Proper operation of the sewage system has an impact not only on comfort but also on safety. It is worth being aware that sewage systems can freeze, which unfortunately generates major problems. This is influenced by the depth of ground freezing, which can vary depending on the terrain.
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Why do sewer networks freeze?
Both internal and external sewage systems should function properly. At the same time, not only the design is important, but also the use of materials. All components must meet strict quality and strength standards. The sewage pipe can be made of PVC material. Models with a socket or thread must be used.
In the case of pressure installations, a non-return valve is also necessary. However, this will not prevent the sewage system from freezing or freezing over. Many people wonder what causes this? One of them is an incorrectly applied slope and a poorly selected diameter and incorrect depth. If the pipe is too close to the surface, the water may freeze in it.
In addition, pipes cannot be located close to the groundwater level. You should also pay attention to the frost zones, which tell us at what depth the frost phenomenon occurs. Note that sewage connections located, for example, between the house and the street canal or manhole must be placed below the frost zone and with a minimum two percent slope.
The occurrence of different depths of ground freezing can increase problems with the correct operation of the entire installation. Connections such as pipes must be located sufficiently deep in the ground. At the same time, the depth depends on the region of Poland. To provide additional protection for pipelines placed in the ground, they must be laid below the freezing zone, with the top of the pipes being at least 40 cm below the ground freezing zone. In the case of sewage installations, a minimum of 20 cm must be maintained.
How can you tell if your sewer pipes are frozen?
Water supply networks and connections can operate properly regardless of the level at which the frost zone occurs, and therefore it is important to comply with the PN-81/B-03020 standard. This will help avoid problems with freezing or freezing of sewage pipes. It is important to know that the frost zone ranges from 0.8 to 1.4 m below the ground surface.
Sewer pipes can freeze easily and this can be seen when water backs up, but also when there is a complete blockage and a blocked drain. Frozen sewer pipes can damage the entire sewer system. There can also be dents and cracks in the main sewer line. Contrary to appearances, such failures do not only occur in winter, but also in the autumn or spring months.
In addition, frozen pipes can cause problems with the operation of the entire installation and lead to its damage, which is associated with high repair costs. Difficult water supplies can also be expected. Research conducted in the freezing zone clearly shows that incorrectly laying sewage pipes, when the ground layer is too close to the freezing zone, can lead to pressure on the pipes, and as a result, not only their damage, but also their expansion. Too small slopes also lead to blockages. Therefore, too shallow laying and lack of insulation can cause the pipes to burst.
There are four zones of ground freezing:
- Zone I – 0.8 m
- Zone II – 1 m
- Zone III - 1.2 m
- Zone IV – 1.4 m
Taking these zones into account, it is necessary to maintain the appropriate depth of the sewage system:
- Zone I – 1 m
- Zone II – 1.35 m
- Zone III - 1.6 m
- Zone IV – 1.85 m
Effective removal of frost from water and sewage networks
Ground freezing also depends on air temperature and snow cover. The most susceptible to freezing are loose soils, e.g. peat. Of course, before installing a sewage system, there is an obligation to perform geotechnical tests of the ground. This does not apply only to single-family houses, which are classified in the first geotechnical category.
However, due to the possibility of problems with the proper functioning of the sewage system, this type of examination is absolutely necessary. But what to do when frost occurs? It must be admitted that the situation is very problematic. The heating technique works best, but it must be performed by professionals. In addition, sewage unclogging tips are used. In the event of the occurrence of not only frost, but also plugs, mechanical removal is necessary.
There are also pipe unblocking agents that cause a chemical reaction to increase the temperature. Soda with hot water is also used. However, if this does not help and the pipes are additionally damaged, they must be replaced. You can possibly heat the pipe after digging it out, but this procedure must also be carried out by professionals. Specialists also use potassium hydroxide solutions. You should first close the main valve and open the nearest end valve. To avoid such problems, you should follow the rules of sewage system installation, taking into account the ground freezing zones.