Do-it-yourself installation of a sewer collector in an apartment or house requires careful calculations so that the diameter of the sewer pipe allows for the correct free outflow of wastewater with optimal filling of the collector. The master professional always understands that too small a diameter of the collector threatens to form traffic jams and blockages in the sewer system. And this, in turn, will lead to the conversion of the collector and repairs in the room. Do you need such costs, while you can simply choose the right diameter of sewer pipes, regulated by SNiP for each case, type of sewer system and type of plumbing equipment.
About how to make calculations, choose the diameter of the tubes for the toilet bowl and other plumbing points in the house, and how to make the sewer work, in the material below.
Important: the calculations and tables below are equally applicable to both a plastic manifold and a cast-iron sewer. For clarity, below is a video on the topic.
Types of pipes
The sewer system in an apartment or internal sewerage in a private house can be installed using two types of elements - cast iron or plastic. However, cast iron is increasingly losing ground to PVC plastic tubes due to their technical characteristics, such as anti-corrosion, lightness and durability. Among the polymer pipes for the installation of a sewer system, several types can be distinguished by the type of material of manufacture and by purpose (internal / external system).
So, the modern market offers these types of polymer pipes.
Polyvinyl chloride (PVC) tubes
Are intended for the device of the internal and external sewerage. At the same time, plastic cuts for different types of collectors differ in color. For the internal system, the elements are gray, for the external collector - brown or orange. It is forbidden to change and use pipes for other purposes, since gray pipes for internal sewerage can burst when the temperature threshold drops and under mechanical stress. Needless to say, this will be followed by an expensive repair of the outer part of the sewer system in a private house. For the sewerage device in the apartment, only gray PVC tubes are used.
The plastic collector made of PVC both in the apartment and in a private house perfectly withstands the effects of aggressive environments and is able to pass drains with temperatures up to 45 degrees through the system. A short-term increase in the temperature of effluents up to 90 degrees is allowed (but not more than 3 minutes). Effluent pressure in PVC pipes can reach 6-26 atm.
The laying of sewerage in a private house, when arranging its outer part from PVC elements, is carried out either with either the deepening of the collector below the level of freezing of the soil, or with its careful warming.
The diameter of plastic elements for sewerage can vary within 160-500 mm with a length of 0.5-0.6 m or within 50-110 mm with the same length. There is a range of diameters and 150-300 mm, but such PVC pipes are most often used for installing an external sewage system in a private house.
Polyvinyl chloride tubes for an external collector can also be divided according to the strength class into the following types:
- Elements marked S These hoses are lightweight and are used for mounting a collector in an apartment or in a private house.
- Plastic pipes S4. They have an average resistance to loads, and therefore they are laid mainly during the installation of the outer part of the system and in those places where an increased load on the sewer is expected.
- Tubes plastic S8. The most durable of all PVC elements. They are mounted under freeways and similar objects.
All elements of the PVC manifold are connected into a single manifold using fittings and fittings with a sealing ring.
Polypropylene pipes
This type of element is marked PP. In terms of the temperature regime that PP pipes can withstand, this parameter is 80 degrees. A short-term increase in the temperature of the drains is permissible up to 110 degrees. Wastewater pressure in the system is permissible within 20 atm. At the same time, polypropylene elements for sewage are less prone to susceptibility to sub-zero temperatures outside. That is, they are ideal for external sewage if the collector cannot be deepened enough. But PP pipes have one significant disadvantage - their rigidity. Therefore, it is better to mount a polypropylene collector inside an apartment or house, or lay it outside, but in places where the load on them will be minimal.
The diameter of PP-tubes varies between 16-110 mm, which is ideal for sewerage in an apartment in general and installation of a toilet bowl in particular. The polypropylene manifold is connected using sockets or hot welding.
Corrugated low pressure polyethylene pipes (HDPE)
- This type of cuts for sewerage is made with a smooth inner surface and a corrugated outer one. The corrugation plays the role of stiffeners, which allows you to lay the collector in the ground without fear of the impact of heaving earth on the walls of the collector.
- HDPE pipes withstand the transportation of wastewater at a pressure of 2.5-16 atm. At the same time, the wastewater temperature should not exceed +40 degrees, which is optimal for an external collector.
- HDPE pipes have a diameter of 10-1000 mm. For the device of the internal part of the sewerage system in a private house or apartment, pipes with a diameter of 50-110 mm are produced. For the toilet, the tube should be only 110 mm.
- The connection of corrugated elements is carried out using special compression couplings or by welding.
Corrugated PET pipes
Here, the collector cuts are made of two-layer polyethylene grade PE63-80. Such elements are suitable for laying external sewerage and can have a diameter of up to 300 mm. Tubes made of two-layer polyethylene can be laid in the ground to a depth of 20 meters. At the same time, their resistance to mechanical stress ensures the durability of the collector.
Sewer pipe marking
All sewer pipes at the factory are marked depending on the diameter and thickness of their walls. The marking is affixed in increments of 0.5-1 m. In addition, in the marking you can see all the GOSTs and TUs in accordance with which they were produced.
An important parameter in the marking is the inner and outer diameter of the hoses. However, it can be indicated both in mm and in inches. For example, marking the diameter in inches "4" is interpreted as an outer diameter of 110 mm, and in this case the inner diameter will be 101.6 mm. One inch equals 25.4 cm.
All sewer pipes have their own diameter, which is relevant for one section of the system and cannot be applied at all. Below are the data on the internal diameters of the collector cuts for each section of the sewer:
- For internal sewerage for the installation of a toilet bowl - pipe diameter 110 mm;
- For mounting a bathtub, sink, sink, shower cabin - 50 mm;
- Bidet - 50 mm;
- Dishwasher or washing machine - hose diameter 25 mm;
- Drain combined type under the sink, bathtub, washing machine - 50 mm;
- Central riser - diameter 110 mm;
- Riser bends - 65-75 mm.
For external sewerage, pipes of the following diameters are used:
- As an external collector from the house - diameter 110-160 mm;
- In case of connection to the pipeline of the collector from the sauna or bath - 150-200 mm;
- If drainage from the pool is added, then the diameter of the sewage system should be 200-300 mm or more, depending on the number of drains.
Performing calculations
In order for the sewage disposal system to work properly and without interruption, it is necessary to calculate the diameter of the external sewage pipeline in a private house. The calculation is performed according to the formula:
V(√h/d) > K
- V is the speed of effluent transportation through the collector. However, it should not exceed 0.7/s. The type of speed for each diameter can be calculated from the table.
- h/d is an indicator of the level of filling of the waste system during the outflow of gray water. It consists of the height of the moving flow (h) in relation to the inside diameter of the collector. The norm is the range within 0.3-0.6. Deviation in one direction or another is unacceptable.
- K is a coefficient that depends entirely on the material from which the pipes are made. For tubes made of polymers, it is 0.5, for elements made of cast iron and reinforced concrete - 0.6.
Knowing this simple formula and using it when designing a sewer system, you can develop and install an ideally working network for draining wastewater.
