Depth of rainwater drainage. How to choose the correct sewer installation depth

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

First of all, I would like to note that SNiP “Sewerage...” 2.04 03 – 85 provides, in addition to specific figures, a rather vague formulation - “The choice of laying depth should be based on practical experience in operating sewer networks in a given region.” That is, the standards leave sufficient reserve for choosing optimal values ​​in relation to a specific area.

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

• From the level of soil freezing
• On geological conditions and soil composition at the installation site
• Depending on the type of sewer system (gravity, pressure)
• On the method of pipe laying (open or in trays)

There are minimum and maximum laying depths.

Minimum depth

It should be remembered that sewage drains are warm types of liquids, therefore SNiP allows their laying above the freezing level of the soil.

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, due to some technological or natural conditions, the minimum depth
sewerage laying cannot be sustained, network insulation or frost protection methods associated with the laying of electrical heating cables should be used.

Besides, given value It also depends on the type of loads to which the ground surface is exposed at the site where the sewer networks are laid. Under 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.

When using minimum values, signaling devices should be considered that can identify the locations sewer pipeline and prevent its damage during future excavation work.

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

Maximum depth of sewer pipes

This parameter is also very important and must be taken into account when laying external sewer networks. The mass of soil can exert significant pressure on the pipe walls, so exceeding the critical depth can lead to damage to the pipeline.

Given the significant level of the pipe, repair work will involve a large volume of excavation work. 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 and 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 laying depth of the sewer pipeline tray must be determined based on a calculation that will take into account the resistance of the material to mechanical loads.

Several individual cases of determining the depth of sewer backfill

Construction of a pressure sewer system. These schemes differ in that there will always be wastewater in the pressure pipelines, and when the pumping stations are turned off, they will be stationary, which can lead to freezing of the system.

That is why the depth of laying the pressure sewer is assumed to be similar to the depth of laying the water supply system, that is, it should exceed the level of soil freezing by 30 cm.

When laying such networks in unheated rooms or basements, measures must be taken to insulate them. Neglect of such rules can lead not only to damage to the pipeline section, but also cause failure of quite expensive pumps.

Drainage and storm sewer. They can be classified as ordinary 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 volume of excavation work when laying such networks by reducing the depth.

The installation of such systems below the freezing level is more preferable; the reliability of the network in this case will be higher. Therefore, when deciding what the depth of storm drainage should be in each specific case, try to find the most optimal compromise between economy and feasibility.

A few words about insulating sewer pipes

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

Therefore, we will briefly describe the requirements for insulating sewer pipes:

• Almost any material can be used as insulation existing materials. Rolled heat insulators based on fiberglass are the most affordable. The pipe must be wrapped with them on all sides by at least 10 cm, while paying attention to careful fastening; for this, string or twine is usually used.
• Be sure to attach a layer of waterproofing on top of the insulation layer; regular roofing felt will do just fine.

Remember, only dry insulation can work effectively; a wet layer will not protect the pipe from freezing.

It is customary to lay external sewerage outside the house to a depth under a layer of soil. This is due climatic conditions. In addition, pipes are buried in the ground for technical reasons, including so that they do not “dangle underfoot.” But what should be the immersion depth of the sewer line?

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Reasons for submerging the highway underground

The simplest installation of the collector is to place it on the surface of the site. This is what they do in some parts of the country. For example, in areas of northern climate zone, installation of water supply and sewerage communications is carried out on top of the ground. Such a laying system is dictated by local conditions - climate, presence of permafrost, easy access at repair work oh and economic feasibility. Therefore, the problem of what the depth of the sewer pipe in a private house should be is absent.

However, a tenth of the population lives in places with a harsh climate. Not all of them live in the private sector. In other regions it predominates temperate climate, the ground does not remain frozen and thaws in warm time year. Hence, when installing sewerage in country house, the main way is to lay the highway underground. Reasons for using this method:

• requirements regulatory documents;
• protection from mechanical damage;
• defrost protection;
• less likelihood of contamination of the surface layer of the earth with biological and chemical components;
• saving priceless square meters land area on your own plot.

The idea that sewer pipes should be hidden underground is a voice of common sense and a competent technical solution. The only thing left to do is determine the required depth for laying sewer pipes in a private house.

Composition of the external communications system

Before deciding at what depth to bury a sewer pipe, you need to decide on the design external system drainage.

A device for discharging domestic wastewater and draining storm water is being installed in a suburban area. In the latter case, special events are carried out over a significant area of ​​the land plot and roof sizes of above-ground buildings. These requirements are met by plots of more than 10–15 acres. building structures from 100–150 m².

Storm sewer

The main purpose is to remove liquid precipitation, as well as moisture generated from economic activity person. For example, when washing a car, or from a summer garden pool.

In the cold season, in the main part of the country, there is no need for rainfall. Therefore, the depth of the storm sewer is determined:

• requirements of SNiP 2.04.03-85 “Sewerage. External networks and structures";
• local climatic and geological conditions.

• the average freezing depth is in the range of 0.7–1.2 meters; digging a deep trench in a relatively small area is simply not practical;
• another limitation is the structure and composition of the soil; It is difficult to cultivate rocky or sticky clay soil.

An important factor is economic. It is sometimes simply not profitable to build a drainage system that operates sporadically during the warm season according to all the rules. But precipitation must be removed. Practical options have been created:

• Laying pipes in trays, buried in the ground and covered with decorative slabs. In order to save land space, the structure is laid along pedestrian paths. Main advantages:
• simplified installation;
• saving time and material resources;
• quick and convenient access for maintenance or repair work.
• Installation of storm collectors with immersion of 30–50 cm. Warming up is carried out by thermal electric cable. Additionally, if necessary, thermal insulation with mineral materials is provided.

Domestic sewerage

It is a system of interconnected:

• collectors, fittings;
• examination rooms and overflow wells;
• cesspool or septic tank;
• more complex design– complete treatment station, includes drainage fields.

The drainage system is based on gravity or forced (pressure) pumping. In private housing construction, the first option for drainage has been developed.

Collectors material

Structures located outside the home are exposed to several factors:

• the inner surface of the pipeline comes into contact with solid and liquid waste, which forms a chemically aggressive environment;
• the outer side comes into contact with the composition of the soil, groundwater, which forms an alkaline and acidic environment;
• the collector is affected by the weight of the backfill soil;
• in the event of land subsidence in some areas, bending loads begin to act on the pipe;
• in the cold season, a temperature bridge with a range of 20–50°C is formed between the outer and inner walls.

The depth of the sewer system in a private house affects the choice of products that are resistant to the listed influences. For external use, uPVC (unplasticized polyvinyl chloride) pipes are used. Most often, they have a red tint. The collector diameter is 110 mm, but it can be larger, 160 or 200 mm. The size depends on the daily volume of discharged wastewater.

Laying rules

The development of installation rules is based on the requirements of SNiP 2.04.03-85 “Sewerage. External networks and structures.” Taken into account:

• Local climatic factor is the level of soil freezing. The depth of laying sewer pipes depends on it. Optimal value: the lowest point with zero temperature plus 20–50 cm. Generalized data on this are given on the climate map of the region. Information can be obtained from your local climate service.
• Level groundwater. This indicator determines how deep the product needs to be so that its performance is not affected by groundwater.
• Straightness of the gasket. The presence of bends, transitions, and joints increases the risk of blockages.
• Possibility of revision. An extended highway requires periodic preventive inspections. To do this, it is necessary to install inspection wells every 25–40 meters.
• Soil composition and structure. One of the main factors. In a private house, the depth of the trench is determined by the technical capabilities of its construction. Sands, loams and clays are processed manually or using earthmoving equipment. From here, it becomes possible to comply with all standard indicators. Rock formations make adjustments to the laying scheme and installation method.
• Pipe slope. Provides the required flow rate and removes all residues from the manifold.

The rules are taken into account when designing the drainage system. The project specifies the depth of the sewer, the laying pattern, the presence of intermediate wells, the dimensions of the trench and collector.

Installation

The depth of the sewer pipe is determined by the vertical dimensions of the trench. Installation of an external drainage system consists of the following steps:

• preparatory work;
• installation of trenches and pits;
• pipe laying;
• performance check.

Preparation

Before starting excavation work, the following is carried out:

• cleaning the site from foreign objects, construction waste;
• the future route is marked, the location of inspection wells is established, storage tank(septic tank);
• the depth of laying the sewer pipe is checked against the existing terrain;
• reference points are marked at the junction of several collectors, the connection of storm drainage structures and domestic discharge.

To the number preparatory activities relates to procurement required material and delivery of equipment.

Construction of trenches and pits

Sewer depth is the vertical dimension of the trench. The installation conditions depend on how the hole is formed and dug correctly. For comfortable work, the width of the earthen gap is in the range of 50–70 cm. This value is influenced by the vertical size, dimensions of the excavator and its technical capabilities.

Excavation work is carried out manually or using earthmoving equipment. Depends:

• on the dimensions of the trench (depth, width, length);
• soil composition and structure;
• time of year when work is carried out.

The bottom of the ditch is necessarily covered with a sand and gravel cushion of thickness

10–30 cm. The soil is compacted by manual tamping or mechanically. By means of the interlayer, the level of inclination of the main line is precisely set.

It is easier to dig a pit for a wastewater storage tank (cesspool) using a small excavator. But, if the soil is soft (sand, sandy loam, loam), then the operation is carried out manually. Under a septic tank or treatment station, due to overall dimensions structures, the hole is dug mechanically.

An important point is the crumbling of the trench walls. This phenomenon is typical for deep (from 1.5 meters) ditches built in light soil. Or the presence of underground quicksand (clay, sand, water) under a dense layer of earth. In such cases, it is necessary to observe safety precautions (for example, work together or as a team).

Note. In difficult conditions, such as rocky or viscous clay soil, the maximum possible vertical size of the trench is made. But, in this case, thermal insulation measures must be taken.

Laying

The sewer pipe is collected on the surface of the site. All necessary connections are made. The connecting nodes are treated with plumbing grease.

Note:

• the bells are directed along the direction of the flow - the wide side faces the movement of the drains;
• a pit is made under the location of the bell;
• shaped elements and sockets cannot be shortened - this will ultimately compromise the strength of the connection and tightness.

The assembled line must be laid in a single strand. Installation starts from the building. Sudden movements and strong bends should be avoided. It is more convenient to work with two or three pairs of hands. The level of slope is determined by the pre-tensioned cord. The exhibition is made by spreading or removing the sand and gravel mixture. As the pipe moves to the sides, side pegs are driven in.

The system can be assembled in a trench. In this case, the width should be at least 60 cm. In a narrower version, human movement causes soil to crumble from the side walls of the excavation device.

In case of insufficient depth, laying in the thickness of the frozen ground, the main line is insulated. Shell or matte thermal insulation is used. Another option is to use a heat cable. The downside for the latter case is the presence of electricity (in winter time, some country houses are disconnected from the network).

Protection from excess external weight (the collector is laid under the parking lot of the car) is carried out by installing concrete trays or in halves (the product is cut lengthwise) metal pipes larger diameter. It is possible to use corrugated (multilayer) parts.

Examination

It is allowed to bury a trench after commissioning. Stages:

• the correct assembly of the line is checked;
• the angle of inclination is measured and corrections are made;
• the assembled structure is watered; identified deficiencies are eliminated;
• The thermal cable is tested (if available).

The collector is covered with a layer of sand and gravel mixture 20–30 cm thick. The sides of the pipe are compacted. Such actions are prohibited above the highway itself, due to the possibility of damage to the assembled structure.

Advice. On the laying diagram, it is advisable to note the actual location of the main line. Make a reference on the ground (on a fence, house, outbuildings). This will make it easier to search in emergency situations, especially in winter.

Rain and melt water can seriously waterlog the soil and thereby cause irreparable damage to buildings and soil. To avoid damage due to moisture, good drainage should be installed. The depth of installation of closed or open storm drains must comply with established SNiP standards. Otherwise, communication will be useless.

The importance of correct calculations when designing a storm drainage system

• poor outflow of rain/snow water and, as a result, waterlogging of the area;
• formation of stagnation of moisture and debris in the form of silt, sand, earth in specific sections of the sewer system;
• pushing out laid pipes due to the tendency of the soil to heave;
• the need to carry out complex repair work to clean the drainage line;
• freezing of pipes or sewer trays in frosty weather, and hence the possible rupture of drains;
• the risk of dismantling the entire system and reinstalling it.

At the time of drawing up the storm sewer design scheme, it is advisable to familiarize yourself with SNiP 2.04.03-85 or the updated version of the seal SP 32.13330.2012.

Determining the depth of storm drainage

Soil freezing depth map

In order for the installed communication to work properly for decades, it is important to correctly determine the depth of laying the storm drain in a private house. SNiP 2.04.03-85 regulates the following minimum standards:

• for gutters/pipes of the drainage system with a cross-section of up to 500 mm, the recess is from 30 cm;
• for trays/pipes with a diameter of 500 mm or more, the depth of the storm drain starts from 70 cm.

For a closed drainage system being laid, the drainage pipes should be located 20 cm below the groundwater level. This will allow moisture to freely fall and escape through the pipes during the spring melting of snow.

It is important to consider the level of soil freezing in winter. The more porous the soil in the area, the smaller the thickness of the ice in the ground will be when sub-zero temperatures. In addition, pay attention to the thickness of the snow in winter period. If it is 10 cm or more, then it is a kind of cushion that reduces the thickness of freezing of the ground. Thus, knowing the level of soil freezing and taking into account the thickness of the snow, you can derive the minimum laying indicators drainage pipes on the site: from the existing level of ice in the ground in winter, approximately 30 cm (for pipes with a cross-section of up to 50 cm) and 50 cm (for a drain cross-section of 50 cm) are subtracted from the snow cap.

Example: the level of soil freezing in the area is 1200 mm. The thickness of the snow layer in the region is 10 cm. The diameter of the pipe is 50 cm. This means that from 120 cm we subtract 30 cm allowed and get the minimum depth of occurrence - 90 cm. It is important to remember that 90 cm is the depth along the upper edge of the already laid pipe with all bedding made of sand and gravel.

If you lay a closed system at or above the soil freezing level, the ice in the pipes will melt slowly during the spring flood season. During this time, melt water will flood buildings and garden/garden crops.

If for any reason laying drainage pipes at the recommended depth is impossible, they will have to be properly insulated. It is necessary to provide for the level of dynamic and static load on the system with a decrease in the depth of drains.

The minimum slope of storm sewer according to SNiP

An important criterion for storm drainage design is the slope of the system. If you follow it rainwater goes by gravity towards the receiver. The minimum slopes of storm sewers according to SNiP 2.04.03-85 vary depending on the internal cross-section of the pipe. The regulations look like this:

• For a drainage system with pipes/gutters with a diameter of 20 cm or more, the permissible slope for each linear meter of stormwater is 7 mm.
• If trays/drains of smaller diameter are used for sewer installation, the slope increases from 8 mm to 1.5 cm. Since the smaller diameter of the pipes creates greater resistance to the free outflow of liquid.

SNiP 2.04.03-85 also specifies the maximum level of storm drain inclination - it is equal to 1.5 cm/m. With an arbitrary increase in slope, the system will become clogged with sand and earth, which, due to greater specific gravity will not be able to move along with the flow of water at the same speed.

The slope of open drainage systems depends on the level of roughness of the internal walls of the communication. The regulations establish the following indicators:

• drainage ditches and trays on asphalt concrete roads - 0.003;
• crushed stone and cobblestone road surfaces - 0.004;
• cobblestone coverings - 0.005.

As a rule, in the private sector they make open ditches covered with broken bricks and cobblestones.

Calculation of the minimum storm drain slope

Calculation of sewer pipe slope

• type drainage system(open/closed);
• diameter of the pipes/gutters used;
• the material from which the drains are made (water slides faster on plastic than on concrete);
• storm drain slopes of 1 meter according to SNiP, depending on the cross-section of the drains.

Here it is important to choose the correct pipe diameter for the volume of water discharged on the site. It is calculated using the following formula:

• Q=q20×F×Ψ

All values ​​in the formula are interpreted as follows:

• Q is the total volume of rainwater that will flow through the drains.
• q20 – annual precipitation intensity coefficient (calculated in liters per second per 1 hectare of land area). The coefficient is taken from the local environmental organization in the region.
• F – total area area, taking into account the roof, from which water will be drained (calculated in hectares).
• Ψ is a correction factor that takes into account the absorbency of the soil.

The coefficient Ψ is equal to the following indicators:

• open soil – 0.35;
• crushed stone – 0.4;
• concrete – 0.85;
• asphalt – 0.95;
• roofing – 1.

Based on the derived value, the cross-section of pipes for the drainage system or stormwater system is selected. According to practical experience, the diameter of drainage pipes in private property is often 110-150 mm.

If, due to the topography of the construction site or for other objective reasons, it is impossible to comply with the slope standards recommended by SNiP, it is allowed to reduce it to 5 mm for pipes with a cross-section of 20 cm and to 7 mm for pipes with a cross-section of 15 cm or less.

It is important to consider: the larger the diameter of the system pipes, the smaller the slope may be; The rougher the surface of the internal walls of the drains, the more you need to tilt the collector for the free outflow of water from the area.

When installing a closed drainage system, it is necessary to observe the security zone. It implies indentations from each pipe wall of 3-5 meters. It is prohibited to build, plant trees, or organize landfills in this place. It is also undesirable to block approaches and entrances to inspection/difference wells.

When carrying out design and installation work for the installation of sewer systems it is necessary to be guided by a number of standards. Moreover, if the slope angle, pipe diameter and other factors have constant values, then the depth of the sewerage system according to SNiP can vary significantly depending on the climatic zone in which the work is carried out. In this article we will look at this issue in more detail and highlight the most important aspects.

Nuances that should be taken into account when determining the depth of the gasket

All information relating to the issue under consideration is set out in SNiP 2.01.01-82, from this normative act The following important factors can be identified:

Work order

Let's consider the sequence in which all activities are carried out, and how to properly organize the work process in order to minimize the likelihood of errors and miscalculations ().

Freezing depth

This indicator can be found either in the “Building Climatology” directory or in local metrological authorities. It is worth noting that the indicator can vary significantly depending on the type of soil, as can be seen by reading the table.

This type of communication also has some features that you need to know when calculating the depth:

• Due to the fact that drains with positive temperatures constantly flow through the pipes, the depth of their location differs from conventional communications and standard plumbing systems. This is a very important factor that directly affects the complexity of the work and the time required to complete it.
• The index of change in gasket depth depends on the diameter of the elements used. If this indicator is less than 50 centimeters, then 0.3 meters can be subtracted from the freezing depth, if more than 50 centimeters, then 0.5 meters. That is, with an indicator of 1.5 meters, communications with a diameter of 110 mm can be laid in a recess of 1.2 meters.

Advice! If it is impossible or very difficult to lay communications at the required depth, then you can use a special insulation for pipes, which will prevent freezing and will significantly simplify the work. In some situations this is the only practical solution.

Relief features

If the site has differences in height, then it is important to follow several important rules:

• The most simple option Calculating the depth is to determine the lowest section, and make calculations precisely from this point, since differences are undesirable, in no case should you dig a stepped trench, because the slope must be uniform along the entire length of the highway.

Important! An excessively large or too small slope negatively affects the operation of the system and leads to accelerated plaque formation on the internal walls of the pipes, which significantly increases the risk of blockages.

• If the work is difficult due to a large difference in height or other factors, it is possible to insulate part of the system that will be closer to the surface than it should be, and lay the remaining sections without the use of thermal insulation elements.
• It is very important to ensure high-quality fixation of each element so that after falling asleep the pipes do not bend, since in such cases there is a high probability of leaks.

Very important within preparatory stage laying depth diagram - sewerage in a private house is not complicated, so it will not be difficult to create a project, and the factors described above will serve as a kind of instruction.

Features of the work

If you have decided at what depth to bury the sewer pipe, you can get to work:

• A trench is dug 15-20 cm deeper than required. This is necessary in order to make a sand and gravel cushion, which must be thoroughly compacted.

• Next comes the installation process, it should start from the foundation of the house. It is important that the depth of laying the sewer pipe also provides for the required slope; for pipes with a diameter of 100 to 200 mm, this figure is 2 cm per meter, that is, the height difference per 10 linear meters should be 20 cm.
• To ensure the least pressure on the pipes, you need to dig narrow trenches; you can also install wooden spacers over the pipe every meter to reduce the pressure.
• To ensure maximum tightness, joints can be further strengthened by applying silicone sealant, after hardening it will create an insurmountable barrier to moisture.
• After assembly, the system needs to be checked for leaks; the easiest option is to fill it with water.
• The last stage is filling the communications with soil.

The depth of the rainwater drainage system may be less, since in winter the pipes are empty and are not afraid of frost. But it is important that water does not accumulate in the system during precipitation.

Conclusion

As you can see, the depth of the sewer is very great value, otherwise frosts can simply stop the system from working (

One of the most important quantities when executing construction projects external sewerage– this is the depth of laying sewer communications, taking into account the complexity of installing pipe networks and the cost of the scope of work. How to determine what this significant value should be - the depth of the sewer pipes?

Depth of sewerage

There is no clear answer to this question on Internet construction forums. However, when referring to the rules of SNiP 2.04.03-85 clause 4.8. we find the answer.

The extremely low depth of laying sewer pipes is determined experimentally, based on the experience of work carried out in a particular area. But this formulation also does not have specific values. In the absence of proper information, you can operate with the following figures, showing the dependence of the depth of laying sewer networks on the diameter of the pipeline. The dependency is shown in the table below:

The minimum depth for laying pipes with a stable waste flow rate is calculated using data on statics and thermal engineering.

TIP: when constructing a storm drain, you must follow an identical work plan.

The depth of the trench for the sewerage system of a private house must meet several conditions:

• performing a minimum amount of earthmoving work
• be able to protect pipes from damage that may occur when loaded on the ground surface
• ensure that liquid does not freeze in waste pipelines
• and also ensure the reception of wastewater into central communications or a septic tank from the most distant and low-lying point of the site

• proximity to groundwater
• quality soil composition
• relief of the site, its length and greatest depths
• soil freezing level
• type of sewer system (gravity or pump)
• technology of work performed (in trays or open)

Minimum sewer depth

The most important factor that you need to focus on when calculating the minimum sewerage laying is the freezing mark of the soil. The depth of laying sewer networks is taken above the soil freezing mark to a certain height (as shown in the table above), since the temperature waste water above the zero mark.

For example, for residents of warm regions, the pipe laying depth will be from 30 to 50 cm from the surface of the earth. Whereas for residents of the northern regions, the depth should be calculated as follows: for a pipe with a diameter of up to 500 mm, subtract 30 cm from the freezing value of the soil, for a pipe over 500 mm, 50 cm. Let’s assume that the freezing value of the soil is 2 meters, then for a pipe up to 500 mm the laying depth pipes will be 2000-300=1700 mm or 1.7 meters.

In addition, when laying a sewer system, it is necessary to take into account the slope of the sewer pipe to the wastewater collection system or septic tank (if the sewer system operates on a gravity flow system). According to SNiP “... sections of pipelines with a diameter of 40-50 mm should be laid with a slope of 0.03, and with a diameter of 85 and 100 mm - with a slope of 0.02 mm.”

All these calculations refer to large projects and big houses, if you are laying pipes for country house the laying depth can be reduced to 0.7 m or 0.9 m in places with increased load (for example, where vehicles pass through).

Measures to reduce pipe laying depth

1. using a heating cable
2. use of high quality plastic pipes
3. trench insulation
4. increase in diameter and wall thickness

Using a heating cable

This is a successful solution to the issue of heating pipes, the cable is mounted on the outer surface of the pipe, it contains an automatic device that automatically turns on in those sections of the pipeline where problems arise with the temperature dropping below zero degrees.

Use of high quality plastic pipes

In our age of prosperity chemical industry, polymer pipes used for laying sewer networks have become especially popular. Modern construction of buildings does not provide for the provision of sewer systems with cast iron or asbestos-cement pipelines.

Compared to previous substances for making pipes, their plastic counterpart has quite a few “advantages”, namely:

• increased wear resistance
• plastic pipes are not subject to overgrowing
• no corrosion
• Due to the relative lightness and pliability of the substance, installation of networks does not require unusual skills or physical stress

TIP: polymer sewer pipes are practically not susceptible to freezing; if they are installed and used correctly, there is no stagnation of liquid in them, which can freeze.

Trench insulation

Insulation of the trench with expanded clay, mineral fiber or modern insulation materials. The thickness of the layer that provides thermal insulation varies between ten and eighty millimeters. The thermal insulation layer on top is covered with waterproofing (special hydrophobic materials).

Increasing diameter and wall thickness

Provided that pipes of increased diameter and high wall thickness are laid, the risk of sewerage freezing is significantly reduced.

In theory, a large volume of waste liquid is also beneficial in reducing the risk of freezing. In practice, it has been established that the volume of wastewater can be significantly lower than the planned volume, which has a bad effect on the freezing factor of the system. The large depths used for laying the network depend precisely on this natural phenomenon, they protect the network from freezing. The thickness of frozen soil in various areas is indicated in Construction Climatology, and the value of soil freezing can be found in construction documentation.

Important features of laying sewer pipes

1. When installing a pipeline system in basements with great depth, or in places with low relief, versions with an extremely low sewer installation depth are provided, in which installation is provided pumping station. The depth of the pressure line must be calculated according to the requirements of regulatory documents.
2. Practice has shown that in problem soils (water-saturated, compacted to strong and silty) communications should be laid to a depth of four meters, in dry soils the depth is determined from four to seven meters.
3. Communications built with a depth of less than 0.7 meters must necessarily have a sewerage protection zone on the surface of the earth. The security zone is equipped with a system to protect against possible mechanical damage to the pipeline.
4. When carrying out projects for laying sewer communications, it is mandatory to take into account the difference in terrain relief lines.

How to reduce the cost of laying pipes

To reduce financial investments in the installation of a sewer system, in order to obtain economic benefits, the minimum depth of the sewer system can be made, if possible, at the lowest possible level.

In order to achieve maximum benefits, the following conditions must be met:

• reveal the possibility of adding soil in certain areas of the network
• use high-quality sewer pipes with improved strength properties
• find the possibility of laying communications at shallower depths, use pumping stations

Implementation of the above measures will help to significantly reduce costs, volumes, and complexity of work.

After the construction of a sewer system, its owner is in a state of anxiety about the possible occurrence of any engineering problems in the network. During the operation of sewer networks, problems may arise, but to avoid them, the project must plan the construction of the network in accordance with the requirements of SNiP and other regulatory documentation. When implementing a project, it is necessary to strictly monitor the careful implementation of design surveys by the construction team.

As has been repeated many times in this article, the most significant quantity in construction design sewer network is the depth of laying the sewerage pipeline and the following main components of the projects depend on its planned value in various sections of the territory where the sewerage system is laid - its cost, the complexity of the design and the volume of work performed.