Norm of laying the 70th sewer pipe. Sewer pipe laying depth: technological standards and recommendations of specialists. Calculation taking into account the sand cushion

To reduce the cost of sewerage construction, the depth sewer pipe must be calculated correctly. With an increase in the depth of the pipeline in the ground, as a rule, its installation also becomes more expensive. In addition, this affects the possibility of efficient operation of the sewer system. Therefore, taking into account technical standards and climatic features terrain, you need to choose the minimum possible depth.

Factors affecting the depth of sewerage

The calculation of the depth of laying sewer pipes takes into account the following parameters:

  • climate mark, which displays the power of annual soil freezing, this indicator is regulated by the normative act SNiP 2.01.01.82;
  • technical properties of materials used in construction;
  • specific features of the pipeline;
  • the depth at which the sewer system is connected to a collector or septic tank;
  • terrain;
  • the maximum dynamic load acting on the sewer system (if the laying is carried out under the road).

The depth of soil freezing is a fundamental factor

The design of sewer pipelines begins with determining the depth of freezing of the soil into which the sewer will be laid. The maximum depth, measured in standard units of measurement, below which moisture in the soil does not crystallize, is considered the mark of soil freezing. The depth of the sewer pipes depends on it.

Below the freezing mark, the soil does not freeze, its volume does not increase and, therefore, there is no effect on the pipeline laid in it. The depth of freezing for each region can be found in the collection of standards "Construction climatology", in the section of cartographic materials.

If for some reason it is not possible to access the collection, the local metrological service. Employees of the organization will tell you the value of the indicator, which was revealed as a result of many years of studying the properties of the soil. For example, studies have shown that in central Russia, the freezing depth is on average 1.4 m, in the North region - 1.8÷2.4 m, and on the Black Sea coast - 0.8 m.

A feature of the construction of sewerage is that, in contrast to water networks, the depth of the sewer pipes is calculated by subtracting a certain distance from the soil freezing depth indicator, since the sewer pipes transport effluents of positive temperature. The value by which the laying depth is reduced depends on the diameter of the sewer pipes:

  1. with a diameter of up to 0.5 m, it is 0.3 m. For example, in order to sewer into a house using pipes with a diameter of 0.4 m, in an area with a soil freezing depth of 1.6 m, it is necessary to lay pipes in the soil to a depth of 1, 30 m (1.60 - 0.30 = 1.30 m);
  2. with a larger diameter of pipes - 0.5 m. For example, to improve the same house, but using pipes with a diameter of 0.6 m, the required depth of laying sewer pipes will be 1.10 m (1.60 - 0.50 \u003d 1, 10 m).

Having completed the calculation of the sewer pipes, they begin to dig trenches into which the pipeline is then laid. It is possible to reduce earthwork costs by making trenches as narrow as possible. Reducing the depth of the pipes is prohibited.

Relief features

The depth of laying sewer pipes will also greatly depend on the features of the terrain. When constructing a sewer on a relatively flat area, the depth will be the same along the entire length of the pipeline.

But if the landscape has pronounced differences in height, the depth of the sewer pipe is calculated from the lowest point of the landscape on the site. In this case, the statement that the higher the pipes are laid in the ground, the less cost on materials and earthworks, is not true, because the result will be a complex undulating construction of the highway. For uneven terrain, it is advisable to build a direct sewer pipeline to a constant depth with a certain slope.

Pro tip: When sewer system laid in places of movement of vehicles or people, it is necessary to take into account the dynamic load on polymer pipeline. In such areas, laying should be carried out in a closed way or use reinforced polymer corrugated pipes.

Technical characteristics of sewer pipes

Ceramic and metal sewer pipes have been replaced by their modern counterparts - plastic pipes. The advantages of polymer products are enough:

  • acceptable price;
  • durability;
  • ease of transportation to the installation site;
  • ease of installation, etc.

However, there is a significant drawback: the depth of laying polymer pipes into the soil is limited. Therefore, before purchasing the material, carefully read technical specifications products contained in the manufacturer's instructions.

When constructing a sewer system from polymer pipes, they are mainly guided by the experience of building and operating identical communications in a particular region. And in the absence of reliable data, the calculation of the strength of polymer products is carried out according to SP 40-120-2000, which regulates the principles for the design and installation of plastic sewer pipelines.

Pro tip: When reading information about polymer sewer pipes, pay special attention to the laying depth indicator. It must necessarily meet all the conditions of the sewerage project on your site. Otherwise, the pipeline may not withstand the pressure of the soil and fail, which will lead to the need to dismantle the sewer and build a new one.

Additional aspects

The calculated depth of laying sewer pipes is an approximate value. It is subject to mandatory adjustment taking into account the length of the pipeline, the landscape of the site and design features sewer systems.

Private houses are most often supplied with gravity sewers. In such a system, when laying, it is necessary to observe the slope of the pipeline towards the treatment plant by 0.02 m for each running meter pipes (for example, with a sewer pipeline length of 20 m, the depth of the point at which the pipes connect to the septic tank will be 0.40 m more).

If a pump is installed in the sewer network that performs the forced transportation of effluents through the pipeline, a slope is not needed. The operation of the pump will not allow wastewater to stagnate and freeze at low temperatures, forming an ice plug. However, a pressure (forced) sewer system is less popular in the construction of private houses.

A qualified calculation of the depth of the sewer pipeline ensures its long and efficient operation, the absence of breakdowns and other problems. In addition, knowing this indicator, you can choose the best option laying pipes and thus reduce costs in acceptable ways.

One of the main parameters of the sewer system is the depth of the sewer pipes. At the same time, the standards define both the minimum and maximum values ​​of these indicators. In addition, for different networks, as well as laying methods, these figures may vary.

First of all, I would like to note that SNiP “Sewerage ...” 2. 04 03 - 85, in addition to specific numbers, also gives a rather vague wording - “The choice of laying depth should be based on practical experience operation of sewer networks in the region. That is, the standards leave a sufficient margin for choosing optimal values tied to a particular area.

But in general cases, the depth of the sewer pipeline depends on:

  • From the level of soil freezing
  • From the geological conditions and composition of the soil at the place of laying
  • From the type of sewerage (gravity, pressure)
  • From the method of laying pipes (open or in trays)

Distinguish between minimum and maximum bookmark depths.

Minimum depth

It should be remembered that sewer drains refer to warm views liquids, therefore, SNiP allows their laying above the level of soil freezing.

For pipes with a diameter of up to 50 cm (all pipes used for domestic purposes), the depth can be 30 cm above the freezing mark. For large pipes, this figure increases to 50 cm.

If for any technological or natural conditions minimum depth
sewerage can not be sustained, insulation of networks or methods of frost protection associated with the laying of electrical heating cables should be applied.

Besides, given value also depends on the type of loads to which the surface of the earth is exposed at the place where sewer networks are laid. At high mechanical loads (vehicle traffic), the depth should not be less than 0.9 m, under normal loads it can be 0.7 m. In other cases, laying sewer pipes in trays should be used.

Using minimum values signaling devices should be assumed that can determine the location of the sewer pipeline and prevent its damage in future earthworks Oh.

We would recommend, if possible, to still adhere to the freezing depth, this is especially true for soils prone to heaving. The smallest depth of laying sewer pipes in this case will protect the pipeline from damage during soil shifts and maintain the standard slope.

Maximum sewer pipe depth

This parameter is also very important and should be taken into account when laying external sewerage networks. The mass of the soil is capable of exerting significant pressure on the pipe walls, therefore, exceeding the critical depth of laying can lead to damage to the pipeline.

Given the significance of the level of laying the pipe, repair work will be associated with a large amount of earthworks. In dry soils, laying an open sewer pipe is allowed at depths of up to 5-8 meters, if the soil is saturated with moisture, has rock inclusions, this depth is reduced to 4 meters.

If these standards are exceeded, it is necessary to provide for the laying of sewer pipes in special reinforced concrete trays. In this case, the depth of laying the tray of the sewer pipeline must be determined on the basis of a calculation that will take into account the resistance of the material to mechanical stress.

Several individual cases of determining the depth of laying sewers

Device of pressure sewer system. These schemes differ in that pressure pipelines there will always be drains, while, during the shutdown of pumping stations, they will be motionless, which is fraught with freezing of the system.

That is why the depth of the pressure sewerage is assumed to be similar to the depth of the water pipe, that is, it must exceed the level of soil freezing by 30 cm.

When laying such networks in unheated premises or basements, it is imperative to take measures to insulate them. Neglect of such rules can lead not only to damage to the pipeline section, but also to cause the failure of quite expensive pumps.

Drainage and storm sewer. They can be classified as common gravity drainage devices, so it is logical to apply the same requirements to them.

We can only say one thing you should not try to minimize the amount of excavation work when laying such networks by reducing the depth of occurrence.

The device of such systems below the level of freezing is more preferable, the reliability of the network in this case will be higher. Therefore, when deciding what should be the depth of the storm sewer in each case, try to find the best compromise between savings and expediency.

A few words about the insulation of sewer pipes

Unfortunately, in private construction, many neglect this method of protecting pipes from freezing. There is no need to talk about the use of a heating cable either. But it is these methods that make it possible to ensure trouble-free operation of the network in most cases.

Content:

The withdrawal of sewage in a private house is carried out at the stage of laying the foundation or after its installation. There are enough nuances in this work. As in fact, in all undertakings tied to the construction in a private house. And one of these issues that needs to be addressed is the correct depth of the sewer pipe, relative to the house and the place where it is connected to the collector.

Technical points and material selection

The minimum depth of occurrence is calculated with respect to several factors. One of these is the type of pipe. The fact is that some materials are less susceptible to cold and in this case there is no need to dig them deep.

Except factor cold weather The following points affect the result:

  • ground pressure;
  • underground springs.

So that during the installation of sewer pipes, they are not damaged and lie as long as possible, performing their functions, it is necessary to take into account all the nuances.

Before determining what sewerage depth is acceptable in your private home, understand the types of pipelines and components used to connect and arrange branches.

When choosing branch pipes and connections, remember the significant differences between the external and internal wiring of the sewage system. All elements located in the house are plumbing fixtures, sockets and couplings that serve to connect the branches directly in the house. They cannot be used outside. External elements for laying in the ground are local cleaning systems (septic tanks), storage tanks and pipelines located directly behind outside walls.

Elements are marked with color. For laying outside the building, elements painted in orange-brown are used. Internal wiring is carried out with materials marked with a light gray tint.

Important. When purchasing pipes and fittings, be sure to read the recommendations for use, or consult with the sales department.

SNiPs and other norms for determining depth

Having dealt with the elements used in the sewerage wiring in the bathroom toilet, as well as outside the home, you can proceed to consider options placing them in the ground.

The regulations have recommendations on how deep to dig trenches. To determine what is the minimum value of the occurrence of pipes is permissible so as not to carry out unnecessary work on digging a deep trench, refer to SNiP 2.01.01.82. The documentation has a clearly defined zone map, indicating the depth of soil freezing relative to your region.

All data are calculated taking into account weather conditions and the type of pipes used, which are also indicated in the advisory annexes. But, nevertheless, determining the depth to which the pipe can be buried, the masters make their own adjustments.

The calculation is approximately as follows: if branch pipes with a cross section of up to 500 mm are used for the branches from the value indicated in the map climate indicators, then 300 cm can be safely subtracted from the depth. When laying a larger diameter of the pipeline, the laying level is reduced by 500 cm.

Additional factors worth noting

According to the SNiP standards, the branch pipe, located at the exit from the foundation in an honest structure, is located 30 cm higher than the average height of the soil freezing level. But at the same time, minimum performance should not be less than 70 cm.

Provided that you live in central Russia, the laying can be reduced to 50 cm, and the output from the house can be raised higher. If the foundation was insulated , plus the heating system works in the underground space, the pipes will not freeze. Such indicators are sufficient if there is no roadway on the site or playground which is cleared of snow in winter.

Important. The last condition must be observed strictly. Having laid the pipe to a depth not exceeding 50 cm, it can be damaged under the weight of the soil if there is a passing highway above the laying site. In turn, the lack of snow in winter will lead to freezing of the soil below the declared value.

Of course, when laying sewers in a private building, the slope is also taken into account. It must be arranged in such a way that wastewater flows by gravity. In this case, the calculation is also carried out relative to the average indicators of SNiP.

Let's assume that according to the recommendation for middle lane In Russia, the branch pipe leaving the house must be located at least 30 from the level of soil freezing. And the minimum depth of laying the branch pipe is 70 mm. In this case, they are guided by the distance at which the septic tank or collector pipe is located.

If the exit point is located at a distance from the house, for example, 10 meters, then the pipe laid from the private building to the tie-in point will lie under the desired degree. As the distance increases, the slope of the sewer pipe will decrease, and this may affect the quality of the random discharge. You can fill the gap by installing a septic tank at a lower depth.

Problems in the work of laying sewerage according to the norms and ways to solve them

In some cases, the depth of sewerage according to SNiP is not possible. This happens if the site has “difficult” soils with large interspersed rocks. It is unrealistic to dig a trench with a shovel, and hiring equipment is expensive or there is simply no access to the place.

What kind of trench can be dug in this case? Enough of the depth to which you can reach. But in this case, the diameter of the pipe is chosen larger. Remember that increasing the size affects the degree of freezing. Additionally, the outlet must be isolated.

Before laying, the pipeline is wrapped with roofing material, then with several layers of cold insulator and again with hydrophobic material. In such clothes, the branch will lie even at a depth of 30 cm.

Deviation from the rules is recommended if private house located at the bottom. Even observing the norms, you can subject the system to freezing. This is justified by the fact that even warm days in such places there is low temperature in the ground. It is necessary to pay attention if the place where the outlet lies is in the shade and does not warm up properly.

What protection can be arranged yet? Great solution there will be a laying of a heating cable for sewer pipes. Don't let the power consumption scare you. The system works by means of installed sensors, and turns on only when the temperature in the sewer drops to the critical norm recommended by the SNiP of your Region.

When considering options for laying sewers in a private house, always be guided by SNiP. Be sure to consider the angle of inclination. Remember that in the northern and southern regions bookmark difference is significant.

At the same time, do not try to dig the branch to the maximum depth. You will only increase the complexity. The sewage system mainly discharges water room temperature, and when they exit, they wash off the frost that has come through the thickness of the soil. Therefore, the option of complete freezing is possible only with gross violations of the norms.

There is a lot of controversy about this on the construction forums. Although in paragraph 4.8 of SNiP 2.04.03-85 “Sewerage. External networks and facilities "everything is said quite clearly

The smallest depth of laying sewer pipelines must be taken on the basis of the experience of operating networks in the area. In the absence of operating data minimum depth laying of the pipeline tray is allowed to be accepted, for pipes with a diameter of up to 500 mm - by 0.3 m; for pipes of larger diameter - 0.5 m less than the greater depth of penetration into the soil of zero temperature, not less than 0.7 m to the top of the pipe, counting from the marks of the ground surface or layout. The smallest depth of laying collectors with a constant (low fluctuating) flow Wastewater must be determined by thermal and static calculations

Here is the wording "depth of penetration into the soil of zero temperature" , and this is nothing more than the depth of freezing of the soil.

You can find out the depth of freezing from many normative documents. closest engineering networks SNiP 2.01.01-82 "" Construction climatology and geophysics". And although this document has already been replaced by a new SNiP 23-01-99 * " Construction climatology" map of freezing zones remained only in the old Soviet SNiP.

For the hero city of Moscow, the freezing depth is 1.4 meters, for St. Petersburg - 1.2 meters, and for Sochi - less than 80 centimeters. Take a "small" pipe with a diameter of 200 mm. For it, you need to subtract 0.3 meters from the freezing depth. Having made a simple arithmetic calculation, we obtain the minimum depth of the sewer pipe tray Du200 - 1.1 meters. For Moscow. Visually - in the drawing:

This is how pipes should be laid.

Now about the sad. About how pipes are actually laid. If it concerns some capital objects, then everything is fine. State or non-state expertise is obligatory, and projects for serious objects are made by serious designers.

Whether business - a private house. In almost all instructions for small treatment facilities such as Topas, Biofluid, etc., it is written in black and white - the sewer pipe from the house should exit at a depth of 0.5 meters. Otherwise, the pipe simply will not fall into the inlet of the treatment plant. SNiP also provides for such cases of laying - with mandatory insulation.

... Pipelines laid to a depth of 0.7 m or less, counting from the top of the pipe, must be protected from freezing and damage by ground transport.

In practice, sewer pipes are rarely insulated or heated. Installers say that nothing will freeze, refer to their vast experience and global warming. Therefore, in winter, the Internet multiplies with numerous questions and detailed instructions what to do if the sewer pipe is frozen.

Before you know how deep to lay sewer pipes, it is very important to understand various types pipelines.

When choosing pipes, be sure to consider that there are different pipelines for internal and external sewage systems. The internal sewer system includes all plumbing fixtures and branch pipes that are in the house. External - pipelines, local treatment plants such as, and drives located outside the house.

Spigots used outside the home are brown-orange, used indoors are light gray shade. Important: when purchasing a pipeline, be sure to carefully read the instructions, as it details the specifics of using the structure.

What materials are the tubes made from?



For example, a few years ago, metal pipes were especially popular. But now this trend does not take place due to the fact that the metal is subjected to special corrosion. In turn, now most people install. Plastic pipes are lightweight, durable, long operational life. When installing them, you do not need to call a welder or use special equipment.

Also, collectors are made of cast iron, concrete, ceramics and fiberglass. Cast iron pipes are heavy and difficult to install. Ceramic - a high degree possible damage. Concrete - a lot of weight and also the complexity of installation.

If you choose a PVC pipeline, then keep in mind that polypropylene installations can withstand temperatures of 80 degrees, while PVC structures can only withstand 40 degrees.

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