Internal sewerage in a private house: design and installation rules + analysis of frequent mistakes

When designing and installing internal sewerage for a private home, no one is immune to errors that can lead to unpredictable consequences, from the appearance of an unpleasant odor to the complete inoperability of the system. Consider in this article the concept of internal sewerage in a private house: the rules of design and installation + parsing the frequent errors that arise in the process of all this.

General description of the modern internal sewerage system

Today, the construction of private suburban housing is experiencing a real boom. Therefore, it became necessary to create a convenient and modern sewerage system, which would be able to mount an ordinary person who does not have a building education. Such a system should have a good performance, as the number of sanitary devices that produce domestic wastewater increased significantly. After all, with the advent of automatic washing machines, dishwashers, jacuzzi and shower cabins, the water consumption of an ordinary household increased to 200 liters per person per day.

Increasing the number of plumbing devices leads to a significant complication of the pipeline networks themselves. Fortunately, today PVC pipes are used for the installation of sewerage, which are supplied with auxiliary shaped parts, by means of which the installation of the pipeline becomes no more difficult than manufacturing articles from a children's designer. All these parts are provided with sealing rings, which can be easily replaced if necessary.

Internal sewerage is a collection of plastic pipes and shaped parts for their connection, serving for drainage of sewage from plumbing devices. The devices themselves are equipped with siphons, necessary to prevent penetration of the smell into the premises. Laying pipes obeys strict rules, non-observance of which is fraught with a violation of the entire system.

Rules for laying pipes for the construction of internal sewerage

As a central outlet in the whole sewage system of the house is a riser. He can be one for the whole house. If the house is too big or the bathrooms are located at a considerable distance from each other, the risers are made two or more. They are vertically installed pipes that start in the basement, and end on the roof. The lower part of the riser is connected to an inclined pipe of the same or larger diameter that extends outward to the drainage tank or sewage treatment plant. The upper part of the riser rises above the roof by at least 0.5 m. It is open or equipped with a check valve. For what it is needed - we will consider further. All carts leading from plumbing are connected to risers.

Fluid dynamics in the pipes

The pipe is a cylinder inside which water moves. When the pipe is fully filled with water, the piston effect occurs. This means that on top of the water plug the pressure drops sharply, and from the bottom, on the contrary, it rises. In a situation where there is an explosive discharge from the toilet bowl, the vacuum formed can suck out all the water from the siphons. This is fraught with the appearance of an odor in the premises. On the contrary, in the course of the movement of the liquid, there is an excessive pressure, which is capable of pushing the sewage from the devices below the toilet.

Ignoring the laws of hydrodynamics leads to two common mistakes in the design and installation of sewerage. The first mistake is the refusal of the ventilation device. The background pipe, going from the riser to the roof, not only removes the unpleasant odor, but also serves as a pressure compensator in the system. After all, if it is available, the reduced pressure above the water piston does not suck out the water from the siphons, but will ensure the flow of air into the system from the atmosphere, which again puts pressure.

The second common mistake is that all plumbing devices are connected through the supply pipes to the riser below the toilet. This is unacceptable, as it will certainly cause the discharge of impurities into the sink or shower enclosure during flushing. Similar problems occur when the chimney pipes have a length greater than that permissible for them. In order not to encounter such troubles, it is necessary to formulate some important rules for the installation of in-house sewers.

Rules for the installation of internal sewerage, the violation of which is unacceptable

Warning! Violation of the following rules may lead to a serious disruption to the internal sewer system or the occurrence of an emergency.

• The connection of the toilet bowl to the riser must be done separately from other plumbing fixtures.
• All other plumbing elements are included in the system above the point of attachment of the toilet. On one supply pipe there can be several devices, if their performance allows.
• Any supply pipe must be as large as diameter than the largest diameter feeder from the unit.
• The outlet from the toilet bowl has a diameter of 100 mm, therefore, the riser should not be thinner than it.
• The toilet is installed at a distance of not more than 1 m from the riser and the remaining devices not further than 3 m.
• If the house has a supply pipe longer than 3 m, then it should not be thinner than 70 mm. A padding that is longer than 5 m is made from a 100 mm pipe.

If the increase in the diameter of the supply tubes is impossible for some reason, then there is a way around this rule. To do this, you need to bring the end of such a pipe to the roof and equip it with a vacuum valve or loop it over the riser above all other devices.

Quantitative characteristics of the laying of sewage pipes

There are important nuances that will ensure the operation of the sewerage in the optimal mode:

• The slope of all horizontal pipes depends on the diameter of their sections. The standards indicate that a pipe 50 mm in diameter should be lowered by 3 cm each running meter of length, having a diameter of 100 to 110 mm per 2 cm per meter. Pipes having a diameter of more than 160 mm can be tilted no more than 0.8 cm per running meter.
• Such an indicator as the height difference for a toilet bowl should be 1 m, and for other devices 3 m. Exceeding these parameters should be accompanied by the organization of ventilation at the ends of the corresponding outlets.

Another common mistake is the wrong design of the corners. If you make angles of 90 degrees, then as a result of a rebound at this place will be formed clog from the waste, and the pipe will quickly clog. For this reason, a smooth flow of water must be created at the corners. To do this, use shaped parts that have an inclination angle of 135 degrees.

The fourth mistake is the withdrawal of the fan pipe not to the roof, but to the general house ventilation. Such a device will create an unforgettable "aroma" in the whole house, you can get rid of it only by changing the whole system.

In order to not hear the sound of moving water through the pipes, it is necessary to arrange noise insulation. For this, the pipes are wrapped with mineral wool and placed in boxes of plasterboard sheets. For timely and convenient maintenance work, the pipes are equipped with inspection hatches every 15 m. The same applies to all turns. Fifth mistake. A non-return valve is not installed in the pipe connecting the sewage system and the septic tank. In this case, when the external devices for recycling are overfilled, water can rise up the pipes and fill the basement.

Errors associated with the connection of the

siphons The connection of any plumbing fixture to the sewer is carried out through siphons that have the form of a letter U. Such a curved shape allows the water to remain in it continuously. It forms a hydro-barrier and does not allow smell to enter the room. However, this system stops working when making some mistakes. The main mistake is the lack of ventilation. In this case, the vacuum simply sucks the water out of the siphon, allowing smells to freely walk around the house. Another reason for the appearance of an unpleasant smell is the banal evaporation of water from the siphon. This occurs when the instrument is used infrequently. You just need to stuff a rag with a rare device.

What calculations are made when planning the internal sewerage system

The design of the internal sewage system must be carried out strictly in accordance with the above rules. In addition, certain calculations are required to comply with them:

• In the general scheme indicate the places where this or that device will be located. Its distance from the riser, the diameter of the supply pipe, the option of fixing and connecting to the sewer are thought out in advance. At the same time, the necessary quantity of materials is calculated.
• Defined with the type of sewage system itself. They are pressure and gravity. Usually, because of simplicity, a system is used in which water flows under the influence of gravity of the Earth. The main thing here is to calculate the slope of pipes according to the rules stated above.
• According to the technical characteristics of each sanitary unit, its one-stage flow is calculated. The thickness of the supply pipe depends on this index. In most cases, 50 mm
• pipe is suitable for all devices except the toilet bowl. Calculate the optimum location for the riser assembly. Most often it's toilets. If there are two in the house, in different vertical planes, then it is better to make the riser two.
• Calculate the sewerage scheme in such a way as to minimize the number of available angles of rotation. This will significantly reduce the risk of blockages.

The above calculations, carried out correctly, will make the sewerage the most efficient and effective even in the event of overloads.

What you need to build an in-house sewage system

As already mentioned above, the main thing in the sewerage system inside the house is drawing up a detailed drawing showing all the devices and the size of the elements. For installation use sewer pipes made of polyvinyl chloride. The device of their ends is such that two pipes can be connected, putting the end of one into the socket of another. For risers use pipes with a diameter of 100 mm, and for the remaining devices 50 mm. For connection with external sewage, a corrugated pipe is used, because of its better resistance to soil movements.

The tool is usually used: a saw for cutting plastic pipes, a sharp knife and rubber mounting seals. Saw the pipes with a saw, straighten the slices with a knife and make chamfers. Rubber seals are inserted into the sockets. To connect pipes to the system, various fittings are used:

• Knees or bends, which are needed for decorating corners. They are produced with a bend of 45 and 90 degrees. Their ends are also equipped with sockets with seals to create tight connections.
• If it is necessary to connect pipe cuttings of the same diameter, the adapter bends are used.
• Tees of various types are fittings for the organization of branching pipes.
• Transition couplings are needed to create transitions between pipes of different thicknesses.

A common mistake in installing plastic sewer pipes is ignoring their heating. To make the pipes lighter and more tightly fit into each other and into the connecting fittings, the sockets must be heated in hot water.

Sequence of works for the installation of internal sewerage

The installation of the sewer system inside the house is carried out in the following order:

First, install the risers, taking their ends to the roof and into the basement. They should pass in close proximity to the toilet bowls. In the basement they are connected to an inclined pipe that goes out into the septic tank, and the upper ends are left open or equipped with check valves.

Secondly, bring to the riser carts from the toilet. They should be separate.

Third, connect the risers from other devices above the toilet entries.

Fourth, install siphons on all appliances.

Fifth, connect the siphons with the liners.

This can be considered the installation of an internal sewerage system finished. It is important that all joints are dense, and all pipes rigidly fixed to walls or floors, and their divergence would be ruled out.

In conclusion, let's say that properly designed and assembled sewerage system will work all its long time without serious problems.