Systems and schemes of water supply for buildings. Installation of a cold water supply system Design of an internal water supply system

Do you know how cold water supply is organized in an apartment building? Today we have to get acquainted with the main elements of the water supply system, study its typical problems and try to find their solutions. Let's go!

Water supply standards

As always, we will start by getting acquainted with the regulatory documentation. Water supply standards (including cold water) are established by the set of rules SP 30.13330.2012.

Here are the key requirements of this document:

• Water pressure on plumbing fixtures should not exceed 4.5 kgf/cm2;

However: if a building is being erected in a microdistrict with an existing multi-storey building and is powered from a common water supply with the surrounding houses, the pressure can be increased to 6 atmospheres.

• The minimum water pressure must ensure the functionality of household and sanitary appliances;

Help: most washing machines, dishwashers and water heaters operate at a pressure of 0.3 atmospheres or higher.

• The composition and quality of water must comply with SanPiN 2.1.4.1074-01 standards;

• The pipes used for installing water supply systems must last at least half a century;
• During operation of the water supply system, its hydraulic resistance must remain unchanged.

It’s curious: this clause of the joint venture actually prohibits the use of non-galvanized steel pipes, which are used to install most of the water supply systems in Soviet-built buildings. However, most of these buildings, along with standard water supply systems, continue to be used at the present time.

How everything works

So, how does a building’s cold water supply system work?

Enter

It connects the internal water supply network with the main water supply and is laid below the freezing level of the soil. Where this is problematic (for example, on rocky soils or in permafrost zones), the inlet is equipped with cable heating, which prevents water from freezing in the absence of water intake.

As a rule, the drainage of water from the main water supply to a separate apartment building or a small group of houses is equipped with shut-off valves installed in the well and allowing the water supply system of the building to be completely drained during repair work. In addition to valves or ball valves, vents for draining water and control valves for measuring pressure are installed in the well.

In Soviet-built apartment buildings, water and gas pipes manufactured in accordance with GOST 3262-75 were used for inlet installation. Currently, they are almost completely replaced by more durable polyethylene pressure pipes GOST 18599-2001, resistant to low temperatures and soil movements.

Water metering unit

Its function is fully described by its name: the water meter is responsible for recording the water flow in the building.

The node includes:

• The actual metering device is a vane or turbine water meter;
• A sump filter or strainer installed in front of the meter;

• Shut-off valves before and after the meter;
• Pressure gauge or control valve for measuring pressure;
• Optionally - a bypass line with shut-off valves installed on it (gate valve, valve or ball valve).

A caveat: if a building has two or more cold water inlets from different water supply sources, each water meter is additionally equipped with a check valve, which prevents the flow of water between the inlets due to pressure differences.

After installing the meter, its connection to the pipeline and the fittings on the bypass line are sealed by representatives of the water supply organization. The seals are removed when the meter is dismantled for repairs or regular verification. If there is no bypass, a pipe of appropriate size is installed instead of the meter.

The thread diameter of the meter (and, accordingly, the entire water meter unit) is determined by the average daily water flow.

The notorious SP 30.13330.2012 establishes the following standard values ​​for the diameter of metering devices:

Daily consumption, cubic meters	Meter connection size, inches
Less than 10	1/2
9-25	3/4
24-35	1
34-50	1 1/4
49-78	1 1/2
77-150	2
148-410	2 1/2
400-680	3
650-900	4

A nuance: when water consumption is 49-150 cubic meters per day, vane and turbine meters can be used. At lower flow rates, only vane devices are used, at higher flow rates, only turbine devices are used.

Paging

There is much more reinforcement in new buildings:

• Ball valves (by the way, much more fail-safe compared to screw valves) are often located not only at the inlet, but also in front of all water collection points (including water heaters and household appliances);

• After the taps at the inlet, mesh filters are usually installed to retain sand and other large suspended matter;

Please note: the presence of filters is mandatory if you have faucets with ceramic water fittings (cartridge or faucets). Trying to close a tap jammed by a grain of sand usually leads to chipping of the ceramic plates.

• The entry of cold water into the apartment is equipped with an individual metering device. The diameter of the water meter in the apartment is 15 mm. The priority is the installation of devices with a GSM module that independently transmit readings to the server of the management company;

• If there are two water supply inputs (cold and hot), each of them is additionally equipped with a check valve, making it impossible to unwind the meter due to the pressure difference between the water supply lines;
• On the lower floors of multi-storey buildings, pressure reducers are often installed, reducing its level to the standard values ​​stipulated by SP 30.13330.2012;

Reference: 1 kgf/cm2 of excess water pressure raises the water column to a height of 10 meters. To ensure a minimum pressure of 3 meters on the 15th floor (with an average height of one floor of the same three meters), at the level of the lower water intake points the pressure must be at least 4.8 kgf/cm2, which exceeds the norms established by the notorious set of rules.

• Pressure gauges are usually installed before and after the reducer for visual monitoring of pressure.

Often, instead of a tee water distribution system, a collector system is used: all water collection points or part of them are equipped with their own connections and connected to a common comb collector. Manifold wiring allows you to avoid loss of pressure on all faucets when using one of them: if you open the cold water tap in the kitchen all the way, you won’t hear the battle cry of your wife scalded by boiling water coming from the shower.

Problems and solutions

Alas, often the cold water supply to buildings does not function as well as home owners would like. Fortunately, some problems are easy to solve on your own.

Weak pressure

Problem number one is insufficient water pressure.

Possible reasons:

• Mixer aerator clogged. In this case, you observe equally weak pressure of cold and hot water at one water intake point;

• Clogged cold water line. It can be caused by large debris stuck at a pipeline bend or in front of fittings (including in the mixer body), or by the accumulation of deposits on the walls of a steel pipe;
• Clogged mechanical filter at the inlet;
• The valve or tap on the inlet or riser is not fully open;
• Deposits in the riser or bottling;

• Low pressure in the main water supply.

Hint: in the last two scenarios, the management company or higher-level organizations should deal with the problem of low pressure. The function of residents is reduced only to submitting an application to the maintenance service.

Solutions:

• Unscrew the aerator and rinse it under running water. If the aerator is equipped with several stainless mesh, remove most of them, leaving one or two;

• Try plugging the faucet spout with your finger and opening the cold and hot water taps at the same time. As a rule, the pressure of the hot water supply is higher, and the reverse flow of water often eliminates the blockage of the supply line;
• Turn off the tap on the supply line, open the mixer and try to clear the blockage in the supply line with a cable or elastic steel wire;
• If the water is blocked, open the filter and clean its mesh from sand and other debris;

• Open the taps on the inlet and riser all the way.

Valve leak

Another typical problem is a screw valve or ball valve leaking along the stem. It usually occurs after it closes.

In most cases, to stop the valve from leaking, it is enough to open it all the way with a little force. At the same time, the thread of the rod presses the stuffing box.

If this does not help, you need to fill the oil seal.

Here are step-by-step instructions for performing this generally simple job:

1. Close the valve;
2. Remove the lamb from it;
3. Unscrew the gland nut with an open-end, adjustable or pipe wrench;
4. Pry the seal with a screwdriver and remove it from the valve stem;
5. Place several turns of a graphite or oil seal around the rod, sealing each turn with a screwdriver;
6. Reassemble the valve in reverse order and open it, checking the stem for leaks.

Ball valve stems are usually sealed with a fluoroplastic or Teflon washer. To stop the leak, just tighten the oil seal nut 1-2 turns.

Fistula of the riser or eyeliner

Through fistulas occur, as a rule, on welds (transverse or longitudinal - all water and gas pipes are made by welding a flat piece).

To eliminate a leak, the easiest way is to use a bandage made of an aluminum clamp and a piece of rubber (for example, a gasket for a valve housing).

1. The section of the pipe near the fistula is cleaned with a file or knife to remove rust and paint;
2. A clamp corresponding to its diameter is put on the pipe;
3. A rubber gasket is inserted under it;
4. The clamp is tightened, pressing the gasket to the leak.

By the way: instead of a clamp, you can use annealed steel or copper wire. In this case, the bandage is tightened with pliers.

Conclusion

We hope that we were able to satisfy the curiosity of our dear reader. You can learn more about how the cold water supply to an apartment is organized in the video in this article. Good luck!

In order for any residential building to function normally, it is necessary to install a water supply system. Its proper design will ensure timely supply and sufficient water pressure. This article will discuss in detail the hot water supply scheme, types of connection and its features in an apartment building.

Water supply and sanitation scheme - Photo 01

What is special about the water supply of an apartment building?

It is very difficult to provide water to a building with a large number of storeys. After all, the house consists of many apartments with separate bathrooms and plumbing fixtures. In other words, water supply schemes in apartment buildings are a kind of complex with separate pipe distribution, pressure regulators, filters and metering equipment.

Most often, residents of high-rise buildings use water from the central water supply. With the help of a water supply, it is supplied to individual plumbing fixtures under a certain pressure. Often water is purified using chlorination.

Composition of the central water supply system

Centralized water supply schemes in multi-storey buildings consist of a distribution network, water intake structures and treatment plants. Before entering the apartment, water travels a long way from the pumping station to the reservoir. Only after purification and disinfection is water sent to the distribution network. With the help of the latter, water is supplied to appliances and equipment. Pipes for the central hot water supply circuit of a multi-storey building can be made of copper, metal-plastic and steel.

Schematic diagram of a centralized water supply system - Photo 02

The latter type of material is practically not used in modern buildings.

Types of water supply schemes

There are three types of water supply system:

• collector;
• sequential;
• combined (mixed).

Recently, when a large amount of plumbing equipment is increasingly found in apartments, a manifold wiring diagram is used. It is the best option for the normal functioning of all devices. The collector-type hot water supply scheme eliminates pressure drops at different connection points. This is the main advantage of this system.

Collector pipe distribution diagram - Photo 03

If we consider the diagram in more detail, we can conclude that there will be no problems with using the plumbing equipment for its intended purpose at the same time. The essence of the connection is that each individual water consumer is connected to the cold and hot water supply riser collectors separately. The pipes do not have many branches, so the likelihood of leakage is very low. Such water supply schemes in multi-storey buildings are easy to maintain, but the cost of the equipment is quite high.

According to experts, the collector hot water supply system requires the installation of a more complex installation of plumbing fixtures. However, these negative aspects are not so critical, especially considering the fact that the collector circuit has many advantages, for example, hidden installation of pipes and taking into account the individual characteristics of the equipment.

Sequential layout of water supply pipes in an apartment - Photo 04

A sequential hot water supply circuit for a multi-storey building is the simplest wiring method. This system is time-tested; it was put into operation during the Soviet era. The essence of its device is that the cold and hot water supply pipelines are parallel to each other. Engineers advise using this system in apartments with one bathroom and a small amount of plumbing equipment.

Popularly, such a hot water supply scheme for a multi-storey building is called a tee scheme. That is, from the main highways there are branches that are connected to each other by tees. Despite the ease of installation and saving on consumables, this scheme has several main disadvantages:

1. In the event of a leak, it is difficult to look for damaged areas.
2. Inability to supply water to a separate plumbing fixture.
3. Difficulty in accessing pipes in case of breakdown.

Hot water supply for an apartment building. Scheme

Pipe connections are divided into two types: to the hot and cold water supply riser. Briefly they are called cold water and hot water. The hot water supply system of an apartment building deserves special attention. The DHW network diagram consists of two types of wiring - lower and upper. To maintain high temperatures in the pipeline, looped wiring is often used. The gravitational pressure forces the water to circulate in the ring, despite the absence of water intake. In the riser it cools and enters the heater. Water with a higher temperature is supplied to the pipes. This is how continuous circulation of the coolant occurs.

Home hot water supply - Photo 05

Dead-end highways are also not uncommon, but most often they can be found in utility rooms of industrial facilities and in small residential buildings with low storeys. If water selection is planned intermittently, then a circulation pipeline is used. Engineers advise using hot water supply in apartment buildings (the diagram was discussed above) with a number of floors of no more than 4. A pipeline with a dead-end riser is also found in dormitories, sanatoriums and hotels. Dead-end network pipes have a lower metal consumption and therefore cool faster.

DHW networks include a horizontal main pipeline and distribution risers. The latter provide pipe distribution to individual objects - apartments. DHW is installed as close as possible to plumbing equipment.

For buildings with a large length of main pipes, schemes with circulation and looped supply pipelines are used. A prerequisite is the installation of a pump to maintain circulation and constant water exchange.

Single-pipe DHW circuit - Photo 06

Two-pipe DHW circuit - Photo 07

Modern builders and engineers are increasingly resorting to the use of two-pipe hot water systems. The principle of operation is that the pump takes water from the return line and supplies it to the heater. This pipeline has a higher metal consumption and is considered the most reliable for consumers.

The main problem when organizing an autonomous water supply for a country house is to find a source of cold water, preferably with a stable flow rate that does not depend on the time of year. The best option for organizing cold water supply is a well.

The quality and quantity of water flowing into the kitchen and bathroom taps is mainly influenced by the following factors: the type of well, at what depth the aquifer is located, the type and power of the well pump, and the water treatment filter system.

Internal cold water supply

It is recommended to distribute water - cold and hot - inside the house with solid polypropylene (PP) pipes. This is especially convenient if the house is wooden, or you don’t want to drill into the walls to organize hidden wiring in a stone house. Boards and logs are not designed for channeling and drilling large holes without reducing the strength of walls and floors. Even if a hot pipe is laid in such a wall without thermal insulation, the wood will warp. PP pipes allow for accurate internal wiring with external installation. The advantage of this solution is simple installation and maintenance of pipes, quick detection of leaks.

If you decide to completely hide the hot and cold water supply system in a brick house, then durable and flexible pipes made of cross-linked polyethylene PEX are at your service. The flexibility of these pipes can help implement the most complex design solutions. They withstand high operating temperatures and pressures and are resistant to thermal expansion. Additionally, we will say that flexible pipes have the necessary reliability and can be placed in a concrete screed to create a heated floor.

Internal wiring diagram

For cold water, the pipe layout is also critical, as is the case with hot water or a water heating system, when it is necessary to deliver coolant with the same temperature to the furthest radiators in the house. Only in the case of cold water, the wiring diagram should provide a constant pressure. Therefore, in order to ensure high-quality cold water supply, when the water pressure in the kitchen tap does not drop when you turn on the shower in the bathroom, and remains sufficient at the farthest point of the water supply, use the most effective wiring methods - tee or manifold. Both schemes are designed in such a way that they provide the required water pressure for all water points. This happens because the points are not connected in series, but in parallel.

Water supply pipe layout diagrams

This advantage is especially pronounced in the collector wiring - all consumers are absolutely independent of each other, since each has a separate connection to the water distribution riser. In this case, turning on the shower in the bathroom will not affect the water pressure in the kitchen tap. Moreover, you can adjust the pressure in each tap independently of the others. The only drawback of the collector wiring is the high consumption of materials, since you have to pull a separate pipe to each point. But it is precisely thanks to the use of a large number of pipes that the collector circuit is very reliable and has high maintainability. In case of problems, you can turn off one or more branches with water collection points and repair them, while the rest will continue to work.

As additional variations to the already described pipe laying schemes, you can add upper and lower wiring. The difference is that in the first case, water comes to the water collection point from above - from the ceiling or from the wall, in the second - from below, from the baseboard. The choice of two options depends on the number of floors of the house and the method of supplying the bulk of water to the house - through a riser, through a storage tank on the top floor or in the basement, etc.

It must be said that cold and hot water supplies are distributed throughout the house together, therefore the advantages of tee and collector circuits maintain not only the level of water pressure in the taps, but also the temperature of the hot water supply.

Important! The wiring throughout the house should allow easy and quick inspection of the pipeline for leaks, etc. Fittings should not be made inaccessible by hiding them under screed or decorative trim. Solid plastic pipes should be 1.0-1.5 cm away from the wall. For steel pipes, the distance increases to 1.5-2.0 cm, since welding is expected to be used during repair work. For any installation, there must be a drain valve at the lowest point of the water supply system.

How much water does a cottage need?

In the city, water consumption per person is approximately 200 liters. If you are going to provide completely “urban” comfort in a country cottage, then we will not reduce this figure. A family of 4-5 people spends at least 1 ton of water per day. But purely country water consumption - watering, car washing, etc. - is not taken into account here. Obviously, only an artesian well can provide the required amount of water for a large family. The optimal solution for organizing high-quality cold (and hot) water supply to a dacha or cottage would be a well on limestone, the diameter of the casing pipe is 133 mm, the flow rate is 3 m cubic / h - this is 5-6 simultaneously open taps, from which water is poured out under a pressure of 5 atmospheres, 30 l per minute. Such a well will even cope with the additional needs of several unexpected guests!

Internal water supply consists of the following elements: water supply entry into the building, distribution pipeline networks, booster installations, which include booster pumps, water tanks and reservoirs located inside the building. Depending on the scheme of water supply to water points inside the building, the following internal water supply systems (Fig. 8) are arranged: without booster pumps, in this case, the water supply is ensured by pressure in the external water supply network and with a booster pump (hydraulic accumulator tank), in the case autonomous water supply.

Rice. 8. Example of internal water supply diagrams

Cold water supply systems without booster pumps are used in cases where the water supply network is under constant pressure sufficient for an uninterrupted supply of water to the highest and most remote water supply point of the building. This internal water supply system, which does not have any devices other than a pipeline network, is the simplest and most common. The installation of booster pumps in country houses connected to a village (rural or urban) main must be agreed upon with the local water utility service. Otherwise, with your immoderate ambitions, you can leave all your neighbors without water.

The connection diagram of plumbing fixtures to water risers can be made using traditional tee wiring or using manifolds. The use of collectors (parallel wiring), in contrast to the tee circuit, equalizes the water pressure within the riser. The pressure and temperature of the water, for example, in the shower will not change if the water in the washbasin is turned on nearby. In a tee cold water supply system, the inclusion of sequentially located devices, as a rule, leads to a loss of pressure in the water fittings. For example, if the shower has a tap that mixes hot and cold water, then turning on a tap with cold water next to it leads to a loss of pressure in the cold line and, as a result, an increase in the temperature of the water in the shower mixer. In a collector system, nothing like this happens; all water taps are connected in parallel to the collector, and turning on water in one tap does not in any way affect the pressure in another tap. However, this statement is only true for cold water supply systems with normal operating pressure. If the pressure in the water supply network is below normal, creating a more expensive collector system does not have a positive effect: when you turn on the water supply at two points simultaneously, the water pressure will drop, as with a tee (sequential) wiring, although not as noticeably.

One solution to compensate for pressure loss in tee wiring can be a ring connection of consumers. Water is supplied to each water distribution point from both sides at once (Fig. 9). Due to this, the water pressure is equalized.

Rice. 9. Ring connection of water consumers

A well-designed water supply system with correctly selected pipe diameters and the power of the suction pump can be made using both a tee and a manifold scheme. There will of course be a pressure drop in a series tee circuit, but it will not be very noticeable. An example of this is houses built in Soviet times, in which only tee wiring was used. With normal water pressure in the pipeline, residents located at the end of the pipeline do not feel deprived of water in the same way as residents “sitting” at its beginning. However, when the pressure in the network drops, end consumers are the first to experience a water shortage.

A cold water supply system with tee wiring is the simplest and cheapest piping scheme. With this scheme, most often, open laying and any methods of connecting pipes are used (Fig. 10).

Rice. 10. Connection diagrams for water fittings (plumbing fixtures)

The cold water supply collector system uses a large number of pipes; their open installation will be, to put it mildly, unaesthetic. Therefore, the “pipe-in-pipe” scheme and/or laying pipelines in the wall, niches or floor screed is used. In any case, all pipe connections to the manifold remain accessible, since they are connected to it in the distribution cabinet. The other end of the pipes is connected to the water fittings and can be laid openly or hidden in the wall. When the connection to plumbing fixtures is open, you can use any pipe connection; when it is closed, crimp and push-in fittings, soldering, welding and gluing pipes are used.

Pipes laid according to the “pipe-in-pipe” principle (in a protective casing) can be replaced, in some cases without damaging the tiles, wall or floor. To do this, dismantle the connection on the plumbing fixture and the manifold. Using a coupling fitting, connect the damaged pipe to the new one and, while simultaneously pulling out one, drag the second into the protective pipe. Then the new pipe is cut and the ends are connected to the plumbing fixture and manifold. True, such a replacement is only possible for metal-plastic pipes, and only if the pipes are laid with a small number of turns and a large bend radius. It is clear that you cannot fit a polypropylene, copper or thin-walled steel pipe into a protective casing. Although they also need to be mounted in insulated protective casings.

Collectors (Fig. 11) come with two, three or four terminals; they can be connected in series (end to end) to each other. However, it is not recommended to connect more than 10 consumers to one collector.

Rice. 11. Location of collectors for cold and hot water supply in the cabinet

The manifold circuit for connecting to plumbing fixtures is more convenient to maintain when laying hidden pipelines, since all shut-off valves are located in one place - the manifold cabinet. By placing the cabinet in a place convenient for you, you can safely turn off the malfunctioning device and repair it, while the other water fittings will work as before. In addition, automatic water pressure regulators can be installed on any “nipple” of the collector and the pressure on each plumbing fixture can be individually adjusted, which is impossible or difficult to achieve with a tee circuit.

In an individual country house, a mixed water supply layout can also be used. For example, a main pipeline runs through the basement (which, by the way, plumbers also call a collector), risers rise from it, and on the floors, collectors are connected to the risers, from which plumbing fixtures are powered. Thus, a tee circuit is used in the lower distribution and along the risers, and a collector circuit is used on the floors. And the collector circuit in its pure form looks like installing one for the whole house or several, according to the number of floors, collectors directly in the basement, and from them power is supplied to the devices. Or one common collector in the basement and floor collectors connected to it by pipes.

The water supply of apartment buildings is a complex system consisting of a huge number of structures, equipment and engineering installations necessary for the extraction, storage and purification of water, as well as its delivery to consumers. The cold water supply system (CWS) in most cases is designed at the same time as the sewer system. Cold water supply must meet certain technical and economic conditions, as well as sanitary standards.

The main structural elements in the water supply system to residential apartment buildings are: water pipes, water supply fittings, wells and tanks, pumping equipment.

For the construction of external water supply and external networks, pipes must meet the following requirements:

Have good strength, i.e. they must withstand the pressure of the working environment, transport and soil loads;

Have a long service life;

The inner wall of the pipes should have maximum hydraulic smoothness.

Both metal (ferrous metal - cast iron and steel) and non-metal (plastic, reinforced concrete and asbestos-cement) pipes meet these requirements. However, the former have a number of disadvantages: they are very heavy, there is a high risk of damage when water freezes in them, they have low heat-protective properties, and are not resistant to corrosion. In this regard, it is recommended to use stabilized polyethylene pipes that do not have these disadvantages.

The pipeline fittings of the water supply and supply system consist of compensators, fire hydrants, check valves, coupling valves, air release valves, shutters. In addition, during repairs it is necessary to drain water from the system, therefore, in addition to everything else, outlets are additionally installed to drain the liquid.

In water supply wells, which are made from prefabricated reinforced concrete, there are outlets for draining the working environment, shut-off valves and connection of branches.

Internal plumbing includes pipelines and pumping equipment that transport fluid from the external plumbing system to places of use in the buildings themselves. Water can be supplied from the central or district water supply system, as well as from autonomous sources.

The components of the plumbing system include:

Pipes for supplying cold water to the apartment;

Distribution lines;

Water meter and various pipeline fittings ensuring its functionality;

Risers and pipelines;

Pipeline shut-off and control valves;

Devices for watering and extinguishing fires.

Depending on the type of pipeline layout, water supply systems are divided into three types: dead-end, ring and combined. Wiring according to the first type is very widely used in residential buildings, since it is in them that water can be turned off only in case of an emergency.