In case of independent construction, one of the main engineering systems is the water supply. Let’s try to answer one of the most important questions during its construction.
The desire to independently organize water supply for private households is accompanied by a host of important issues, on the solution of which the efficiency of using the utility network depends. In particular, not everyone knows at what depth to lay a water supply system so that its contents do not turn into ice in winter, breaking pipes, and in summer warm water does not come from a cold tap.
The option “the deeper the better” is considered not very acceptable for the water supply network for several important reasons:
- high groundwater levels complicate pipe-laying;
- deeper deepening leads to an increase in the volume of earthworks;
- further repairs to the pipeline are more expensive due to access difficulties.
In some cases, it is difficult to do without deep laying of water pipes. This can be facilitated by the difficult terrain, the presence of natural or artificial barriers, and permafrost. But under normal conditions, the depth of the laying is taken depending on the calculated level of soil freezing, which depends on the region of construction, in particular, on the real indicators of the minimum winter air temperatures. Several other factors are also taken into account, namely:
- technological mode of water supply;
- type of soil;
- features of the bedding of soil layers;
- proximity of groundwater;
- the thickness of the snow cover in winter;
- the intensity of heating the site in summer;
- pipe material:
- possible external loads exerting additional pressure on the pipeline.
If, for some reason, the water supply system is supposed to be laid in the zone of penetration of negative temperatures into the ground, then it is imperative to provide for high-quality pipe insulation. It is possible to refuse thermal protection only when using the water supply network exclusively in the summer and subject to the installation of the system, taking into account the possibility of emptying the pipeline before the start of the winter season.
The water supply system is not allowed to be mounted in the freezing zone of heaving soils, since their movements can damage the integrity of the pipe joints. In extreme cases, a partial replacement of heaving soil is performed.
The main operational factor that ultimately determines at what depth to lay the water supply system is the absence of ice formation in pipes in frosty weather. SP 31.13330.2012 (aka SNiP 2.04.02-84 * in the updated version) indicates that they should be mounted at a depth exceeding the thickness of the soil freezing zone by at least half a meter. The standards allow laying the pipeline higher, but provided that thermal protection is provided not only for pipes, but also:
- fittings installed on the water supply system;
- butt joints;
- pumping equipment.
In order to avoid unforeseen situations, with a high laying of an external water supply system, pipes and fittings from frost-resistant materials should be chosen. And when laying the network on the surface of the earth, it is required to protect the structural elements from possible mechanical damage. SNiP 3.05.04-85 * specifies additional conditions for the installation of water pipes in special conditions. However, the requirements of the previous standard remain valid even for temporary pipelines outside trenches.
When installing a water supply system in conditions of frozen soils, measures should be taken to thaw them. In this case, the bottom is carefully tamped, and backfilling is performed with mandatory compaction. In earthquake-prone areas, it is necessary to provide measures to prevent deformation of the water supply network in the event of possible ground movements. The depth of pipe laying, in this case, is chosen individually, taking into account the calculations performed by specialists.
Difficult installation conditions also apply to swampy areas. To prevent the pipeline from rising from the design depth, it is “weighted” in accordance with the instructions in the explanatory note. In each case, the issue is resolved taking into account the peculiarities of the hydrogeological conditions of the site. Another nuisance is associated with subsidence soils. In this case, when determining the depth of pipe laying, the careful compaction of the soil and the addition of a sand-crushed stone cushion of greater thickness than usual conditions are taken into account.
The value of the estimated depth of soil freezing can be found in the corresponding tables located in building directories, or with the help of online calculators located on numerous specialized sites that are easily found on the Internet. One has only to enter the desired phrase into the search engine, and the results will immediately appear on the monitor screen.
In both cases, the indicator is established on the basis of long-term observations of the real thickness of the freezing zone, taking into account a specific region, region and even an area. At the same time, winters with little snow in combination with maximum subzero temperatures are taken into account. Often, for a more accurate study, snow cover is removed on the sites.
If there are no data from real observations of winter soil freezing, then the depth of penetration of frosty air into the soil is determined based on heat engineering calculations.
An equally important factor for regions with hot climates is to prevent water heating when the soil is directly exposed to sunlight. According to the norms, the depth of the water supply should be taken, in this case, it should be at least half a meter from the ground level to the top of the water pipe. A closer arrangement is possible if the dimensional indicator is confirmed by heat engineering calculations.
According to sanitary standards, the water supply must always be located above the sewer pipe. If the intersection of two networks happens differently, then a pipe with water is laid in a casing. This condition must be taken into account at the design stage. published by econet.ru
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