Portal about the device of the sewerage and drainpipes / Sewerage / The distance between the sewer wells snip. Snip external sewerage network

The distance between the sewer wells snip. Snip external sewerage network

25.09.2018

(as amended by Amendment No. 1, approved by the Resolution of the Gosstroy of the USSR

dated 05/28/1986 N 70)

Effective Date

January 1, 1986

Developed by Soyuzvodokanalproekt (G.M. Mironchik - topic leader; D.A. Berdichevsky, A.E. Vysota, L.V. Yaroslavsky) with the participation of VNIIVODGEO, Donetsk PromstroyNIIproekt and NIIOSP named after N.M. Gersevanov Gosstroy of the USSR, Research Institute of municipal water supply and water purification of the Academy of Public Utilities named after K.D. Pamfilov and Giprokommunvodokanal of the Ministry of Housing and Communal Services of the RSFSR, TsNIIEP of engineering equipment of the Gosgrazhdanstroy, MosvodokanalNIIproekt and Mosinzhproekt of the Moscow City Executive Committee, the Research and Design Institute of Urban Economics and the UkrkommunNIIIproekhite of the Ministry of Construction and Social Development M.T. Urazbayev Academy of Sciences of the Uzbek SSR, Moscow Civil Engineering Institute. V.V. Kuybyshev Ministry of Higher Education of the USSR, Leningrad Civil Engineering Institute of the Ministry of Higher Education of the RSFSR.

Introduced by Soyuzvodokanalproekt Gosstroy USSR.

Prepared for approval by Glavtekhnormirovaniye Gosstroy of the USSR (B.V. Tambovtsev).

Agreed by the Ministry of Health of the USSR (letter of 10.24.1983 N 121-12 / 1502-14), the Ministry of Water Economy of the USSR (letter of 15.04.1985 N 13-3-05 / 366), the Ministry of Fishery of the USSR (letter of 04.26.1985 . N 30-11-9).

With the introduction of SNiP 2.04.03-85 "Sewerage. External networks and structures," SNiP II-32-74 "Sewerage. External networks and structures" expires.

These rules and regulations must be observed when designing newly built and reconstructed permanent sewage systems for settlements and national economy objects.

When developing sewage projects, one should be guided by the "Fundamentals of Water Legislation of the USSR and Union Republics", comply with the "Rules for the Protection of Surface Water from Pollution from Wastewater" and the "Rules for the Sanitary Protection of Coastal Waters of the Sea" of the USSR Ministry of Water Economy, USSR Ministry of Fishery and USSR Ministry of Health, requirements of the "Regulations on of water protection and coastal stripes of small rivers of the country "and" Instructions on the procedure for approval and issuance of permits for special water use "of the USSR Ministry of Water and Water, as well as instructions for other regulatory documents, ut erzhdennyh or concerted USSR State.

1. General instructions

1.1. Sewerage facilities should be designed on the basis of approved schemes for the development and deployment of sectors of the national economy and industry, schemes for the development and distribution of productive forces in economic regions and union republics, general, basin and territorial schemes for the integrated use and protection of water, schemes and projects for district planning and urban development and other settlements, master plans of industrial nodes.

When designing, it is necessary to consider the feasibility of cooperating with sewage systems of objects regardless of their departmental affiliation, and also take into account the technical, economic and sanitary assessments of existing facilities, provide for the possibility of their use and intensification of their work.

Sewerage projects of facilities should be developed, as a rule, simultaneously with water supply projects with a mandatory analysis of the balance of water consumption and disposal wastewater. In this case, it is necessary to consider the possibility of using treated wastewater and rainwater for industrial water supply and irrigation.

1.2. In the rainwater drainage system, the most polluted part of the surface runoff generated during the period of rainfall, snowmelt and washing of road surfaces should be cleaned, i.e. at least 70% of the annual runoff for residential areas and sites of enterprises close to them in terms of pollution, and the total volume of runoff for sites of enterprises whose territory may be contaminated with specific substances with toxic properties or a significant amount of organic substances.

1.3. The main technical decisions made in the projects, and the sequence of their implementation should be justified by comparing possible options. Technical and economic calculations should be performed according to those options whose advantages and disadvantages cannot be established without calculations.

The best option should be determined by the smallest amount of reduced costs, taking into account the reduction in labor costs, the consumption of material resources, electricity and fuel, as well as on the basis of sanitary-hygienic and fishery requirements.

1.4. When designing sewage networks and structures, progressive technical solutions, mechanization of labor-intensive work, automation of technological processes and maximum industrialization of construction and installation works through the use of prefabricated structures, standard and standard products and parts manufactured at factories and procurement workshops should be provided.

1.5. Wastewater treatment plants for industrial and rain sewers should, as a rule, be located on the territory of industrial enterprises.

1.6. When connecting sewer networks of industrial enterprises to the street or intra-quarter network of a settlement, outlets with control wells located outside the enterprises should be provided.

It is necessary to provide devices for measuring the discharge of waste water from each enterprise.

Combining the production wastewater of several enterprises is allowed after the control well of each enterprise.

1.7. The conditions and places for the release of treated wastewater and surface runoff to water bodies should be coordinated with the bodies regulating the use and protection of waters, the executive committees of local Councils of People's Deputies, bodies implementing state sanitary supervision, protection of fish stocks, and other bodies in accordance with Union law Soviet Socialist Republic and Union republics, and places of release into navigable water bodies, watercourses and seas - also with the management bodies of the river fleet of the Union Republics and the Ministry of the Marine ota.

1.8. When determining the reliability of the sewage system and its individual elements, it is necessary to take into account technological, sanitary and hygienic and water protection requirements.

In case of inadmissibility of interruptions in the operation of the sewage system or its individual elements, measures must be provided to ensure the uninterrupted operation of their work.

1.9. In the event of an accident or repair of one structure, the overload of the remaining structures of this purpose should not exceed 8 - 17% of their estimated capacity without reducing the efficiency of wastewater treatment.

1.10. Sanitary protection zones from sewage structures to the borders of residential buildings, sections of public buildings and food industry enterprises, taking into account their prospective expansion, should be taken:

from structures and pumping stations of the sewage system of settlements - according to the table. 1;

Consultant Plus: note.

SN 245-71 expired in connection with the publication of the Decree of the Gosstroy of the USSR of 05/10/1990 N 39. By the Decree of the Chief State Sanitary Doctor of the Russian Federation of 30.04.2003 N 88 from June 25, 2003 SP 2.2.1.1312-03 "Hygienic requirements for designing newly built and reconstructed industrial enterprises. "

from wastewater treatment plants and pumping stations of industrial sewage systems not located on the territory of industrial enterprises, both during self-cleaning and pumping of industrial wastewater, and when they are combined with domestic wastewater - in accordance with SN 245-71, the same as for production, from which sewage arrives, but not less than specified in tab. 1.

Table 1

─────────────────────────────┬────────────────────────────────────

Facilities │ Sanitary protection zone, m, at

│ estimated performance

│ structures, thousand m3 / day.

├────────┬────────┬────────┬─────────

│ up to 0.2 │ st. 0.2 │ st. 5 │ st. 50

│ │ to 5 │ to 50 │ to 280

─────────────────────────────┼────────┼────────┼────────┼─────────

Mechanical and │ 150 │ 200 │ 400 │ 500

biological treatment with silt- │ │ │ │

high fermentation sites - │ │ │ │

precipitation, as well as individual │ │ │ │

but located silt │ │ │ │

platforms │ │ │ │

Mechanical and │ 100 │ 150 │ 300 │ 400

biological treatment with │ │ │ │

thermomechanical treatment │ │ │ │

precipitation in enclosed spaces │ │ │ │

Filtration fields │ 200 │ 300 │ 500 │ -

Agricultural irrigation fields │ 150 │ 200 │ 400 │ -

Biological ponds │ 200 │ 200 │ 300 │ 300

Circulation facilities│ 150 │ - │ - │ -

oxidizing channels │ │ │ │

Pump stations │ 15 │ 20 │ 20 │ 30

Notes. 1. Sanitary protection zones of sewer

facilities with a capacity of over 280 thousand m3 / day, as well as

when deviating from accepted wastewater treatment technology and

sludge treatment are established in agreement with the main

sanitary and epidemiological departments of ministries

health of the union republics.

2. Sanitary protection zones indicated in the table. 1 allowed

increase, but not more than 2 times in case of location

leeward residential development in relation to the sewage treatment plant

structures or reduce by no more than 25% if available

auspicious wind rose.

3. In the absence of silt sites in the territory

treatment facilities with a capacity of over 0.2 thousand m3 / day.

the size of the zone should be reduced by 30%.

4. Sanitary protection zone from filtering fields up to

0.5 ha and from structures of mechanical and biological treatment on

biofilters with a productivity up to 50 m3 / day. should be taken

5. Sanitary protection zone from underground filtering fields

productivity less than 15 m3 / day. should be taken 15 m.

6. Sanitary protection zone from filtering trenches and sand

gravel filters should be taken 25 m away from septic tanks and

filter wells - 5 and 8 m, respectively, from aeration wells

complete oxidation plants with aerobic stabilization of sludge at

capacity up to 700 m3 / day. - 50 m.

7. The sanitary protection zone from the drain stations should be

take 300 m.

8. Sanitary protection zone from treatment facilities

surface water from residential areas should be taken

100 m, from pumping stations - 15 m, from treatment facilities

industrial enterprises - as agreed with the authorities

sanitary and epidemiological service.

9. Sanitary protection zones from sludge collectors should be

take depending on the composition and properties of the sludge as agreed

with the bodies of the sanitary-epidemiological service.

──────────────────────────────────────────────────────────────────

Approved and enforced
Order of the Ministry
regional development
Russian Federation
(Ministry of Regional Development of Russia)
dated December 29, 2011 N 635/11

SET OF RULES

SEWERAGE. EXTERNAL NETWORKS AND STRUCTURES

UPDATED EDITORIAL
SNiP 2.04.03-85

Seewerage. Pipelines and wastewater treatment plants

SP 32.13330.2012

Date of introduction
January 1, 2013

Foreword

The goals and principles of standardization in the Russian Federation are established by the Federal Law of December 27, 2002 N 184-ФЗ "On Technical Regulation", and the development rules - by the Decree of the Government of the Russian Federation of November 19, 2008 N 858 "On the procedure for the development and approval of codes of practice "

Rule Set Information

1. Contractors - LLC "ROSEKOSTROY", OJSC "Research Center" Construction ".
2. Submitted by the Technical Committee for Standardization TC 465 "Construction".
3. Prepared for approval by the Department of Architecture, Construction and Urban Policy.
4. Approved by Order of the Ministry of Regional Development of the Russian Federation (Ministry of Regional Development of Russia) dated December 29, 2011 N 635/11 and entered into force on January 1, 2013.
5. Registered by the Federal Agency for Technical Regulation and Metrology (Rosstandart). Revision of SP 32.13330.2010 SNiP 2.04.03-85. Sewerage. External networks and structures.

Information on amendments to this set of rules is published in the annually published information index "National Standards", and the text of amendments and amendments is published in the monthly published information signs "National Standards". In case of revision (replacement) or cancellation of this set of rules, the corresponding notification will be published in the monthly published information index "National Standards". Relevant information, notice and texts are also posted in the public information system - on the official website of the developer (Ministry of Regional Development of Russia) on the Internet.

Introduction

Updating was performed by ROSEKOSTROY 000 and SIC Building, responsible executors: G.M. Mironchik, A.O. Dushko, L.L. Menkov, E.N. Zhirov, S.A. Kudryavtsev (LLC "ROSEKOSTROY"), M.I. Alekseev (SPbGASU), D.A. Danilovich (OJSC MosvodokanalNIIProekt), R.Sh. Neparidze (LLC Giprokommunvodokanal), M.N. Orphan (TsNIIEP Engineering Equipment OJSC), V.N. Shvetsov (NII VODGEO OJSC).

1 area of \u200b\u200buse

This set of rules establishes design standards for newly built and reconstructed outdoor sewerage systems for permanent use of urban and close to them in the composition of industrial wastewater, as well as rain sewage.
This set of rules does not apply to sewage systems of greater capacity (more than 300 thousand m3 / day).

This set of rules provides links to the following regulatory documents:
SP 5.13130.2009. Fire protection systems. Automatic fire alarm and fire extinguishing systems. Norms and design rules
SP 12.13130.2009. Definition of the category of premises, buildings and outdoor installations for explosion and fire hazard
SP 14.13330.2011 "SNiP II-7-81 *. Construction in seismic areas"
SP 21.13330.2012 "SNiP 2.01.09-91. Buildings and structures in the developed areas and subsidence soils"
SP 25.13330.2012 SNiP 2.02.04-88. Foundations and foundations on permafrost soils
SP 28.13330.2012 "SNiP 2.03.11-85. Protection of building structures from corrosion"
SP 30.13330.2012 "SNiP 2.04.01-85 *. Internal water supply and sewerage of buildings"
SP 31.13330.2012 "SNiP 2.04.02-84 *. Water supply. External networks and structures"
SP 38.13330.2012 "SNiP 2.06.04-82 *. Loads and effects on hydraulic structures (wave, ice and from ships)"
SP 42.13330.2011 "SNiP 2.07.01-89 *. Urban planning. Planning and development of urban and rural settlements"
SP 43.13330.2012 SNiP 2.09.03-85. Construction of industrial enterprises
SP 44.13330.2011 "SNiP 2.09.04-87 *. Administrative and domestic buildings"
SP 62.13330.2011 "SNiP 42-01-2002. Gas distribution systems"
SP 72.13330.2012 "SNiP 3.04.03-85. Protection of building structures and structures from corrosion"
SP 104.13330.2011 "SNiP 2.06.15-85. Engineering protection of territories from flooding and flooding"

Consultant Plus: note.
SP 131.13330.2011 referred to in this document was subsequently approved and published with SP 131.13330.2012.

SP 131.13330.2011 "SNiP 23-01-99 *. Construction climatology"
GOST R 50571.1-2009. Low voltage electrical installations
GOST R 50571.13-96. Electrical installations of buildings. Part 7. Requirements for special electrical installations. Section 706. Cramped Rooms with Conductive Floors, Walls, and Ceilings
GOST R 50571.15-97. Electrical installations of buildings. Part 5. Selection and installation of electrical equipment. Chapter 52. Electrical Wiring
GOST 12.1.005-88. Occupational safety standards system. General hygiene requirements for workplace air
GOST 17.1.1.01-77. Protection of Nature. Hydrosphere. Use and protection of water. Key Terms and Definitions
GOST 14254-96. Degrees of protection provided by enclosures (IP code)
GOST 15150-69 *. Machines, devices and other technical products. Versions for different climatic regions. Categories, operating conditions, storage and transportation regarding the impact of climatic environmental factors
GOST 19179-73. Hydrology of sushi. Terms and Definitions
GOST 25150-82. Sewerage. Terms and Definitions.
Note. When using this set of rules, it is advisable to check the validity of reference standards and classifiers in the public information system - on the official website of the national standardization body of the Russian Federation on the Internet or on the annually published information index "National Standards", which is published as of January 1 of this year , and according to the corresponding monthly published information indexes published in the current year. If the referenced document is replaced (changed), then when using this set of rules should be guided by the replaced (changed) document. If the referenced material is canceled without replacement, the provision in which the link to it is given shall apply to the extent not affecting this link.

3. Terms and definitions

In this set of rules, the terms and definitions used in accordance with GOST 17.1.1.01, GOST 25150, GOST 19179, as well as the terms with the corresponding definitions, are given in Appendix A.

4. General

4.1. The selection of schemes and systems of sewage facilities should be made taking into account the requirements for wastewater treatment, climatic conditions, terrain, geological and hydrological conditions, the current situation in the drainage system and other factors.
4.2. When designing, it is necessary to consider the feasibility of cooperating with sewage systems of objects, take into account the economic and sanitary assessments of existing structures, provide for the possibility of their use and the intensification of their work.
4.3. Treatment of industrial and municipal wastewater is allowed to be carried out jointly or separately, depending on their nature and subject to maximum reuse.
4.4. Projects of sewage facilities, as a rule, should be linked to the scheme of their water supply, with a mandatory consideration of the possibility of using treated wastewater and rainwater for industrial water supply and irrigation.
4.5. When choosing a sewage scheme for industrial enterprises, it is necessary to take into account:
the possibility of reducing the volume of polluted wastewater generated in technological processes due to the introduction of non-waste and waterless production, the installation of closed water systems, the use of air cooling methods, etc .;
the possibility of local treatment of wastewater flows in order to extract individual components;
the possibility of consistent use of water in various technological processes with various requirements for its quality;
conditions for the discharge of industrial wastewater into water bodies or into the sewage system of a settlement or other water user;
conditions for the disposal and use of sludge and waste generated during wastewater treatment.
4.6. The combination of industrial wastewater streams with various pollutants is allowed when it is advisable to co-treat them.
In this case, it is necessary to take into account the possibility of chemical processes in the communications with the formation of gaseous or solid products.
4.7. When connecting sewer networks of subscribers that are not related to the housing stock to the networks of a settlement, it is necessary to provide releases with control wells located outside the territory of subscribers.
It is necessary to provide devices for measuring the flow rate of discharged wastewater from each enterprise if the subscriber has a substantially open water balance, at least in the following cases:
if the subscriber is not connected to a centralized water supply system or has (or may have) water supply from several sources;
if more than 5% of the water consumption consumed from the water supply system is added or withdrawn during the production process.
Combining the production wastewater of several enterprises is allowed after the control well of each enterprise.
4.8. Industrial wastewater to be disposed of and treated together with domestic wastewater of a settlement must meet current requirements for the composition and properties of wastewater taken into the sewage system of a settlement.
Industrial waste water that does not meet the specified requirements must be pre-treated. The degree of such treatment should be agreed upon with the organization (organizations) operating the sewage system and treatment facilities of the settlement (or, in the absence thereof, with the organization designing this sewage system).
4.9. It is forbidden to discharge into water bodies untreated to the established standards rain, melt and irrigation water, which is organized away from residential areas and sites of enterprises.
4.10. When designing wastewater treatment plants for general alloy and semi-divided sewage systems, which carry out joint diversion of all types of wastewater, including surface runoff from residential areas and enterprise sites, one should be guided by the instructions in this set of rules, as well as other regulatory documents governing the operation of these systems, including including regional.
4.11. The most polluted part of the surface runoff, which is formed during periods of rainfall, snowmelt and from the washing of road surfaces, in the amount of at least 70% of the annual runoff volume for residential areas and sites of enterprises close to them in terms of pollution, and all the volume of runoff from the sites of enterprises whose territory may be contaminated with specific substances with toxic properties or a significant amount of organic substances.
For the majority of settlements in the Russian Federation, these conditions are fulfilled when calculating treatment facilities for receiving runoff from low-intensity, often repeated rains with a period of one-time excess of the calculated rain intensity of 0.05 - 0.1 years.
4.12. Surface wastewater from industrial areas, construction sites, warehouses, car farms, as well as highly polluted areas located in residential areas of cities and towns (gas stations, car parks, bus stations, shopping centers), before being discharged into a rain sewer or centralized The municipal sewage system must be treated at a local treatment plant.
4.13. When determining the conditions for the release of surface runoff from residential areas and enterprise sites into water bodies, one should be guided by the standards of the Russian Federation for the conditions for the discharge of urban wastewater.
The choice of the scheme of diversion and treatment of surface runoff, as well as the design of treatment facilities, is determined by its qualitative and quantitative characteristics, conditions of disposal and is carried out on the basis of assessing the technical feasibility of implementing a particular option and comparing technical and economic indicators.
4.14. When designing rainwater drainage facilities in populated areas and industrial sites, it is necessary to consider the option of using treated wastewater for industrial water supply, irrigation or irrigation.
4.15. The main technical solutions used in the projects, the sequence of their implementation should be justified by a technical and economic comparison of possible options, taking into account sanitary and hygienic and environmental requirements.
4.16. When designing sewage networks and structures, progressive technical solutions, mechanization of labor-intensive work, automation of technological processes, industrialization of construction and installation works through the use of structures, structures and factory-made products, etc. should be provided.
It should also include measures for energy saving, as well as for the maximum possible use of secondary energy resources of wastewater treatment plants, the disposal of treated water and sludge.
It is necessary to ensure appropriate safety and sanitary-hygienic working conditions during the operation and implementation of preventive and repair work.
4.17. The location of the sewage system and the passage of communications, as well as the conditions and places for the release of treated wastewater and surface runoff into water bodies, must be agreed with local authorities, organizations that carry out state sanitary supervision and protection of fish stocks, as well as with other bodies, in accordance with the legislation of the Russian Federation, and the place of release into navigable water bodies and seas - with the relevant authorities of the river and sea fleet.
4.18. The reliability of the sewage system is characterized by the preservation of the required estimated throughput and the degree of wastewater treatment when the wastewater costs and composition of pollutants change (within certain limits), conditions for their discharge into water bodies, in the event of interruptions in power supply, possible accidents in communications, equipment and structures, production of scheduled repair work, situations related to special environmental conditions (seismic, subsidence of soils, permafrost, etc.).
4.19. To ensure uninterrupted operation of the sewage system, the following measures should be provided:
appropriate reliability of power supply of sewage facilities (two independent sources, stand-alone autonomous power station, storage batteries, etc.);
duplication of communications, arrangement of bypass lines and bypasses, switching on parallel pipelines, etc .;
arrangement of emergency (buffer) tanks with subsequent pumping out of them in normal mode;
sectioning of parallel working structures, with the number of sections providing the necessary and sufficient effectiveness of the action when one of them is disconnected for repair or maintenance;
reservation of working equipment for one purpose;
providing the necessary margin of power, throughput, capacity, strength, etc. equipment and facilities (determined by technical and economic calculations);
determination of the allowable reduction in system capacity or the efficiency of wastewater treatment in emergency situations (as agreed with the supervisory authorities).
The application of the above measures should be studied during the design, taking into account the responsibility of the object.
4.20. Sanitary protection zones from sewage structures to the borders of residential buildings, sections of public buildings and food industry enterprises, taking into account their prospective expansion, should be adopted in accordance with sanitary standards, and cases of deviation from them should be agreed with the sanitary and epidemiological surveillance authorities.

5. The estimated costs of urban wastewater.
Hydraulic calculation of sewer networks.
Unit costs, uneven coefficients
and estimated wastewater costs

5.1. General directions

5.1.1. When designing sewage systems in settlements, the calculated specific average daily (for the year) water disposal of domestic wastewater from residential buildings should be taken equal to the calculated specific average daily (for the year) water consumption according to SP 31.13330, excluding water consumption for irrigation of territories and green spaces.
5.1.2. Specific wastewater to determine the estimated costs of wastewater from individual residential and public buildings, if necessary, account for concentrated costs should be taken in accordance with SP 30.13330.
5.1.3. The amount of wastewater of industrial enterprises and the coefficients of unevenness of their inflow should be determined by technological data with an analysis of the water balance in terms of possible water circulation and reuse of wastewater, in the absence of data - by the aggregated norms of water consumption per unit of production or raw materials or according to similar enterprises.
From the total amount of wastewater of enterprises, it is necessary to single out the costs accepted in the sewers of a settlement or other water user.
5.1.4. Specific drainage in non-canalized areas should be taken 25 l / day per inhabitant.
5.1.5. The estimated average daily wastewater flow rate in the village should be determined as the sum of the costs established in 5.1.1 - 5.1.4.
The amount of wastewater from local industrial enterprises serving the population, as well as unaccounted for expenses, may (if justified) be additionally accepted in the amount of 6 - 12% and 4 - 8% of the total average daily drainage of the settlement (if justified).
5.1.6. Estimated daily wastewater costs should be taken as the product of the average daily (for the year) consumption according to 5.1.5 by the daily unevenness coefficients, adopted in accordance with SP 31.13330.
5.1.7. Estimated total maximum and minimum wastewater costs, taking into account daily, hourly and intra-hourly irregularities, should be determined by computer simulation of water disposal systems that take into account schedules of wastewater inflow from buildings, residential areas, industrial enterprises, the length and configuration of networks, the availability of pumping stations, etc. d., or according to the actual water supply schedule during the operation of similar facilities.
In the absence of these data, it is allowed to take general coefficients (maximum and minimum) according to table 1.

Table 1

Estimated total maximum and minimum costs
sewage, taking into account daily, hourly
and intra-hourly unevenness

Total ratio
flow irregularities
wastewater Average wastewater consumption, l / s
5 10 20 50 100 300 500 1000 5000
and more
Maximum at 1%
security 3.0 2.7 2.5 2.2 2.0 1.8 1.75 1.7 1.6
Minimum at 1%
security 0.2 0.23 0.26 0.3 0.35 0.4 0.45 0.51 0.56
Maximum at 5%
security 2.5 2.1 1.9 1.7 1.6 1.55 1.5 1.47 1.44
Minimum at 5%
security 0.38 0.46 0.5 0.55 0.59 0.62 0.66 0.69 0.71
Notes. 1. General wastewater inflow rates given in
table, it is allowed to take with the number of production waste
water not exceeding 45% of the total flow.
2. With an average wastewater flow rate of less than 5 l / s, the maximum
non-uniformity coefficient is accepted 3.
3. 5% security implies a possible increase
(decrease) in consumption on average 1 time per day, 1% - 1 time per
during 5-6 days.

5.1.8. The estimated costs for networks and structures for the supply of sewage by pumps should be taken equal to the productivity of pumping stations.
5.1.9. When designing drainage communications and facilities for wastewater treatment, one should consider the feasibility and sanitary-hygienic possibility of averaging the estimated costs of wastewater.
5.1.10. Sewerage facilities should be designed to allow the total estimated maximum flow rate (determined by 5.1.7) and the additional influx of surface and ground water to be displaced into the gravity sewer networks through leaks in manhole covers and due to groundwater infiltration.
The magnitude of the additional inflow, l / s, is determined on the basis of special surveys or data on the operation of similar facilities, and in their absence, by the formula

where L is the total length of gravity pipelines to the calculated structure (pipeline alignment), km;
- the value of the maximum daily amount of precipitation, mm (according to SP 131.13330).
Verification calculation of gravity pipelines and channels with a cross-section of any shape for the passage of increased flow should be carried out when filling 0.95 height.

5.2. Hydraulic calculation of sewer networks

5.2.1. Hydraulic calculation of gravity sewer pipelines (trays, channels) should be performed at the estimated maximum second flow rate of wastewater according to tables, graphs and nomograms. The main requirement for the design of gravity collectors is to pass the estimated costs at self-cleaning speeds of the transported wastewater.
5.2.2. Hydraulic calculation of pressure sewer pipelines should be made in accordance with SP 31.13330.
5.2.3. Hydraulic calculation of pressure pipelines transporting raw and fermented sludge, as well as activated sludge, should be made taking into account the mode of movement, physical properties and characteristics of the composition of the sediments. At a moisture content of 99% or more, the sediment obeys the laws of movement of the waste fluid.
5.2.4. The hydraulic slope i when calculating pressure head sludge pipes with a diameter of 150 - 400 mm is determined by the formula

where is the moisture content of the sediment,%;
V is the sediment speed, m / s;
D is the diameter of the pipeline, m;
- diameter of the pipeline, cm;
- coefficient of resistance to friction along the length, determined by the formula

For pipelines with a diameter of 150 mm, the value should be increased by 0.01.

5.3. Smallest pipe diameters

5.3.1. The smallest pipe diameters of gravity networks should be taken, mm:
for a street network - 200, an intra-quarter network, a network of domestic and industrial sewage - 150;
for rain street network - 250, intra-quarter - 200.
The smallest diameter of pressure pipes is 150 mm.
Notes. 1. In settlements with a wastewater flow rate of up to 300 m3 / day for the street network, the use of pipes with a diameter of 150 mm is allowed.
2. For the production network, with appropriate justification, the use of pipes with a diameter of less than 150 mm is allowed.

5.4. Estimated speeds and filling of pipes and channels

5.4.1. In order to avoid siltation of sewer networks, the estimated speed of the wastewater should be taken depending on the degree of filling of pipes and channels and the size of suspended solids contained in the wastewater.
The minimum speed of movement of wastewater in domestic and rainwater networks with the highest estimated filling of pipes should be taken according to table 2.

table 2

Estimated minimum wastewater speeds
depending on the highest degree of tube filling
in domestic and rainwater networks

│ Diameter, mm │ Speed \u200b\u200bV, m / s, when filling H / D │
│ │ min │
│ ├───────────┬───────────┬───────────┬───────────┤
│ │ 0,6 │ 0,7 │ 0,75 │ 0,8 │

│150 - 250 │ 0,7 │ - │ - │ - │
├─────────────────────────┼───────────┼───────────┼───────────┼───────────┤
│300 - 400 │ - │ 0,8 │ - │ - │
├─────────────────────────┼───────────┼───────────┼───────────┼───────────┤
│450 - 500 │ - │ - │ 0,9 │ - │
├─────────────────────────┼───────────┼───────────┼───────────┼───────────┤
│600 - 800 │ - │ - │ 1,0 │ - │
├─────────────────────────┼───────────┼───────────┼───────────┼───────────┤
│900 │ - │ - │ 1,10 │ - │
├─────────────────────────┼───────────┼───────────┼───────────┼───────────┤
│1000 - 1200 │ - │ - │ - │ 1,20 │
├─────────────────────────┼───────────┼───────────┼───────────┼───────────┤
│1500 │ - │ - │ - │ 1,30 │
├─────────────────────────┼───────────┼───────────┼───────────┼───────────┤
│St. 1500 │ - │ - │ - │ 1.50 │
├─────────────────────────┴───────────┴───────────┴───────────┴───────────┤
│ Notes. 1. For production wastewater, the lowest speeds│
│ Accept in accordance with the guidelines for building design │
│ enterprises of individual industries or operational │
│ data. │
│ 2. For industrial wastewater similar in nature to suspended │
│ substances to household, take the lowest speeds as for domestic sewage │
Water. │
│ 3. For rain sewage at P \u003d 0.33 years, the lowest speed│
│ Take 0.6 m / s. │

5.4.2. The minimum design speed of clarified or biologically treated wastewater in trays and pipes is allowed to take 0.4 m / s.
The highest estimated speed of wastewater should be taken, m / s: for metal and plastic pipes - 8 m / s, for non-metallic (concrete, reinforced concrete and chrysotile cement) - 4 m / s, for rain sewage - 10 and 7 m / s, respectively .
5.4.3. The estimated speed of movement of unclarified wastewater in the siphons must be taken at least 1 m / s, while in places where the wastewater approaches the siphon, the speed should be no more than the speeds in the siphon.
5.4.4. The lowest calculated speeds of movement of raw and fermented sediments, as well as compacted activated sludge in pressure pipes, should be taken according to table 3.

Table 3

Estimated minimum raw speeds
and fermented sediments as well as compacted
activated sludge in pressure pipes

┌─────────────────────────┬───────────────────────────────────────────────┐
│ Sediment moisture,% │ V, m / s, at │
│ │ min │
│ ├───────────────────────┬───────────────────────┤
│ │ D \u003d 150 - 200 mm │ D \u003d 250 - 400 mm │

│ 98 │ 0,8 │ 0,9 │
├─────────────────────────┼───────────────────────┼───────────────────────┤
│ 97 │ 0,9 │ 1,0 │
├─────────────────────────┼───────────────────────┼───────────────────────┤
│ 96 │ 1,0 │ 1,1 │
├─────────────────────────┼───────────────────────┼───────────────────────┤
│ 95 │ 1,1 │ 1,2 │
├─────────────────────────┼───────────────────────┼───────────────────────┤
│ 94 │ 1,2 │ 1,3 │
├─────────────────────────┼───────────────────────┼───────────────────────┤
│ 93 │ 1,3 │ 1,4 │
├─────────────────────────┼───────────────────────┼───────────────────────┤
│ 92 │ 1,4 │ 1,5 │
├─────────────────────────┼───────────────────────┼───────────────────────┤
│ 91 │ 1,7 │ 1,8 │
├─────────────────────────┼───────────────────────┼───────────────────────┤
│ 90 │ 1,9 │ 2,1 │
└─────────────────────────┴───────────────────────┴───────────────────────┘

5.4.5. The highest speeds of rainfall and allowed to be discharged into the reservoirs of industrial wastewater in canals should be taken according to table 4.

Table 4

The highest speeds of rain and permissible
to discharge into the reservoirs of industrial wastewater in canals

┌────────────────────────────────┬────────────────────────────────────────┐
│ Ground or type of channel fastening │ Maximum speed in channels, движения
│ │ m / s, with a flow depth of 0.4 to 1 m │

│ Fastening with concrete slabs │ 4 │
├────────────────────────────────┼────────────────────────────────────────┤
│Limestones, medium sandstones │ 4 │
├────────────────────────────────┼────────────────────────────────────────┤
│Operating: │ │
│ flat │ 1 │
│ about the wall │ 1.6 │
├────────────────────────────────┼────────────────────────────────────────┤
│ Paving: │ │
│ single │ 2 │
│ double │ 3 - 3,5 │
├────────────────────────────────┴────────────────────────────────────────┤
│ Note. With a flow depth of less than 0.4 m, the velocity values│
Принимать accept wastewater movements with a coefficient of 0.85; with depth over│
│1 m - with a coefficient of 1.24. │
└─────────────────────────────────────────────────────────────────────────┘

5.4.6. The calculated filling of pipelines and channels of any section (except for a rectangular one) should be taken no more than 0.7 diameter (height).
The estimated filling of the channels of rectangular cross-section is allowed to take no more than 0.75 height.
For rainwater pipelines, it is allowed to accept full filling, including with short-term wastewater discharges.

5.5. Slopes of pipelines, channels and trays

5.5.1. The smallest slopes of pipelines and channels should be taken depending on the permissible minimum speeds of movement of wastewater.
The smallest slopes of pipelines for all sewerage systems should be taken for pipes with diameters: 150 mm - 0.008; 200 mm - 0.007.
Depending on local conditions, with appropriate justification, for individual sections of the network it is allowed to accept slopes for pipes with diameters: 200 mm - 0.005; 150 mm - 0.007.
The slope of the connection from the storm water inlets should be 0.02.
5.5.2. In an open rain network, the smallest slopes of the roadway trays, ditches and drainage ditches should be taken according to table 5.

Table 5

The smallest slopes of the carriageway trays,
ditches and drainage ditches

Name Least bias
Asphalt Concrete Trays 0.003
Trays coated with paving or crushed stone coating 0.004
Cobblestone pavement 0.005
Single trays and ditches 0.006
Gutter Ditches 0.003
Polymer, polymer concrete trays 0.001 - 0.005

5.5.3. The smallest sizes of cuvettes and ditches of a trapezoidal section should be taken: width along the bottom - 0.3 m; depth - 0.4 m.

6. Sewer networks and structures on them

6.1. General directions

6.1.1. Gravity-free (non-pressure) sewerage networks are designed, as a rule, in one line.
Notes. 1. In parallel laying of gravity sewer collectors, it is necessary to consider the arrangement of bypass pipelines in separate sections (where possible) to ensure their repair in emergency situations.
2. It is allowed to transfer to emergency tanks (with subsequent pumping) or, in agreement with the Sanitary-and-Epidemiological Supervision authorities, to rain collectors equipped with treatment facilities at the outlets. At bypasses to rain collectors, gates to be sealed must be provided.

6.1.2. Reliability of the operation of pressureless networks (collectors) of sewage is determined by the corrosion resistance of the material of the pipes (channels) and butt joints both to the transported wastewater and to the gas environment in the surface space.
6.1.3. The location of the networks on the master plans, as well as the minimum distances in the plan and at intersections from the outer surface of the pipes to structures and utilities, should be taken in accordance with SP 42.13330.
6.1.4. Sewage pressure pipelines should be designed taking into account the characteristics of the transported waste fluid (aggressiveness, high content of suspended particles, etc.). It is necessary to provide for additional measures and constructive solutions that ensure prompt repair or replacement of pipeline sections during operation, as well as the use of appropriate non-clogging pipeline valves.
The drainage of water from the emptied area during repair should be provided without discharge into a water body - in a special tank with subsequent transfer to the sewer network or removal of a tanker truck.
6.1.5. The design of deep-laid collectors laid by paneling or mining must be performed in accordance with SP 43.13330.
6.1.6. Ground and elevated laying of sewer pipelines in the territory of settlements is not allowed.
When laying sewer pipelines outside settlements and on the sites of industrial enterprises, surface or elevated pipelines are allowed to ensure the necessary reliability of operation and safety, taking into account the strength characteristics of the pipe when exposed to wind supports, etc.
6.1.7. The material of pipes and channels used in sewage systems must be resistant to the influence of both transported waste fluid and gas corrosion in the upper part of the collectors.
In order to prevent gas corrosion, appropriate protection of pipes and measures to prevent the formation of aggressive media (ventilation of the network, exclusion of stagnant zones, etc.) should be provided.
6.1.8. The type of pipe base must be taken depending on the bearing capacity of soils and loads, as well as the strength characteristics of the pipe. Backfill of pipelines should take into account the bearing capacity and deformation of the pipe.

6.2. Pivots, connections and piping depth

6.2.1. Connections and turns on the collectors should be provided in the wells.
The radius of the curve of rotation of the tray must be taken at least the diameter of the pipe, on collectors with a diameter of 1200 mm or more - at least five diameters with the installation of inspection wells at the beginning and end of the curve.
6.2.2. The angle between the connected and the outlet pipe must be at least 90 °.
Note. When connecting with a differential, any angle between the connected and outlet pipelines is allowed.

6.2.3. Connections of pipelines of different diameters in wells should be provided for along pipe hoses. When substantiating, it is allowed to connect the pipes at the calculated water level.
6.2.4. The smallest depth of the laying of sewer pipelines must be determined by heat engineering calculation or taken based on the experience of operating networks in the area.
In the absence of data, the minimum depth of the pipeline tray can be accepted for pipes with a diameter of up to 500 mm - 0.3 m, and for pipes of a larger diameter - 0.5 m less than a greater depth of penetration into the ground at zero temperature, but not less than 0.7 m to the top pipes, counting from the surface of the earth or layout (to avoid damage by land transport).
6.2.5. The maximum pipe laying depth is determined by calculation depending on the pipe material, their diameter, soil conditions, method of work.

A properly designed and installed external sewage system will not create unnecessary trouble in its operation, it will provide not only comfort and all kinds of conveniences for residents of certain houses, office workers and other buildings, but also a full guarantee of sanitary and hygienic safety of human health.

That is why it is very important to follow all sanitary norms and rules (SNiP) established at the state level.

SNiP provide complete relevant information on how to accurately calculate and create a project of external sewage networks in order to avoid epidemics, contamination of drinking water and soil areas as a result of sewage emissions, breakthrough of sewer pipes and other emergency situations in their future operation.

Unlike internal sewer networks, which are located inside residential and non-residential premises, the external ones are communications that stretch from the house to the tanks, which store wastewater.

Such sewer installations are installed both for city-wide building objects, and for private houses, where there is a slope for gravity sewage or pressure networks are installed with pumping stations or sewage pumps.

City-wide buildings relate, as a rule, to the department and maintenance of municipal utilities, while private buildings are serviced autonomously and independently.

And in both cases, the construction or installation and installation of an external sewage system requires strict adherence to specially developed state sanitary and hygienic standards and rules.

According to the structure of the installation and installation method, sewer external networks are divided into such systems:

separate - the drain of domestic and fecal wastewater is separated from rainwater and melt, it flows through different pipes and is collected in different containers;
semi-separate - in this case, rain, melt and domestic water flowing through separate pipes are collected in a single sewer, where they are stored for some time and then disposed of;

Photo: half-divided sewer networks

general alloy - according to this scheme, drains of all types flow down the same pipeline into the same sewer tank.

Photo: Alloy Sewer Networks

According to the type of location and purpose, there is a sewerage system for its outdoor use in such places:

intra-yard and intra-quarter networks - tracing (laying of the pipeline by vectors from point A to point B) of the entire sewage system is carried out along the walls of buildings at a distance of 3 m from their outer walls, using the shortest path to the collectors located on the streets. Such a concept as a courtyard network is applicable only to sewers that connect to centralized urban systems, but does not apply to autonomous sewers;
street - This is a whole system of pipelines and wells, branched out in various ways, which runs directly along the streets and ensures the transportation of wastewater to the center of the entire external sewer system - city sewers;
collectors - their role is to collect wastewater and, if necessary, redirect it to other collectors. For the most part, sewer collectors are located both on the territory of the sewer basin and on its outskirts. Sewerage basin is a part of the territory limited by watersheds where sewer pipes run and sewage is transported either by gravity or pressure method;

Photo: sewer network collectors

treatment facilities - The final point of wastewater dispatch is treatment facilities where the water is treated and the treated water is discharged into the reservoir, or for the use of industrial and economic needs of large and small production facilities.

Photo: Wastewater Treatment Plant

There are also some options for the location and arrangement of the schemes for laying the external sewage pipeline themselves.

Differences in schemes are formed due to the diversity of the terrain where sewer pipes are laid.

Indeed, it can depend on turns and bends on the lines of passing pipes, the level of groundwater, which means supplying the system with inspection, drainage or revision wells and other specific subtleties.

The most basic schemes of external sewers can be distinguished:

perpendicular pattern - the perpendicular is formed here due to the laying of sewer pipes or collectors perpendicular to the movement of water in the reservoir. Such a scheme effectively removes dirty water from clean waters;

crossed circuit - collectors that are located on the territory of the sewage basin are installed perpendicular to the reservoir and intercepted by the main or main collector, which is installed parallel to the coastline of the river. This scheme is used where there is too much slope towards a river or some other reservoir, and where more thorough wastewater treatment is required;

fan or parallel circuit - in the case of sharp slopes towards the river, the external sewage pipe is laid parallel to each other, but at an obligatory angle with respect to the reservoir. Such systems are also intercepted by the main collectors, which successfully divert waste water away from settlements to treatment facilities;
zone or zone diagram - this scheme allows dividing the city sewer into sections or zones, but it is not possible to let wastewater into the sewage treatment system by gravity, so pumping pumping stations are installed on the lowest intercepting collector;
radial or decentralized scheme - here the wastewater is directed in a non-centralized way and gets to different treatment facilities. This scheme works very well only on flat terrain and large volumes of sewage entering the external sewage pipe.

Photo: schemes of external sewer networks: a - perpendicular; b - crossed; in - parallel; g - zone; d - radial

All types and classifications of external sewage systems differ among themselves in the structure of construction, purpose, relief terrain conditions, wastewater volumes and other parameters and factors that affect the planning and routing of various types of sewers in its outer part.

Network Composition

External sewage systems have certain sections of pipelines, complex and simple designs of all kinds of wells, slopes, transitions and turns in laying the pipes themselves, tanks where sewage is temporarily accumulated or transported, treated, and then purified water is drained into water bodies.

By and large, the external sewage system consists of such structures, components and structures:

pipeline - along the length of which pipes of various lengths and diameters are used;

Photo: sewage pipeline

wells - as a rule, inspection (revision), drainage, overflow and rotary wells are involved;

Photo: sewage wells

releases to the receivers - they provide the unhindered exit of wastewater from the pipeline to the tank;
collectors are whole tunnels, which are huge pipes that provide sufficient space for the accumulation and collection of sewage water, as well as their subsequent distribution and transportation to treatment facilities or pumping stations;
local treatment facilities are various septic tanks, aerators, biodisk equipment, and other structures whose purpose is to treat wastewater and discharge it into water bodies, rivers, or use it for technical or, for example, agricultural needs;

Photo: local sewage treatment plants

pumping stations - are not used in all external sewage systems, namely, where a portioned supply of wastewater to treatment plants is required;
other elements are all kinds of components, additional mechanisms and other elements of the external sewer network.

Basic design requirements

As already noted, the need for strict adherence to all state standards and rules of the sanitary-hygienic and construction order.

This is necessary to avoid violations and accidents that may occur in the further operation of a particular section of the external sewage system.

Important! Only when all Construction Norms and Regulations are observed and all work is done in proper quality, then only the object of sewer networks can be put into operation.

All these points relate not only to the exact implementation of the rules and norms by state or commercial structures, but also to individuals who independently lay pipes for autonomous sewage, or sewage, which is supplied from the cottage, private house to a centralized sewage system.

Photo: SNiP

Before proceeding with the design of any external sewage system, you must first determine the nature of the terrain on whose territory the sewage system will be located, as well as its type: separate, semi-divided or alloyed.

The rules and norms provided by the Guest require strict compliance with the phased implementation of works on laying and installing the sewage system.

To start, preparatory excavation is carried out according to the project plan:

digging trenches with a larger diameter than the pipes themselves, in accordance with the norms of SNiP;
ramming trenches or supplying them with “pillows” or any other covering elements;
in order to avoid freezing, various heaters and deeper trenches are used.

Photo: sealing seals of sewer pipe joints pipe insert

After warming, laying the pipeline with all the wells and other fittings, the system must pass all the relevant SNiP hydraulic tests and only then it will be filled up with soil and rammed.

Photo: laying sewer pipes

Septic tanks

Structures such as septic tanks must be placed at a distance from the foundation of the house or well with drinking water from 10 to 12 m.

These requirements must be strictly observed, otherwise sewage or fumes may enter the soil drinking water, which subsequently leads to the appearance of various infectious and bacterial diseases.

For installation and installation, a cottage or a country house, you must first dig a large pit.

Given that modern septic tanks are almost all made of light materials: plastic or fiberglass plastic, you need to prepare a platform for it from concrete and fixing belts, or reinforced concrete rings.

All this is done so that the septic tank does not “pop up”, but remains fixed underground. All connecting pipes with wells should consist of anti-corrosion materials that are not exposed to the aggressive environment of sewage.

Thus, these pipes and wells can last as long as possible.

Photo: septic tank

The mechanism of operation of the septic tank also contains aerobic and anaerobic bacteria, with the help of which the wastewater entering the first chamber decomposes, forming water and sludge.

Then, water, filling the first chamber to a certain level, is poured into the second chamber, and from there (if the septic tank is 2-chamber) into the perforated pipe, through the openings of which the purified water enters the soil, thereby not infecting the soil.

Biological deep wastewater treatment

Modern solutions for effective wastewater treatment have come to the best solution - a biological deep wastewater treatment, which is carried out using entire plants and structures using bio-disks, where bacteria are present that work to decompose sewage into water and sludge.

The operating mechanism of the deep-cleaning station is based on the principle of operation of septic tanks, but only in an improved and modified version to such an extent that it cleans dirty waste water by 98%.

Photo: biological deep wastewater treatment

It is good to install such a structure in private houses, dachas, cottages, where the centralized external sewage system is located far enough and the installation of an autonomous sewer system is required.

Such a deep-cleaning station is installed almost in the same way as a septic tank, only with the obligatory consideration of all the norms and rules for external autonomous sewer systems.

Consequences and liability of non-compliance with Construction Norms and Regulations on design, installation and installation

The legislation of the Russian Federation provides for appropriate penalties and liability for violations of SNiP on installation and laying of external sewers.

Compliance with SNiP is checked by specially created commissions if appropriate documentation is available.

Responsible for compliance with all rules and regulations are the following persons:

developers (customers) - are responsible for preparing for the operation of the finished sewer network, taking into account all personnel issues, ensuring the proper operation of the equipment, setting up technological processes, developing project capacities within the time frames specified in SNiP “Sewerage. External networks and structures ”;
design organizations - are responsible for the accuracy of all calculations, drawings and design plans for outdoor sewage networks;
research organizations - are responsible for all issued documents and digital data on climate, ecology in the region or area where the outdoor sewage was laid;
construction and installation organizations - are fully responsible for observing all the rules and regulations during the work and testing of the finished structure, prescribed in SNiP 2.04.03-85 “Sewerage. External networks and facilities. ”

In case of violations of SNiP by any of the above listed persons, they are brought to administrative, disciplinary, criminal and other liability in accordance with the legislation of the Russian Federation.

All penalties are imposed on the perpetrators because their negligence if all the relevant rules and regulations are not followed, may lead to or lead to disasters, epidemics, or any accidents associated with a violation of the sewer pipeline, blockage or any other breakdown.

All the issues discussed regarding the preparatory and installation work on the design and installation of external sewer systems can shed light on the correct conduct of all installation and construction works in this type of activity.

This applies not only to the construction of the state central system of external sewage, but also to autonomous sewer structures.

Important! Any deviation from SNiP by any citizen who decided to do the independent laying of the sewage system, or by any organization or enterprise that installs the external sewage pipeline, can lead to catastrophic consequences, various diseases of the population or emergency breakdowns that will cause irreparable damage to the environment.

Video: how to properly arrange sewers in a private house

External sewer networks, according to SNiP, are used both in private country houses and in city apartments. Such a sewer system is very convenient, easy to operate and environmentally friendly. For its installation, you must familiarize yourself with the rules of use for SNiP

Features and types of sewer systems SNiP

Sewerage network data is a branched pipeline that delivers wastewater from the premises (residential and non-residential) to special tanks. To ensure that sewage flows into the tank by gravity, the water pipes are installed under a slight slope.

The second version of the system involves the installation of pressure networks or the connection of a special pump.

Types of sewage systems according to SNiP

Depending on the purpose, sewer networks are divided:

Household, which is divided into two types: central (serving the entire village) and autonomous (for one or more houses).
Industrial (industrial treatment facilities).
Storm, providing drainage after rain.

All of these species are divided into two subspecies:

Outdoor (pipes are located on the street, including sewage treatment plants and structures).
Internal (everything that is indoors).

According to the method of installation and laying of the SNiP pipeline, external communications are divided into several types:

In addition, sewer networks differ in other ways.

SNiP outdoor sewage systems

Outdoor communications can be located in various places and vary in purpose. There are several types of outdoor sewage networks:

Laying methods water pipes are determined in each case individually. This depends on several factors, such as bends and turns along the route, the level of groundwater passage, etc. It should be remembered that sewer pipes in any case are laid with a slope that varies depending on the diameter of the pipe. In some cases, it may be necessary to install a pump, drainage or manhole.

Component systems of external sewage

The sewage network consists of various elements that allow the transportation of waste water to wastewater treatment plants. In general, the sewage system includes the following details:

In addition, for the full operation of the sewage system, it is possible to use other additional elements.

Material for the manufacture of sewer pipes

The life of the pipeline depends on the choice of material. To date, the rules provide for the use of such materials as:

In rare cases, it is possible to use pipes made of glass or ceramic.

Since wastewater with all sewage immediately flows from the internal sewage system to the outside, the latter must cope with a huge amount of sewage at the same time.

Installation of an external sewage system

To ensure the reliability and long life of the sewer system during its installation, a number of rules must be observed.

SNiP requirements are based on such factors as:

soil properties;
climate features;
ground water level;
average volume of wastewater;
distance to the nearest pumps and treatment plants.

It is also very important to observe the level of inclination of the pipe to ensure unhindered passage of sewage by gravity. According to the requirements of SNiP, pipes must be laid under a certain slope in the sides of the well. The angle of inclination is determined by the diameter of the pipe and is 2-3 cm per meter of the pipeline.

Do not try to make a large slope: this, of course, will contribute to the rapid discharge of a huge amount of effluents, but it can lead to clogging of the system, since solid particles will be trapped in the pipe.

According to the requirements of SNiP, the size of the pipe for the external sewage of several houses included in the system should be at least 20 cm, and for one suburban cottage - 10–11 cm. When planning the installation of a sewage system, additional factors affecting future performance should be taken into account .

Before proceeding directly to the installation of the sewage system, it is necessary to carry out preparatory work: to study the features of the soil, to calculate all the elements, to lay the route of the pipeline.

The first step is to determine the location of the collection well where the sewage will flow. At the same time, the type of water collector is also taken into account: a septic tank that is able to not only accept, but also utilize pollution or an ordinary well.

The ideal location for the septic tank or well is the lowest place in the pipeline. If it is planned to clean the collection by means of a cesspool machine, it is better to place the well, for its comfortable maintenance, closer to the roadway.

A trench is excavated, which, if necessary, is supplied with additional details. The pipe joints must be carefully fixed and sealed. In order to prevent freezing of the water supply system in the winter, it is necessary to carry out thermal insulation. Then the sewer system is connected to the treatment plant or collector and a trial run is performed.

The ditch is filled up and tamped only after a complete check of the entire structure as a whole.

Requirements for pipeline parts:

Resistance to corrosion or providing additional protection.
The presence of the foundation for the installation of the pipeline, taking into account the characteristics of the soil.
Mandatory use of valves, plungers and other additional elements for pressure sewer networks.
Installation of manholes only in places of slopes, intersections and bends of the water supply. The size of the well is determined by the diameter of the pipe and its length. Wells must have sewer manholes, stairs and fences.
Rainwater receivers should be installed near pedestrian crossings, lowlands and crowded areas.

SNiP requirements for the sewerage of a private house

Sewerage in apartment buildings is taken for granted and almost invisible. Another thing is the removal of wastewater in a private house. Cesspools and street toilets are already considered a relic of the past, and many owners of suburban cottages are thinking about building a sewer system on their site. In order to independently mount and connect the sewage pipeline, it is necessary to know the building codes and rules, compliance with which will ensure a long and uninterrupted operation of the system.

Sewerage is laid immediately during the construction of a new house, but it’s also quite possible to equip the apartment with an outdoor toilet with street amenities.

Private houses are divided into two types: with the ability to connect to a central sewer system and those that cannot be connected.

The procedure for conducting intra-house installation work will be the same, the difference is only in the discharge of wastewater from the premises.

The sewage system of a private house, as well as an apartment building, consists of sewer pipes and a riser, interconnected. Wastewater from toilets, bathtubs and sinks falls into horizontal pipes and flows into the sewage treatment plant or sewer in a riser. If the construction of the house is only planned, it is necessary to arrange the kitchen and the bathroom next to the place where the sewer pipe comes out of the house. If the cottage is multi-storey, then for ease of installation of the pipeline, bathrooms must be placed one above the other.

Pipe installation and plumbing installation

The toilet is attached to the riser separately. So that the drains do not fall into the pipes, the remaining elements should be located above the toilet.

To reduce the noise level, the risers can be closed in a box of drywall or wrapped with mineral wool. All necessary parts are attached to the pipes with knee siphons, in which there is always a small amount of water, which blocks the unpleasant odors of the system and prevents them from escaping.

Horizontal pipes that are under the floor, in the basement or basement, are connected to the riser with external pipes. Elements located outside the premises should be well insulated to prevent them from freezing during the cold season. At the exit from the house, all pipes are collected in one and connected to an external sewage system. Clamps are used as fasteners.

In order to prevent the appearance of specific odors when draining water, ventilation should be installed: the vertical riser is discharged to the roof, and its upper part must be well fixed not to be covered, but only protected from debris and precipitation. An aeration valve can also be installed to protect against odors.

A trench is being prepared, the depth of which is determined by the level of soil freezing in a particular region. A sand cushion is necessarily laid at the bottom of the ditch, on which downpipes are mounted under a slight slope. If, due to the nature of the soil, it is impossible to dig a deep trench, the pipeline should be carefully insulated.

Private houses mainly have an autonomous sewage system, which can be of 4 types:

Dry closet. Convenient, but requiring constant costs type of sewage.
Cesspool. Cheap, but very uncomfortable to use look.
Septic tank. It is able not only to take wastewater, but also to clean it independently.
Sewage treatment plant. Cleaning is carried out using special bacteria. Quite effective, but at the same time - an expensive type of sewer system.

Each of these options has its pros and cons. For example, a cesspool is best installed in areas that have a periodic pattern of use.

The treatment plant does not require constant care, but its disadvantage is its high cost. Of the proposed sewerage options for a private house, a septic tank can be ideal, which you can assemble yourself or buy ready-made.

So, following the rules of SNiP outdoor sewage networks, and following the recommendations made, you can easily install a sewer system in your home and thereby ensure yourself and your loved ones a comfortable stay.

SNiP 2.04.03-85

BUILDING REGULATIONS

SEWERAGE.

EXTERNAL NETWORKS AND STRUCTURES

Introduction Date 1986-01-01

DEVELOPED by Soyuzvodokanalproekt (G.M. Mironchik - topic manager; D.A. Berdichevsky, A.E. Vysota, L.V. Yaroslavsky) with the participation of VNIIVODGEO, Donetsk PromstroyNIIproekt and NIIOSP them. N.M. Gersevanova Gosstroy of the USSR, Research Institute of municipal water supply and water purification of the Academy of Public Utilities named after KD Panfilov and Giprokommunvodokanal of the Ministry of Housing and Communal Services of the RSFSR, TsNIIEP of engineering equipment of the Gosgrazhdanstroy, MosvodokanalNIIproekt and Mosinzhproekt of the Moscow City Executive Committee, the Scientific Research and Design Institute of Urban Economics and the UkrkommunzhIIShimkost and the Institute of Mechanics and the Institute of Mechanical Engineering and the Institute of Mechanics and Industrial Engineering of the USSR and the Institute of Mechanics M.T. Urazbaev of the Academy of Sciences of the Uzbek SSR, Moscow Civil Engineering Institute. V.V. Kuybysheva of the Ministry of Higher Education of the USSR, Leningrad Civil Engineering Institute of the Ministry of Higher Education of the RSFSR.

INTRODUCED by Soyuzvodokanalproekt Gosstroy USSR.

PREPARED FOR APPROVAL by Glavtekhnormirovaniye Gosstroy of the USSR (B.V. Tambovtsev).

APPROVED by resolution of the USSR State Committee for Construction Affairs of May 21, 1985 No. 71.

AGREED by the Ministry of Health of the USSR (letter of 10.24.83 No. 121-12 / 1502-14), the Ministry of Water Economy of the USSR (letter of 04.15.85 No. 13-3-05 / 366), the Ministry of Fisheries of the USSR (letter of 26.04.85 No. 30-11- 9).

With the introduction of SNiP 2.04.03-85 "Sewerage. External networks and structures," SNiP II-32-74 "Sewerage. External networks and structures" ceases to be in force.

SNiP 2.04.03-85 “Sewerage. External networks and structures” introduced Amendment No. 1, approved by resolution of the USSR Gosstroy of May 28, 1986 No. 70 and entered into force on July 1, 1986 Paragraphs, tables, as amended are marked in these Building codes and rules with a sign (K).

Changes were made by the Kodeks Law Bureau according to the official publication of the Ministry of Construction of Russia - M .: GUP TsPP, 1996

These rules and regulations must be observed when designing newly built and reconstructed permanent sewage systems for settlements and national economy objects.

1. General instructions

When designing, it is necessary to consider the feasibility of cooperating with sewage systems of objects regardless of their departmental affiliation, and also take into account the technical, economic and sanitary assessments of existing structures, provide for the possibility of their use and intensification of their work.

Sewerage projects of facilities should be developed, as a rule, simultaneously with water supply projects with a mandatory analysis of the balance of water consumption and wastewater disposal. In this case, it is necessary to consider the possibility of using treated wastewater and rainwater for industrial water supply and irrigation.

1.2. In the rainwater drainage system, the most polluted part of the surface runoff generated during the period of rainfall, snowmelt and washing of road surfaces, i.e. at least 70% of the annual runoff for residential areas and sites of enterprises close to them in terms of pollution, must be treated, and the total volume of runoff for the sites of enterprises, the territory of which may be contaminated with specific substances with toxic properties or a significant amount of organic substances.

1.5. Wastewater treatment plants for industrial and rain sewers should, as a rule, be located on the territory of industrial enterprises.

1.6. When connecting sewer networks of industrial enterprises to the street or intra-quarter network of a settlement, outlets with control wells located outside the enterprises should be provided.

It is necessary to provide devices for measuring the discharge of waste water from each enterprise.

Combining the production wastewater of several enterprises is allowed after the control well of each enterprise.

1.7. The conditions and places for the release of treated wastewater and surface runoff to water bodies should be coordinated with the bodies regulating the use and protection of water, the executive committees of local Councils of People's Deputies, bodies implementing state sanitary supervision, protection of fish stocks, and other bodies in accordance with Union law Soviet Socialist Republic and Union republics, and places of release into navigable water bodies, watercourses and seas - also with the management bodies of the river fleet of the Union Republics and the Ministry of the Marine ota.

1.8. When determining the reliability of the sewage system and its individual elements, it is necessary to take into account technological, sanitary and hygienic and water protection requirements.

In case of inadmissibility of interruptions in the operation of the sewage system or its individual elements, measures must be provided to ensure the uninterrupted operation of their work.

1.9. In the event of an accident or repair of one structure, the overload of the remaining structures of this purpose should not exceed 8-17% of their estimated capacity without reducing the efficiency of wastewater treatment.

from structures and pumping stations of the sewage system of settlements - according to the table. 1;

from wastewater treatment plants and pumping stations of industrial sewage systems not located on the territory of industrial enterprises, both during self-cleaning and pumping of industrial wastewater, and when they are treated together with domestic wastewater - in accordance with SN 245-71, the same as for production, from which sewage arrives, but not less than specified in tab. 1.

Table 1

Facilities	Sanitary protection zone, m, with the design capacity of the facilities, thousand m / day
		st. 0.2 to 5	st. 50 to 280
Mechanical and biological treatment facilities with silt sites for fermented sediments, as well as separately located silt platforms
Mechanical and biological treatment plants with thermomechanical treatment of precipitation in enclosed spaces
Filter fields
Agricultural irrigation fields
Biological ponds
Structures with circulating oxidizing channels
Pumping stations
Notes: 1. Sanitary protection zones of sewage facilities with a capacity of more than 280 thousand m / day, as well as when deviating from the adopted technology for wastewater treatment and sludge treatment, are established in agreement with the main sanitary and epidemiological departments of the ministries of health of the Union republics. 2. Sanitary protection zones indicated in the table. 1, it is allowed to increase, but not more than 2 times in the case of the location of residential buildings on the leeward side in relation to the treatment facilities, or reduce by no more than 25% in the presence of a favorable wind rose. 3. In the absence of silt sites on the territory of treatment facilities with a capacity of more than 0.2 thousand m / day, the size of the zone should be reduced by 30%. 4. A sanitary protection zone from filtration fields of up to 0.5 ha and from mechanical and biological treatment facilities on biofilters with a capacity of up to 50 m / day should be taken 100 m. 5. A sanitary protection zone from underground filtering fields with a productivity of less than 15 m / day should be taken 15 m. 6. The sanitary protection zone from filtering trenches and sand and gravel filters should be taken 25 m, from septic tanks and filtering wells, respectively 5 and 8 m, from aeration plants for complete oxidation with aerobic stabilization of sludge at a capacity of up to 700 m / day - 50 m 7. The sanitary protection zone from the drain stations should be taken 300 m. 8. The sanitary protection zone from surface water treatment facilities from residential areas should be taken 100 m, from pumping stations - 15 m, from treatment facilities of industrial enterprises - in agreement with the bodies of the sanitary-epidemiological service. 9. Sanitary protection zones from sludge collectors should be taken depending on the composition and properties of the sludge in agreement with the bodies of the sanitary-epidemiological service.

2. Estimated wastewater costs.

Hydraulic calculation of sewer networks

Unit costs, rates of unevenness and

estimated wastewater costs

2.1. When designing sewage systems in settlements, the calculated average daily average (per year) of sewage from residential buildings should be taken equal to the estimated average daily (annual) water consumption according to SNiP 2.04.02-84, excluding water consumption for irrigation of territories and green spaces.

2.2. Specific wastewater to determine the estimated costs of wastewater from individual residential and public buildings, if necessary, account for concentrated costs should be taken in accordance with SNiP 2.04.01-85.

2.3. The estimated average daily costs of industrial wastewater from industrial and agricultural enterprises and the coefficients of unevenness of their inflow should be determined on the basis of technological data. At the same time, it is necessary to provide for the rational use of water through the use of low-water technological processes, water recycling recycling, etc.

2.4. Specific drainage in non-canalized areas should be taken 25 l / day per inhabitant.

2.5. The estimated average daily discharge of wastewater in the village should be determined as the sum of the costs established in paragraphs 2.1-2.4.

The amount of wastewater from local industrial enterprises serving the population, as well as unaccounted for expenses, may be accepted in addition in the amount of 5% of the total average daily drainage of a settlement.

2.6. Estimated daily wastewater costs should be defined as the sum of the products of the average daily (per year) wastewater costs, as defined in clause 2.5, by the daily unevenness coefficients, adopted in accordance with SNiP 2.04.02-84.

2.7. The estimated maximum and minimum wastewater discharge should be defined as the product of the average daily (for the year) wastewater discharge, as defined in clause 2.5, by the total unevenness coefficients given in table. 2.

table 2

General coefficient of irregularity of wastewater inflow	Average waste water consumption, l / s
		5000 and more
Maximum
Minimum
Notes: 1. General coefficients of unevenness of the influx of wastewater given in table. 2, it is allowed to take with the amount of industrial wastewater not exceeding 45% of the total flow. If the quantity of industrial wastewater is more than 45%, the general unevenness coefficients should be determined taking into account the unevenness of the discharge of domestic and industrial wastewater by the hours of the day according to the actual inflow of wastewater and the operation of similar facilities. 2. At average wastewater costs less than 5 l / s, the estimated costs should be determined in accordance with SNiP 2.04.01-85. 3. At intermediate values \u200b\u200bof the average wastewater flow rate, the general unevenness coefficients should be determined by interpolation.

2.8. The estimated costs of industrial waste water from industrial enterprises should be taken:

for external collectors of the enterprise receiving sewage from the workshops - at maximum hourly costs;

for factory and off-site collectors of the enterprise - according to the combined hourly schedule;

for an off-site collector of a group of enterprises - according to the combined hourly schedule, taking into account the time of the flow of wastewater through the collector.

2.9. When developing the schemes listed in clause 1.1, the specific average daily (per year) water disposal can be taken according to table. 3.

The volume of wastewater from industrial and agricultural enterprises should be determined on the basis of consolidated norms or existing analogous projects.

Table 3

Sewerage Objects	Specific daily average (per year) water disposal per inhabitant in settlements, l / day
	until 1990	until 2000

Rural areas
Notes: 1. The specific average daily drainage can be changed by 10-20% depending on climatic and other local conditions and the degree of improvement. 2. In the absence of data on the development of industry outside 1990, it is allowed to accept additional wastewater flow from enterprises in the amount of 25% of the flow determined according to Table. 3.

2.10. Gravity lines, collectors and channels, as well as pressure pipelines of domestic and industrial wastewater should be checked for the passage of the total estimated maximum flow rate in PP. 2.7 and 2.8 and additional influx of surface and groundwater during periods of rains and snowmelt, disorganized entering the sewer network through leaks in manhole covers and due to groundwater infiltration. The value of the additional inflow, l / s, should be determined on the basis of special surveys or data on the operation of similar objects, and if they are absent, according to the formula

, (1)

where is the total length of pipelines to the calculated structure (pipeline alignment), km;

The maximum daily precipitation, mm, determined according to SNiP 2.01.01-82.

Verification calculation of gravity pipelines and channels with a cross-section of any shape for the passage of increased flow should be carried out when filling 0.95 height.

Estimated rainwater discharge

2.11. Rainwater discharge, l / s, should be determined by the method of limiting intensities by the formula

where is the average value of the coefficient characterizing the surface of the drainage basin, determined according to clause 2.17;

Parameters determined in accordance with clause 2.12;

Estimated flow area, ha, determined in accordance with paragraph 2.14;

Estimated duration of rain, equal to the duration of surface water flowing along the surface and pipes to the calculated area, min, and determined in accordance with paragraph 2.15.

Estimated rainwater flow for hydraulic calculation of rainwater networks, l / s, should be determined by the formula

where is the coefficient that takes into account the filling of the free capacity of the network at the time of the onset of the pressure mode and is determined by Table 11.

Notes: 1. If the estimated duration of the rainwater flow is less than 10 min, a correction factor equal to 0.8 at \u003d 5 min and 0.9 at \u003d 7 min should be entered into formula (2).

2. With a large deepening of the initial sections of the rainwater drainage collectors, an increase in their throughput due to the pressure created by the rise in the water level in the wells should be taken into account.

2.12. Parameters and should be determined by the results of processing long-term records of self-recording rain gauges registered in this particular paragraph. In the absence of processed data, the parameter is allowed to be determined by the formula

, (4)

where - rain intensity, l / s per 1 ha, for a given area lasting 20 minutes at \u003d 1 year, determined by the devil. 1;

Figure 1. Rain Intensity Values

The exponent determined by the table. 4;

The average rainfall per year, taken according to the table. 4;

The period of a one-time excess of the calculated rain intensity, as adopted in clause 2.13;

The exponent taken on the table. 4.

Table 4

	N value for

Coast of the White and Barents Seas
North of the European part of the USSR and Western Siberia
Plain regions of the west and the center of the European part of the USSR
Plain regions of Ukraine
Uplands of the European part of the USSR, the western slope of the Urals
East of Ukraine, the lower Volga and Don, Southern Crimea
Lower Volga
The windward slopes of the hills of the European part of the USSR and the North Ciscaucasia
Stavropol Upland, northern foothills of the Greater Caucasus, northern slope of the Greater Caucasus
Southern part of Western Siberia, the middle course of the river. Or, the area of \u200b\u200bthe lake. Ale-Kul
Central and North-Eastern Kazakhstan, Altai foothills
Northern slopes of the Western Sayans, Zailiysky Alatau
Dzungarian Alatau, Kuznetsk Alatau, Altai
North Slope of the Western Sayan Mountains
Middle siberia
Hamar-Daban Range
Eastern Siberia
Shilka and Argun pools, Middle Amur Valley
The basins of the Kolyma and the rivers of the Sea of \u200b\u200bOkhotsk, the northern part of the Lower Amur Lowland
The coast of the Sea of \u200b\u200bOkhotsk, river basins of the Bering Sea, the center and west of Kamchatka
The east coast of Kamchatka is south of 56 ° N. w.
Coast of the Tatar Strait
Lake District Hanka
River basins of the Sea of \u200b\u200bJapan, about. Sakhalin, Kuril Islands
The south of Kazakhstan, the plain of Central Asia and the slopes of the mountains up to 1500 m, the lake basin. Issyk-Kul up to 2500 m
The slopes of the mountains of Central Asia at an altitude of 1500-3000 m
South West Turkmenistan
The Black Sea coast and the western slope of the Greater Caucasus to Sukhumi
The coast of the Caspian Sea and the plain from Makhachkala to Baku
East slope of the Greater Caucasus, Kura-Araksinskaya lowland up to 500 m
The southern slope of the Greater Caucasus is higher than 1500 m, the southern slope is higher than 500 m, DagASSR
The Black Sea coast below Sukhumi, the Colchis Lowland, the slopes of the Caucasus up to 2000 m
Kura basin, eastern part of the Lesser Caucasus, Talysh Range
Northwest and central parts of Armenia
Lankaran

2.13. The period of one-time excess of the calculated rain intensity must be selected depending on the nature of the sewage system, the conditions of the collector location, taking into account the consequences that may be caused by rainfall exceeding the calculated ones, and taken according to table. 5 and 6 or determined by calculation depending on the conditions of the location of the collector, the intensity of the rains, the area of \u200b\u200bthe basin and the runoff coefficient for the limiting period of excess.

When designing rain sewers at special facilities (metro, stations, underground passages, etc.), as well as for arid regions where the value is less than 50 l / (s · ha), with P equal to one, the period of a one-time excess of the calculated rain intensity follows determine only by calculation, taking into account the limit period for exceeding the calculated rain intensity specified in the table. 7. At the same time, periods of a one-time excess of the calculated rain intensity determined by the calculation should not be less than those indicated in the table. 5 and 6.

When determining the period of a one-time excess of the calculated rain intensity by calculation, it should be taken into account that for the limiting periods of a one-time excess specified in Table. 7, the collector of rainwater drainage should allow only part of the flow of rainfall, the rest of which temporarily floods the carriageway of the streets and, if there is a slope, flows down its trays, while the height of the flooding of the streets should not cause flooding of basements and basements; in addition, one should take into account the possible flow from pools located outside the village.

Table 5

Collector Location Conditions		The period of one-time excess of the calculated rain intensity P, years, for settlements with values
on local roads	on the main streets
Favorable and average	Favorable
Unfavorable
Especially unfavorable	Unfavorable
	Especially unfavorable
Notes: 1. Favorable conditions for the location of the collectors: a pool with an area of \u200b\u200bnot more than 150 ha has a flat topography with an average surface slope of 0.005 or less; the collector passes through the watershed or in the upper part of the slope at a distance from the watershed no more than 400 m. 2. Average conditions for the location of the collectors: a pool with an area of \u200b\u200bmore than 150 hectares has a flat topography with a slope of 0.005 m or less; the collector runs in the lower part of the slope along the thalweg with a slope of 0.02 m or less, while the basin area does not exceed 150 ha. 3. Adverse conditions for the location of the collectors: the collector passes in the lower part of the slope, the basin area exceeds 150 ha; the collector runs along a thalweg with steep slopes with an average slope of more than 0.02. 4. Particularly unfavorable conditions for the location of the collectors: the collector removes water from a closed low place (basin).

Table 6

Result of short-term network overflow	The period of one-time excess of the calculated rain intensity, years, for the territory of industrial enterprises at values
		st. 70 to 100
Technological processes of the enterprise:
not violated
are violated
Note. For enterprises located in a closed basin, the period of a single excess of the calculated rain intensity should be determined by calculation or taken equal to at least 5 years.

Table 7

The nature of the reservoir served by the collector	The value of the limiting period of excess of rain intensity, years, depending on the conditions of the location of the collector
	favorable	unfavorable	especially unfavorable
Territories of neighborhoods and local roads
Main streets

2.14. The estimated drainage area for the calculated network section must be taken equal to the entire drainage area or part of it giving the maximum discharge flow rate.

In cases where the collector drain area is 500 ha or more, a correction factor should be entered into formulas (2) and (3), taking into account the uneven rainfall over the area and taken according to Table. 8.

Table 8

Area of \u200b\u200bflow, ha
Coefficient value

The estimated costs of rainwater from undeveloped catchment areas of more than 1000 hectares that are not included in the territory of the settlement should be determined by the relevant runoff standards for calculating artificial road structures in accordance with VSN 63-76 of the Ministry of Transport Construction.

2.15. The estimated duration of rainwater flow along the surface and pipes, min, should be taken according to the formula

, (5)

where - the duration of the rainwater flow to the street tray or in the presence of storm water inlets within the block to the street collector (surface concentration time), min, determined in accordance with paragraph 2.16;

The same, on street trays to the storm water inlet (in the absence of them within the quarter), determined by the formula (6);

The same, for pipes to the calculated section, determined by the formula (7).

2.16. The time of the surface concentration of rainfall should be determined by calculation or taken in settlements in the absence of intra-quarter closed rain networks equal to 5-10 minutes or if they are equal to 3-5 minutes.

When calculating the intra-quarter sewer network, the surface concentration time should be taken equal to 2-3 minutes.

The duration of rainwater flow along street trays, min, should be determined by the formula

where - the length of the sections of the trays, m;

The duration of rainwater flow through the pipes to the calculated section, min, should be determined by the formula

where - the length of the calculated sections of the collector, m;

Estimated flow velocity in the area, m / s.

2.17. The average value of the drain coefficient should be determined as the weighted average value depending on the coefficients characterizing the surface and taken according to the table. 9 and 10.

Table 9

Surface	Coefficient
Roofing of buildings and structures, asphalt concrete pavement of roads	It is taken according to the table. 10
Cobblestone pavement and black gravel road pavement
Cobblestone Pavement
Crushed stone not treated with binders
Gravel garden paths
Ground surfaces (planned)

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