Products with thin walls, unstable to shocks and ground movements, are not suitable for external sewage, therefore a different type is used - red sewer pipes. They are much stronger and more durable. The market offers a variety of materials that differ in specifications. It is possible to choose a type of pipes for an autonomous sewage system that will meet all the parameters.
Purpose of external sewage pipes
An external sewage system is a system that delivers domestic wastewater to the place of its treatment or disposal. It includes:
- pipeline;
- drives;
- wells - inspection and service;
- cleaning systems.
Hoppers are containers that need to be emptied periodically. The main component is septic tanks. They are made from several materials - concrete rings, stone, brick, plastic, steel, cast iron. The cost of the system depends on what material is used, how long it lasts, how often it needs to be cleaned in order for the sewage system to work without interruption.
Inspection wells are part of the sewage system, which are installed in the most problematic places - wiring, bends, places where the diameter of the pipe changes. They are equipped with platforms for workers who serve a section of the highway, as well as brackets that act as steps. The well shaft is also made from various materials. Most often, these are concrete rings, but now, when building new sites, builders use plastic, since in terms of strength it is not inferior to steel and concrete structures, for example, polypropylene or polyethylene, and in installation it is much easier and more practical - it does not require welding.
Treatment systems - biological stations, two or three-component septic tanks for wastewater treatment. They are located outside the building, most often installed in the ground, therefore, they must correspond to local weather conditions. The industry offers septic tanks for sewage treatment plants made of different materials, of different designs - prefabricated and monolithic, so that buyers can choose the best option for themselves.
Sewer pipes are the main element that connects all parts of the system. For the arrangement of an autonomous home sewage system, special modifications are chosen that, in conditions of cold winters and hot summers, do not lose their characteristics, do not clog up, and do not corrode. The easiest to install is plastic and its various types.
Manufacturing materials
Polypropylene structures are one of the most popular in the construction of domestic water supply, heating and sewerage systems. The material has several advantages that compete with the more expensive and heavy ones - steel and cast iron:
- service life with correct operation is more than 50 years;
- plaque in the form of lime, silt, rust is not deposited on the walls, because the walls are smooth from the inside - the substances in the water do not have time to attach to the material;
- low weight of products, which does not require the use of heavy construction equipment;
- you can connect polypropylene parts by welding or fittings;
- the cost of the material is several times less than that of steel and cast iron products.
To select pipes, you need to know which marking corresponds to certain conditions - the temperature of the liquid, its chemical composition.
PVC-U pipes for outdoor sewerage are made of unplasticized polyvinyl chloride. They are used in the arrangement of artesian wells, wells, sand wells, for home water intake and sewerage systems. They have the following characteristics:
- suitable for laying in the ground to a depth of 8 meters;
- transport liquids, the temperature of which does not exceed 78 degrees;
- resistant to water hammer, pressure up to 25 bar from the inside and up to 160 atmospheres from the outside;
- react neutrally to acids, alkalis, salts, fat, gasoline, but dissolve in acetone, dichloroethane, nitrobenzene;
- do not affect the taste of food liquids, therefore they are used in enterprises that produce juices, dairy products, vegetable fats;
- do not support combustion;
- can be used at temperatures from minus 50 degrees, melt and turn into a fluid state at 180 degrees.
The pipes are lightweight, but do not float when immersed in water - this quality is used in the arrangement of the walls of wells.
Polyethylene is a lightweight durable material that is used in sewer systems. Has the following properties:
- elastic - does not crack during deformation;
- withstands high temperatures - up to 80 degrees;
- does not change characteristics under the influence of acids, alkalis and alcohol;
- high strength - they are not damaged during unloading work.
The service life is more than 50 years, therefore it is used in urban sewerage and water supply systems. There are several types of strength, wall thickness and diameter. The cost compares favorably with metal structures and cast iron.
Steel pipes for sewage are used in those environmental conditions where there is a risk of damage due to ground movement or the pipe is exposed to high loads in the form of vibrations - under a highway with heavy traffic. It has its drawbacks - susceptibility to corrosion. Over time, deposits in the form of iron oxide or limestone build up on the inner walls, which narrows the pipe diameter and makes drainage ineffective. Steel products during installation require the use of technology, since they are heavy. In home autonomous sewerage systems, they are practically not used, as they require increased care. If the weld seam bursts, then the tightness of the line is broken, and expensive repairs are required.
Cast iron pipes for domestic sewage are rarely used, but sometimes they are even found in a home autonomous system. Cast iron has both positive and negative qualities - it all depends on the composition and additives, as well as processing methods. The main disadvantage of cast iron pipes is the rough inner surface. Over time, a silty layer forms on it, on which organic matter adheres. This narrows the pipe diameter, necessitating frequent cleaning of the drain with organic dissolving chemicals.
Cast iron is a rather fragile material and therefore requires careful handling during loading and stacking. Cast iron pipes are connected by hand using oiled rope, which sometimes leads to depressurization. The cost of cast iron products is much higher than the price of plastic outer pipes for sewage.
Sewer pipe dimensions
In stores, you can buy red sewer pipes of the following sizes:
- in length from 1 to 6 meters;
- by inner diameter from 11 to 50 cm;
- along the wall thickness from 3 to 15 mm.
In a private area, external pipes with a diameter of up to 16 cm are most often used.If the sewage system runs along the street, then a diameter of up to 20 cm is used. The central highway, depending on the load, can be 50 cm or more.
If there are few turns and bends of the line on the site, the purchase of straight long products will be cheaper - there is no need to purchase fittings to connect short lengths. You can save on arranging viewing wells, which are also made using plastic products.
Based on the dimensions of the pipe itself, other parts of a suitable size are selected:
- adapters;
- tees;
- crosses;
- contours;
- rubber sealing rings;
- stubs.
The shallower the burial depth, the smaller the wall thickness you can choose. Consequently, the cheaper the pipeline will be.
For outdoor installation, a corrugated pipe is often used. Its advantage is the presence of stiffeners - inside and outside. Small inside, barely noticeable, outside - large. The most durable are two-layer plastic pipes with a corrugated surface. They are used in areas where ground movement occurs periodically. The ribs do not allow the product to deform, as they increase the elasticity. Under linear tension, the corrugated surface also affects the safety and integrity of the line.
The main criteria for choosing pipes for outdoor sewerage
Product selection criteria include:
- the quality of the soil on the site;
- depth of occurrence;
- pressure in the system - pressure or gravity sewage;
- ways of connecting parts of the line;
- single-layer or double-layer, the presence of corrugation;
- material of manufacture;
- the diameter of the external sewage system - depends on the size of the house, the number of water intake points and daily water consumption;
- resistance to external influences - temperatures, ultraviolet light;
- domestic sewerage or industrial wastewater transportation;
- chemical composition of effluents - aggressive or neutral;
- system cost.
One of the main selection criteria is the need to clean the sewage system - how often this will have to be done, based on the characteristics of the inner surface.
Installation steps
Work on the arrangement of an external sewage system begins with the creation of a project and the necessary measurements. After laying the internal wiring, external work begins:
- Digging a pit for a septic tank and trenches for a highway.
- Laying and connecting parts of orange pipes using fittings, tees, adapters, O-rings.
- Installation of inspection chambers in the most problematic areas.
- To create a support, a sand cushion is used, as well as geotextiles, so that in the event of a breakthrough, wastewater does not fall into the ground.
- After connecting all the elements of the system, it is tested in operation. If the water flows down normally, fill the trenches and septic tank with sand and soil, install hatches on the inspection wells.
In order to correctly calculate the length of the line and the slope of the pipes, it is better to invite specialists. If the work on laying the sewage system is performed with errors, it threatens with permanent blockages. It will be possible to eliminate the problem by completely digging the water supply system, and this is a large expenditure of labor, time and money.
Pipe cost
The size of the product and its brand affect the cost. The density of the outer pipes is initially higher, therefore, the price of the product will be higher. Larger pipes are more expensive than smaller ones.
In terms of materials, there is nothing more expensive than ultra-high molecular weight polyethylene. Polypropylene and ordinary polyethylene have an affordable cost.
Of metals, the steel structure will cost more, but there is no need to buy metal for a home autonomous water supply or sewage system. Cast iron is cheaper, but if it is enriched with magnesium, then the price will be about the same as steel.
