When arranging a sewer system with your own hands, it is important first of all to ensure that the wastewater is subsequently discharged from the house freely and without obstruction. Pipes during the installation of such utilities are laid for this at a certain angle. In this case, the waste water goes into a septic tank or centralized system by gravity. The slope of the sewer pipe is determined by the tables. You can also use a special formula to calculate this parameter.
What is a sewer of a private house
The engineering systems of suburban residential buildings are usually not too complicated. When arranging a home drain system, the sewers are mounted:
The first network is laid directly in the building itself. Its elements are:
The riser and plank bed always have a larger diameter than plumbing equipment lines.
An external sewage system is mounted outside the house and connects the riser to a septic tank or centralized highway. Pipes of the street system are laid underground below the level of soil freezing with the use of insulation. A septic tank is a sump in which effluents accumulate and purify. According to the rules, such a structure is installed no closer than 5 m from the foundation of the building.
What is the slope of the sewer pipe: a little theory
It is known that solid waste is most easily followed by water at a uniform flow velocity of the latter at 0.7 m / s. This happens when the diameter of the pipes of the sewer system is selected so that the line is filled with drains by about 50% and not less than a third.
It is to this indicator of the speed of the waste water that you need to strive for when arranging a water drainage system and choosing a slope of the sewer pipe. In this case, solid inclusions will settle on the walls of the external and internal highways in a minimal amount. In addition, such a water flow rate ensures the most silent operation of the system.
If the slope of the sewage system pipes is too large, the water will begin to drain very quickly into the septic tank. Moreover, solid waste will “lag behind” it. The result will be frequent blockages of highways. If the angle of inclination of the pipes is insufficient, heavy fractions will have time to settle to the bottom of the pipeline due to the weak flow of water. And this, of course, is also fraught with traffic jams. Blockages in this case will appear very often.
What indicators should be taken into account when determining the required bias
When choosing materials for assembling the sewer system of a country house, you should first determine the diameter of the pipes. When installing engineering systems in private residential buildings, they usually extend to 40, 50, 80, 100, 150, and 200 mm standard highways. It is taking into account the cross-section of the pipes in the future that the necessary slope is determined.
In principle, it is not difficult to determine the method of laying pipes for self-assembly of the waste water system. According to SNiP, the slope of the sewer pipes is calculated as the ratio of the length to the required distance between the extreme lower and upper points of the highway. It is most convenient to determine the angle of inclination, focusing on a coefficient numerically equal to the height difference between the extreme points of the pipe 1 m long.
So, for a 40 mm highway this figure will be 0.03-0.04, 50 mm - 0.025-0.035, 80 m - 0.015-0.02, 100 m - 0.012-0.02, 150 m - 0.007-0.01, 200 m - 0.005-0.008. To determine the angle of slope, you need the coefficient provided for the pipe of a given diameter, divided by its length.
Using the formula
To determine the required slope of sewer pipes in a country house can be another way. In this case, the following formula is used:
V = H / d> = K, where V is the speed of the wastewater, d is the diameter of the line, K is the slope coefficient.
The indicator H, according to SNiP, is taken equal to 0.6 * d. Thus, it is easy to calculate that, for example, for a pipe with a diameter of 100 mm, a slope of 2 cm per linear meter is required, for a pipe with a diameter of 50 mm - 3 cm, etc. It is this method for determining the laying angle of highways that private owners houses are used most often.
Slope of the internal sewer pipe
To equip the drainage system in a private house, pipes with a diameter of 40 to 80 cm are usually used. In this case, the section on which all the lines converge is mounted in most cases using a 100 mm pipe.
When arranging the internal sewage system, it is necessary to install the adapters in order to connect the highways so that they form an even line along the lowest part. With this installation method, a continuous channel for discharging waste water is created, which significantly increases the efficiency of the system. Actually the very angle of inclination of each line is selected taking into account the coefficient for a given specific diameter.
The laid down slope of the sewer pipes in the house must be observed. But you also need to connect the trunk of the internal drainage system to the riser, of course, correctly. In this case, according to the standards, it is supposed to use exclusively tees or crosses in which the branch has an inclination of 67 (87) degrees. The use of such materials reduces the risk of clogging.
Rules for installing an external sewage system
According to the norms of SNiP, the slope of the sewer pipe is thus selected so that the speed of movement of the wastewater inside the main is subsequently equal to 0.7 m / s. This rule also applies when laying the system outside the house.
In this case, according to the standards, it is supposed to use pipes of the same diameter along the entire length of the highway. Therefore, the slope of the external sewage system is uniform and the same from the riser to the septic tank itself.
Sometimes, when installing drainage systems in country houses, the trunk must, of course, be laid with a vertical drop or turns. According to the rules, it is compulsory to equip viewing wells at pipe mating points in such places.
When laying the external sewage of a country house, among other things, earthwork should be performed correctly. The bottom of the trench dug under the highway should be absolutely flat. In addition, in the ditch you need to equip a sand pillow. In this case, the slope of the sewer pipe in a private house when laying on the street will be uniform along the entire length. Any unevenness at the bottom of the trench can cause a significant difference and, as a result, frequent blockages.
How to set the angle
So, what kind of slope of the sewer pipe should be inside and outside the building, we found out. But it is important not only to correctly determine the indicator of the laying angle of the highway. It is also necessary to stretch the pipes themselves in accordance with the calculations.
When installing sewer systems in country houses, tools such as the construction level and tape measure should be used. You can observe the required angle when laying highways in several ways:
Using a special bubble level. In such an instrument, there are 3 traits on each side of the flask. Each line at this level corresponds to a slope of 1 cm per meter.
Using roulette. In this case, first measure the length from the ends of the plot in the horizontal plane. Then, the ratio of the length of the mounted trunk and the obtained indicator is determined, thus determining the necessary slope coefficient.
Using a cord and pegs. In this case, labels are first set at the edges of the route. Then a cord is pulled between them.
You can also set the angle of inclination of the highway and with the help of a modern tool - level. Such a device is particularly useful when laying pipes in a strob or stitching them into walls using a duct.
Laying sections of the line from household appliances
The average slope of pipes of one diameter or another is presented in the article above. Usually, various kinds of complex formulas are not used when installing a sewer of a simple design in a private house. Most often, the slope of the sewer pipe per meter from each plumbing fixture to the riser is simply chosen equal to 1.5-2.5 cm per meter.
But if you wish, you can stretch the segments and with the exact observance of the recommendations of SNiP, provided mainly for multi-apartment buildings. So, for example:
with a distance to the siphon of 100-130 cm and a drain diameter of 40 mm, the slope coefficient of the pipe coming from the bath will be 0.03;
with the corresponding figures of 80 mm and 40 cm for the sink, this figure will be 0.08;
for a toilet with a distance of up to 600 mm to its siphon and a pipe diameter of 100 mm, the coefficient will be 0.05.
What problems may arise if the slope is not observed
The biggest nuisance caused by errors in the laying of home sewers can, of course, be blockages. Also, if the angle of the pipes is not observed during the installation of such an engineering system, the owners of a suburban residential building will experience, for example, problems such as:
quick pipe failure;
overgrowing of the inner surface of highways with sludge;
if the slope is too large - disruption of water gates in siphons, which is fraught with the arrival of unpleasant odors in the interior of the house;
filling the sewer above with air and, as a result, pipe corrosion.
If the slope is too large, the sewage system in the house will also be very noisy.
Instead of a conclusion
Thus, it will be absolutely easy to calculate the required pipe slope when laying a home sewage system. It is most likely that it will not be difficult to set up the highway in the right way. However, laying pipes when equipping such an engineering system with the required angle, of course, is necessary. Otherwise, the use of sewage in the house in the future will actually be extremely inconvenient due to frequent blockages.