Laying pipes in a trench
External pipeline water supply systems can be installed from almost all types of existing pipes. Naturally, their installation is carried out taking into account the specifics of the material from which they are made, since each type of pipe has its own connection methods and its own fittings.
However, when putting water supply pipelines into operation, the systems must meet uniform requirements. What are they, what are the features of pipeline construction, how are they tested and quality controlled? You will find the answer to many pressing questions related to the installation of external water supply networks in our article.
Requirements for the arrangement of an external water supply network
The internal plumbing system is connected to the external network. Pumps and pipelines are used to transport fluid to the site. Installation work is carried out in compliance with certain parameters. In this case, the soil freezing depth is maintained at 0.5 m.
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.
Conclusion
Polypropylene products, which replaced metal pipes, greatly simplified the installation of water pipes. Now you don’t need to have the skills of a welder to independently assemble the necessary circuit for cold and hot water supply, as well as heating, on a country plot or in an apartment.
You just need to follow the instructions and perform the work carefully, taking into account the recommendations presented above. The video in this article will give you the opportunity to find additional information on the above topic.
Types of external water supply
Experts distinguish the following types of external water supply networks:
- Centralized - provides water to a populated area.
- 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.
Laying depth
For central Russia, it is recommended to lay the pipe to a depth of at least 1.8 meters, and for the northern part of Russia - more than 2.5 meters. In the central part of Russia, the depth of soil freezing reaches 1.5 meters. It should be borne in mind that the level of freezing may depend on humidity and soil density. It doesn’t matter what the pipe will lie under - under a concrete base or under a foundation - you still need to dig deeper.
It is better to dig immediately to a depth of 2 meters. You can do this on your own, but if you don’t have the time or opportunity, you can hire a specialized company or guest workers.
The average price for excavating a trench is approximately 350 rubles/m3.
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 the 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.
What mistakes to avoid
There are the most common mistakes that should be avoided when installing polypropylene water pipes. For example, due to the plastic-like material of the pipes, some people believe that they can be bent. Alas, this is not so: for places where the pipe turns, it is necessary to use special corners. There are also those who, when welding, insert one element into another, try to rotate it. This also does not need to be done, since the strength of the connection is impaired. Finally, when installing on a wall, it is best to place the cold water pipes above the hot water pipes. This makes it possible to avoid the appearance of condensation during operation of the water supply system.
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.
Pipe selection
The best option for pipes for external water supply is made of low-density polyethylene (HDPE). Specifications:
- high plasticity, hence the ability to lay water pipes without using additional fittings;
- low abrasion;
- high strength;
- withstands water temperatures up to +40C;
- not subject to corrosion;
- during the freezing process, polyethylene does not crack or deform;
- service life – 50 years;
- low price;
- ease of installation.
Pipes are sold in coils 50 or 100 m long. When purchasing, you can cut the required quantity from the coil.
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.
Plumbing testing
Any pipe connection cannot guarantee 100% protection against leaks. Therefore, the water supply network is tested before installing thermal insulation. Algorithm of the processes carried out:
- the entire water supply system is filled with water without pressure and remains in this state for 2 hours;
- pressure is created inside the pipes, which is maintained for half an hour;
- The water supply system is checked for leaks, paying special attention to joints.
The final stage after installing the thermal insulation material is backfilling the trenches with soil. It is first recommended to fill the pipe with sand with a layer thickness of 15-20 cm, then fill the trenches with the selected soil. It is imperative that the water supply system be flushed until the water coming out is clean.
Sewage slope of 1 m: SNiP and general rules
With regard to pipelines through which liquid (especially liquid with solid inclusions) flows into a centralized sewer or septic tank, certain rules apply:
- reducing the diameter of the pipe requires increasing its slope and at the same time a lower percentage of filling;
- if the diameter of the pipe is calculated incorrectly, then the correctly selected slope will not save it from clogging and insufficiently rapid waste drainage;
- An increase in the angle of inclination of the pipes above normal leads to the fact that the water does not have time to wash away organic deposits from the walls; it is also possible that the pipe mouth is completely blocked and the water seals are broken.
Thus, the maximum and minimum slope of sewer pipes for gravity flow (gravity system, drainage without creating excess pressure) is determined from tables compiled on the basis of long-term observations and experiments.
When making calculations, it is necessary to take into account that, depending on the source of reference information, the slope angle can be given in degrees (deviation of the center line of the pipe from the horizontal), millimeters per meter of length of the pipeline section, or in the form of a fraction. In the latter case, the fraction is the ratio of the height difference in the pipe section to its length.
Insulation of the water supply system
In order to prevent pipes from freezing and to use the water supply all year round, it is necessary to take measures to insulate it. Materials that are resistant to fire and have low thermal conductivity are used as thermal insulation. If mineral-based fiber insulation is used, the water supply system should be additionally insulated from moisture, otherwise the insulation effect will be reduced to a minimum value. More convenient to use is polystyrene foam, which is produced in the form of shells of two semicircles, treated on the outside with a layer of waterproofing.
Insulation using expanded polystyrene
Particular care should be taken when insulating water pipes at the entrance to the house, since this section is most susceptible to freezing. To avoid such phenomena, in the area from the water supply outlet from the ground to the entry into the house, the pipe is wrapped with a heating cable, and a special sensor is installed to reduce energy costs. It monitors the pipe temperature and turns on the heating system at a critical value.
After insulation, plastic pipes for the external water supply are covered with soil, after a preliminary check of its functioning.
List of documents
Two documents are of interest to us:
- SNiP 2 04-02-84 - external water supply, structures and networks;
However: we will not get acquainted with the original text of SNiP, but with its updated version - SP 31.13330.2012.
- Regulating internal sewerage, hot and cold water supply SNiP number 2-04-01-85, and its current presentation in SP 30.13330.2012.
External water supply and drainage system: what needs to be taken into account when constructing them
Before you begin installing external communications, you should remember that the requirements for them are contained in SNiP for external water supply and sewerage. Failure to comply with its requirements may disrupt the ecological balance of the site, leading to the penetration of runoff into the ground and contamination of the aquifer. In addition, the system itself can quickly fail.
The external water supply system must be installed in accordance with the regulations.
