The minimum slope of the sewerage is the norms of snip. Sewer pipe slope selection and SNP requirements Optimum sewer slope

Discharge of sewage into the city sewerage system or into an autonomous septic tank is 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.

General information

The main task in the arrangement sewer system consists in configuring the pipeline in such a way that effluents, including liquid and solid fractions, pass without delay and without creating congestion and plugs. 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 sewage, 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.

Behind the established norms 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:

The diameter is selected based on the average volume of drains.
The slope is determined to provide an optimum flow velocity of 0.7 m/s.

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, uninterrupted operation is a priority, which does not require constant monitoring and cleaning.

Slope depending on the diameter

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 applies only to the general requirements for the formation of internal and external sewerage and slope on even extended sections in the absence of a direct connection to siphons, outlet pipes, etc. A number of rules apply to fittings and connection points.

internal

Slope for pipes:

D 40 mm - 0.035;
D 50 mm - 0.03;
D 80 mm - 0.2;
D 100 mm - 0.015.

In 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. The slopes on opposite sides of 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.

Area up to 1.5 meters from sink drain or connection 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

outdoor

Slope for pipes:

D 100 mm - 0.012;
D 150 mm - 0.01;
D 200 mm - 0.07.

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 you need to move away from this rule, then a manhole is formed at the junction point 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 individual element. Next, the rest of the sand is poured with tamping.

How to set the angle of the pipe

The easiest way– use of a 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 a laser level to build the required plane. This will especially help when laying pipes in a strobe and sewing into walls using a box.

It is impossible to lay pipes according to the “how it goes” principle, since most houses have a gravity drain system installed. And it is very capricious: an insufficient slope of the sewer pipe leads to blockages, too much - to leaks and increased noise. Since the wastewater contains both food residues, and fats, and small debris, plaque forms on the walls, and they grow over time. The tilt angle in the specialized literature is indicated in centimeters, and not in degrees, as is usually the case. We suggest you figure out how to correctly apply the standards and make calculations.

How to correctly calculate slope values?

In all specialized literature: reference books, norms and rules - the slope of the external sewer pipe is given as a decimal fraction. The numbers 0.07 or 0.003 indicate the ratio of the height of the decline to the length of the drainage system. The data is easily converted into familiar units of measurement, for example, seven centimeters or three millimeters per meter. To calculate how much sewer pipe slope (H) to make, you just need to multiply the length of the pipe (L) by the slope (x).

Initial data for calculation:

L = 5600 millimeters;
x = 0.07;
H \u003d L * x \u003d 5600 * 0.07 \u003d 392 millimeters.

The optimal height difference between the beginning and the end of the drainage system was 39.2 centimeters.

The main parameters for determining the slope of sewer pipes are their diameter and length. However, when designing, many forget that the number of turns and drainage joints also matters. You need to take into account the number of discharge points and the nature of the drains. Agree that for the toilet and washbasin they will be significantly different

The slope angle of the sewer pipe depends on the diameter of the drainage system. With a diameter of 50 millimeters, one side of it should be lowered by 30 millimeters per meter segment. An 11-centimeter pipe is lowered by 20 millimeters per meter. For a drainage system with a diameter of 16 centimeters, the minimum slope is 0.008 meters (8 mm). If the calculation is made for large pipes (Ø 200 mm), you need to tilt the pipe by seven millimeters per meter.

We measure the slope of the internal pipeline

According to SNIP, the slope of the pipes in the apartment depends on the diameter. The kitchen and bathroom use different pipes, so there are minimum and normal values. Within these values, you should work.

For kitchen sinks, as well as sinks, urinals, washbasins and bathrooms, 40 or 50 mm pipes are usually used, for which the normal slope is 0.035, and the minimum is 0.025. When installing a toilet bowl for wastewater, a drain line with a diameter of 100 millimeters is taken. For him, the minimum slope is 0.012, and the normal one is 0.02.

To calculate the desired angle of inclination, it is better to use a laser or bubble level. The floor, no matter how smooth it may seem, cannot serve as a standard of horizontality. Cheaper to buy right tool than to redo the sewerage system or make repairs to yourself and your neighbors.

Standards for outdoor sewer pipes

Building codes contain optimal dimensions slope of external sewer pipes. Their diameter is significantly larger than that of the internal drainage systems used for installation.

It is absolutely impossible to significantly exceed the established values, otherwise the sewer system will not be able to work correctly: the pipes will silt up and clog very quickly.

For a pipe Ø150 millimeters, the normal slope is 0.008 meters or 0.8 centimeters per meter of length. For a 200 mm pipeline, this value is less and is 0.007 m or 0.7 cm.

For conditions when it is impossible to create a normal slope, the minimum allowable values of the parameter are defined: 0.007 m (0.7 cm) and 0.005 m (0.5 cm) for pipes with a diameter of 150 and 200 mm, respectively.

Too much slope will lead to silting: water will not wash away solid particles of sewage that stick to the walls and narrow the gap. As a result, water constipation in siphons may break.

The maximum allowable slope is 0.15 meters or 15 centimeters per 1 meter.

We determine the fullness of the discharge pipes

When laying a drainage system, it is important not only what slope of the sewer pipe will be made, but also the level of its fullness. For calculations, the following formula is used:

K = H / D, where

K - fullness of the sewer pipe;
H is the height of the level of effluents in the drainage system;
D is the diameter of the sewer pipe.

The indicator of fullness is equal to one if the pipe is completely filled. For an empty drain, the value of K is zero.

The optimal filling of sewer pipes is in the range from 50% to 60%. The difference is due to the possibility of using pipes with different roughness of the inner surface. Insufficient filling of the drain negatively affects its service life: the flow of air to the walls in such an aggressive environment contributes to the destruction of materials

The optimal value of K, at which the system operates in normal mode, is in the range from 0.5 to 0.6.

The figures may vary within these limits depending on the materials from which they are made. All of them are distinguished by the ability to form a boundary layer. For asbestos-cement or ceramic pipes, for example, the fullness index should be 0.6. They are rougher than the same plastic ones, for which the recommended fullness is 0.5.

Subject to these indicators, wastewater will pass at a speed of about 0.7 m / s. This is enough to keep solid particles in suspension and prevent them from settling and sticking to the pipe walls.

As a result, the design parameters of the sewer pipeline must correspond to the formula:

K≤V√y, where

K - fullness of the sewer pipe (optimum value 0.5-0.6);
V is the speed;
√y is the square root of the filling of the pipeline.

It is quite obvious that for normal living in a modern house or apartment it is impossible to do without a reliable sewerage system. It is a piping system for removing Wastewater. Malfunctions in the operation of the latter lead to not the best consequences, therefore, when arranging sewerage in a private house, it is necessary to comply with the requirements of building codes and regulations.

In a modern house, sewerage must be correct

Wastewater moves by gravity under the influence of gravitational forces, so it is important to calculate the correct sewer slope of 1 meter. If it is too large or too small, there will be disturbances in the operation of the system, up to the occurrence of unpleasant emergencies. What kind of slope for the pipes of the sewerage system to install is determined by a number of circumstances.

Consequences of too little or too much slope

Too small a slope of the pipe does not provide a sufficient flow rate of wastewater. A weak pressure is not able to ensure the removal of large fragments of waste, and they will settle on the inner walls of the pipeline system. As a result, it will become clogged and the system will fail.

The smaller the angle of inclination of the pipe compared to the correct value, the more often emergencies will occur. The minimum slope of the pipes in the apartment should ensure the self-cleaning of the system.
Incorrect sewer slope leads to blockages

An excessively large slope of the sewer pipe causes too high a flow rate of wastewater. In this case, large fragments of waste will be thrown to the inner walls of the pipeline system, stick to them and will not be able to move on. It is important to ensure the optimal slope of the sewer pipes by 1 meter in a private house.

The consequence of an excessive slope will again be a blockage of the sewer system. In addition, with a high flow rate of wastewater flange connections pipelines and hydraulic valves will experience an increased load, which will lead to leakage at the joints and the rapid failure of structural elements.

Optimum angle of inclination depending on the diameter of the pipe

When designing a sewage system, depending on the diameter of the pipe, the optimal angle of its inclination is selected. For the system to work properly, pipes of a smaller diameter must be provided with a greater slope. It is measured in centimeters per linear meter of pipe length. SNiP define the following parameters for pipes in accordance with their diameter:

50 mm - 3 cm of slope per 1 meter of length;
110 mm - 2 cm;
160 mm - 0.8 cm;
200 mm - 0.7 cm.

Illustration of the required slope for pipes of different diameters

These optimal values are calculated for even extended sections of the external and internal pipeline network. There are some peculiarities when connecting to flange connections, siphons and fittings.

Features of determining the slope in the bathroom, kitchen and toilet

Features of determining the slope in the bathroom, kitchen and toilet are determined by the fact that there are appropriate plumbing fixtures. Under kitchen sink pipes with a maximum diameter of fifty millimeters are installed, the optimal angle for them will be 3.5 cm. Pipes with a diameter of one hundred millimeters are used in the toilet, the optimal slope for them is 2 cm. The values \u200b\u200bof this parameter for household plumbing fixtures are summarized in the following table.

Sewer slope table for different devices
Device name	Slope per linear meter, mm	Pipe length from siphon to drain, cm	Pipe diameter, mm
Common drain from sink, shower and tub	50	150-240	50
Bath	30	90-140	40-50
Shower	50	150-170	40
Sink in the bathroom	10	0-80	40
Bidet	20	60-110	40
Washing in the kitchen	35	140-160	40
Toilet	20	up to 500	80-100

Rules for determining the angle of inclination for external sewerage

For laying an external network, pipes of a much larger diameter are used than inside the house. As a result, their installation angles are different. For example, for a pipe with a diameter of one hundred and fifty millimeters, the slope will be 0.8 cm per meter of length, if the diameter is two hundred millimeters, the value of this parameter is reduced by one millimeter and will be 0.7 cm.

The maximum level drop for the external network piping system should not exceed fifteen centimeters per meter of length. This rule does not apply to short sections of the pipeline, less than one and a half meters long.

Calculation of the required slope of the sewer pipe on your own

In order to calculate the slope of the pipe on your own, you need to know its length and diameter. Special tables with the values of this parameter have been published in SNiP. In the general case, you can determine the angle of inclination of the pipe on your own according to the following rules:

the calculation should be made taking into account the diameter of the vertical pipe;
for a pipe with a cross section of up to one hundred and ten millimeters, a slope of twenty millimeters is required;
a diameter of up to one hundred and sixty millimeters requires a pipe slope of eight millimeters;
narrow pipes up to fifty millimeters in diameter are installed with a slope of three centimeters.

Sewer slope is easy to control level

Certain difficulties in perception are caused by the unit of measurement of this parameter, expressed in hundredths of a number. However, there is really nothing complicated, for example, a slope value of 0.05 means that the difference in heights between the beginning and end of a meter-long pipe section is five centimeters.

The value of the fullness of the sewer

One of the most important operational characteristics of the sewage system is its fullness with fecal water. The value of this parameter is determined by dividing the height of the wastewater level by the size of the pipe section.

The normal functioning of the sewerage system is ensured when it is not more than fifty or sixty percent full.

In this case, the material from which the pipes are made matters. If it is ceramic or asbestos, such a pipeline network can be sixty percent full. When using a more slippery plastic material the fullness of the sewer should not exceed fifty percent. Compliance with these conditions provides a sufficient flow rate of wastewater to remove large fragments of waste.

Calculation of the diameter of the sewer pipe

When designing a sewer system for its trouble-free operation, it is necessary to correctly select such an important operational parameter as the diameter of the pipeline network. It is determined by a combination of the following conditions:

the cross section of the pipes of plumbing fixtures should not be greater than the diameter of the main sewer pipe;
an increase in diameter leads to an acceleration of wastewater permeability exponentially;
the occupancy rate should not exceed sixty percent;
building codes and regulations contain the data necessary to calculate the diameter of the sewer pipe.

The drainage of the sewerage of the bathroom on the second floor to the riser is made with a 110 mm pipe

Building codes and regulations determine the diameter of pipes on the main sections of the network at one hundred and ten millimeters. Connecting household plumbing fixtures is carried out to pipes whose diameter does not exceed fifty millimeters. The exception is the toilet bowl, the operational load on which is increased. The diameter of the common riser is one hundred millimeters. The cross section of sewer pipes of large urban highways can reach one thousand two hundred millimeters.

Laying of external sewerage taking into account the level of soil freezing

Installation of external sewerage must be carried out with the obligatory consideration of the depth of soil freezing at the place of work. This level varies depending on climatic conditions and is different in different areas. SNiP 23-01-99 contain the exact values of this parameter for different regions.

Map of normative freezing depths

For example, if the depth of soil freezing is one and a half meters, the sewer system cannot be laid closer to the surface of the earth. In this case, fecal water will freeze and break the pipeline network, which will lead to its complete failure. For the region near Moscow, the depth of soil freezing is 1.4 meters, in the central regions of our country it is approximately the same.

Rules for organizing a mounting cushion for laying pipes

Proper laying of the sewer system provides for the arrangement of the mounting pad. It is a sand embankment on which the pipeline network is directly laid. To maintain the desired angle of inclination of the system, the mounting pad is intended. This parameter can be changed by pouring sand in one place or another.

The pillow should provide a uniform slope of the sewerage system

Before laying the pipeline network, all elements of its structure are checked for integrity, the presence of cracks and visible defects is unacceptable. Otherwise, leaks and emergencies are inevitable. Checked sewer pipes are laid on the mounting pad and leveled using the building level. If it is necessary to adjust the angle of inclination, sand is poured in the right place in such a way that the pipe lying on the embankment fits snugly against it and is motionless.

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.

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, that is, wastewater is delivered to the treatment plant under the influence of gravity. Even a slight deviation from the regulations will lead to the malfunction of the entire system.

What is pipe angle

Pipe angle - change 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.

How to calculate slope

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:

calculation in accordance with the speed of movement of wastewater through the pipeline to the normative coefficient;
Callbrook-White formula.

Pipe diameter

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:

the cross section of the pipe must match the drain pipe of the plumbing fixture;
the patency of the pipe depends on the diameter, that is, for a pipe with a diameter of 200 mm, the useful volume is 2 times greater than for a pipe with a cross section of 110 mm;
when draining water, the pipes should not be completely filled.

Slope angle according to SNiP

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.

Minimum slope

When installing an external sewer system, it is necessary to adhere to the minimum value - 0.015 m per 1 linear 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.

Max Angle

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%.

The slope of the internal sewerage pipeline

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 industrial 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:

internal section;
flow rate;
fluid viscosity;
wall smoothness.

Slope for sewer pipelines of different diameters

In conclusion, it is worth adding a few tips:

Lay the pipeline, taking into account natural shrinkage. Over time, the pipe may bend or sag, which means adjustment will be required, and this requires space.
Connect pipes at an angle of at least 120 degrees. If such an angle cannot be set, install additional inspection hatches.
When connecting, make sure that the piping is tightly connected.
Try to avoid unnecessary joints and turns. Remember - the simpler the system, the less likely it is to break.

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

The sewerage system is divided into two parts: internal and external. internal system consists of taps (from bathrooms, showers, sinks, toilets), a riser and an outlet from the house. External system - from the pipeline and storage tank or septic tank. The internal pipeline, in turn, can be divided into vertical (risers) and horizontal (branches).

Sewer pipes

The vertical part requires ventilation and protection against clogging. Horizontal sections are called so conditionally, since in practice they are mounted at a certain angle with respect to the horizontal surface.

The rate of slope of sewer pipes - snip 2.0401-85. This document also defines the conditions for installing the system from the exit from the house to the first well, which must be located at least 12 m.

Sewer pipe slope calculation: basic concepts

If the sewer is gravity-flowing, then its efficiency in transporting wastewater due to the laws of gravity depends entirely on the angle of inclination. It is believed that wastewater should move through the pipeline at a speed of 0.7-1 m/s. Only in this case the flow is able to remove solid particles from the system. To keep the flow rate indicator, for each individual diameter, it is required to calculate the slope angle of the sewer pipe.

At first glance, it may seem that the angle should be measured in degrees. But in building codes and reference books on sewerage, this parameter is defined as decimal. These figures represent the ratio of level reduction to the length of a particular section of pipeline.

For example, on a pipeline section 5 m long, one end is 30 cm lower than the other. In this case, the slope of the sewer pipe will be 0.30/5=0.06.

Formula - determining the maximum, minimum value

The formula for calculating the slope of the sewer pipe

wherein:

V speed of fluid flow (m/s);
H filling pipeline;
d pipe diameter;
K is the calculated slope factor.

To determine the coefficient (slope), you can substitute V \u003d 0.7-1, d is the value of the diameter of a particular section of the pipeline, H \u003d 0.6xd (according to building codes and rules). It turns out that for a pipeline with a diameter of 100 mm per meter, a slope of 2 cm is required, with a diameter of 50 mm - 3 cm per meter.

It can be seen from the formula that the wastewater flow rate directly depends on the angle of inclination (coefficient). For optimal speed, a minimum sewer pipe slope of 0.02 and a maximum of 0.03 is required. If the roll is less than 0.02, large particles will settle and form a blockage.

If the bank is too large, the speed will increase, which will also lead to the formation of precipitation, since the water will leave too quickly, not having time to carry away the heavy particles of effluent. Increasing the flow rate can also lead to disruption of siphons and constipation.

Required standards in the apartment

When constructing a sewer, there is no need to use a formula for calculations. There is a table that defines the slopes for all taps from plumbing fixtures.

Optimal slope sewer pipes in the apartment
device	Drain diameter (mm)	Distance to siphon (cm)	Incline
Bath	40	100-130	0.033
Shower	40	150-170	0,029
Toilet	100	no more than 600	0,05
Sink	40	Up to 80	0,08
Bidet	30-40	70-100	0,05
Washing	30-40	130-150	0,02
Combined drain for bath, sink and shower	50	170-230	0,029
Riser	100
Withdrawal from the riser	65-754

Each section of the sewerage system in the apartment must have a siphon in the form of a device or a bend at the end so that unpleasant odors. To determine the required values, the principle of the golden mean is important - 1.5-2.5 cm per meter. This is quite enough for an apartment or country house. The use of formulas is necessary when building large facilities with a maximum volume of wastewater.

In addition, for domestic sewage, the formula is difficult to use, since there is no constant flow. Here it is better to pay attention to another indicator - the ability to self-clean (remove solid particles).

Since domestic wastewater contains waste with different weights, for heavy components the flow rate is the determining factor, for floating ones it is the filling of the system diameter. When determining the correct slope, it should be borne in mind that it will be different in each individual section.

The slope of the outer and inner parts of the system

In private country house it is necessary to arrange not only internal, but also external sewage. In addition, we need outlets for water, which is formed as a result of melting snow and precipitation in the form of rain. Storm sewers can be installed together with the main system or separately.

The slope of the internal sewer pipe is strikingly different from that of the external system. Tubular products are required for storm drainage large diameter(from 100 mm) and gratings, since various vegetable contaminants will certainly get into this system. The slope of the sewer for storm water should also be greater - 0.05-0.07, but not more than 0.15.

External waste from the house is usually directed to the central sewer or septic tank and is laid underground. The diameter of this pipeline is most often 100-150 mm. The minimum slope is 0.02. Based on this, a trench should be dug. If at earthworks inaccuracies were made, you can correct the situation with a sand cushion.

Any sewage system must provide unobstructed flow to drains and guarantee a high level of self-cleaning. It should certainly be borne in mind that the standards and textbooks indicate averages, so common sense and practicality will never interfere.