Cast iron and plastic pipes are used for internal sewage. In apartment buildings, they used to put heavy metal products, but gradually builders switched to polymers, since many of their positive qualities are able to compete with metal.
Types of plastic pipes for domestic sewage
In order to choose the right material for internal sewage or water supply, you need to know the characteristics of how a particular material reacts to an aggressive environment, high and low temperatures, and system pressure.
Cast iron products are known for their strength and durability. Service life about 80 years. Much depends on the composition of the liquid that flows inside, but the material is considered chemically inert, that is, it does not lend itself to exposure and does not change its characteristics in an acidic or alkaline environment. At the moment, the industry produces several types of cast iron, which makes it possible to choose for price and quality.
It is still believed that the inner walls of cast-iron pipes are rough and that in the process of operation, organic matter sticks to them, and traffic jams are created. But this shortcoming has long been fixed, now the inner surface is as smooth as that of polymer products. The walls are able to withstand pressure and not deform from temperatures. They also value metal for its good soundproofing properties. Of the minuses - a lot of weight and problems with self-assembly, as well as the need to perform welding work on straight sections.
Polymeric materials are much easier to install and have a long service life. In internal systems, several types of pipes are used, depending on the connection location.
Polypropylene
The material is more suitable for transporting cold liquids, but can withstand hot runoffs for a short time. Considering that washing and dishwashers drain hot water at a temperature of about 70 degrees, polypropylene can be used for house wiring. White pipes for domestic sewage are a good solution if you do not plug them into the wall. They look aesthetically pleasing and do not change color over time.
Due to the chemical inertness, the internal structure of polypropylene does not deform, which is important if you use chemicals in the kitchen or in the bathroom to clean acid-based pipes.
The material has light weight, which makes it one of the most popular. Parts of the internal sewage system are easy to assemble and install. Together with pipes you can buy couplings and fittings of various configurations.
Prolonged exposure to hot liquid can render polypropylene pipes unusable.
Polyethylene
Among plastic pipes for domestic sewage, a large selection is provided by manufacturers of polyethylene products. There are several brands of this material that differ in technical characteristics. You can choose any, based on needs - for hot or cold water supply, sewage, pressure or pressureless system.
Among the HDPE grades, cross-linked polyethylene stands out, whose resistance to high temperatures is 30 degrees higher than usual. Such material is used for external and internal sewerage and water supply, as it does not respond to ultraviolet radiation and environmental factors - frost and heat. In addition, it does not absorb water and is mechanically durable.
Polyvinyl chloride
This material is recognized as a leader in domestic sewer wiring:
- It is simply mounted and, if necessary, dismantled.
- Affordable cost and price / quality ratio.
- Absolutely smooth inner surface, on which minerals and organics do not stick.
- Resistance to mechanical damage.
- Chemically does not interact with aggressive substances of sewage.
Of the minuses:
- The weak point is hot water. The material is resistant to the temperature range from - 15 to + 65 degrees. Short-term capable of withstanding +95 degrees. Under the influence of high temperatures it becomes brittle.
- At temperatures below 15 degrees, insulation is required.
Sound insulation is practically absent. If this parameter is important, it is recommended to use appropriate materials for wrapping pipes.
Distinguish between pressure and non-pressure PVC products, as well as corrugated reinforced structures, which are often used in external systems for laying in the ground under the roadway. The wall thickness of pressure pipes is less, they are used in autonomous gravity systems.
For internal wiring, pipes with a diameter of 50 and 75 mm are used. The exception is the toilet drain, for which it is recommended to use 110 mm. With increasing diameter, the wall thickness increases.
Basic pipe selection criteria
Sewerage is a system that must be operated for a long time. Therefore, the choice of materials must be taken seriously. If polymers are used for internal wiring, most of them fit into the temperature frame.
When arranging a bath or sauna, you need to keep in mind that the main part of the drains there will have a high temperature. Most owners do not take risks and put cast iron, which tolerates temperature extremes well. Hot water contains iron oxides and carbonates, these substances are able to settle on the walls of cast iron over time and close the gap. Perhaps you should buy a more expensive polymer, for example, cross-linked polyethylene, which is not afraid of high temperatures.
The connection method also plays a role. For internal wiring, masters prefer a bell-shaped. Plastic can also be joined by cold welding, but this requires skills and tools.
Another condition is the right choice of diameter. In order for the system to run smoothly, it is recommended that the aspect ratio between internal and external wiring be maintained.
Mounting Features
The internal system is connected into a single unit using fittings of different configurations:
- knee - for turns and in places of diameter change;
- reduction - serves to connect pipes of different sections;
- tee - is necessary for branching the system, there are tees with different connection angles;
- a crosspiece - serves to connect 4 pipes into a single wiring.
To connect pipes without a socket, couplings are used, which also have different input and output diameters. There are special transitional elements with which the old cast-iron pipe is connected to the inner plastic.
The most well-proven plastic pipes Sinikon (SINIKON). This is a joint Russian-Italian production, producing products according to standards in force in Russia. The entire line of pipes and fittings is presented. At the moment, the company is a leader in terms of price / quality ratio.
Advantages and disadvantages of plastic pipes for domestic sewage
The advantages of plastic pipes are greater:
- They are easy to assemble with your own hands without the experience of such work. No additional tools required.
- Tightness is guaranteed through the use of gaskets.
- Due to the smooth inner surface, the flow rate does not decrease, and organic particles do not have time to stick to the walls.
- Almost all polymers are chemically inert and do not change their properties under the influence of acids and alkaline elements.
- Large selection of sizes.
Of the minuses:
- low sound absorption;
- as the temperature threshold rises or falls, they lose strength.
After a detailed study of the characteristics of polymeric materials, it is recommended to clarify the properties of products upon purchase, as the industry is constantly releasing new modifications.
Cost of pipes
The price of products from polymeric materials is an order of magnitude lower than cast iron. Despite this, some owners of private houses and cottages prefer the old method. If the budget allows, cast iron will do a good job of the task.
For more economical solutions for internal wiring, any type of plastic is used. Prices for PVC pipes for domestic sewage depend on the diameter of the products and their length. When ordering in large quantities, stores offer a discount on fittings or delivery.
