How to install external water supply networks? Section I. Availability of water supply facilities Design and location of external networks

External water supply networks are one of the main components of the water supply system, the sources of which are: 1) open natural and artificial reservoirs - rivers, reservoirs and lakes; 2) groundwater - springs, wells.

The location of water supply lines depends on the following factors taken into account during the design of engineering structures:

Terrain and obstacles: rivers, railway tracks, highways, etc.;

Green spaces;

Layout of a residential area;

Layout of objects to which networks are connected.

Types of external water supply networks

Branched

The complex of the main line and branches, which are dead-end sections, is considered a branched scheme of an external water supply network. Water along dead-end lines moves in only one direction. Being the shortest along the length of pipelines, dead-end sections are considered the least reliable in terms of uninterrupted supply of water to consumers.

The main disadvantage of an extensive water supply scheme: an accident in one of the network sections will deprive all consumers located behind the emergency section of water.

In large populated areas, a branched scheme is not used, since long interruptions in water supply are not allowed. In dacha settlements, an extensive water supply scheme can be designed, provided that consumers have backup tanks installed in case of lack of water.

Ring

A water supply network that does not have dead-end branches is called a ring network. The ring water supply scheme assumes that all sections are connected to each other and are closed to each other.

Combined

The complex of ring and dead-end sections is a combined water supply network. Ring and combined schemes of water supply networks are considered more reliable in operation, since turning off an emergency section does not affect the water supply to other consumers. In addition, in a ring water supply network, water constantly circulates through the pipes without stagnating.

Plumbing equipment for external water supply systems

• Pumping stations.
• Treatment plants.
• Shut-off and control valves.
• Control and measuring devices.
• Manholes and other equipment.

"Types of external water supply networks and equipment for water supply systems", BC "POISK", tell friends: May 21st, 2017

An external water supply network provides water supply to facilities in this area. Experts distinguish between centralized and local water supply networks.

During the installation of an external water supply system, the following requirements are met:

• preparation of the project and availability of permits to carry out these works;
• availability of appropriate permits from technical supervision;
• control over the implementation of hidden work;
• use of high-quality consumables.

In the process of arranging an external water supply system, it is necessary to carry out proper installation of the network. Damage to other communications that run in this area must not be allowed. Installation work is carried out taking into account SNiP and SES requirements.

Types of external water supply

Experts distinguish the following types of external water supply networks:

1. Centralized - provides water to a populated area.
2. Local - provides water supply to the building if there is no central system.

To equip a central water supply network, you will need:

• water intake - open reservoir;
• complex for liquid purification for subsequent delivery of drinking water to the consumer;
• a pump with the help of which liquid under pressure passes through a pipeline to the final consumer;
• shut-off valves.

Types of local water supply networks

Taking into account the type of system being installed and the method of its installation, delivery of drinking water in different containers is allowed. This water supply option is considered temporary, until the permanent water supply network is completed.

Since water lies at different depths, preparatory work will be required to “extract” it. To bring it to the surface and use it for personal purposes, experts recommend building a well or well.

If a well is used as a permanent water supply, you will need to dig, removing liquid from the surface layers of the soil. Such waters are distributed unevenly. They can flow along the contour of the earth's surface or lie at different depths.

The water supply method under consideration is inexpensive to install and operate. Its disadvantages include seasonal filling of the well, if during the digging process you get to the lower or upper section of the groundwater flow. On a flat area, the well will fill regardless of the season and weather conditions.

To simplify the process of operating a well, a submersible or surface electric pump is used. He lifts and delivers water to the house. In this case, you can collect water with a bucket.

To construct such a system, different pipes are used. The well itself is constructed as a monolithic structure equipped with a lid. You can make it from a log or special rings.

It is possible to equip an external water supply network by drilling wells of various capacities:

• at the dacha, the approximate liquid consumption is 2 cubic meters per hour;
• in a house with permanent residence, the approximate consumption is 3 cubic meters per hour.

Before drilling begins, you will need to obtain permission for the work being carried out. Groundwater is a strategic reserve of the country, which is protected by the legislation of the country. The received passport for the well contains technical information, including the diameter of the well. Upon completion of installation work, the water is sent to the laboratory for testing.

Consumables used

Cast iron, steel and other pipes are used for mains. For local networks - ceramic and plastic products.

More often, the external water supply system is equipped with plastic pipes, which have the following advantages:

• no corrosion;
• high resistance to aggressive environments;
• strength and ability to withstand high soil loads;
• rapid passage of water;
• low weight of pipes;
• easy pipeline installation;
• a wide range of.

If the external water supply network is installed using PVC, then a special tool is used to connect such pipes. Such connections are mounted in a socket or using specialized “cold welding” glue.

PVC products are rigid; to make bends and turns, tees and bends are used. PVC pipes withstand loads well during installation in the soil. Moreover, their price is acceptable for consumers.

If the external pipeline network is equipped with polypropylene consumables, then single- and multi-layer pipes with an aluminum layer are used. To connect polymer pipes, a fitting or welding machine is used. In the latter case, it is necessary to have proper experience working with the equipment. If it is not available, the help of a welder will be required. When performing welding work, it is imperative to take precautions by using a protective mask. It is better to carry out welding work in a “clean area”, without unauthorized persons.

If the system is constructed from low- and high-pressure polyethylene pipes, then a fitting and a welding machine are used to connect them. The consumable material can be used at low temperatures.

The system can be constructed from elastic polyethylene pipes, which are installed in coils. With their help, network rotations are easily performed. To carry out intersections of water supply networks, an angle of 90 degrees is maintained. If cast iron pipes are used, it is recommended to use a steel casing. The local sewer system is installed above the water supply unless a casing is used.

If the networks are laid parallel and at the same level, then the distance between the walls of the installed pipes must exceed 1.5 m. In this case, the diameter of the pipeline must be 200 mm. If the value of the indicator is above 200 mm, then the pipeline is installed at a distance above 3 m. The installation of a water supply system passing below the drainage point is carried out taking into account some deviations. It depends on the type of consumables used and the area.

Preparation for installation of a water supply network

Installation of an external water supply network is carried out according to a specific scheme. A draft of the future network is being drawn up in advance. The soil type and groundwater level are established. To find out the level of soil freezing, the help of a specialist is required. Then the water consumption and drainage per day is calculated. The value of this indicator will help determine the diameter of the pipes. Taking into account the data obtained, the necessary equipment is selected.

If necessary, the external system is insulated. If the highway must pass through a certain area that is not being dug up, a puncture is made in the soil. To perform it, different tools are used (drill, crowbar, shovel). If you need to make a puncture under the road, special equipment is used.

If the water supply intersects with the sewer, then metal sleeves are installed at the intersection point. Their length in sandy soil is 10 m, and in clayey terrain - 5 m. When crossing, the water supply network is mounted 40 cm above the sewer, and when installed in parallel, a distance of 1.5 m is maintained. The water supply is introduced into a residential building at a distance of 1. 5 m from sewerage and gas pipelines.

To install an external water supply system, you can dig a trench from the water source to the point of entry into the building. Land work is carried out taking into account a previously prepared project. In this case, a certain trench depth is maintained. The value of this indicator should be within 1.5-2.5 m. The trench is dug below the freezing level by 50 cm. A sand and gravel cushion is poured onto its flat bottom. After compacting it, pits are dug (in places where pipes are connected). It is recommended to carry out the above work using plastic pipes. Their diameter is calculated taking into account the length of the water pipe and the volume of liquid consumed. Experts recommend taking extra.

If the length is 10 m, then installation work is performed from 25 mm pipes. If the length is 30 m, then installation is carried out using pipes with a diameter of 32 mm. If the length exceeds 30 m, then pipes with a diameter of 38 mm are used. If necessary, the type of diameter is selected with the help of professionals. Consumables are purchased in reserve, since a certain length is used for connections.

Installation work

If the pipeline is laid, the crossed pipes will need to be connected. To glue polypropylene products together, electrofitting is used.

The connection method depends on the type of material used:

• welding;
• couplings;
• soldering.

The amount of the above consumables depends on the total length of the network and the frequency of connections. For soldering, special equipment is used, which functions like a soldering iron. Couplings are presented in the form of special connecting devices that come complete with consumables. Otherwise, the couplings can be purchased separately.

Regardless of the type of pipe used, the installation of the network begins from the source and ends at the point of entry into the room. If necessary, the system is equipped with shut-off valves. An inspection well is installed at the place where it is installed.

A drain valve is installed at the lowest point of the system, intended for emergency situations. If the installation work is completed, a hydraulic test of the network is carried out. To do this, it is filled with liquid without pressure for 2 hours. After the specified time, pressure is applied. The system is maintained in this state for about 30 minutes.

During this period, all connections must be checked. If the test is successful, the pipeline can be insulated. For this purpose, various thermal insulation materials are used. Mineral wool is most often used. If leaks are detected in the system, they are eliminated. To do this, it is recommended to turn off the emergency valve.

It is also used if various problems arise during the operation of the pipeline. If you cannot fix the problem yourself, you need the help of specialists.

Soft soil, sand and gravel are used to backfill the trench. Such materials will not damage the pipes. At the last stage, the dug trenches are completely backfilled.

Any water supply network is presented in the form of a complex of structures and elements that provide water to industrial and domestic facilities.

• pipes made of polypropylene, steel, LDPE;
• water intake tank;
• pump;
• inspection well with water shut-off valves;
• storage tanks and water purification system.

In the process of arranging external water supply networks, the established standards and requirements of SNiP are observed. External water supply is classified into the following types (according to purpose):

• household;
• fire protection;
• production;
• irrigation;
• negotiable.

According to the pipeline layout method, the network can be laid according to several schemes:

• dead-end - used to provide water to small objects;
• annular - designed for uninterrupted supply of liquid. A large number of consumables are used for its arrangement.

Experts distinguish the following methods of laying pipes:

1. Ground.
2. Underground.
3. Trench.
4. Trenchless.

System design

For successful and uninterrupted operation of the system, it is recommended to carry out the correct structural arrangement of the pipeline. More often, the system is equipped from factory pipes. There are certain requirements for the arrangement of water supply:

• strength to withstand external and internal loads;
• tightness;
• smooth surface of the internal walls, which reduces pressure loss due to friction;
• durability.

The consumables used must be quickly and easily assembled at the site where the system is installed. The water supply network must meet the requirements of increased efficiency. Pressure pipes are selected taking into account water resistance. To calculate the working pressure, the footage of the entire network and the diameter of the pipeline used are taken into account. Calculations can be carried out independently or by seeking help from specialists.

Taking into account the requirements for the installation of consumables, the pipes must have the required strength. This will allow them to withstand the pressure exerted by the soil, including deflection of their own weight. In this case, possible loads exerted by transport are taken into account. The tightness of pipes and joints is an important condition for the successful and economical operation of the network. If tightness is not observed, excess fluid consumption is observed, which contributes to an increase in the cost of operating the water supply network.

Water leakage from the system can result from soil erosion and a serious accident on the highway. To equip the system under consideration to serve any object, pipes are used, the choice of which depends on the following criteria:

• volume of liquid supplied;
• soil type;
• working internal pressure.

Therefore, different types of pipes can be used for water supply systems, taking into account the conditions of the area where construction work is being carried out. To improve the external water supply, steel, reinforced concrete and cast iron pipes are used. You can lay a pipeline from synthetic pipes. To make the right choice, it is first recommended that you familiarize yourself with the performance characteristics of all types of pipes.

Types of plumbing

Before installing outdoor water supply, it is recommended to decide on its type. Depending on the methods of transporting water to the final facility, the water supply network can be technical. In this case, water is used only for production. You can't drink it. To save money, technical networks are partially cleared. This allows the waste water resource to be reused.

The fire network is being set up for fire extinguishing. Such systems are equipped with special equipment and a hydrant. If it is necessary to save money when performing installation work, the fire system is combined with a technical, household or dead-end circuit. To carry out installation work, it is necessary to follow the principles of fire safety. Therefore, before laying the pipeline, it is necessary to obtain permission from the relevant authorities. Installation work is carried out independently or with the help of professionals.

To use water in everyday life, a household system is installed. Water supplied under this scheme is used for drinking. Before laying the pipeline, a plan for the initial purification of the liquid is developed. For this purpose, special stations or filters can be used.

Plumbing diagrams

A diagram is being prepared to lay the pipeline for the future water supply system. It indicates all network elements and the main technical characteristics of the pipeline. To transport water from the source to the desired object, water pipelines are used. They can consist of 2 or more pipelines, which are located parallel to each other.

To supply water to the point of consumption, an external water supply system is installed. Water supplied to specific water collection points inside the facility requires the installation of an internal water supply system. Taking into account the configuration, the external network is installed in a closed or branched type.

A ring network ensures a constant supply of liquid. But to set up such a system, a large amount of consumables will be required, including fittings and fittings.

A closed network is effective if you need to provide water to a small household. A dead-end system is installed at facilities where there are interruptions in water supply or frequent accidents occur.

The external water supply system consists of main and secondary lines. A separate pipeline is necessary for process water, which should not be mixed with drinking water. In this case, it is recommended to make 3 diagrams.

A drawing is prepared separately for the technical and drinking pipelines. Additionally, a general diagram of the system is made. If you are doing the drawing yourself, it is recommended to use graph paper. If you do not have the skills to draw up diagrams, it is recommended to consult with specialists.

Water from the water supply under pressure enters the internal network. For this purpose, a special input is provided in the soil, presented in the form of a pipeline branch from the external network to a water metering unit or shut-off valves installed inside the serviced facility.

Taking into account the location of the distribution line in relation to the water distribution points, a distinction is made between the upper and lower distribution of the water supply system. In the upper distribution the main line is located above the water collection points, and in the lower distribution - below. The external network has low pressure, while the internal network requires high pressure. For this, a pump and a special tank are installed.

A ring internal water supply network is being installed for technological purposes. If it has 10 or more points, then it is connected to an external system using two or more inputs. The use of a deadlock circuit is limited.

The external water supply network is laid in the soil. In areas with permanent permafrost, water supply is installed above ground. For this purpose, special supports are prepared that require subsequent thermal insulation. Mineral wool is used as insulation.

Installation features

Before laying a pipeline, the following criteria are taken into account:

• depth of soil freezing and pipe laying;
• liquid temperature;
• water supply mode.

If it is necessary to lay a main pipeline, then the depth of the pipes is calculated individually. This takes into account the mode in which the system will operate. Calculations can be carried out independently or with the help of specialists. In any case, the value of the main indicator depends on the external loads exerted on the soil and the climatic conditions of the area.

The pipeline line corresponds to the topography of the land plot. When arranging the system, the slope is taken into account, which must be observed on level ground. With the help of such a slope, it is possible to empty the network and release air masses at the maximum points of the water supply system. The last process takes place with the help of plungers.

If fittings and fittings with special connections are used to equip the system, then brick or ready-made wells are installed in the places where they are installed. Their parameters depend on the dimensions of the reinforcement used and the depth of the network. The well can have a rectangular or round shape. The well is closed above the ground with a special hatch. It can be bought or made from cast iron.

When installing the internal system, the open method is used. The pipeline is laid over building structures. This technical solution facilitates the installation process and operation of the entire system. The installation of any water supply network can be done independently or with the help of professionals.

For installation, use a level and other construction equipment. Upon completion of installation work, the system is checked for leaks. If leaks are detected, they are repaired as soon as possible. Only after repair work is it possible to restart the water supply system.

Water is one of the main elements necessary to support the life of humanity and all life on our planet. In parallel with the natural water cycle, artificial water supply systems designed and built by people actively participate in this process. Water supply systems can be internal or external.

Function of external water supply systems

External water supply networks are an important element of water supply systems, providing uninterrupted supply water for the population and enterprises. The supply of resources through these systems is usually made from natural sources. Used as The groundwater(groundwater, artesian and springs) and surface reservoirs (rivers, lakes, reservoirs).

Groundwater is usually fresh. Therefore, they are mainly used for consumer purposes. Surface waters can be either fresh or salty. Such resources are used for technical purposes: in enterprises, in agriculture, etc.

External water supply systems provide cold and hot water.

Types of water supply networks

External water supply systems are divided into two types according to their purpose:

1. Central water supply.
2. Individual water supply.

The central water supply system provides simultaneous water supply to a large number of consumers. Used in cities and towns. Pressure in such systems is generated when using water towers. For the uninterrupted supply of water (both cold and hot) in centralized systems, special utility services.

Individual water supply is designed for a small amount of consumers. May so provide for exclusively private use. In individual water supply, it is common to use storage tanks.

Depending on the design of the water supply system, there are:

1. Branched (dead-end).
2. Ring.
3. Combined (includes the first and second options at the same time).

Design and location of external networks

Designing an external water supply network is a very important and mandatory process without which it is impossible to practically carry out the upcoming construction work.

Three main design stages:

• technical task;
• design documentation;
• working documentation.

Technical specifications (TOR) are original document. It contains a list of all conditions for the organization of work that determine the number of design stages. The TOR defines work boundaries, list of equipment and materials taken into account in the composition of the subsequent project documentation.

Design documentation is developed by the design organization in sufficient quantities to passing the examination volume. Project documentation is being carried out in accordance with Decree No. 87 of the Government of the Russian Federation.

Working documentation is developed by the design organization in sufficient for construction volume.

When designing external water supply networks, it is worth considering the presence of other underground engineering networks. The location of the water supply system in relation to other possible utility networks should provide the possibility of free access to them, if necessary, repair work. In the event of damage to the water supply, it is important to exclude the possibility of undermining the foundations of nearby buildings.

On driveways, pipelines are laid strictly along the route, straight and parallel to the building line. All water supply crossings must be carried out at an angle of 90°. The permissible minimum distance between the water supply system and structures depends both on the characteristics of the water supply networks themselves (pipe diameter, operating pressure, etc.), and on the type of structure and foundation depth the buildings.

The main factors that influence the location of external water supply networks:

1. Features of the terrain.
2. Presence of obstacles (railway, river, etc.).
3. Facility layout.
4. Location and layout of residential areas, their sizes.
5. Presence of vegetation.

An equally important component of the project is detailing, that is network diagram. Symbols on it applied equipment, shaped parts, fittings. When compiling it, first of all, the location of pipeline fittings and hydrants is determined. Valves must be located in a manner that allows shut off the water supply to individual areas, without stopping its supply to facilities that require a continuous supply of water resources. Detailing is carried out schematically, without observing scales. If necessary, individual nodes are drawn separately on a larger scale.

SNiP requirements for external water supply networks

Construction norms and rules (SNiP) have a number of requirements, mandatory for the design and construction of external water supply networks. The main ones of these rules are listed below:

Due to the rapidly developing civilization and new technologies, It is possible that in the future new types of water supply networks and new technologies for their construction will appear. Accordingly, there will be a need to make certain amendments to building codes and regulations regarding plumbing systems. But only some numbers will be adjusted. And the main task is to provide humanity with industrial and drinking water in conditions complete safety,- will remain unchanged.

Rice. 1 . Water supply network diagrams:
A - dead end;
B - ring;
B - combined

Main lines designed for transporting transit water within a water supply facility.
Distribution lines laid at the necessary points when transporting water from mains to consumers. If the water supply network supplies one house, then the functions of the main and distribution lines are combined in one thread.

Schemes of water supply networks are dead-end, ring and combined (Fig. 1).

Dead-end circuit The grid consists of a main line and branches that branch off in the form of dead-end sections. In a dead-end network, water moves in one direction - to the end of the branch. The dead-end circuit is the shortest in length, but less reliable regarding uninterrupted water supply.

During an accident on one section of the highway, all sections located behind it will not be provided with water supply.

Ring circuit has no dead-end sections and all its branches are interconnected and closed.

Combined scheme consists of looped and dead-end lines.

Ring and combined schemes of water supply networks are more reliable in operation. In a looped network, water does not stagnate, but constantly circulates. Emergency areas are turned off without stopping the water supply to other consumers.

The route of water supply networks is linked to the vertical and horizontal layout of the area and taking into account other underground utility networks. Water supply networks on driveways, as a rule, are laid straight and parallel to the building line, strictly along the route.

Pipeline intersections must be performed at right angles to each other and to the axis of the passages. The placement of water supply lines in relation to other underground communications should ensure the possibility of installing networks and prevent undermining of foundations in the event of damage to the water supply system.

The distance in plan from water supply networks to parallel buildings and structures must be determined depending on the design of the building foundations, their depth, the diameter and characteristics of the networks, the water pressure in them, etc.

The external water supply network is one of the main parts of every water supply system. The cost of the water supply network in populated areas is about 50-70% of the cost of the entire water supply system, so great attention should be paid to its routing, design and construction.

Soviet scientists A. A. Surin, N. N. Geniev, L. F. Moshnin, V. P. Sirotkin, M. M. Andriyashev, V. G. Lobachev, N. N. Abramov, M. V. Kirsanov, F.A. Shevelev and others did a lot of work to develop the theory of calculation, create methods and techniques for calculating water supply networks, improve their performance and reduce costs.

Thanks to the high development of calculation theory, conditions have been created for the effective use of the opportunities provided by modern computer technology. Currently, electronic digital computers (EDCs) are used to calculate multi-ring networks.

Water supply networks are divided into main lines and distribution lines.

Main lines serve to transport transit masses of water; distribution lines - for transporting water from mains to individual buildings in which consumers receive water directly from external distribution lines.

Main and distribution lines must have sufficient capacity and provide the necessary water pressure at points of consumption.

The required throughput and pressures are ensured by the correct selection of pipe diameters during design.

The reliability of water supply networks is ensured by the good quality of the material of pipes and fittings, as well as laying and installation.

The lowest cost of water supply networks is obtained when they are laid along the shortest routes from water sources to places of consumption.

According to their plan outline, water supply networks can be dead-end or circular.

A stub network, the diagram of which is shown in rice. 33,a, in short, circular ( rice. 33, b), but cannot guarantee uninterrupted

Rice. 33. Water supply network:

a - branched; b - ring; NS - pumping station; “The WB is a water supply tower, because at the time of liquidation of an accident in one section of the main line, all subsequent sections along with its branches will not be supplied with water.

Rice. 34. Location of pipelines on a large-width city highway

Ring networks are more reliable in operation, since in the event of an accident on one of the lines when it is turned off, consumers will be supplied with water through the other line.

Water supply networks that are fire protection must be ring-shaped. As an exception, dead-end lines of no more than 200 m in length are allowed when measures have been taken to prevent these lines from freezing.

The distance of water supply networks to buildings, structures, roads, and other networks should be determined depending on the designs of building foundations, type of roads, depth, diameter and nature of networks, pressure in them and the size of wells.

The approximate location of water pipes and other pipes on the street of a large city is shown in Fig. 34.

A water pipeline is a complex of engineering structures and equipment designed to collect water from natural sources and supply it to places of consumption, as well as, if necessary, purify and store it.

Typically, water pipelines consist of the following structures:

1) water intakes for collecting water from natural sources;

2) pumping stations for lifting water;

3) water treatment facilities;

4) water pipelines and water supply networks for supplying water to consumers;

5) water towers and pressure tanks to maintain pressures and regulate water flow;

6) water storage tanks.

The relative location of individual water supply structures when it is necessary to lift, store and purify water is shown in Fig. 1. Here is a general diagram of the city’s water supply from a surface source (river) with the construction of treatment facilities.

Using a water intake 1, water is taken from the river and through gravity pipes 2 enters the coastal well 3, and from it, with first lift pumps 4, it is supplied to settling tanks 5 and then to filters 6 for cleaning and disinfection.

From the treatment plant, purified water enters reserve clean water reservoirs 7, from which it is supplied by second lift pumps 8 through water conduits 9 to the pressure control structure 10 (above-ground or underground reservoir located on a natural elevation - a water tower or pneumatic installation), and also into the main pipes 11 of the city’s water supply network, through which water is transported to various areas of the city and through a network of distribution pipes 12 and house inlets 13 to individual consumers 14.

According to their purpose, water pipelines are divided into the following:

household and drinking - to meet the drinking and household needs of the population;

industrial - to supply industrial enterprises with water;

fire protection - supplying water to extinguish a fire;

combined - designed to simultaneously satisfy various needs, while in some cases, utility and drinking water supply systems can be combined with fire safety or industrial ones. These include economic fire safety, industrial fire safety and other systems.

Based on the method of water supply, pressure and gravity water pipelines are distinguished.

Pressure water pipelines are those in which water is supplied from the source to the consumer by pumps; gravity - in which water from a high-lying source flows to the consumer by gravity. Such water pipelines are sometimes installed in mountainous regions of the country.

Depending on the quality of the water at the source and the requirements for water by consumers, water pipelines are built with or without facilities for water purification and treatment. The first include household and drinking water pipelines that receive water from surface sources - rivers, lakes, and reservoirs. Water supply systems without treatment facilities include drinking water supply systems fed with water from artesian wells. For the technological needs of industrial enterprises, water from surface sources is often suitable without purification.

Depending on the method of water use by industrial enterprises, industrial water supply systems are arranged as direct-flow, circulating, or with sequential use of water.

In the case of direct-flow water supply, water used in production is discharged into the reservoir without treatment, if it is not contaminated, or after treatment if it is contaminated (from gas cleaning, rolling mills, iron casting, etc.).

With recycling water supply, water heated in production is not discharged into a reservoir, but is supplied again to production after cooling it in ponds, cooling towers or spray pools. To replenish water losses (in cooling structures, leaks, etc.), fresh water from the source is added to the recycling cycle.

A diagram with rotary use of water is shown in Fig. 2.6. By pumps 1, water after cooling in structure 2 is supplied through pipes 3 to production units 4. Heated water enters pipelines 5 (it is shown as a dotted line in the drawing) and is discharged to cooling structures 2 (cooling towers, spray pools, cooling ponds). The addition of fresh water from the source through the water intake 6 is carried out by pumps 7 through water lines 8.

Recycling (re-) water supply is usually arranged when the flow rate of a natural source is limited; however, even with a sufficient flow rate, it can be more economical than direct-flow water supply.

Water pipelines with sequential use of water are used if it is possible to use it after one consumer by others. It is recommended to use such water pipelines as widely as possible.

Water pipelines are divided into external and internal. External water supply includes all structures for collecting, purifying water and distributing it through the water supply network. Internal water pipelines take water from the external network and supply it to consumers in buildings.

Rice. 1 Scheme of the city water supply; a - plan; b - section

If there is a source of water that meets the quality requirements of consumers, there is no need to build treatment facilities. Sometimes a second lift pumping station is also not required. In these cases, water from the source is supplied by submersible pumps directly through water pipelines and main networks, and through them to consumers. An example of such water supply is water intake from artesian wells ( rice. 2,A).

Rice. 2 a. General diagram of an artesian water supply: 1 - well; 2 - water supply network; 3 - tanks; 4 - pumping station P lift; ZSO - sanitary protection zone

Rice. 2 b. Plumbing scheme with water reuse

Pressure control structures are designed to accumulate excess water supplied by pumps, which is formed when the water supply by pumps exceeds its withdrawal from the network, as well as to store a supply of water for fire extinguishing and to supply water to the water supply network in cases where water withdrawal consumers exceeds its supply by pumps. In addition to rice. 2 and there are two nodes of structures. In water pipelines with relatively uniform water consumption, there may not be pressure control structures. In this case, water is supplied by pumps directly into the pipes of the distribution network, and to store the fire-fighting water supply, reservoirs are installed, from which water is drawn by pumps to extinguish the fire.

§ 4. Determination of the estimated water flow- (All images)

The estimated water flow rate is its maximum flow rate, obtained by multiplying the average flow rate by the unevenness coefficient.

The estimated water consumption for populated areas is determined using the following formulas:

Here q is the rate of water consumption in l per person per day (see Table 1); N - estimated population; Ksut - coefficient of daily uneven water consumption; Ksut is the general coefficient of uneven water consumption, equal to

The estimated consumption of domestic and drinking water in industrial and auxiliary buildings is determined using the following formulas.

Daily water consumption

where q"n is the rate of water consumption per person per shift (see Table 2); Ni is the number of workers per day (separately in cold and hot shops). Water consumption per shift is

where N2 is the number of workers per shift.

Maximum second water consumption in liters for a given shift

where Khour is the coefficient of hourly unevenness of water consumption (see Table 2); T is the duration of the shift in hours. The estimated consumption for using a shower in the domestic premises of industrial enterprises is determined using formulas (7), (8) and (9).

Daily water consumption for showering is

where 9d is the rate of water consumption per procedure (separately by production); N3 - number of shower users per day (separately by

productions). Shower water consumption per shift is equal to

where Nt is the number of shower users per shift.

Secondary water consumption (per capita sec in a given shift

since the duration of showers after shifts should be no more than 45 minutes.

The estimated water consumption for irrigation of an area with an irrigated area F ha is determined by the formula

where q floor is the watering rate l/day per 1 m2. The second water consumption for irrigation is equal to

The annual average daily amount of water Qcp.mx for irrigation can be approximately determined by the formula

(12)

where Tpol is the number of days per year in which irrigation is carried out, determined taking into account climatic and other local conditions. Water consumption in canteens of industrial enterprises is taken into account especially. The daily water consumption in canteens is

(13)

where dst - the rate of water consumption in the dining room per diner is taken from 18 to 25 liters with a coefficient of hourly unevenness of water consumption of 1.5.

The maximum second water consumption in canteens is

where T„ is the number of opening hours of canteens.

Water consumption for production needs, both daily and per second, is taken according to data from technologists for each production unit or group of units.

Water consumption for humidification, dust removal and air conditioning is taken according to the ventilation projects of industrial buildings.

The water consumption regime depends on the size of the settlement, climatic and other conditions. Fluctuations in hourly water consumption are usually depicted in the form of tables or graphs, which are compiled based on monitoring the water consumption regime on existing water pipelines.

Rice. 3. Schedule of daily water consumption in the city

In Fig. Figure 3 shows, as an example, a graph of fluctuations in water consumption in the city during the day. Here, the hours of the day are plotted on the abscissa axis, and the hourly water consumption, expressed as a percentage of its daily consumption, is plotted on the ordinate axis.

Fluctuations in water consumption for production needs in each individual case are set by technologists based on a study of the technological process of a given production.

The supply of water by a pump operating 24 hours a day, i.e., supplying 4.17% of the daily flow rate every hour, is indicated on the graph by a dotted line.

It follows that excess water supplied by pumps during hours of lower flow from the network accumulates in the tank of the water tower. This accumulation can also occur in an underground tank or in a pneumatic installation tank.

The regulating water supply is intended to cover the difference between the withdrawal of water from the network and its supply by the pump during hours of maximum flow. The volume of the control reserve during single-stage operation of pumps in populated areas with a population of up to 200 thousand is 10-15% of the daily flow; during two-stage operation of pumps it can be reduced to 1.5-3%.

The reservoirs of water supply systems must contain an emergency supply of water for fire-fighting needs.

Fluctuations in water consumption for household and drinking needs and during the day with maximum water consumption are shown in Table. 5.

Maximum hourly water consumption for household and drinking needs in table. 5 corresponds to the specified hourly unevenness coefficient Khour = 1.25.

The schedule of water consumption for irrigation is drawn up taking into account the morning, general cleaning of the streets; In addition, it is required that irrigation does not coincide with the highest water consumption for household and drinking needs.

We assume that emergency reserves for extinguishing a fire of 500 m3 should be stored in reserve tanks. After a fire, it must be replenished within 24 n. Therefore, water consumption when replenishing the fire water supply increases to 3910 + 500 = 4410 m3/day.

The water supply system must be designed to supply this amount of water.

§ 5. Pressures in the water supply network

The so-called free pressure must be created at all points of the water supply network. Under this pressure, water is supplied to buildings to consumers.

The pressure in the water supply network is created by pumps, a water tower, a pneumatic installation or a pressure tank. The design pressure is the pressure at the point in the network that is farthest from the pumps and the highest located.

Free pressures in the drinking water supply network of a populated area, depending on the number of storeys of buildings, must be taken to be no less than the following values: for one-story buildings - 10 liters above the ground; with a two-story building - 12 m; with a three-story building - 16 m.

In industrial water supply systems, minimum free pressures are created according to the requirements of the technological design.

The required pressure in the fire-fighting water supply depends on the extinguishing method adopted. If a fire is extinguished with jets of water created directly by the pressure in the water supply system, i.e., obtained from fire hydrants, then such a water supply system is called a high-pressure extinguishing system.

The pressure for extinguishing a fire in high-pressure water pipes is created only for the duration of the fire by special pumps installed at the pumping station and put into operation upon receipt of a fire signal no later than 5 minutes after its receipt.

Table 5 Example of water consumption in the city for drinking and irrigation purposes

		Water consumption
	household and drinking	watering	general
Hours of the day	in % of max.
	per day	m"/h	m3/h	m"/h
0-1	3,35		_
1-2	3,25		-
2-3	3,30
3-4	3,20	BY
4-5	3,25
5-6	3,40
6-7	3,85
7-8	4,45
8-9	5,20		-
9-10	5,05		-
10-11	4,85		-
11-12	4,60
12-13	4,60
13-14	4,55
14-15	4,75		-
15-16	4,70		-
16-17	4,65		-
17-18	4,35
18-19	4,40
19-20	4,30
20-21	4,30
21-22	4,20		-
22-23	3,75		-
23-24	3,70		-
Total...	100,00

Fire-fighting high-pressure water supply systems are installed only at those industrial enterprises where this is justified by technical and economic calculations.

If a fire is extinguished with jets that are created by fire pumps (motor pumps), brought to the place of the fire and receiving (sucking) water from the water supply through hydrants, then such a water supply is called a low-pressure fire-fighting water supply.

In high-pressure fire-fighting water supply systems, the free pressure must ensure that a compact (unfragmented) jet of at least 10 m is obtained at full fire water flow and when the nozzle is located at the level of the highest point of the tallest building.

where Npozh is the free pressure in the water supply (at the hydrant);

Neck - the height of the building to the highest point (usually to the ridge of the roof), counting from the surface of the earth; h is the sum of pressure losses in the hydrant, in fire hoses and in the trunk.