after. F.F. Erisman (Karagodina I.L., Smirnova T.G.).

2. Approved and put into effect by Resolution of the State Committee for Sanitary and Epidemiological Supervision of Russia dated October 31, 1996 No. 36.

3. Introduced to replace the “Sanitary Standards for Permissible Noise Levels in Workplaces” N 3223-85, “Sanitary Standards permissible noise in the premises of residential and public buildings and in residential areas" N 3077-84, "Hygienic recommendations for establishing noise levels in workplaces, taking into account the intensity and severity of work" N 2411-81.

APPROVED
Resolution of the State Committee for Sanitary and Epidemiological Supervision
Russia dated October 31, 1996 N 36
Date of introduction from date of approval

1. Scope and general provisions

1.1. These sanitary standards establish the classification of noise; standardized parameters and maximum permissible noise levels in workplaces, permissible noise levels in residential and public buildings and in residential areas.

1.2. Sanitary standards are mandatory for all organizations and legal entities on the territory of the Russian Federation, regardless of forms of ownership, subordination and affiliation, and individuals, regardless of citizenship.

1.3. References and requirements of sanitary standards must be taken into account in State standards and in all regulatory and technical documents regulating planning, design, technological, certification, and operational requirements for production facilities, residential, public buildings, technological, engineering, sanitary equipment and machines, vehicles, household appliances.

1.4. Responsibility for compliance with the requirements of Sanitary Standards is assigned in accordance with the procedure established by law to managers and officials enterprises, institutions and organizations, as well as citizens.

1.5. Control over the implementation of Sanitary Standards is carried out by bodies and institutions of the State Sanitary and Epidemiological Supervision of Russia in accordance with the Law of the RSFSR “On the Sanitary and Epidemiological Welfare of the Population” dated April 19, 1991 and taking into account the requirements of current sanitary rules and norms.

1.6. Measurement and hygienic assessment of noise, as well as preventive measures must be carried out in accordance with guideline 2.2.4/2.1.8-96 “Hygienic assessment of physical factors of production and environment"(under approval).

1.7. With the approval of these sanitary standards, “Sanitary standards for permissible noise levels in workplaces” N 3223-85, “Sanitary standards for permissible noise in residential and public buildings and in residential areas” N 3077-84, “Hygienic recommendations for establishing levels noise at workplaces, taking into account the intensity and severity of work" N 2411-81.

2.1. Law of the RSFSR “On the sanitary and epidemiological welfare of the population” dated April 19, 1991.

2.2. Law of the Russian Federation “On Environmental Protection” dated December 19, 1991.

2.3. Law of the Russian Federation “On the Protection of Consumer Rights” dated 02/07/92.

2.4. Law of the Russian Federation “On Certification of Products and Services” dated June 10, 1993.

2.5. “Regulations on the procedure for the development, approval, publication, and enforcement of federal, republican and local sanitary rules, as well as on the procedure for the operation of all-Union sanitary rules on the territory of the RSFSR,” approved by Resolution of the Council of Ministers of the RSFSR dated 01.07.91 N 375.

2.6. Resolution of the State Committee for Sanitary and Epidemiological Supervision of Russia “Regulations on the procedure for issuing hygienic certificates for products” dated 01/05/93 N 1.

3. Terms and definitions

3.1. Sound pressure is a variable component of air or gas pressure resulting from sound vibrations, Pa.

3.2. Equivalent (energy) sound level, LА.eq., dBA, of intermittent noise - the sound level of constant broadband noise, which has the same root-mean-square sound pressure as this intermittent noise over a certain time interval.

3.3. The maximum permissible level (MAL) of noise is the level of a factor that, during daily (except weekends) work, but not more than 40 hours a week during the entire working period, should not cause diseases or deviations in the state of health detected modern methods research in the process of work or in the long term of life of the present and subsequent generations. Compliance with noise limits does not exclude health problems in hypersensitive individuals.

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

3.5. Maximum sound level, LA.max., dBA - the sound level corresponding to the maximum indicator of a measuring, direct-indicating device (sound level meter) during visual reading, or the sound level value exceeded during 1% of the measurement time when registered by an automatic device.

4. Classification of noise affecting humans

4.1. Based on the nature of the noise spectrum, the following are distinguished:

• broadband noise with a continuous spectrum more than 1 octave wide;
• tonal noise, in the spectrum of which there are pronounced tones. The tonal nature of noise for practical purposes is established by measuring in 1/3 octave frequency bands by the excess of the level in one band over neighboring ones by at least 10 dB.

4.2. According to the temporal characteristics of noise there are:

• constant noise, the sound level of which over an 8-hour working day or during measurement in the premises of residential and public buildings, in residential areas, changes over time by no more than 5 dBA when measured on the time characteristic of a sound level meter “slowly”;
• non-constant noise, the level of which during an 8-hour working day, work shift or during measurements in the premises of residential and public buildings, in residential areas, changes over time by more than 5 dBA when measured on the time characteristic of a sound level meter “slowly”.

4.3. Variable noises are divided into:

• time-fluctuating noise, the sound level of which continuously changes over time;
• intermittent noise, the sound level of which changes stepwise (by 5 dBA or more), and the duration of the intervals during which the level remains constant is 1 s or more;
• impulse noise consisting of one or more sound signals, each lasting less than 1 s, while the sound levels in dBAI and dBA, measured respectively on the “impulse” and “slow” time characteristics, differ by at least 7 dB.

5. Standardized parameters and maximum permissible noise levels in workplaces

5.1. Characteristics of constant noise in workplaces are sound pressure levels in dB in octave bands with geometric mean frequencies of 31.5; 63; 125; 250; 500; 1000; 2000; 4000; 8000 Hz, determined by the formula:

Where P is the root mean square value of sound pressure, Pa;
P0 — original value sound pressure in air equal to 2·10-5Pa.

5.1.1. It is allowed to take the sound level in dBA as a characteristic of constant broadband noise in workplaces, measured on the time characteristic of a “slow” sound level meter, determined by the formula:

Where PA is the root-mean-square value of sound pressure taking into account the correction “A” of the sound level meter, Pa.

5.2. A characteristic of non-constant noise in workplaces is the equivalent (energy) sound level in dBA.

5.3. Maximum permissible sound levels and equivalent sound levels in workplaces, taking into account the intensity and severity of work activity.

Quantitative assessment of the severity and intensity of the labor process should be carried out in accordance with Guideline 2.2.013-94 “Hygienic criteria for assessing working conditions in terms of harmfulness and danger of factors in the working environment, severity, intensity of the labor process.”

6. Standardized parameters and permissible noise levels in residential, public buildings and residential areas

6.1. The normalized parameters of constant noise are sound pressure levels L, dB, in octave bands with geometric mean frequencies: 31.5; 63; 125; 250; 500; 1000; 2000; 4000; 8000 Hz. For an approximate assessment, it is allowed to use sound levels LA, dBA.

6.2. The normalized parameters of non-constant noise are equivalent (in energy) sound levels LAeq., dBA, and maximum sound levels LAmax., dBA.

The assessment of non-constant noise for compliance with permissible levels should be carried out simultaneously using the equivalent and maximum sound levels. Exceeding one of the indicators should be considered as non-compliance with these sanitary standards.

6.3. Permissible values ​​of sound pressure levels in octave frequency bands, equivalent and maximum sound levels of penetrating noise in residential and public buildings and noise in residential areas.

Bibliography

• Guideline 2.2.4/2.1.8.000-95 “Hygienic assessment of physical factors of production and the environment.”
• Guideline 2.2.013-94 “Hygienic criteria for assessing working conditions in terms of harmfulness and danger of factors in the working environment, severity, intensity of the labor process.”
• Suvorov G. A., Denisov E. I., Shkarinov L. N. Hygienic standardization of industrial noise and vibrations. - M.: Medicine, 1984. - 240 p.
• Suvorov G. A., Prokopenko L. V., Yakimova L. D. Noise and health (ecological and hygienic problems). - M: Soyuz, 1996. - 150 p.
• Permissible levels of noise, vibration and sound insulation requirements in residential and public buildings. MGSN 2.04.97 (Moscow city building codes). - M., 1997. - 37 p.

1. Architectural and planning

Functional zoning of the territory of a settlement;

Rational planning of the territory of a residential area - the use of the shielding effect of residential and public buildings located in close proximity to the noise source. At the same time, the internal layout of the building should ensure that the sleeping and other premises of the living area of ​​the apartment are oriented towards the quiet side, and rooms in which people spend a short time - kitchens, bathrooms, staircases - should be oriented towards the highway;

Creating conditions for continuous movement of vehicles by organizing traffic without traffic lights (transport interchanges at different levels, underground pedestrian crossings, one-way streets);

Creation of bypass roads for transit transport;

Landscaping of residential areas.

2. Technological

Modernization of vehicles (reducing noise of the engine, chassis, etc.);

The use of engineering screens - laying a highway or railway in a excavation, creating screen walls from various wall structures;

Reducing noise penetration through window openings of residential and public buildings (use of soundproofing materials - sponge rubber seals in window sills, installation of triple-hung windows).

3. Administrative and organizational

State supervision of the technical condition of vehicles (monitoring compliance with deadlines Maintenance, mandatory regular technical inspections);

Monitoring the condition of the road surface.

TEST TASKS

CHOOSE ALL CORRECT ANSWERS

1. WHEN SELECTING A LAND FOR DEVELOPING A SETTLEMENT, YOU SHOULD CONSIDER

1) terrain

3) availability of water and green areas

4) the nature of the soil

5) population size

2. BASIC REQUIREMENTS FOR PLANNING A SETTLEMENT

1) placement of functional zones on the ground, taking into account the wind rose

2) the presence of functional zoning of the territory

3) ensuring a sufficient level of insolation of the territory

4) providing convenient communication routes between individual parts of the city

5) the presence of a sufficient number of high-rise buildings

3. THE FOLLOWING ZONES ARE DISTRIBUTED ON THE CITY TERRITORY

1) residential

2) industrial

3) communal and warehouse

4) central

5) suburban

4. TYPES OF PLANNING OF SETTLED AREAS

1) perimeter

2) lowercase

3) mixed

4) arachnoid

5) free

5. THE FOLLOWING REQUIREMENTS ARE FOR THE LOCATION OF AN INDUSTRIAL ZONE

1) take into account the wind rose

2) organize a sanitary protection zone

3) take into account the terrain

4) take into account the population size

5) located downstream of the city along the river

6. IN THE RESIDENTIAL ZONE THEY ARE PLACED

1) residential areas

2) commercial warehouses

3) administrative center

4) car parks

5) forest park area

7. THE MOST IMPORTANT HYGIENIC FUNDAMENTALS OF URBAN PLANNING IN OUR COUNTRY ARE

1) the state of the territory for the location of the settlement

2) limiting the growth of large and super-large cities

3) the possibility of landscaping the territory

4) functional zoning of the city

5) use of natural and climatic factors

8. SUBURBAN AREA IS NECESSARY FOR

1) placement industrial enterprises

2) recreation of the population

3) placement of public utility facilities

4) organization of forest park zone

5) placement of transport hubs

9. The type of development of the settlement is determined

1) terrain

2) wind conditions of the territory

3) population size

4) the presence of green spaces

5) location of roads

10. THE DISADVANTAGE OF PERIMETERAL DEVELOPMENT IS

1) difficulty in providing good conditions insolation of dwellings

2) the difficulty of organizing ventilation of the area

3) inconvenience for the population

4) difficulty in organizing the internal territory of the microdistrict

5) impossibility of use in major cities

STANDARD ANSWERS

1. 1), 2), 3), 4)

3. 1), 2), 3), 5)

7. 1), 3), 4), 5)

9. 1), 2), 4), 5)

HOME HYGIENE

According to WHO experts, people spend more than 80% of their time in non-production premises. This suggests that the quality of the indoor environment, including the home environment, can influence human health. Hygienic requirements for housing are regulated by SanPiN 2.1.2.2645-10 Sanitary and epidemiological requirements for living conditions in residential buildings and premises; SanPiN 2.2.1./2.1.1.2585-10, amended. and additional No. 1 to SanPiN 2.2.1/2.1.1.1278-03 Hygienic requirements for natural, artificial and combined lighting of residential and public buildings.

Page 7 of 21

Due to the fact that noise in modern power plants generally exceeds permissible levels, last years Noise reduction work was carried out extensively.
There are three main methods for reducing industrial noise: reducing noise at the source; reduction of noise along its propagation paths; architectural, construction and planning solutions.
The method of reducing noise at the source of its occurrence is to improve the design of the source and change the technological process. The most effective use of this method is when developing new power equipment. Recommendations for reducing noise at the source are given in § 2-2.
To soundproof various rooms of a power plant (especially the machine and boiler rooms), as the most noisy ones, construction solutions are used: thickening the external walls of buildings, using double-glazed windows, hollow glass blocks, double doors, multi-layer acoustic panels, sealing windows, doors, openings, right choice places of air intake and exhaust of ventilation units. It is also necessary to ensure good sound insulation between the machine room and basements, carefully sealing all holes and openings.
When designing a machine room, avoid small rooms with smooth, non-sound-absorbing walls, ceiling, and floor. Covering walls with sound-absorbing materials (SAM) can reduce noise levels by approximately 6-7 dB in medium-sized rooms (3000-5000 m3). For large rooms, the cost-effectiveness of this method becomes debatable.
Some authors, such as G. Koch and H. Schmidt (Germany), as well as R. French (USA), believe that acoustic treatment of the walls and ceilings of station premises is not very effective (1-2 dB). Data published by the French Energy Authority (EDF) show the promise of this noise reduction method. Treatment of ceilings and walls in boiler rooms at the Saint-Depis and Chenevier power plants made it possible to achieve a sound reduction of 7-10 dB A.
At stations, separate soundproofed control panels are often built, the sound level in which does not exceed 50-60 dB A, which meets the requirements of GOST 12.1.003-76. Service personnel spend 80-90% of their working time in them.
Sometimes acoustic booths are installed in machine rooms to accommodate service personnel(on-duty electricians, etc.). These soundproofing cabins are an independent frame on supports, to which the floor, ceiling, and walls are attached. Cabin windows and doors must have increased sound insulation (double doors, double glass). For ventilation it is provided ventilation unit with silencers at the air inlet and outlet.
If it is necessary to have a quick exit from the cabin, it is made semi-closed, that is, one of the walls is missing. At the same time, the acoustic efficiency of the cabin is reduced, but there is no need for ventilation. According to the data, the maximum value of average sound insulation for semi-closed cabins is 12-14 dB.
The use of separate closed or semi-closed cabins in station premises can be classified as individual means of protecting operating personnel from noise. Personal protective equipment also includes various types of earplugs and headphones. The acoustic efficiency of earbuds and, especially, headphones in the high frequency range is quite high and amounts to at least 20 dB. The disadvantages of these products are that, along with noise, the level of useful signals, commands, etc. decreases, and skin irritation is also possible, mainly at elevated ambient temperatures. However, it is recommended to use earbuds and headphones when working in environments with noise levels that exceed acceptable levels, especially in the high frequency range. Of course, it is advisable to use them for short-term exits from soundproof cabins or control panels into high-noise areas.

One of the ways to reduce noise along the paths of its propagation in station premises is acoustic screens. Acoustic screens are made of thin sheet metal or other dense material, which may have sound-absorbing lining on one or two sides. Usually acoustic screens have small sizes and provide local reductions in direct sound from the noise source without significantly affecting the level of reflected sound in the room. In this case, the acoustic efficiency is not very high and depends mainly on the ratio of direct and reflected sound at the design point. Increasing the acoustic efficiency of screens can be achieved by increasing their area, which should be at least 25-30% of the cross-sectional area of ​​the room enclosures in the plane of the screen. In this case, the effectiveness of the screen increases due to a decrease in the energy density of reflected sound in the screened part of the room. Application of screens large sizes It also makes it possible to significantly increase the number of workplaces where noise reduction is ensured.

The most effective use of screens is in conjunction with the installation of sound-absorbing linings on the enclosing surfaces of premises. A detailed description of methods for calculating acoustic efficiency and issues of designing screens is given in and
To reduce noise throughout the machine room, installations emitting intense sound are covered with casings. Soundproofing enclosures are usually made of sheet metal lined with inside ZPM. The surfaces of the installations can be completely or partially sheathed with soundproofing material.
According to data presented by American noise reduction experts at the International Energy Conference in 1969, fully equipping high-power turbine units (500-1000 MW) with sound-insulating casings can reduce the level of emitted sound by 23-28 dB A. When placing turbine units in special insulated boxes efficiency increases to 28-34 dB A.
The range of materials used for sound insulation is very wide and, for example, for the insulation of 143 steam units that were introduced in the USA after 1971, distributed in the following way: aluminum -30%, sheet steel - 27%, gelbest -18%, asbestos cement -11%, brick -10%, porcelain with external coating - 9%, concrete - 4%.
In national teams acoustic panels apply following materials: soundproofing - steel, aluminum, lead; sound-absorbing - polystyrene foam, mineral wool, fiberglass; damping - bitumen compounds; sealing materials - rubber, putty, plastics.
Polyurethane foam, fiberglass, sheet lead, and vinyl reinforced with lead powder are widely used.
The Swiss company VVS, in order to reduce the noise of the brush apparatus and exciters of high-power turbo units, covers them with a continuous protective casing with a thick layer of sound-absorbing material, into the walls of which mufflers are built in at the inlet and outlet of the cooling air.

The design of the casing provides easy access to these units for carrying out current repairs. As research by this company has shown, the soundproofing effect of the casing of the front part of the turbine is most pronounced at high frequencies (6-10 kHz), where it is 13-20 dB, at low frequencies (50-100 Hz) it is insignificant - up to 2-3 dB .

Rice. 2-10. Sound pressure levels at a distance of 1 m from the body of a GTK-10-Z gas turbine unit
1- with decorative casing; 2- with body removed

Particular attention should be paid to sound insulation at power plants with gas turbine drives. Calculations indicate that at gas turbine power plants the placement of gas turbine engines (GTE) and compressors is most economical in individual boxes (if the number of GTEs is less than five). When placed in common building With four gas turbine engines, the construction cost of the building is 5% higher than when using individual boxes, and with two gas turbine engines, the difference in cost is 28%. Therefore, when there are more than five installations, it is more economical to place them in a common building. For example, Westinghouse installs five 501-AA gas turbines in one acoustically isolated building.

Typically, individual boxes use sheet metal panels with sound-absorbing lining on the inside. The sound-absorbing cladding can be made of mineral wool or semi-rigid mineral wool slabs in a fiberglass shell and covered on the noise source side with a perforated sheet or metal mesh. The panels are connected to each other with bolts, and at the joints there are elastic gaskets.
Multilayer panels made of internal perforated steel and external lead sheets, between which a porous sound-absorbing material is placed, are very effective, used abroad. Panels with a multi-layer internal lining made of a layer of vinyl reinforced with lead powder and located between two layers of fiberglass - an internal one, 50 mm thick, and an external one, 25 mm thick - are also used.
However, even the simplest decorative and soundproofing cladding provides a significant reduction in background noise in machine rooms. In Fig. Figures 2-10 show sound pressure levels in octave frequency bands, measured at a distance of 1 m from the surface of the decorative casing of a GTK-10-3 type gas pumping unit. For comparison, the noise spectrum measured with the casing removed at the same points is also shown. It can be seen that the effect of a casing made of a steel sheet 1 mm thick, lined inside with glass fiber 10 mm thick, is 10-15 dB in the high-frequency region of the spectrum. The measurements were carried out in a workshop built according to a standard design, where 6 GTK-10-3 units were installed, covered with decorative cladding.
A common and very important problem for energy enterprises of any type is the sound insulation of pipelines. Pipelines modern installations form a complex extended system with a huge surface of heat and sound radiation.

Rice. 2-11. Sound insulation of a gas pipeline at the Kirchleigeri thermal power plant: a - insulation diagram; b - components of a multilayer panel
1- metal cladding from sheet steel; 2- mats made of stone wool 20 mm thick; 3- aluminum foil; 4- multi-layer panel 20 mm thick (weight I m2 is 10.5 kg); 5-bituminized felt; 6-layers of thermal insulation; 7-layer foam

This is especially true for power plants with a combined cycle, which sometimes have a complex branched network of pipelines and a system of gates.

To reduce the noise of pipelines transporting highly disturbed flows (for example, in areas behind pressure reducing valves), enhanced sound insulation shown in Fig. 2-11.
The sound insulating effect of such a coating is about 30 dB A (reduction in sound level compared to a “bare” pipeline).
For lining large-diameter pipelines, multilayer thermal and sound insulation is used, which is strengthened with the help of ribs and hooks welded to the insulated surface.
The insulation consists of a layer of mastic sovelite insulation 40-60 mm thick, on top of which a wire armor mesh 15-25 mm thick is laid. The mesh serves to strengthen the sovelite layer and create air gap. The outer layer is formed by mineral wool mats 40-50 mm thick, on top of which a layer of asbestos-cement plaster 15-20 mm thick is applied (80% grade 6-7 asbestos and 20% grade 300 cement). This layer is covered (pasted) with some technical fabric. If necessary, the surface is painted. This method of sound insulation using previously existing thermal insulation elements can significantly reduce noise. The additional costs associated with the introduction of new sound insulation elements are negligible compared to conventional thermal insulation.
As already noted, the most intense is the aerodynamic noise that occurs during the operation of fans, smoke exhausters, gas turbine and combined cycle units, and discharge devices (purge lines, safety lines, lines of anti-surge valves of gas turbine compressors). This also includes ROU.

To limit the spread of such noise along the flow of the transported medium and its release into the surrounding atmosphere, noise suppressors are used. Silencers occupy an important place in the overall system of measures to reduce noise at energy enterprises, because through intake or discharge devices, sound from working cavities can be directly transmitted to the surrounding atmosphere, creating the highest sound pressure levels (compared to other sources of sound emission). It is also useful to limit the spread of noise throughout the transported medium in order to prevent excessive penetration through the walls of the pipeline to the outside by installing noise mufflers (for example, the section of the pipeline behind the pressure reducing valve).
On modern powerful steam turbine units, noise suppressors are installed at the suction of blower fans. In this case, the pressure drop is strictly limited by an upper limit of the order of 50-f-100 Pa. The required efficiency of these mufflers is usually from 15 to 25 dB in terms of installation effect in the spectrum region of 200-1000 Hz.
Thus, at the Robinson TPP (USA) with a capacity of 900 MW (two blocks of 450 MW each), to reduce the noise of blower fans with a capacity of 832,000 m3/h, suction silencers were installed. The muffler consists of a housing (steel sheets 4.76 mm thick), in which a grid of sound-absorbing plates is located. The body of each plate is made of perforated galvanized steel sheets. Sound-absorbing material is mineral wool protected by fiberglass.
The Coppers company produces standard sound-attenuating blocks used in fan silencers used for drying pulverized coal, supplying air to boiler burners, and ventilating rooms.
The noise of smoke exhausters often poses a significant danger, since chimney it can escape into the atmosphere and spread over considerable distances.
For example, at the Kirchlengern thermal power plant (Germany), the sound level near the chimney was 107 dB at a frequency of 500-1000 Hz. In this regard, it was decided to install an active silencer in the chimney of the boiler building (Fig. 2-12). The muffler consists of twenty scenes 1 with a diameter of 0.32 m and a length of 7.5 m. Taking into account the complexity of transportation and installation, the scenes along the length are divided into parts that are connected to each other and bolted to the supporting structure. The slide consists of a body made of sheet steel and an absorber (mineral wool) protected by fiberglass. After installing the muffler, the sound level at the chimney was 89 dB A.
The complex task of reducing gas turbine noise requires an integrated approach. Below is an example of a set of measures to combat gas turbine noise, an essential part of which are noise suppressors in gas-air ducts.
To reduce the noise level of a gas turbine unit with a 17.5 MW Olympus 201 turbojet engine, an analysis of the required degree of noise attenuation of the installation was carried out. It was required that the octave noise spectrum measured at a distance of 90 m from the base of the steel chimney should not exceed PS-50. The layout shown in Fig. 2-13, provides attenuation of gas turbine suction noise by various elements (dB):

Geometric mean frequency of the octave band, Hz............................................					1000 2000 4000 8000
Sound pressure levels at a distance of 90 m from the gas turbine suction to noise attenuation................................................................. .............
Attenuation in an unlined 90° turn (knee) ....................................
Attenuation in a lined 90° turn (knee).................................
Weakening due to the air filter. . . .................................................. .........
Weakening due to blinds.........
Attenuation in the high-frequency part of the muffler.................................................... ...
Attenuation in the low-frequency part of the muffler.................................................... ................
Sound pressure levels at a distance of 90 m after noise reduction....

A two-stage plate-type muffler with high and low frequency stages is installed at the air inlet to the gas turbine unit. The muffler stages are installed after the cycle air filter.
An annular low-frequency muffler is installed on the gas turbine exhaust. Results of the analysis of the noise field of a gas turbine engine with a turbojet engine at the exhaust before and after installing a muffler (dB):

Geometric mean frequency of the octave band, Hz........
Sound pressure level, dB: before installing a muffler. . .
after installing the muffler. .

To reduce noise and vibration, the gas turbine generator was enclosed in a casing, and silencers were installed at the air inlet of the ventilation system. As a result, the noise measured at a distance of 90 m was:

American companies Solar, General Electric, and the Japanese company Hitachi use similar noise suppression systems for their gas turbine units.
For high-power gas turbines, the mufflers at the air intake are often very bulky and complex engineering structures. An example is the noise suppression system at the Vahr gas turbine thermal power plant (Germany), on which two gas turbines from the Brown-Boveri company with a capacity of 25 MW each are installed.

Rice. 2-12. Installation of a silencer in the chimney of the Kirchlängerä thermal power plant

Rice. 2-13. Noise suppression system for an industrial gas turbine unit with an aviation gas turbine engine as a gas generator
1- outer sound-absorbing ring; 2- internal sound-absorbing ring; 3- bypass cover; 4 - air filter; 5- turbine exhaust; 6- plates of high-frequency suction muffler; 7- plates of low-frequency muffler on suction

The station is located in the central part of the populated area. A muffler consisting of three sequential stages is installed at the gas turbine suction. The first-stage sound-absorbing material, designed to dampen low-frequency noise, is mineral wool covered with synthetic fabric and protected by perforated metal sheets. The second stage is similar to the first, but differs in smaller gaps between the plates. Third stage
consists of metal sheets coated with sound-absorbing material and serves to absorb high-frequency noise. After installing a muffler, the noise of the power plant, even at night, did not exceed the norm accepted for this area (45 dB L).
Similar complex two-stage mufflers are installed at a number of powerful domestic installations, for example, at the Krasnodar Thermal Power Plant (GT-100-750), Nevinnomysskaya State District Power Plant (PGU-200). A description of their design is given in § 6-2.
The cost of noise suppression measures at these stations amounted to 1.0-2.0% of the total cost of the station or about 6% of the cost of the gas turbine plant itself. In addition, the use of noise suppressors is associated with a certain loss of power and efficiency. The construction of silencers requires the use of large quantities of expensive materials and is quite labor-intensive. Therefore, issues of optimization of noise suppressor designs become especially important, which is impossible without knowledge of the most advanced calculation methods and the theoretical basis of these methods.