The sewer system is a basic element of comfort and coziness for residents of a private house. Its construction requires strict adherence technical regulations provided for by SNiP. Ignoring the calculated data included in them will inevitably lead to disruption of the uninterrupted functioning of the wastewater disposal structure. In the individual sector, as a rule, it is of a non-pressure nature. Water and organic matter are driven by gravity, that is, by gravity. The slope angle plays a decisive role sewer pipe. Its exact definition depends on a combination of factors. They consist of the diameter of the pipe, the material of its manufacture, the total length of the pipeline, and its filling level.
Choosing an angle of inclination for external sewerage
During construction sewer system it is taken into account that it is complex technological device, combining several pipes, plumbing fixtures and a treatment facility. Not only water is transported through it, but also solid inclusions of an organic nature. Most often they are represented by food debris, fat, vegetable and fruit peels, and feces. Fractions have different speeds of movement through the pipe and a tendency to form blockages. If some of the drainage does not reach the end point (treatment well), then over time the blockages will completely block the pipe. A complex procedure for cleaning the water supply will be required. In a normal system, organics are pushed through the pipe by liquid components.
If the minimum sewer slope is less permissible norm, then organic elements are not able to independently move along the highway, and the water does not have enough kinetic and potential (gravitational) energy to wash them away. This leads to the formation of molding deposits with subsequent disruption of the entire drain.
An excessively high sewer slope in a private house leads to the liquid speed limit being exceeded, which at a minimum pushes water out of the hydraulic barriers. The main barrier to penetration is removed sewer odors to the house. There are frequent cases of siphons being completely knocked out of the system by water, with obvious negative consequences.
The question arises, what should the slope of the sewer pipe be and how to calculate it? The answer to this lies in the accurate calculation of the speed of liquid fractions along the drain. Regulatory documents recognize that the norm is 0.7-1 meters per second. Further calculation of the angle of inclination is made based on complex mathematical formulas. The final data are summarized in various tables. Homeowners can easily glean the necessary information from them and determine which slope is right for them. The peculiarity of the construction of structures for sewerage is to measure the angles of laying pipelines not in degrees or radians, but in millimeters and centimeters per 1 linear meter.
The angle of inclination of the sewer pipe depends on the degree of filling of the system. This indicator is directly proportional to the volume of the liquid medium in the water conduit and inversely proportional to the diameter of the water conduit. A zero value indicates the absence of wastewater in the structure, 1 indicates its filling. Indicators of 0.5 for plastic and 0.6 for cast iron, reinforced concrete, and asbestos concrete pipes are considered appropriate.
Tilt data internal sewerage according to design standards are given in table 1.
Correct slope of sewer pipes outdoor system comparable to indicators internal structure. For a pipe of 110 mm diameter it is 0.2. With a diameter of 160 mm, the minimum slope external sewerage determined by an indicator of 0.008 (normal 0.01). With a diameter of 200 mm – 0.008 (recommended) and 0.006 (minimum). 50 mm pipe is used in external system rarely. But in external distribution networks, water conduit 50 is common. In them, the sewer slope reaches 0.04.
In fecal economic activity private sector, the slope should be:
Table 2. Sewage angle in the private sector, mm
The minimum slope values of the sewer pipe in SNiP are given to determine the lower limits of the use of the structure. Installing a system with such an angle will inevitably lead to frequent silting and clogging of the pipeline. It is better to focus on numbers close to the optimal options.
Selecting the slope of an external sewer with a 110 mm pipe
In the external sewer system of a private house, the most common pipe is 110. Experts have already determined the minimum and optimal angles for laying it, depending on the material of the product. However, practice shows that there are often times when strict adherence to standards does not lead to efficient work designs. It often becomes clogged, and it is not possible to achieve optimal fluid speeds. There is a need to increase the slope of the sewer pipe to 110 mm. Homeowners need to find out what maximum sewer pipe slope is allowed by regulations. This is where they run into problems.
A pipe with a diameter of 110 mm in an external sewer cannot be classified as an element of the city sewerage system. Among other options, the documents regulate intra-block, street, industrial and domestic sewerage in relation to external networks. In the Code of Rules of 2012, as minimum diameter for external networks the figure is 150 mm. For them, the optimal pipeline inclination angle is 0.02. Therefore, widespread tabular information indicating slope parameters of the same 2 cm per 1 meter for a 110 mm pipe for external sewerage requires additional justification.
efficient experts suggest calculating the sewer slope per 1 m with expanded values (2 - 2 cm). If with normal values angle the situation is more or less clear, then with the question of what maximum slope is permissible - no. The SP does not mention diameter 110. In SNiP 1985, for pipes of all diameters, the maximum height difference is 15%. Calculations demonstrate the need to achieve an inclination angle of 0.005 (5 cm per meter). The construction of a sewer structure with a slope less than this indicator is safe. Taking into account that the total length of the water pipelines is insignificant and rarely exceeds 30 meters, the height difference between the upper and lower points will be 1.5-2 meters at maximum. This is not significant for construction.
When installing a 110 mm pipe, the point where the riser exits the house is taken as the upper reference point of the external sewer system. The depth of laying the pipe depends on the level of soil freezing. The pipe is laid with the expectation that it will be completely below the freezing point. The entry point of the main line into the drain well is determined by subtracting the zero mark (connection of the riser to the main line) and the height difference. It is determined by multiplying the angle of inclination by the length of the conduit. In accordance with SP, 110 will fall under the category of products with dimensions less than 150 mm. When passing at a depth of 1.2 meters, construction is permitted for them manhole minimum diameter (600 mm). Through them, cleaning devices can be introduced into the system without letting people down.
It is impossible to lay sewer pipes as you wish, for the simple reason that a private house uses a gravity sewer system. That is, used water and sewage flow into treatment facilities independently under the influence of gravity.
Such systems have special requirements. One of them is the angle of inclination of the pipes. If the slope is made small, water will stagnate in the pipe, which will lead to blockage. With a large slope, the liquid flows faster than heavy fractions, which will settle and accumulate on the walls of the pipeline.
In addition, a strong angle leads to noise from sewer pipes when draining water. Therefore, in order for the sewerage system to work without failures, it is necessary to correctly calculate the angle of inclination of the pipes.
Slope calculation
The minimum pipe slope at which the sewage system will work effectively can be calculated using the formula: U = L × Y. Where U is the slope, L is the length of the pipe, Y is the minimum slope value.
Let's imagine that:
- L = 5 m
- Y = 0.07
Then: U = 5 × 0.07 = 0.35 m.
The optimal difference between the beginning and end of a 5 meter long pipeline is 35 cm.
The design of the sewer system is determined by building codes and regulations (SNiP) and must be taken into account at the design stage of the house. In accordance with SNiP optimal inclination sewer pipes with a diameter (Ø) of 50 mm is 3 cm per 1 linear meter. For pipes Ø 100 mm, the slope will be 2 cm.
The table below shows the main values of the angle of external sewerage based on SNiP 2.04.03-85 (clause 2.41) and SNiP 2.04.01-85 (clause 18.2)
External sewage standards
Tilt device during installation
Additional requirements
- For external sewerage pipes, the rules provide for a number of additional requirements:
- The maximum slope is 15 cm/m, with the exception of pipeline sections shorter than 1.5 m;
- The bottom of the trenches must be solid, without stones or sharp inclusions. A sand cushion is required; it must contain sand and fine gravel of a 20 mm fraction. Pillow thickness from 10 to 20 cm;
- The distance from the walls of the ditch to the edge of the pipe is 20 - 30 cm on each side;
- Sewage pipes are laid below the soil freezing level; if it is impossible to fulfill this requirement, they.
Construction reference books They offer two methods for calculation: using the formula (described above) and tabular. The table below shows average values for pipes of different diameters.
From all of the above, it turns out that the optimal slope in the external sewerage network is from 1.5 to 2 cm per 1 linear meter, depending on the diameter of the pipe and the material. For normal operation The entire system must comply with the rules of installation and operation.
Video: sewer slope and their installation methods
The wastewater system is an integral part of any home. In order for it to function correctly, you need to arrange it correctly, that is, choose the right angle at which it will be laid. Many people ask a well-founded question whether, according to SNiP, a sewerage slope of 1 meter will be sufficient or whether it needs to be made larger (or maybe smaller). Let's figure it out.
On a note! Even if you install a wastewater system under right angle, this will not guarantee normal and durable operation of the sewer system. Since there are a number of other points that need to be taken into account when installing it: location (pipeline layout indoors or outdoors), configuration, diameter and material of pipes.
Why is the tilt angle needed?
Why do we need a very specific angle of inclination of the wastewater system? Maybe it’s enough to just lay the pipes and not “bother” about how to make the sewerage slope 1 meter - the recommended values according to SNiP?
The main arguments for installing a sewer system at a certain angle:
- Without it, the liquid will begin to stagnate in the pipes (and this is not good).
- The sewerage system must function without any failures, despite the impossibility of predicting the consistency and nature of the wastewater.
- The main purpose of arranging a slope is the desire to practically minimize the possibility of settling of solid fractions (or sludge) on the walls of the laid pipeline.
- Ensure silent operation of the system, while preventing the backflow of wastewater and eliminating the unpleasant odor directly in the room.
Too little slope or too much - which is better?
The most important thing is to determine exactly the minimum slope, since if it is too small wastewater will not leak out completely. As a result, you will inevitably end up with clogged pipes and all the ensuing consequences.
Fine. Maybe then do it big slope and be sure that everything is in order with the leakage of liquid and not have to calculate the minimum angle so that the slope of the sewer pipe by 1 meter - the recommended values according to SNiP - is observed? No, it's bad again. This is not an option. The fact is that if the slope is too large, large fractions are absolutely guaranteed to accumulate in the pipe and contribute to the formation of a blockage. The fact is that with a very large slope, the liquid quickly flows out, and to remove solid elements it takes more time (and there is nothing to wash them off with). As a result, the pipe is clogged and you panic.
It turns out that we need to find a “golden mean”, namely, determine the minimum angle of inclination of the wastewater system so that it functions well. If the design and installation of the sewer system are carried out strictly according to the standards of such a document as “ Building codes and rules”, that is, the sewerage slope of 1 meter (SNiP recommended values) is maintained, this will significantly increase the service life of the system that removes wastewater, and, naturally, the quality of its work.
Calculate the minimum angle of inclination
To determine the minimum angle of inclination, it is necessary to perform mathematical calculations using a certain formula. Here it is - V√H⁄D≥K: V - liquid drainage speed (optimally, it is 0.7 m/s); H - waste liquid level (that is, it determines the degree of filling of the pipeline and should be about 50-60%); D - pipeline diameter; K is the pipeline slope coefficient (optimally, it should vary from 0.5 to 0.7; that is, the closer to 1, the better).
Important! The degree of filling of the pipeline should not be less than 1/3.
Pipeline slope coefficient
This indicator can be determined in two ways:
- Calculate it yourself using the formula - H/D.
- Refer to reference material.
On a note! The value of this coefficient indicated in the reference book is directly dependent on the material from which the pipes are made: 0.5 - for glass and plastic; 0.6 - for materials such as cast iron, asbestos cement or steel. Also, do not forget about the degree of roughness of the inner surface of the pipe, which negatively affectsK.
It is known from practice that approximately a slope of 20 mm (per 1 meter of sewerage pipeline) will be sufficient.
Pipe diameter
If you don’t want to make any calculations, you can do without them: it is possible to determine the required slope of the sewer system depending on the diameter of the pipes. Practical, convenient and fast.
Naturally, all this can be done if the diameter is selected in such a way that the conditions for pipeline fullness (50-60%) and fluid velocity (0.7 m/s) are met. Otherwise, nothing will work.
As a rule, the calculation simply comes down to choosing a certain diameter (200, 150 (160), 100 (110), 80, 50 mm) and specifying the angle of inclination accordingly.
Important! Don't forget about the margins of error.
In SNiP, depending on the diameter, the values of the minimum and maximum slopes. If you multiply these values by 100, you will get these figures in centimeters.
Important! All these values can be used for arranging slopes exclusively on flat areas (that is, without connecting to outlet pipes, siphons and other systems).
Wastewater system location
There are two wastewater systems:
- Internal. This is a set of pipelines that ensure the removal of existing wastewater from plumbing devices and their removal outside the building. Most often, owners of private houses arrange such a system on their own. Fortunately, the construction market offers a wide range of different plastic elements.
- An external wastewater system ensures the delivery of wastewater from the building to the septic tank (storage and treatment complex).
Internal piping
In addition to the slope of the internal sewerage system by 1 meter (SNiPom recommended values), the following recommendations must be adhered to:
- We use pipes with a diameter of 100, 80, 50 or 40 mm (and a diameter of 100 mm is used to connect zones general purpose, that is, in places where pipelines converge).
- We make the most optimal slope values for pipes of these diameters, namely: 0.015, 0.2, 0.03 and 0.035, respectively.
- If according to technological process it is necessary to use adapters (for example, when moving from a larger size to a smaller one), we do this in such a way that the evenness of the lower part of the channel is not disturbed. Otherwise, the continuity of water flow may be disrupted.
- We provide the required slope using fastening systems or the slope of the box in which we install the sewer system.
On a note! We make sure to maintain the required slope when installing the pipeline from the device to the sewer system. Moreover, we equip the turn to such a system with a tee or elbow (the inclination should be about 70 degrees).
- We do not allow pipes to bend at right angles. We use exclusively bends (at 45 degrees and only).
On a note! If the pipe is of insignificant length, then deviation from a certain slope is quite acceptable.
External piping
In addition to the slope of the external sewer system by 1 meter (SNiP recommended values), the following recommendations must be adhered to:
- Depending on the soil and climatic conditions, the depth of the trench can vary between 100-200 cm.
- To correctly carry out the required slope, do not forget to take into account the ever-increasing recess. To do this, we initially make the depth deeper by 25 centimeters, so that it is convenient to arrange a sand support for the system.
- We carry out the line at a depth below the freezing level (350 mm). When laying above the level, it is worth considering enhanced thermal insulation.
- The diameter of the pipes used is 110-200 mm. In this case, the minimum slope is: 200 mm - 7 mm, 160 mm - 8 mm. But according to SNiP, the sewer slope per 1 meter (110 mm pipe in diameter) is about 20 mm.
Remember! If you want the slope to be most effective, follow the rule: the slope is no more than 150 mm (based on each linear meter).
- We place the pipes at the same level, without changing the slope along the entire length.
Remember! It is unacceptable to combine pipes of different diameters. Also, level differences in the gasket should not be allowed. If such a need arises, then the installation of a manhole is mandatory.
Storm sewer
Function storm sewer- drainage of melt and rain flows (to avoid waterlogging of the area and preserve the foundation of the building).
In addition to the slope of 1 meter (SNiP recommended values), other factors must be observed, namely: the type of drainage system and the diameter of the pipe.
On a note! The minimum slope for drainage of melted water should be as follows: 7 mm (for pipes with a diameter of 200 mm) and 8 mm (for 150 mm).
In addition, other points need to be taken into account: characteristics local soil, average precipitation for the region of residence and the volume of wastewater.
Pipe configuration
Is the condition of a sewer slope of 1 meter (SNiPom recommended values) the only one for quality work sewage system? No. There is one more important condition, without which blockage is inevitable. This is the configuration of the laid pipeline. After all, if she is too “sophisticated” and has a large number of bends, then wastewater will not be able to quickly flow (without lingering inside the pipes) into the collector, and then straight into the treatment plant. In this case, no sewer slope of 1 meter (SNiP recommended values) will save the situation.
Pipe material
Can be:
- plastic;
- cast iron;
- concrete;
- asbestos-cement;
- ceramic.
Most often, for the construction of an internal sewer system they use plastic pipes, and for the outside - asbestos-cement, cast iron or corrugated.
Finally
After reading the article, it becomes clear that the maximum (recommended by SNiP) will not solve the problem, but will aggravate it. Only correct solution- determination of the minimum angle of inclination. And, of course, do not forget about the configuration and material of the pipeline. And you will be happy.
For slope of external and internal pipes sewerage in a private house, as well as for laying sewerage in an apartment, exact standards have already been calculated and the corresponding SNiPah recommendations have been submitted. However, very often for proper outflow it is necessary to calculate the optimal level of slope based on individual parameters, type of room, material and pipe diameter.
Let's consider SNiPs, recommendations and calculation formulas for what slope a sewer pipe should have for a length of 1 meter in different cases- in an apartment, private house, indoor and external network and depending on the material used to make the sewer pipes.
For the normal operation of the sewer system, it is extremely important to do accurate calculations. What are the consequences of mistakes?
- Too much slope will lead to accelerated outflow, which will be accompanied by loud noise. At the same time, the inner surface is quickly erased and self-cleaning slows down.
- Insufficient level threatens to clog the system, especially if it does not have a sewage pump. The location of a pipeline blockage is difficult to diagnose and repairs take a long time.
It is best when the movement of waste occurs at a speed of 0.7 -1 m/s. IN In the calculation process, it is necessary to take into account the diameter, material and fullness (hydraulic pressure) of the pipes.
SNiP
When designing a sewer system, it is customary to be guided not by formulas, but by the values given in SNiPs. Installation inside the building is regulated by the requirements of section 2.04.01-85, and outdoor installation - by section 2.04.04-85.
Different calculation methods are needed for multi-story buildings and large residential complexes.
All figures are given in the form of coefficients and measured in centimeters per linear meter. The designation in degrees is not used due to large errors in the installation process to a septic tank or sewer well, which are located at a distance of 10-12 m from the house. So, for a diameter of 40-50 mm and a septic tank distance of 12 m, a coefficient of 0.03 (3 cm/lm) is applied, and for a cross-section of 85-100 mm - 0.02.
Minimum permissible slope for outdoor and internal lines sewerage according to SNiP is 0.015; when the slope of sewer pipes is less than the minimum angle, solid particles remain in the pipe. On small areas– no more than 1 m, a coefficient of 0.01 is allowed.
Maximum slope external and internal sewerage according to the standards does not exceed 3% and generally depends on the flow speed; in plastic sewer pipes, a speed of up to 1.4 m/s must be maintained, otherwise the flow will be divided into fractions and solid particles will remain in the system.
Calculation for an apartment
For sinks, sinks, washbasins and bathtubs, pipes with a diameter of 40-50 mm with a slope of 2.5 cm to 3.5 cm per meter are selected. To drain wastewater from the toilet, the line diameter is 100 mm. The minimum value per linear meter is 0.012, and 0.02 is considered the norm. During installation, a bubble or laser level is used.
Can be used separately complex formula Callbrook-White. It looks like this:
Sewerage in multi-storey buildings located vertically. The drains move along the diameter of the walls, and in the center of the flow - compressed air. With this flow, blockages almost never appear.
Calculation for a private house
For small volumes of wastewater, calculations are not necessary. The main thing is that the slope is not less than the minimum allowable according to SNiP standards.
It is important that the slope and cross-section of the sewerage contributed to the filling of the pipeline by at least a third of the diameter.
To increase maintainability and service life, it is recommended to use pipes made of the same material.
Typically, preference is given to sockets mounted against the flow in the main. If it is necessary to change the direction of flow, it is advisable to avoid sharp turns.
So, instead of one fitting for 90 o, it is advisable to use 2 x 45 o.
When forced external sewerage All plumbing is located below the level of the septic tank. Calculating angles along the entire length of the pipeline becomes irrelevant. It is only necessary that the sewage be fed by gravity to a single collector and pumped out from there. Find out what pipes are used for external sewage from this.
Second option– installation in the system after each plumbing fixture. We will tell you how to properly install a sewer system in a private house in this article.
Optimal values for an outdoor system
When laying an external sewer system, the point at which the pipeline exits the wall or foundation is taken as the basis. The rule is followed: the smaller the cross-section, the greater the slope. For normal outflow with a diameter of 110, 0.02 is enough, and for pipes 60-80 mm, 0.03 or more is needed.
There are 3 main factors to consider:
- Relief. Drain wells are usually located at the lowest point of the site, so the natural slope of the trench is also added.
- Pipeline depth near the septic tank should not be lower than the inlet hole in sewer well.
The slope should be rational so that you don’t have to dig a drainage basin too deep - this is both expensive and dangerous due to groundwater entering the septic tank.
- Trench must be deeper than the freezing level of the soil.
Rules for installing internal pipelines
When laying, where all points are reduced to one riser, The drain volume is calculated in total for all devices, connected to the highway. Floor unevenness must be calculated so that the slope and height difference between the plumbing fixtures and the drain are consistent with SNiP standards.
During the design and installation process You need to pay attention to a few more points:
- Natural shrinkage. The soil may be compacted by the action external factors, resulting in a change in slope.
- On separate areas it is advisable to put inspection hatches in increments of 30-40 cm in case of clogging due to poor outflow. For the same purpose, specialists connect pipes at an angle of at least 120°.
- Calculations are carried out starting from the outlet point of the sewer, but installation always occurs in reverse order– in the direction from the drain well.
- The project is designed so that the line length is minimal. The shorter the line, the less likely it is to become clogged or break down.
The correct location of sewer drains avoids blockages and ensures long term all communications services.
The optimal calculation option is orientation to SNiP standards and accounting individual characteristics buildings and locations of bathrooms. Upon completion of installation, before digging the trench, all elements of the main line are checked for tightness and reliability of outflow.
This article discusses in detail such a nuance of system installation as the correct sewerage slope of 1 meter: SNiP and regulatory requirements that should be followed in practice, optimal indicators for certain areas, recommendations for organizing pipeline layout. The text contains an overview of common mistakes and tips to help avoid them, and formulas that you should rely on when designing a drainage line.
To ensure correct and uninterrupted operation when designing the system, it is necessary to comply with SNiP standards
Comfortable stay in country house is possible only if there is a system designed for the drainage and disposal of domestic wastewater. For these purposes, an autonomous sewage system (centralized for apartments) or a septic structure is used. Inside the system, the movement of waste liquid through pipes is carried out in a non-pressure manner. In other words, contaminated wastewater is transported to the purification site by gravity. This is facilitated by natural gravity, which is achieved due to the slope of the highway.
Important! Natural gravity appears only if the sewerage system is located at a certain slope. In this case, the system will function normally only if the sewerage slope for each meter of pipeline complies with the regulatory requirements of SNiP.
The optimal slope coefficient also depends on additional factors:
- diameter of pipeline elements;
- the material from which the pipes are made;
- schemes of external and internal placement of sewerage systems.
Despite its apparent simplicity, as a result of incorrect design of sewerage treatment facilities and drainage mains, blockages and traffic jams can form in the collectors, and the system itself will not be able to fully perform its main task.
How to avoid mistakes when installing sewerage in an apartment with your own hands
When it comes to pipeline slope, it is important not to go to extremes. There are only two types of popular mistakes that inexperienced people make when building a sewer system.
In the first case, there is no slope of the line or it is not enough to move the liquid by gravity. As a result, the flow rate decreases, which is why dense fractions are not washed away, but remain on the inner walls of the pipes. There is a gradual accumulation of sediment, which develops into a blockage.
Partially waste water with fractional impurities various densities lingers on the walls of the pipeline, as a result of which the pipeline becomes covered with silt and begins to leak unpleasant odors, which penetrate back into the room. Therefore, you will have to regularly clean the sewer in a private house or apartment where the installation of the system was carried out in violation of the requirements.
Excessive tilting of the system can also create the prerequisites for frequent cleaning for preventive purposes. An intense flow of liquid at high speed will not be able to capture solid particles from the walls and wash them away. Moreover, in the process of moving water, fecal fractions will be layered and pressed on the walls of the sewer. In this case, all shut-off valves and pipe joints will be subject to severe stress, which increases the risk of failure. Therefore, it is very important to adhere to the recommended parameters prescribed in SNiP documents.
Organization of water supply and sewerage: SNiP internal and external networks
First of all on throughput pipe is affected by its diameter. Therefore, it is recommended to select the angle of laying the highway based on the cross-sectional dimensions of its elements. The larger the diameter of the product, the smaller the slope that is optimal for moving water will be.
Minimum permissible angles of inclination per 1 m of pipeline, taking into account its cross-section:
| Pipe cross-section, cm | Minimum angle tilt |
| 4 | 0,025 |
| 5 | 0,2 |
| 7,5 | 0,013 |
| 11 | 0,01 |
| 15 | 0,0007 |
| 20 | 0,0008 |
If the pipe diameter is 5 cm, then taking into account the minimum angle (0.02) after installing the system, the difference in height between the placement of the ends of a 1 m long section will be 2 cm.
Important! When installing sewerage in a private house, it is not recommended to install pipes at an angle corresponding to the maximum permissible value.
Calculation of pipe filling for the use of SNiP 2.04.01-85 when installing internal sewerage
The recommended parameters for the arrangement of internal sewerage are clearly indicated in SNiP. This data is contained in regulatory document 2.04.01-85, which can be used as a set of rules and the basis for the construction of a communication system for the removal of wastewater.
Calculation of the pipeline fullness indicator is carried out taking into account the characteristics of the material from which the system elements are made. Based on these data, through calculations, you can find out at what speed wastewater should move through the sewer so that blockages do not occur inside the main line. The filling level is taken into account when choosing pipes for the construction of a drainage system.
The following formula is used for calculations:
N=V/D, Where:
- N – level of fullness;
- B – drainage height level;
- D – pipe diameter.
The maximum fill level value is 1. In this case, the slope of the internal sewerage is completely absent, and the degree of filling of the pipe is 100%. The best option placement of the system is 50-60%. In this case, the material on which the pipe is made is of considerable importance, as well as its angle of placement relative to the local treatment plant sewerage - septic tank.
Products made from cast iron or asbestos cement have a rough surface. The presence of texture on inside pipes are provided fast filling. The main purpose of such calculations is to establish the maximum permissible speed in the drain. According to standard standards, the minimum speed of movement of waste liquid is 0.7 m/s. The minimum permissible pipe fill rate is 30%.
Calculation of the speed of movement of wastewater in the internal sewerage network, SNiP and restrictions
For further calculations for free-flow sewerage, you will need the following formula:
V (h/d) ½ ≥ K, Where:
- V is the speed of movement of wastewater within the system;
- h – degree of pipe filling (level of waste in the lumen of the product);
- d – pipe section size (diameter);
- K is a coefficient that depends on the roughness of the inner surface of the pipes and the material of their manufacture, as well as the hydraulic resistance that affects the flow.
For polymer pipes the reference coefficient is 0.5. Other materials correspond to the indicator 0.6. In practice, the consistency of wastewater and its quantity are not constant values. Therefore, it is not always possible to accurately observe the filling of the sewer and the speed of movement of the water flow.
Helpful advice! If it is not possible to perform calculations due to the lack of accurate data using the previously specified formula, you can use the minimum angle of inclination to lay sections that cannot be calculated. It can be obtained using the formula: 1/D, where D is the size of the outer diameter in millimeters.
The optimal pipe diameter for installing internal sewerage is 40, 50 and 60 mm. Unlike SNiP, the current set of rules, which was approved in 2012, does not impose restrictions on the maximum angle of inclination of the pipeline. The minimum angle can be viewed in the table. For a pipe with a cross-section of 80 mm, the coefficient is 0.125.
Arrangement of external and storm sewerage: SNiP 2.04.03-85 and its requirements
External sewerage removes waste liquid from plumbing fixtures installed inside a residential building, and also collects rainwater from the site during heavy rainfall due to storm system. Most often, asbestos-cement and cast iron pipes. The use of polyethylene products with a corrugated texture is allowed.
Pipes intended for the construction of the external part of the sewer system have large diameter. For their installation, a separate SNiP document is provided with the following requirements:
- if diameter outer pipe does not exceed 150 mm, then the minimum permissible angle of inclination of the main line is 0.8 cm per meter of the system;
- maximum permissible value the drainage slope does not exceed 1.5 cm per 1 m of sewerage;
- if the diameter of the outer pipe is 200 mm, then the minimum slope of the main line will be 0.7 cm per 1 m of sewerage.
Sewage slope standards in accordance with the type of device and pipe diameter:
| Device type | Distance between riser and siphon (excluding ventilation), m | Diameter drain pipe, mm | Optimal system slope value |
| Bidet | 0,7-1 | 30-40 | 1:20 |
| Washing | 1,4 | 30-40 | 1:36 |
| Sink | 0,1-0,8 | 40 | 1:12 |
| Bath | 1,1-1,3 | 40 | 1:30 |
| Shower stall | 1,6 | 40 | 1:48 |
| Drain combined type(shower, sink, bath) | 1,8-2,3 | 50 | 1:48 |
| Pipe for drains from the riser | - | 1000 | - |
| Toilet | no more than 6 | 1000 | 1:20 |
| Central riser | - | 65-75 | - |
Designing a sewerage scheme in an apartment and its installation
The internal sewage system of an apartment or private house must include devices that are sources of drainage. The list of this equipment consists of a toilet, sinks and washbasins, a bathtub or shower stall, as well as household appliances which connects to the network. Dishwasher and washing machine the machine must be connected to the sewer system and water supply.
For the construction of internal sewerage, it is recommended to use plastic pipes with a diameter of 110 and 50 mm.
SNiP requirements affecting the installation of a wastewater complex:
- the slope of the sewer system is selected taking into account the diameter of the pipe of the central riser, which is already installed;
- minimum acceptable evasion rate sewer pipeline is 3 cm per 1 m.p., provided that the diameter of the line does not exceed 50 mm;
- The recommended slope of a pipeline with a cross-sectional size of 1600 mm is 8 mm per 1 m.p. gutter
Note! Sewage system in multi-storey buildings installed in a vertical position. The drains move along the perimeter of the internal walls, while compressed air is located in the center of the flow. This approach reduces the likelihood of sewer clogging.
- It is not allowed to turn a pipeline installed horizontally at an angle of 90º; for this it is better to use corner bends of 45º;
- use of right angles in vertical system Absolutely forbidden;
- A slight excess of the slope norm is allowed if the pipe length is short.
Features of installing an autonomous sewer system at a summer cottage
External sewerage is designed to remove contaminated wastewater towards the septic tank. types of systems do not use gravity to move fluid. Contaminated water is transported to a storage tank using a pump. For these systems there are certain requirements SNiP, which stipulate the maximum distance available for pumping wastewater in this way.
Advantages of autonomous sewers:
- the pressure sewer pipeline runs at a shallower depth than the pipeline of other types of systems;
- there is no need to strictly comply with slope standards, since the wastewater is moved using a pumping station;
- The operation of the system is based on self-cleaning of the internal walls of the pipe, so problems with blockages occur extremely rarely.
The presence of such advantages does not eliminate the need to check with SNiP when installing sewerage. Regulations contain requirements regarding the optimal placement of the septic tank and other elements on the site in relation to residential buildings, sources drinking water and other objects. Despite the shallow depth of the pipes, it is necessary to take into account the level of soil freezing in winter.
When working with external sewerage, the relief features of the territory are taken into account. Constructions drainage wells It is recommended to place it at the lowest points of the site. In this case, the pipe is laid so that the end sewer main not placed below the inlet in the septic tank, otherwise wastewater will not be able to flow into the storage tank by gravity.
Drawing up a test report for internal sewerage and drainage systems
After the installation of internal and external sewage systems is completed, a test report is drawn up confirming the functioning of the system and compliance with standards. This requirement is specified in one of the appendices of SNiP 3.05.01-85.
To check the functionality of the sewer system, the pipeline should be drained. To do this, at least 75% of all sanitary equipment that is connected in the area to be checked is started simultaneously. If the sewerage installation was carried out by an installation organization, such an act cannot be avoided.
Data entered into the document:
- name of the system that will be checked;
- name of the construction site;
- name of the general contractor, customer and installation organization, including positions and full names of representatives;
- information from project documentation(drawing numbers);
- a list of devices opened for the duration of the test and the duration of the test;
- data on the presence or absence of defects;
- signatures of the inspection commission.
You can install the sewer system yourself or use the services of specialists. In any case, it is important to adhere regulatory requirements and follow technology.