Creating a comfortable environment, thanks to technology and a variety of materials, in an individual residential development, is really and not difficult. One of the main points of increasing comfort is communications, sanitary facilities, and, consequently, technical conditions for efficient and uninterrupted operation of devices and systems.
A prerequisite is the proper installation of the sewage line. The term “correct” means compliance with SP 55.13330.2016 “Residential single-family houses”, SNiP 2.04.03-85 p. 4.8., SNiP 31-02-2001. The technical conditions include such as the depth of the septic tank, the laying of pipes, the cross-section of the drainage pipes and others.
What determines the depth of the laying
The depth of installation of sewer pipes depends on a number of conditions, each of which can affect the choice of the distance of the pipes from the surface of the earth.
Specific values for all conditions that would be regulated by SNiPs are not indicated in the standards. For each area, the depth of the pipes for the sewage system has its own parameters. This parameter depends, first of all, on the climatic zone, the nature of the soil and the type of sewer system.
Above or below freezing
Installation can be carried out both above and below the level of soil freezing. But in any case, this indicator should be taken into account. When the pipeline is mounted in the freezing zone, then it is insulated with special heat-insulating materials, heating can be additionally installed.
It is not difficult to deepen the sewer line in climatic zones with a moderate minus mark in the cold period. In regions where the temperature in winter drops below -20 and is not uncommon, the depth of the frozen layer is from 1.5 meters or more. It is difficult to dig a trench of such depth on your own, especially if the installation of a septic tank is planned at a considerable distance from the building. In addition, some septic tanks suggest laying the pipeline no more than 1 meter 40 centimeters deep.
In such conditions, it is advisable to install a heating cable that turns on when there is a risk of freezing.
But even for areas with a deep freezing layer, technically, there is no need to deepen the sewer pipeline. The fact is that if all the recommendations for technical specifications are followed, then there is nothing to freeze in the pipes. All incoming liquid biomaterial will immediately drain into the tank. To do this, a slope is created, equal for each meter, 2-3 centimeters. The water used to wash off the waste has room temperature and should not freeze during the moment of movement through the pipes. The exception is situations when the lumen of the pipe is significantly narrowed due to clogging. But this is not a standard situation requiring urgent elimination.
How to choose the right depth
If the conditions regarding the angle of inclination of the sewer pipe are met, then without focusing on the climate zone, you can do with a depth of one meter. Provided that until the septic tank the pipeline “winds”, that is, there are many knee joints in the gasket, the likelihood of blockages increases. In this regard, it is also advisable not to dig deep so that you can open the soil at any time and remove the obstruction in the sewer.
Optimum sewer pipe depth
The classic depth starts from the house with a half meter, systematically deepening towards the septic tank. Deepening to a septic tank is calculated based on the instructions for use of the product. For example, the Topaz septic tank provides for a maximum pipe up to 1.4 meters.
Provided a direct pipeline can be deepened to a greater depth, without fear of blockages.
The depth of soil freezing depends not only on the climate zone, but also on the nature of the soil. For example, clay soils and loams in the MO have a freezing depth of 1.1 meters, while sandy soils freeze to 1.44 meters. In the Adler region, this parameter does not fall below 0.8 meters.
SNiP recommendations
According to SNiP, the location of the pipes leaving the room should be 30 cm above the freezing depth. Moreover, the depth of the trench is within 70 cm. If machines are supposed to move above the pipeline, or if there is a significant snow (other static) load, then increase the depth, to prevent damage to pipes and their freezing.
It is good to ask the neighbors what kind of sewage system they use and how effective it is in work. Given the size of the pipes, elbows, deepening and angle of inclination. If in a neighboring section, with the indicated parameters, the pipes do not freeze in winter, and the system functions without interruptions, then it is better to focus on such a positive experience. The fact is that the soil map does not give a clear understanding of the nature of the soil at a particular point. Official information takes into account the general situation over long distances. For a particular area, it is better to rely on existing experience.
Conclusion
The depth of installation of sewer pipes is an important parameter. But before determining it, it is necessary to prepare a preliminary draft of the entire system. It is important not to allow blockages, and to prevent them, install special covers / revisions that allow cleaning without dismantling the pipeline. Joints and turns can be insulated.
As a heater, polyurethane is used, on top of which a film layer is laid.
Warming makes sense and the length of the pipes at the exit of the room and before deepening. If this section is open, then in addition to thermal insulation, you can add a heating wire.
The legislative framework does not take into account the effectiveness of the system in many respects, and it makes no sense to rely on standards from this point of view. But they must be taken into account. And in technical terms, it is better to be guided by the experience of specialists who have repeatedly launched sewer systems in a specific area.
When designing, it is good to avoid turns and joints as much as possible. The fewer they are, the more reliable the pipeline system as a whole.
