Sewerage slope per 1 meter SNIP
With what slope to lay sewer pipes?
The arrangement of the sewer system requires compliance with certain standards. In particular, the correct bias is very important. sewer pipe, which is accounted for according to SNiP and the length of communication pipelines.
HOW TO CHOOSE THE ANGLE
There are several positions that guide home masters:
1. Make the corner as sharp as possible;
2. Make the slope minimal or skip this point altogether when installing sewer drains;
3. Create a slope in accordance with the rules and GOSTs.
At first glance, the excessive slope of the sewer pipe will help water that needs cleaning to reach the well faster. But on the other hand, while the pipe is subjected to harmful effects drains. Due to the fact that the water passes through the sewer too quickly, sewage solids, food residues and other debris that is often drained into the toilet remain in the pipe. Also, pipe silting will be a problem. Over time, the sewer will clog and you will have to work on its repair. The service life of such a system is much shorter than the standard one and is less than a year.
The minimum slope or its absence is gross mistake during installation sewer pipeline. At the same time, the pipe is not only silted up, but practically not cleaned. naturally. Only the angle at which the septic tank is located in relation to the sewer can save the situation.
It is best to work with certain standards, which indicate the ratio of the angle to the diameter and length of the pipe. Of course, this requires a lot of time and special care, but after such painstaking work, the sewage system will serve you for many years.
Why do you need a slope:
When the pipe is silted up, air siphons break down, which serve as protection against unpleasant odors in room;
Silting of the main pipe threatens with a complete violation of the main functions of sewer outlets, which, in fact, is the cessation of the system;
Protecting the basement of a residential building from leakage and breakthroughs depends on the correct slope.
Also, if there are no problems with corrosion during the slopeless installation of plastic, then gaps may appear in the cast-iron pipe. She will begin to let water and sewage into the basement. Previously, in multi-storey buildings, sewers were not installed with a slope, which is why there are so many cases of drowning in an apartment on the ground floor or a breakthrough in the entire sewer system.
HOW TO CHOOSE A SLOPE
To determine the minimum pipe slope that will be optimal for you, you need to know the length of the entire sewer system. Reference books 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, a slope for a pipe with a diameter of 50 mm and a length of 1 meter needs 0.03 mm. How was it determined? 0.03 is the ratio of slope height to pipe length. Depending on the diameter, it can be from 0.03 to several millimeters. Let's see how the rule works:
Suppose you need to calculate the optimal slope for a pipe of 110 mm, according to GOST it is 0.02 mm. 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 point of the pipe and the last one is 20 cm.
Also, for a cast-iron, plastic or asbestos-cement sewer pipe, the level of fullness 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 fullness using the formula:
LEVEL HEIGHT / PIPELINE DIAMETER
The maximum level of fullness is 1, but in this case the sewer pipe is full, and, therefore, there is no slope, so you need to choose 50-60%. This is a coefficient, often taken as 0.5 - as the definition of half of the tubal cavity. Much depends on the material of the pipe (cast iron and asbestos fill faster due to the high roughness of the inner walls), and its angle with respect to the septic tank.
Your goal is to calculate the maximum allowable speed for sewerage. Professionals say that 0.7 m/s allows waste to pass quickly past the walls without sticking. Investigator, the correct calculation looks like this:
0.5 / 110 = 0.04 is the level of fullness
0.5 ≤ 0.7 / 0.042 = 0.5 ≤ 43.75 - the calculation is correct.
The last formula is a test. The first digit is the fill factor, the second after the equal sign is the speed of the drains, the third is the square of the fill level.
Also, the angle can be expressed in degrees, but then it will be more difficult for you to switch to geometric values when installing an external or inner pipe. This measurement provides higher accuracy.
In the same way, it is easy to determine the slope of the outer underground pipe. In most cases, outdoor communications have large diameters. Investigator per meter will use a larger slope. At the same time, there is still a certain hydraulic level of deviation, which allows you to make the slope a little less than optimal. In most cases this allowable size pressure pipe less than 0.02 - 0.01 mm.
According to SNiP 2.04.01-85 clause 18.2 (the norm when installing water drainage systems), when arranging the corner of the sewer pipes of a private house, you need to follow these rules:
Do not confuse the method of installing sewer pipes in an apartment and a house. In the first case, vertical mounting is often used. This is when from the toilet or shower stall is installed vertical pipe, and already it goes into the main, made under a certain slope. This method can be applied if, for example, the shower or washbasin is located in the attic of the house. In turn, styling external system starts immediately from the rings of the toilet, septic tank or washbasin.
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.
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What is a well-chosen slope of sewer pipelines for a private house? This is primarily 50% freshness in the bathroom. And secondly, a lot of free time that would have to be spent on cleaning pipes. Indeed, with an insufficient slope of sewer pipes, solid particles gradually accumulate in them due to friction forces, which will eventually lead to blockage.
If the slope is too large, the likelihood of leaks will increase, and the noise level will also rise. In addition, the separation of the liquid into fractions is inevitable. In other words, solid particles will sink to the bottom of pipes, since their speed is significantly less speed water.
Recommended pipe slope values can be found in SNiPs 2.04.03-85 (SP 32.13330.2012). "Sewerage, external networks and facilities" and 2.04.01-85* (SP 30.13330.2012) "Internal water supply and sewerage of buildings". Since they contain information about maximum and minimum pipe slopes for external and internal sewerage. But if the goal is to lay a sewer in a private house to a septic tank or cesspool, then the latest regulatory document will suffice.
The values of the smallest slope of pipes for external sewerage can be found in paragraph 5.5. SP 32.13330.2012. So, according to him, the minimum slopes of pipelines and channels for the following pipe diameters must be taken:
In general, for gravity systems, this parameter depends on the speed of wastewater movement and does not depend on the total volume of liquid.
As for the maximum slope of pipelines, it is 0.15, provided that the pipe is longer than 1.5 meters.
The smallest slope for internal pipelines is determined in the following paragraphs of SP 30.13330.2012. So, clause 8.3.2 states that in non-pressure sewer networks, where the liquid must move by gravity, the slope must be at least 1 / D (D - outside diameter pipes in millimetres). Also in this regulatory document there is clause 8.6.6, which limits the minimum slope of overhead pipelines to 0.005.
The maximum value of the slope of the pipelines here is limited to 0.15 (15 cm per 1 meter). But experts still recommend laying sewer pipes with a slope of 0.04-0.07 or 4-7 cm per 1 meter.
Next, I would like to give two tables in which you can find not only the minimum and maximum slope values \u200b\u200bfor internal plumbing, but also its optimal values when connected to various sanitary appliances.
Table 1. Limit values of the slope of sewer pipes, depending on their diameter.
Table 2. Optimum pipe slope for plumbing fixtures.
All of the above was the definition optimal slope sewer pipes in a non-calculated way (well, or almost non-calculated). But this parameter can also be found out using a special calculation, depending on the speed of the liquid, the diameter of the pipes and the filling level of the pipelines. True, this is very long and tedious process, which is usually resorted to in the case of large sewerage systems ( industrial facilities, central sewer for multi-storey buildings etc.). Those who are interested can use the formula presented in paragraph 8.3.2. SP 30.13330.2012 or the Callbrook-White formula.
At the design stage, and then during installation, it is necessary to accurately observe the angle of inclination of the sewer pipes. And it doesn’t matter if it’s internal sewage or, the pipeline must have a slope.
This is due to the fact that the sewer system in most cases is gravity-flowing, that is wastewater are delivered to the treatment plant under the action of gravity. Even a slight deviation from the regulations will lead to the malfunction of the entire system.
The angle of inclination of the pipes is the change in the working surface relative to the horizon. In standard measuring systems, it is customary to measure angles in degrees, while the slope of pipelines is measured in centimeters per 1 meter.
There are two ways to calculate the angle of inclination of sewer pipes: calculated and non-calculated.
The calculation method is used for sewage with a constant pressure of effluents and, in turn, has two methods:
When laying an internal sewage system, the correct diameter of the pipes plays an important role. When choosing, you must be guided by the following parameters:
This method is suitable for large sewer networks. For small systems, the recommended values from SNiP apply. In this guide, you can find out the minimum and maximum values \u200b\u200bof the sewer slope angle.
When installing an external sewer system, it is necessary to adhere to the minimum value - 0.015 m per 1 running meter.
On a note!
By decreasing the minimum angle, solid and heavy particles will remain inside the pipeline and interfere with the passage of liquid (create a blockage).
The pipeline of the internal sewerage is made adhering to the same parameters. As an exception, these values may be reduced in areas less than 1 meter. In such areas, you can make a slope of 0.01 m. However, the risk of blockage increases significantly.
The maximum allowable slope depends on the speed of the drains. The flow velocity must not exceed 1.5 m ⁄ s.
As the speed increases, solid particles will settle on the surface of the pipes, since their speed is less than the speed of the liquid. Therefore, the maximum slope angle should not exceed the recommended values by more than 3%.
For installation of the system inside the house, a pipe with a diameter of 50 to 110 mm is used. The slope angle is taken from the reference book and is the same for home, country or production systems. In order not to engage in complex calculations, you can use the table of tilt angles.
When calculating these data, all the necessary parameters were taken into account:
Slope for sewer pipelines of different diameters
In conclusion, it is worth adding a few tips:
When designing a sewer system, try to run the pipeline along the shortest path. Do not be afraid to seek advice, with the help of specialists you will get a reliable, high-quality and efficient system sewerage.
Video: How to lay a sewer pipe, slopes and bends, do-it-yourself sewerage
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 performance for certain areas, recommendations for organizing the layout of the pipeline. The text provides an overview of common mistakes and tips to help avoid them, and formulas to rely on when designing a sewer line.
To ensure correct and uninterrupted operation, when designing a system, it is necessary to comply with the norms of SNiP
Comfortable stay in country house is possible only if there is a system designed for the removal and disposal of domestic wastewater. For these purposes, an autonomous type sewerage system (centralized for apartments) or a septic structure is used. Inside the system, the movement of the waste liquid through the pipes is carried out in a non-pressure way. In other words, polluted effluents are transported to the place of purification 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 sewer is located at a certain slope. In this case, the system will function normally only if the slope of the sewer for each meter of the pipeline complies with the regulatory requirements of SNiP.
The optimal slope factor also depends on additional factors:
Despite the apparent simplicity, as a result of incorrect design of sewage treatment facilities and the wastewater main, blockages and plugs can form in the collectors, and the system itself will not be able to fully fulfill its main task.
When we are talking about the slope of the pipeline, it is important not to go to extremes. There are only two types of popular mistakes that inexperienced people make when building sewers.
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, due to which the 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, wastewater with impurities of fractions of different densities lingers on the walls of the main, as a result of which the pipeline becomes covered with silt and begins to exude unpleasant odors that penetrate back into the room. Therefore, you will have to regularly clean the sewers in a private house or apartment, where the system was installed in violation of the requirements.
Excessive inclination of the system can also create the prerequisites for frequent cleanings for preventive purposes. An intense fluid flow 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 layer and be pressed on the walls of the sewer. In this case, all shut-off valves and pipe joints will be subjected to severe stress, which increases the risk of breakage. Therefore, it is very important to adhere to the recommended parameters assigned in the SNiP documents.
First of all on throughput pipe is affected by its diameter. Therefore, it is recommended to select the angle of laying the line 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.
The minimum allowable angles of inclination per 1 m of the pipeline, taking into account its cross section:
| Pipe section, cm | Minimum Angle inclination |
| 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 distributing sewerage in a private house, it is not recommended to install pipes at an inclination corresponding to the maximum allowable value.
Recommended parameters for arranging internal sewerage are clearly indicated in SNiP. These data are contained in the normative 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 effluents.
The calculation of the pipeline fullness indicator is carried out taking into account the characteristics of the material from which the system elements are made. On the basis of these data, by calculations, it is possible to find out at what speed the sewage water must move through the sewer so that there are no blockages inside the main. The level of filling 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:
The maximum value of the filling level is equal to 1-nitsa. 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 an indicator of 50-60%. At the same time, the material on the basis of which the pipe is made, as well as its placement angle relative to the local treatment plant sewer - septic.
Products made of cast iron or asbestos cement have a rough surface. The presence of texture on inside pipes are filled quickly. The main purpose of such calculations is to establish the maximum allowable speed in the drain. According to standard regulations, the minimum speed of movement of the waste liquid is 0.7 m/s. The minimum allowable pipe fill rate is 30%.
For further calculations on free-flow sewerage, the following formula will be required:
V (h/d) ½ ≥ K, where:
For polymer pipes the reference factor is 0.5. Other materials correspond to 0.6. In practice, the consistency of wastewater and their quantity are not constant values. Therefore, it is far from always possible to accurately observe the filling of the sewerage and the speed of movement of the water flow.
Useful advice! If it is not possible to perform calculations due to the lack of accurate data using the previously indicated formula, the minimum angle of inclination can be used 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 diameter of pipes for arranging internal sewage 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 seen in the table. For a pipe with a cross section of 80 mm, the coefficient is 0.125.
External sewerage removes waste liquid from plumbing fixtures installed inside a residential building, and also collects rain water from the site with 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 outer part of the sewer have large diameter. For their installation, a separate SNiP document is provided with the following requirements:
Sewerage slope standards in accordance with the type of device and pipe diameter:
| Instrument type | Distance between riser and siphon (excluding ventilation), m | Diameter drain pipe, mm | Optimum System Slope |
| 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 cubicle | 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 | - |
The scheme of the internal sewerage of an apartment or a private house should include devices that are sources of drainage. The list of this equipment consists of a toilet bowl, sinks and washbasins, a bathtub or shower stall, as well as household appliances that 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 waste complex:
Note! The sewerage system in multi-storey buildings is installed in a vertical position. The movement of drains is carried out along the perimeter of the inner walls, while in the center of the flow there is compressed air. This approach reduces the likelihood of clogging the sewer.
External sewerage is designed to lead contaminated drains towards the septic tank. types of fluid-moving systems do not use gravity. Polluted water is transported to storage capacity using a pump. For these systems, certain SNiP requirements are provided, which spell out maximum distance, available for pumping wastewater in such a way.
Advantages of autonomous sewers:
The presence of such advantages does not eliminate the need for reconciliation with SNiP when installing sewers. Regulations contain requirements for the optimal placement of a 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 imperative 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. Drainage well structures are recommended to be placed at the lowest points of the site. At the same time, the pipe is laid so that the end of the sewer line is not located below the inlet in the septic tank, otherwise the wastewater will not be able to enter the storage tank by gravity.
After the installation of internal and external sewerage is completed, a test report is drawn up confirming the functioning of the system and compliance with the standards. This requirement is spelled out in one of the applications of SNiP 3.05.01-85.
To check the operability of the sewer system, the pipeline should be shed. To do this, at least 75% of all sanitary equipment that is connected in the area to be checked is launched simultaneously. If the installation of the sewer was carried out by the installation organization, such an act cannot be dispensed with.
Data entered into the document:
Sewer installation can be done independently or by using the services of specialists. In any case, it is important to follow regulatory requirements and follow the technology.
Discharge of sewage into the municipal sewerage system or into autonomous septic tank carried out through pipes by gravity. Therefore, it is important to observe the slope of the sewer pipes by 1 meter in accordance with the requirements of SNiP. A number of factors affect the normal operation of the drain system, from the diameter and material to the location: internal wiring or external.
The main task in arranging the sewer system is to configure the pipeline in such a way that drains, including liquid and solid fractions, pass without delay and without creating congestion and traffic jams. It is necessary to observe the slope of the pipes, through which, under the influence of gravity forces, wastewater will immediately flow into the collector and further to the treatment plant.
Requirements for the organization of internal and external sewerage, the required slopes and other parameters are strictly stipulated in SNiP SNiP 2.04.01-85 “BUILDING NORMS AND RULES INTERNAL WATER SUPPLY AND SEWERAGE OF BUILDINGS” and SNiP 2.04.03-85 “SEWER. OUTDOOR NETWORKS AND STRUCTURES.
Per established norms it is not a strict calculation, but the result of tests and observations. The nature of the drains and their consistency is not constant, and the sewage system must work without failures. It is necessary to exclude or minimize the settling of solid inclusions and sludge on the walls of the channel, to make sure that the sewer works silently, preventing reverse current and unpleasant odors from entering the room.
It has been established that at a flow velocity of 0.7 m/s, water flows evenly and solid inclusions follow the fluid flow more easily without staying in one place. This is provided that the diameter is chosen so that with a normal number of drains for a given connection, they are filled by about 50-60%, but not less than a third.
The basic formula obtained empirically, based on observations, is:
where V is the effluent flow rate, H is the height of the effluent level in the pipe, d is the pipe diameter, K is the slope coefficient, the value of which is a reference value set depending on the pipe material.
K = 0.5 for plastic and glass.
K = 0.6 for other materials (steel, cast iron, asbestos cement).
The coefficient depends on the roughness of the inner surface and the resistance created by the fluid flow.
If the slope is too great, the water will drain quickly and solids will settle on the surface of the pipe, creating a blockage. With a large slope, the water flow will be turbulent with whirlwind noise and increased air discharge in the upper part of the pipe, which will lead to breakdown of shut-off valves, disruption of siphons, or, at least, retraction of the water seal and the flow of gases from the sewer into the room. Cornering will form a build-up.
If the slope is too shallow or absent, then heavy fractions will have time to settle on the surface and eventually cause blockage. Since water cannot quickly overcome the entire route to the point of discharge, there will be an overflow when the next portion arrives.
It turns out two conditions for pipes to ensure the normal functioning of the sewer:
Tolerances are different for outdoor and indoor networks, as the priorities are different. In the first case, to put it simply, the sewer should not be heard, and without the appearance of unpleasant odors. For outdoor in priority uninterrupted work that does not require constant monitoring and cleaning.
The speed of the flow of effluents and the fullness of the pipe are important so that they flow freely into the collector or septic tank. However, both of these moments depend on the size of the pipe itself and the volume of effluents, and the diameter is selected based on the average daily volume of effluents and filling the pipes by 50-60%, but not less than a third at a speed of 0.7 m / s.
Any calculations come down to choosing one of the standard sizes: 50, 80, 100, 150, 200 mm. In practice, it remains only to clarify the slope for each size and the limits of permissible error.
The slope is defined in SNiP as a fractional coefficient. The value is determined by the ratio of the length to the required distance between the top and bottom points at the edges. The coefficient is numerically equal to the difference in height between the edges of a pipe one meter long, expressed in meters.
To get the slope of a sewer pipe of the same diameter on a flat area, it is necessary to multiply the length by the slope coefficient. If the result is multiplied by an additional 100, the value will be in centimeters.
Why is the angle of inclination different for different diameters? To comply with the requirement for the flow rate of effluents.
In a pipe with a diameter of 50 mm, the volume is much smaller, if only fullness is taken into account, but the contact of water with the surface increases, in comparison with 150 and 200 mm. A pipe with a smaller cross section is set at a large angle so that the water descends through it at the required speed and takes solid inclusions with it.
However, this only applies general requirements to the formation of internal and external sewerage and slope on even long sections in the absence of a direct connection to siphons, outlet pipes, etc. A number of rules apply to fittings and connection points.
Slope for pipes:
In the internal sewerage, pipes with a diameter of 40, 50, 80 mm are used, and a diameter of 100 mm is used for a common section at the connection point where the lines converge.
Adapters from one diameter to another are mounted so as to make a straight line along the lowest part, creating a continuous channel for draining. Slopes along different sides from the adapter are set according to their coefficient value.
The required slope is formed due to the fasteners on which the pipe rests, or due to the inclination of the strobe or box in which the sewer will be sewn up.
A section up to 1.5 meters from the drain of the sink or the connection of household appliances can be laid in an arbitrary way, while maintaining the obligatory slope from the drain to the sewer pipe.
The turn to the line of the sewer pipe is necessarily formed by an elbow or a tee with a slope of 67 degrees. The slope of the bend or the top of the elbow is oriented along the route towards the riser.
The connection to the riser must be formed by a cross or a tee with an outlet slope of 67 (87) degrees. It is advisable to replace rectangular tees, which can still be found in apartment buildings when replacing internal sewerage.
The scheme of the slope of tees and sewer turns Slope for pipes:
The line of external sewerage from the house to the point of discharge must be in the same plane and with the same slope along the entire length. A combination of several pipe diameters or transitions in the line slope is not allowed. If for some reason it is necessary to deviate from this rule, then a manhole is formed at the junction of various sections.
To form the required angle of descent, it is desirable to dig the trench itself, taking into account the increase in depth. Be sure to select the soil 20-25 cm deeper than the sewerage system requires to form a sand cushion. After that, part of the sand is poured, and supports are formed under each separate element. Next, the rest of the sand is poured with tamping.
The easiest way- usage bubble level with additional risks. If the flask with the bubble has three lines on each side, then this level is just right. Each line corresponds to a slope of 1 cm per meter.
The tool is fixed on top of the pipe, and then with the help of linings, a slope is set so that the bubble touches the desired mark.
Second way- this is a measurement of the distance from the horizontal plane of the ends of the section. The ratio of the length of the pipe and the lift height of the upper side corresponds to the required slope factor.
Third way this is the leveling of two marks along the edges of the route. A thread or twine is stretched between them, along which they are already guided when compiling the pipeline.
The most obvious way- use a laser level and laser level to build the required plane. This will especially help when laying pipes in a strobe and sewing into walls using a box.
