What is the slope of the sewer pipe is considered optimal in various situations

1 Why is it important to choose the right pipe slope?

When creating home sewage systems, it is necessary to correctly determine the slope under which the pipes will be laid. If the designer incorrectly calculates the angle of their descent, the sewer simply does not will work properly efficiency level.And over time, it will completely cease to fulfill its functions.

The correct slope of the sewer

Typically, home sewer networks operate on the principle of gravity. This means that a small angle of their descent can cause poor passage of sewage. An excessively large pipe slope will bring no less problems. In such situations, there is a rapid passage of water through the system. This leads to sticking of solid fractions to the inner surfaces of tubular products. After all, water in a banal way does not have time to wash off solid particles. Also, an excessive drop angle of the pipes often causes a breakdown in the siphons of water constipation, which causes an unpleasant smell emanating from the toilet to appear in the living rooms of a house or apartment.

There is also a purely practical reason why each user wants to know exactly which slope of the sewer pipe should be chosen. The bottom line is that the underfilling of the sewage system is the cause of accelerated rusting of sewer pipes. They last much less time than expected, and then require replacement, and immediately. You understand that such repairs cost homeowners a pretty penny.

Setting the slope when installing a sewer pipe

Mathematical calculations are easier to make than to withstand the required parameters when installing a domestic sewer. To facilitate the work can be a special construction device - a goniometer. However, you can do without it.

Since the difference in the position of one end of the drain relative to the other is known values, we calculate the required height and draw a line on the wall from the drain point to the intended location of the entrance to the plumbing fixture, taking into account the angle of inclination of the sewer pipes.Then the outlet is carefully installed and attached to the wall with holders in increments of 40 cm.

When installing sewers in private houses and apartments, it should be borne in mind that pipes of only a certain section are suitable for various plumbing, which affects the slope. For baths, sinks, washbasins and urinals, small pipes from 40 to 50 mm are sufficient. For kitchen sinks, where the amount of large food waste is greater - 50 mm, for toilet bowls - 100 mm.

The table shows not only the maximum slopes of the connecting sections for each home plumbing fixture, but also the approximate distances to the common drain pipe.

There are several rules that must be observed when carrying out work on the installation of sewerage networks in the house:

• channel straightness. Any curvature of the output paths are the "weak" points of the network, in which waste accumulates;
• the slopes of all plums of the dwelling should be the same. If on the first floor of a private house the slope value is 0.02, then on the second floor it should be the same. Then the operation of the entire system will be as productive as possible, without unnecessary noise and frequent accidents;
• minimum length. It is advisable to place all places in the room where plumbing fixtures are located close to each other. Then it will be much easier to comply with the required drain slope;
• smooth pipes withstanding slope. Any depressions on the inside of the sludge line are potential blockages. Therefore, corrugated pipes are not suitable. In some cases, a polypropylene pipe under the influence of hot water can “sag”, forming a counter slope. In this place, particles of food and other waste will inevitably gather. Such areas must be replaced.

Large pipes (110 and 200 mm) arrange outlets for external sewage. At the same time, the principle of straightness of the tracks is preserved. If it is impossible to avoid changing the direction of the channel, triple adapters are used with an inspection pipe with a plug on the surface, which will facilitate the cleaning of the drain.

The external sewer pipe is placed under slope, which is checked by a special two-meter level. After checking the parameters, it is covered with sand and soil. External sewerage is always arranged underground to avoid freezing of drains and blocking the possibility of draining. For each region, the depth of the sewer channels is determined based on the climatic features of the area.

The considered topic, with all the importance and complexity of the calculations, is quite simple. The use of the necessary values ​​​​during construction is facilitated by ready-made tables with the necessary numbers that will help you cope with the self-assembly of the system

But if necessary, you can always turn to specialists who will develop a project and select materials in accordance with established building codes.

I like it I don't like it

How to choose pipes

When choosing pipes, you need to pay attention to their color - sewer pipes are painted gray. A different cross-sectional diameter indicates that each type is designed to perform separate functions.

If an existing sewerage system is being reconstructed, for which there were no complaints, then the easiest way is to compare the diameter of the old pipes with the new ones - in this case, errors are practically excluded.

Depending on the purpose, sewer pipes and tees come in various diameters.

In addition, during installation, you need to consider what household appliances will be connected to the system.To drain the water from the dishwasher and washing machine, a diameter of 2.5 centimeters will be enough, for the bathroom and shower, 3.5 centimeters will be required. In general, pipes no more than 5 centimeters in diameter are run throughout the house, but for the riser you will need to purchase a pipe with a cross section of 11 centimeters.

In order not to buy unnecessary materials or miscalculate the calculations, it is best to measure the old pipes and make a corresponding purchase. In addition, in accordance with the old design, the same number of connecting elements is also bought.

How to choose a slope

To determine what should be the minimum pipe slope that will be optimal for you, you need to know the length of the entire sewer system. The directories use data immediately in finished form, they are depicted in hundredths of a whole number. Some employees find it difficult to navigate such information without explanation. For example, information in directories is presented in the following form as in the figures below:

Table: required slopes and diameters of pipes for drainingTable: slopes of outlet pipes in the apartment

Minimum and maximum sewerage slope per 1 linear meter according to SNiP

Below is a picture that shows the minimum slopes depending on the diameter per 1 meter running pipe. For example, we see that for a pipe with a diameter of 110 - the slope angle is 20 mm, and for a diameter of 160 mm - already 8 mm, and so on. Remember the rule: the larger the pipe diameter, the smaller the slope angle.

Examples of minimum sewer slopes per 1 meter according to SNiP in depending on pipe diameter

For example, a slope for a pipe with a diameter of up to 50 mm and a length of 1 meter needs 0.03 m. How was this determined? 0.03 is the ratio of slope height to pipe length.

Important:
The maximum slope for sewer pipes should not exceed 15 cm per 1 meter (0.15). The exception is pipeline sections whose length is less than 1.5 meters

In other words, our slope always lies between the minimum (shown in the picture above) and 15 cm (maximum).

Sewer pipe slope 110 mm for outdoor sewerage

Suppose you need to calculate the optimal slope for a common 110 mm pipe, which is used mainly in outdoor sewage systems. According to GOST, the slope for a pipe with a diameter of 110 mm is 0.02 m per 1 linear meter.

To calculate the total angle, you need to multiply the length of the pipe by the slope specified in SNiP or GOST. It turns out: 10 m (the length of the sewer system) * 0.02 \u003d 0.2 m or 20 cm. This means the difference between the installation level of the first pipe point and the last one is 20 cm.

Sewer slope calculator for a private house

I suggest you test the online calculator for calculating the slope of sewer pipes for a private house. All calculations are approximate.

Pipe diameter	50mm110mm160mm200mm	Estimated Slope:— Recommended slope:——
Leaving homebelow ground level	at depth cm
The depth of the pipe entry into the septic tank or central sewer	cm
Distance to septic tankthose. pipe length	m

The pipe diameter is understood as the diameter of the pipe, which leads directly to the drain pit or the general sewerage system (not to be confused with the fan one).

General recommendations for laying drain pipes

General recommendations will help you avoid the most common mistakes when laying drain pipes for domestic and external sewer systems. The following factors must be taken into account:

• Structural elements of the pipeline network shrink over time. As a result, it is necessary to periodically adjust the angle of inclination of the pipes.
• When changing the direction of the gasket, flange connections should be made at an angle of at least one hundred and twenty degrees. Otherwise, it will be necessary to equip an additional inspection hatch to control the pipeline network and clean it if necessary.
• The arrangement of a hidden sewage system requires a particularly thorough check of all elements of its design for integrity and the absence of leaks. In this case, the viewing windows should be located at a small distance from each other.
• Pipes are laid in the direction opposite to the flow of wastewater. Installation starts from the drain pipe with further advancement to the connected plumbing fixtures.

This is how the slope of the drain pipe for the sink looks like in practice

It is not difficult to maintain the required angle of inclination of sewer pipes during the construction of a home network. Previously, markings are applied to the wall, outlining the line of the pre-calculated slope. On it, the pipeline network is laid.

The work on arranging an outdoor system is somewhat more complicated. In this case, to ensure the required slope, it is necessary to dig a trench, the depth of which gradually increases. Control is carried out using the building level, the twine stretched at the right angle will greatly facilitate the performance of production manipulations.

Before going outside, I had to sharply lower the sewer pipe and install a revision of the problem area

The efficiency of the system largely depends on the correct angle of inclination of the pipeline network.It is necessary to adhere to the recommended standards. If you deviate from these parameters, emergency situations and clogging of the pipeline network will often occur.

We have selected a special video for you, which contains a lot of useful information on the sewerage device.

Storm sewerage of buildings and its slope

Storm sewers, or storm sewers, are used to collect and drain water that falls in the form of precipitation. Stormwater is designed to protect the building from unpleasant consequences - erosion of the base of the foundation, flooding of the basement, flooding of the adjacent territory, waterlogging of the soil.

Storm and domestic sewer systems operate separately; according to the norms of SNiP, integration into a common network is prohibited. In a closed-type storm sewer, water streams flowing to the ground enter through storm water inlets into a network of underground pipelines, from where they are discharged into a centralized sewer network or nearby water bodies.

The storm drain is filled extremely unevenly, during periods of peak load, the number of drains increases sharply.

Rules for laying stormwater

Pipes are connected both in a straight line and at an angle. If the site slopes away from the outlet, 90° elbow fittings are used to compensate for the difference in ground level.

Height difference compensation with fittings

For storm sewer lines with a maximum diameter of 250 mm, the maximum filling level is 0.6.

The minimum flow velocity for storm water with a period of a single excess of the calculated rain rate of 0.33 years is 0.6 m/s. The maximum speed for pipes made of metal, polymers or glass composite materials is 10 m/s, for pipes made of concrete, reinforced concrete or chrysotile cement - 7 m/s.

What regulations must be followed

The value of a suitable sewer slope depends on the size of the sewer pipe. For pipes with a diameter of 50 millimeters, the maximum slope is 3 cm per 1 meter of pipe. For pipes 110 mm minimum slope - 2 cm per 1 m of pipe.

The smaller the length of the system, the less important it is to maintain the angle of inclination. All necessary norms and rules are specified in SNiP 2 04 01

There are several ways to achieve the desired slope of sewer pipes.

Features of domestic sewage

Intra-house sewerage consists of pipes, siphons, ventilation pipes and channels, it may have special means of protection against flooding. In addition, it has various couplings, elbows, tees, adapters, gaskets, linings, sound insulation, fastening system, shut-off valves, plugs and some other narrowly focused devices that are used only in some cases.

There are several types of domestic sewage in a private house:

1. Cesspool pit. It is a drain hole, the bottom of which is covered with rubble and sand. It has a low cost, is easy to install, but at the same time it does not clean waste well, quickly silts up, pollutes the soil and has an unpleasant odor. Suitable for areas with low groundwater levels.
2. storage capacity. Its advantages are low cost and easy installation, but the tank fills up quickly, has an unpleasant odor, and a prerequisite for its use is the presence of an entrance to the tank.
3. Septic. Low cost, simple installation, but only partially cleans the waste, it is necessary to have a drainage system and call a vacuum truck once a year, the filtration field becomes unusable after 5 years.
4. bioremediation station.It cleans waste well, takes up little space, is easy to install, but it is expensive and requires electricity and a constant supply of air.

Sample interior wiring project

First you need to choose the right pipes. For horizontal pipes, a diameter of 50 mm is enough, for risers - 110 mm. The wiring is designed from the top floor.

Laying of external pipes

The outer pipes are made of plastic (polypropylene or PVC), have a diameter of 110-800 mm and hardness classes SN2, SN4, SN6, SN8, SN10, SN16, SN32. They are smooth inside and out. Polypropylene piping systems are resistant to corrosion caused by water from pH2 to pH12.

The table shows the optimal pipe slope for plumbing fixtures.

For laying external pipes, it is necessary to dig a trench. For pipes with a diameter of 110 mm, the minimum trench width should be 60 cm. You need to dig starting from the foundation of the house. A socket should be put on the end of the pipe leaving the structure.

Since blockages most often appear in pipe bends, for ease of access to blockage points, it is recommended to mount special inspection windows above all elbows. When the output from the house is ready, you need to start laying pipes and connecting them.

After connecting the sewer elements, it is necessary to insulate it. The last step will be backfilling the trench. It must be filled in layers 5 cm high each and compacted to the side of the pipe so as not to damage it. For backfilling, only soft soil without stones can be used.

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How is the optimal slope determined?

So, what needs to be considered when determining the optimal slope angle for internal sewage?

1. Diameter in a particular area.
2. Flow rate.
3. Filling indicator.

According to simple calculations, the filling factor of the pipe depends entirely on the flow rate. That is, a fast flow of water well flushes out the contents of the pipe, respectively, it fills up much more slowly. Conversely, if the water flow is slow, then the pipe fills up quickly, respectively, more water masses remain in the pipe than flows out.

At first glance, it may seem that everything is simple and easy. However, if you mistakenly allow a small slope angle, stagnation can quickly form. As a result, gravity flow will be practically impossible, this will lead to the fact that fat and other particles will have time to stick to the surface of the pipe, respectively, clogging cannot be avoided. A steep slope is also fraught with consequences, as discussed above.

Based on this, we can conclude that the correct slope of the sewer pipe will be in the case when all water suspensions, both light and heavy, will be constantly in motion.

Why you need to calculate slope

The slope of the pipe must ensure rapid drainage of water and the absence of deposits. With an insufficient slope, the drains do not pass well, the pipe will quickly clog. If the pipeline is inclined in the opposite direction with respect to the direction of discharge, the gravity system is completely inoperative.

Sewer pipe clogged with sediment

The decision to position the pipeline at the maximum angle of inclination seems obvious only at first glance. Too strongly inclined pipe is poorly filled, the conveying capacity sharply decreases.The waste stream flies by so fast that the water does not have time to capture the denser fractions that are deposited on the walls. Due to insufficient pressure, overall debris gets stuck. Gradually, the pipeline silts up and clogs.

How not to lay sewer pipes

In addition, with a quick drain, due to a sharp pressure drop, plumbing literally sucks water out of the water seals. Unpleasant air from the sewer enters the premises.

Water trap in the drain hose under the kitchen sink

There is another negative effect of underfilling the pipe. An additional influx of escaping caustic gases to metal surfaces causes accelerated corrosion, and the service life is reduced.

SNIP requirements for the angle of inclination

The pipeline that receives wastewater from the internal sewerage system and transports it to a septic tank or to the city network is an external sewage system. However, the volume of runoff from low-rise buildings and outbuildings is small (for a private house, 1–5 m3 per day). Its supply and degree of pollution are uneven. Therefore, it makes sense to use the rules and regulations governing the construction of both urban and domestic sewers.

Design parameters of the drainage pipeline connecting the internal and street networks:

• the diameter is the smallest and sufficient for efficient operation - 150 mm;
• its characteristic slope values ​​​​are 0.008–0.01 (for pipes 200 mm - 0.007).

In practice, for an autonomous gravity sewerage of a cottage, a diameter of 100 mm is taken as the minimum (then they “evade” the water supply more strongly).

A prerequisite for the device is floatable sewerage - the presence of water supply in the building. It will provide a volume of runoff (at least 60 liters per 1 inhabitant per day), capable of diluting pollution to the extent that will allow it to be transported by gravity in a closed channel.

The average daily water withdrawal is taken equal to the average daily water consumption minus the volume of water for irrigation. (The presence of hot water in the cottage increases the daily consumption - up to 250 liters per person).

The choice of a sewerage system (autonomous, local, centralized), the method of treatment and disposal of wastewater are consistent with Rospotrebnadzor, and when discharged into a water body - with Rosprirodnadzor, Rosvodresursami.

The marks of the bottom of the pipeline are determined by a heat engineering calculation or an analysis of the use of existing communications in a given area. In extreme cases, pipes up to 500 mm in diameter are buried 0.3 m above the lowest level of soil freezing.

One way or another, the deepening is considered safe if at least 70 cm are left from its top to the surface of the earth (if the passage of vehicles is excluded - 50 cm).

The maximum drop in pipeline marks is 15 cm per meter. (The highest design flow velocity of the medium is 8 m / s in metal, plastic pipes, 4 m / s - in concrete).

Deepening may also be excessive. The weight of which soil layer the structure can support determines the calculation based on soil conditions, material and size.

When designing an autonomous sewer, it is necessary to take into account the sanitary and hygienic requirements for autonomous water supply (in particular, to reduce to zero the likelihood of contamination of aquifers due to leaks from underground filtration facilities).

How to calculate?

So, if the pipes for a particular sewer are selected, their diameter is known, the required flow rates are taken into account and are related to the degree of filling, then you can proceed to the calculation with an example of pipes by diameter using the table.

The task of the calculation is the selection of the correct slope of the drainage system. To simplify the task, a metric scheme can be taken as a basis, which will be correlated with a specific building. We assign the diameters of the branch branches without calculation, for drains from the toilet - 10 cm, from other devices - 5 cm.

The highest throughput of a riser of 100 mm is 3.2 l / s, for pipes with a diameter of 50 mm - 0.8 l / s. Q (flow rate) is determined from the corresponding table and for our example this value is 15.6 l-h. If the calculated flow rate is higher, it is enough to increase the size of the outlet pipe, for example, up to 110 mm, or choose a different connection angle with the riser of a particular internal branch to the plumbing fixture.

Calculation of horizontal branches in the yard part includes the selection of sizes and geodetic angles of inclination, at which the speed will be no less than self-cleaning. For example: with products of 10 cm, a value of 0.7 m / s applies. In this case, the figure for H / d should be at least 0.3. The value is taken into account based on 1 linear meter of the drain outer pipe. In the calculation formulas, the coefficient K-0.5 is also taken into account if the pipeline is made of polymeric materials, K-0.6 for drainage systems from other bases

To achieve gravity flow, it is important to take into account the characteristics of the pipe material

Based on the results of the calculations, a number should be determined that determines the maximum and minimum angle of inclination of the line in the control well. At the beginning of the system, the indicator must be no less than the indicator mark in the collector.

When laying a drainage system on the street, it is important to take into account the depth of freezing. Depending on the region, this value can be from 0.3 to 0.7 meters deep

If the highway is laid in a place with an increased traffic flow, it is important for the system to provide a place for mounting protection against destruction by the wheels of cars. If such a device is provided, its location is also calculated by the formulas.

If we take as an example the calculation of the slope of a common version of a 110 mm pipe used for an external sewer system, then according to the standards, it is 0.02 m per 1 meter of the main. The total angle indicated by SNiP for a pipe of 10 m will be as follows: 10 * 0.02 \u003d 0.2 m or 20 cm. This is the difference between the beginning and end of the entire system.

You can also calculate the filling level of the pipe yourself.

This will use the formula:

• K ≤ V√ y;
• K - the optimal value (0.5-0.6);
• V – speed (minimum 0.7 m/s);
• √ y is the square root of the filling of the pipe;
• 0.5 ≤ 0.7√ 0.55 = 0.5 ≤ 0.52 - the calculation is correct.

In the example, the verification formula showed that the speed was chosen correctly. If you increase the minimum possible value, the equation will break.

Using the calculated and optimal filling level

Also in plastic, asbestos-cement or cast iron sewer pipe the filling level must be calculated. This concept determines what the flow velocity in the pipe should be so that it does not become clogged. Naturally, the slope also depends on the fullness. You can calculate the estimated fullness using the formula:

Y=H/D, where

• H is the water level in the pipe;
• D is its diameter.

The minimum allowable SNiP 2.04.01-85 occupancy level, according to SNiP, is Y = 0.3, and the maximum Y = 1, but in this case the sewer pipe is full, and, therefore, there is no slope, so you need to choose 50-60%. In practice, the estimated occupancy lies in the range: 0.3<Y<0.6. This coefficient is often taken as 0.5 or 0.6 and is considered optimal. Much depends on the material of the pipe (cast iron and asbestos fill faster due to the high roughness of the inner walls).

Hydraulic calculation for filling capacity and slope angle

Your goal is to calculate the maximum allowable speed for the sewer device. According to SNiP, the fluid velocity must be at least 0.7 m / s, which will allow the waste to quickly pass by the walls without sticking.

Let's take H=60 mm, and the pipe diameter D=110 mm, the material is plastic.

Therefore, the correct calculation looks like this:

60 / 110 \u003d 0.55 \u003d Y is the level of calculated fullness;

Next, we use the formula:

K ≤ V√y, where:

• K - the optimal level of fullness (0.5 for plastic and glass pipes or 0.6 for cast iron, asbestos-cement or ceramic pipes);
• V is the velocity of the fluid (we take a minimum of 0.7 m/s);
• √Y is the square root of the calculated pipe occupancy.

0.5 ≤ 0.7√ 0.55 = 0.5 ≤ 0.52 - the calculation is correct.

The last formula is a test. The first figure is the coefficient of optimal fullness, the second after the equal sign is the speed of the effluents, the third is the square of the level of fullness. The formula showed us that we chose the speed correctly, that is, the minimum possible. At the same time, we cannot increase the speed, since inequality will be violated.

Also, the angle can be expressed in degrees, but then it will be more difficult for you to switch to geometric values ​​when installing the outer or inner pipe. This measurement provides higher accuracy.

Slope of sewer pipes schematically

In the same way, it is easy to determine the slope of the outer underground pipe. In most cases, outdoor communications have large diameters.

Therefore, a greater slope will be used per meter. At the same time, there is still a certain hydraulic level of deviation, which allows you to make the slope slightly less than optimal.

To summarize, let's say that according to SNiP 2.04.01-85 clause 18.2 (the norm when installing water drainage systems), when arranging the corner of sewer pipes of a private house, you must adhere to the following rules:

1. For one running meter for a pipe with a diameter of up to 50 mm, it is necessary to allocate 3 cm of slope, but at the same time, pipelines with a diameter of 110 mm will need 2 cm;
2. The maximum allowable value, both for internal and external pressure sewers, is the total slope of the pipeline from the base to the end of 15 cm;
3. The norms of SNiP require mandatory consideration of the level of soil freezing for the installation of an external sewer system;
4. To determine the correctness of the selected angles, it is necessary to consult with specialists, as well as check the selected data using the formulas above;
5. When installing sewerage in the bathroom, you can make the filling factor, respectively, and the slope of the pipe, as minimal as possible. The fact is that water comes out of this room mainly without abrasive particles;
6. Before you start, you need to make a plan.

In order to maintain the desired angle during installation, it is recommended to dig a trench under a slope in advance, and pull the twine along it. The same can be done for gender.

Installation of internal sewerage

When laying the internal sewage disposal system, it is necessary to maintain the required slope, avoiding sagging and bending of the elements in the sections of the sewer system. When installing the system, it must be taken into account that in each section, depending on the purpose and section of the pipeline, it is necessary to observe a different angle of inclination. For clarity, we suggest that you familiarize yourself with the table of slopes of elements from various drainage points.

How to withstand the necessary slopes? Repulse the level using a specialized tool (water, laser level or level), after which you should draw a laying pattern on the wall, the lines of which should be used to create a strobe in each section of the system. If it is impossible or impractical to ditch the walls, use special wall holders to fix the elements.

Setting the slope when installing a sewer pipe

The direct installation of the sewerage system is preceded by the correct selection of fittings and pipes of the desired diameter. In doing so, the following must be taken into account:

• Plumbing points are connected to the sewerage using nozzles, the diameter of which must correspond to the diameter of the pipe.
• To calculate the diameter, you should use the data indicated in this review. More detailed information can be obtained from SNiP - 2.04.01-85.

Considering that the internal network of sewer pipes is mainly located along the walls, a projection previously drawn on the walls can be used to set the desired slope during installation.At the same time, brackets (clamps) are installed at the reference points along a given line, which will further simplify installation and will hold the pipes in working position.

Scheme of sewer pipes

To set the optimal outdoor sewage street, a sand mounting pad is created in a trench dug under a calculated slope. After complete assembly of pipes on a sandy base, the entire system is additionally checked by level and, if necessary, corrected in place (add or remove excess sand).

External sewerage, when lying above the freezing level of the soil, requires additional insulation. Otherwise, wastewater may freeze in the pipes, which will lead to their rupture and failure of the entire system. The level of freezing must be specified for a particular region.

As a conclusion, it is worth noting some points that directly or indirectly relate to the topic of setting the slope of the sewer pipe. So, when installing the sewer system in the premises of the house, it is worth periodically checking the shrinkage of the outlet pipes and, if necessary, adjusting the slope level. When installing a hidden sewage system, before final installation, it is necessary to carefully check the tightness of the connections and provide for the presence of inspection hatches.

Individual slope calculation

Do-it-yourself sewer pipe laying in a private house is carried out according to the standards that appear in SNiP. But you can calculate the parameters for the arrangement of sewerage and water supply networks on your own. To do this, use the following formula:

V√H/D ≥ K, where:

• K - a special coefficient that takes into account the properties of the material that was used in the manufacture of the pipe;
• V is the rate of passage of wastewater;
• H is the filling capacity of the pipe (flow height);
• D - section (diameter) of the pipe.

The slope of the sewer pipes can be calculated independently

Explanations:

• coefficient K, for pipes made of smooth materials (polymer or glass), should be equal to 0.5, for a metal pipeline - 0.6;
• indicator V (flow rate) - for any pipeline is 0.7-1.0 m / s;
• H / D ratio - indicates the filling of the pipe, and should have a value from 0.3 to 0.6.

Internal and external sewer systems

When laying sewerage and water supply networks in a private house, one should take into account some features that are determined by the location of their individual sections.

Internal systems

When installing pipes sewers in a private house are mainly used in their two diameters - 50 mm and 110 mm. The first for drainage, the second for the toilet. Sewer pipe laying should be carried out in accordance with the following recommendations:

• turning the pipeline (if it is horizontal) should not be done at an angle of 90 degrees. To change direction, it is better to install bends at an angle of 45 degrees, this greatly facilitates the passage of the main flow and reduces the likelihood of accumulation of solid particles;
• fittings should be installed at the points of rotation of the system for revision and ease of cleaning or dismantling in case of clogging;
• in short individual sections, it is permissible to increase the slope, exceeding the recommended rate. Such a short sewer branch can be a pipe connecting the toilet to the riser;
• on each individual section, the slope of the pipeline must be uniform, without sharp drops, because their presence can create a condition for the occurrence of water hammer, the consequences of which will be the repair or dismantling of an already operating system.

External (outdoor) systems

Proper laying and installation of sewer pipes is necessary not only inside, but also outside a private house, from the exit point of the internal sewer to the septic tank.

Therefore, you should pay attention to the following points:

• laying of sewer networks is carried out in trenches with a depth of 0.5 to 0.7 meters. The depth of penetration depends on the characteristics of the soil and is adjusted for specific conditions;
• when preparing trenches, sand should be used at their bottom, in order to be able to establish the correct slope due to its backfilling;
• the pre-calculated slope (per linear meter) should be highlighted with a guideline from a cord stretched between the driven pegs. This will avoid unnecessary subsidence or elevations of the sewer system in certain areas;
• after laying the pipes at the bottom of the trench, once again check for the correct slope, and, if necessary, correct it with a sand cushion.

Storm sewer

The same slope-demanding system, and its presence is indispensable to eliminate the formation of water accumulation on the soil surface during precipitation.

Storm sewer laying

When arranging a storm drain, the same parameters are taken into account as for the main sewer - the diameter of the pipe and the material from which it is made. Slope averages:

• for pipes with a diameter of 150 mm - the indicator varies from 0.007 to 0.008;
• at 200 mm section - 0.005 to 0.007.

On private courtyards, you can get by with open storm drains.

But even with such a water drainage system, the slope must be present:

• for drainage ditches - 0.003;
• for trays made of concrete (semicircular or rectangular) - 0.005.

When laying sewer pipes, what slope of the sewer pipe should be?

Scheme storm sewer devices for a private house

For normal operation of the sewer, the slope must be in accordance with the recommended standards for SNiP, or calculated using a special formula.

If you adhere to time-tested and operational standards, sewerage and water supply systems will not require repair or dismantling for many years.