The outer part of the stationary system of water supply to a private house is usually placed in the thickness of the soil. So it does not take place on the site, is protected from mechanical effects. However, it must be protected from low temperatures during the frosty period. What to do to eliminate the formation of traffic jams in the pipeline in the winter?
For uninterrupted water supply during the winter period it is necessary to carry out warming of a water supply system in the earth. We will tell you how to protect pipes laid in the ground from freezing. The article presented for review describes in detail the proven solutions to this task.
The content of the article:
-
Rules for the construction of underground water supply
- Basic provisions of regulatory documents
- Low temperature protection
-
Ways of warming outdoor water
- Application of simple techniques
- Types and forms of materials
- Insulating paint and polyurethane foam spraying
- Complete solutions
-
Protection of insulation from negative factors
- Destructive effects of land and water
- The solution to the problem of insects and rodents
-
Heating of external water systems
- Water circulation organization
- Use of electrical cable
- Application of warm air
- Conclusions and useful video on the topic
Rules for the construction of underground water supply
The freezing of the underground water pipeline occurs because of the achievement of negative ground temperatures. One way to prevent a problem is to hold the pipes at a depth where sub-zero temperatures are unattainable.
If this requirement has not been met, it is necessary to take other measures to solve the problem of uninterrupted water supply.
Image Gallery
A photo of
The water pipe laid in the ground is insulated in case it is laid above the seasonal freezing of soils. The area from the freezing point to the input to the heated room is insulated in any case.
For laying pipelines above the level of freezing, they produce ready-made heat-insulating systems with corrugated waterproofing sheath.
For the assembly of underground sections of water pipes produce pipes with polyurethane foam outer protective layer that protects the system from freezing, and pipes from corrosion
The use of insulating foam foam is acceptable. However, it must have a durable and sufficiently powerful waterproofing outer layer, since the foam is able to absorb and pass water through the pores
The tasks of hydro and thermal insulation are perfectly solved by sprayed polyurethane foam, which can be applied after the installation of water supply
In the case of insulation of underground water lines with thermal insulation capable of absorbing water, laying is allowed only in ducts or protective covers.
If the entire water mains is laid above the level of seasonal freezing, it is completely warmed from the point of water intake to entering the heated room
In the device of the casing for pipes insulated with a hygroscopic material, prefabricated boxes, sheet steel, roofing felt or larger pipes are used.
The depth of the insulation of the water supply
Pre-insulated pipeline system
Polyurethane foam protective shell for pipes
Thermal Insulating Foam Shell
Symbiosis of hydro and thermal insulation
Laying of the warmed pipes in a box
Insulation at the outlet of the caisson
Variant of insulating closures
Basic provisions of regulatory documents
According to paragraph 11.40 of the rules of joint venture 31.13330.2012, the depth of laid pipes, counting to the bottom, should be 0.5 meters greater than the calculated depth of penetration into the soil of zero temperature. This is necessary to exclude the formation of ice plugs in the pipeline and rupture of pipes in places of crystallization of water, increasing during freezing in volume.
Estimated depth according to p. 11.41 of the same rules should be established by field observations of the soil freezing isoline, as well as be guided by the experience of operating pipelines in the area.
Such information may be owned by the weather center or water supply organizations. In the absence of field data, it is necessary to determine the depth by thermal calculation.
As a result of the freezing of the water supply, the pipes often break. If they are located in the ground, their replacement will take a long time.
According to paragraph 5.5.3 of the set of rules SP 22.13330.2011 the normative depth of seasonal soil freezing in the absence of data long-term observations must be determined on the basis of thermal calculations presented in the figure. down below.
The values of the average monthly air temperature by settlements of the constituent entities of the Russian Federation should be taken from Table 5.1 of the Code of Rules SP 131.13330.2012.
The value of the estimated normative depth of seasonal freezing of soils depends on their type and climatic features of the cold period for this area.
In case of exceeding the obtained value of 2.5 meters, as well as for mountainous areas with a sharp change in the terrain, climatic or geotechnical conditions it is necessary to determine the normative depth of soil freezing according to the formulas in Appendix “D” of the rules of the joint venture 25.13330.2012.
Estimated freezing depth in accordance with paragraph 5.5.4 of the set of rules SP 22.13330.2011 for areas with non-negative average annual temperature values is determined by multiplying the standard value by a factor of 1.1. For territories with negative values, this value is calculated according to SP 25.13330.2012.
Low temperature protection
It is not always possible to fully or partially lay the water supply system below the zero isotherm. Sometimes this cannot be done for technical reasons, for example, when the outlet of a water pipe from a well is located above the boundary of the freezing zone of the earth.
The depth mark of the level of freezing is determined in accordance with the climatic specifics of the region in which the water supply is constructed.
For the middle lane, this value is 1.0–1.3 m, depending on the type of soil, in areas with severe winters, the depth pipe placement, according to the rules, will be more than 2.0 - 2.5 meters, which is very expensive both when laying and in case of need repair.
In areas with cold and long winters, the depth of the trench for laying water pipelines may be more than 2.0 - 2.5 meters, depending on the type of soil in which the pipeline is laid
If it is impossible or expensive to place the water supply system at a great depth, other measures are used for its uninterrupted functioning. They can be divided into two categories:
- Warming Designed to reduce the loss of heat by an object per unit of time. It is carried out using materials with low thermal conductivity.
- Heating. Designed to increase the temperature of the object. For the implementation of this procedure requires an external source of thermal energy.
Selection insulation options or heating the external branch of the water supply depends on the operating conditions, temperature conditions, system geometry, simplicity of work performed, as well as efficiency, cost and reliability of the solution method Problems.
Ways of warming outdoor water
There are many ways to insulate an outdoor water system located in the ground. If only cold water is supplied, then due to a small temperature difference, the thermal conductivity of the materials used is not as important as their durability, strength or price.
For hot water supply, supplied to a country house by a centralized network, ground routes are warmed. Due to the large temperature difference between hot water and the environment, the thermal conductivity of the material pays great attention
Application of simple techniques
In that case, if the pipes are located almost on the border of the freezing zone, to exclude the probability of stopping water supply can be performed elementary actions that do not require large investments and qualified execution works
For the southern regions, where the depth of the water supply is shallow, it is enough to dig out the pipes in the fall, fill them with an environmentally friendly insulating material and bury the trench again.
For insulation, you can use leaves, straw, shavings or sawdust. They have a low thermal conductivity, but by the next winter they will have time to rot in the ground, so this procedure must be repeated annually.
If, according to the calculations, the pipes are located slightly above the level, which makes it possible to guarantee that the system does not freeze, instead of deepening the water supply system, the problem can be solved by raising the zero isotherm.
This can be done in two ways:
- increase the thickness of the layer of earth, poured it on top;
- use for warming the fallen snow.
In both cases, the center of the landfill or snow strip is located along the aqueduct, and its width should be at least twice the depth of the pipe.
Snow is a good natural insulation. Even its 30-centimeter layer can halve the depth of freezing of the earth.
Landing will change the landscape of a plot of the local area, and insulation with plant and wood waste or snow must be carried out continuously. Therefore, for a long and reliable solution of the problem of water supply insulation, special developed materials are used.
The aqueduct laid below the seasonal freezing of soil in the region is warmed only in the section passing through the rock freezing in winter. Thermal insulation is arranged from the specified level to enter the pipe into the house.
If a running water is put into the house through an unheated basement, located below the depth of frost penetration, the insulation is carried out within the basement. Then a wooden box is arranged around the water supply section, and the space between it and the pipe is filled with sawdust or basalt wool.
Types and forms of materials
For insulating plumbing using materials that are presented in the form of shells - forms that follow the contours of pipes and system components. They are made of basalt cotton wool, glass wool, foam plastic, extruded polystyrene foam, polyurethane foam, foam glass.
In the case of mineral wool and glass wool, the presence of a foil envelope is a prerequisite for underground laying. It prevents wetting of insulation, because of which the insulating properties of the material are practically destroyed. The shell can be replaced by winding the pipe with basalt insulation with roofing felt.
Because of the ability to easily absorb moisture in the arrangement of underground networks is not used wadded heat insulation in the form of mats cut into plates or rolled into bales without external waterproofing protection.
An exception may be the laying of the pipeline in concrete trays with filling the free space between the tray and the pipe with expanded clay or similar material.
The presence of a constructive seam at the cylindrical insulation based on glass wool allows you to easily install the product on the water supply
Insulation shell is a finished billet cylindrical shape, whose inner diameter coincides with the outer diameter of the pipe. Products with a length of 60 cm to 2 meters consist of a solid tube with a structural seam, if the insulating material is elastic or of several (most often two) sections. The main advantage of the sectional material for insulation is the ease of installation of the product.
The connection of the halves of the relatively thin shell occurs with the imposition of the edge of the element on the next element to avoid the formation of unprotected sections of the pipeline. Offset meter segments, as a rule, is 15-20 cm.
If you need to use thickened insulation, it is better to choose the shell with the mounting chamfer on the front edge. The second way to ensure tight joints is to shift the parts of the shell relative to each other.
To form durable shell compounds and increase the rigidity of the heat insulating structure, parts of the shell are recommended to be slightly displaced relative to each other.
At fastening of parts of a shell use a sanitary adhesive tape. Protection of abutment of pipe bends, turns and other system components occurs with the help of special shaped forms.
Insulating paint and polyurethane foam spraying
One of the additional solutions for preventing the freezing of the external water supply line located in the ground is liquid or sprayed heat insulation. This method allows you to reliably, without seams and cold bridges, to protect areas with complex geometry, for which it is difficult to use standard materials for insulation.
Polyurethane foam has a liquid consistency and is applied to heat-insulated objects by spraying. Possessing one of the best thermal conductivity indicators, as well as a number of other positive properties, this material is characterized by a weighty minus: its application requires special equipment.
Polyurethane foam - one of the best insulation for underground water supply. However, its spraying is a technologically complex process requiring expensive equipment, adherence to safety engineering and professional skills.
Find companies that are engaged in insulation using polyurethane foam is not difficult, as it is actively used on different objects. However, all service providers have restrictions on the minimum sputtering area, so it is unlikely that it will be possible to find an affordable option only for 10 or 20 meters of the pipeline.
Special heat-insulating paint for pipe insulation similarly to polyurethane foam can be applied by spraying. It is sold in cans, so this procedure is easy to perform independently. There is also an option in the liquid form, which allows you to paint the elements of the aqueduct with an ordinary paint brush.
Image Gallery
A photo of
Heat-insulating paints - complex multicomponent systems, including modifiers, granules with heat-insulating properties and polymer base
Liquid insulation is applied by various methods, including using a spray gun or a brush. Insulated spray cans are available.
Solid plus ceramic liquid insulation is that the compositions can be superimposed on the rust pipe without prior preparation
Generally, heat insulating paints are used to paint water supply sections at the entrance to the house and in a non-warmed basement.
The composition of the liquid ceramic insulation
Spray paint application
Painting rusty pipes
Pipes in an unheated basement
Heat-insulating paint contains additives in the form of ceramic microspheres, foam glass or perlite. The thermal conductivity of this material is quite low, but due to the thin layer of deposition, it alone can be insufficient to solve the problem of warming a section of the water supply crossing the freezing layer soils.
Due to the high cost, applying a thick layer of heat insulating paint is expensive. Therefore, its use for warming is justified only in areas with a complex geometry or in places of possible occurrence of cold bridges.
The use of heat-insulating paint is justified both for exterior and for areas of a water supply system of complex geometry located in an unheated basement or in the ground
However, in the case of steel pipes, the use of paint along the entire length in conjunction with another heater may be appropriate for another reason. The presence of porous material in the composition leads to a high adhesion index, eliminating the possibility of the formation of external corrosion, which is important for metal structures located in the ground.
Complete solutions
The problem of freezing of the street branch of the water supply is very relevant. Demand creates supply and, therefore, there are a large number of ready-made complete solutions in the form of heat-insulated pipes and connecting elements on the market. They are pipelines surrounded by insulation, which is enclosed in a solid or flexible shell.
Image Gallery
A photo of
For the operational device underground communications produce pre-insulated pipes in a flexible and rigid shell. Flexible options easier styling
Preinsulated pipes are ideal for the installation of underground pipelines of any complexity and length. Hydro-and heat-insulating shells protect from environmental exposure.
In the pre-insulated systems offered for sale, the formation of units was thoroughly thought out and the technologies for their execution were spelled out in detail.
Pipes with pre-made insulation are laid in trenches without the device boxes. They are used in the construction of new systems and lines, in the modernization and repair of existing networks
Preinsulated pipes for communications
The device of pipelines of any complexity
Nodes and connections in pipeline systems
The use of pre-insulated pipes
There are both one-pipe and two-pipe versions of a ready-made solution for the insulation of external pipe laying. For normal cold water supply, constructions containing plastic pipes are the best option. They are cheaper than the metal counterpart and have a high installation speed.
The warmed pipes of PND are delivered in bays up to 200 meters long. Laying of water supply systems based on them can be performed with a minimum number of joints.
If corrugated material is used as the outer shell, it is possible to conduct the pipeline without the use of corner joints. This is possible because of the simplicity of performing bends of small radius of all parts of the kit.
There are ready-made integrated solutions for insulating water supply systems. Available with one and two pipes of different diameters.
Protection of insulation from negative factors
Protection against freezing of water supply located in the ground has its own specifics. The material should not completely or partially lose its insulating properties under the influence of external factors.
Repeated insulation or repair of the outer layers requires expensive and time-consuming earthworks, so you need to take care to preserve the integrity of the protective structure.
Destructive effects of land and water
Underground plumbing is under pressure of the soil, so the material used for warming can be crushed. At the same time its thermal conductivity can significantly increase. To prevent such a development, it is necessary to create a solid outer shell using larger diameter pipes or special trays.
Mineral wool is hygroscopic and can be wrinkled with a small effort of fingers, so the layer of the earth will compress the material and it will lose the property of low thermal conductivity
In the case of using hygroscopic materials as heat insulation of pipelines, it is necessary to prevent possibility of influence on them of groundwater, which is always in the ground, regardless of the degree of water saturation ground.
To protect the mineral and glass wool apply additional means of protection - plastic pipes larger than water pipes, which at the same time solves the problem of crushing insulation.
You can also use the following materials to create a waterproofing shell:
- rolled aluminum foil;
- reinforced (sanitary) tape;
- ruberoid;
- high density plastic film.
Styrofoam, extruded polystyrene foam slightly absorb moisture, but over time, too, become unusable with constant defrosting. Foamglass, polyurethane foam, and also heat-insulating paint are completely not subject to wrinkling and moisture.
Protection of objects located in the ground from moisture with ruberoid - long used, but not the most practical option
The solution to the problem of insects and rodents
Another cause of damage to the insulation of the water supply can be rodents and insects. Ants gnaw through numerous passages that are attractive for their thermal insulation, and mice use it to build a nest. These actions expose parts of pipes, which negatively affects the quality of insulation.
Neither insects nor mice can spoil polyurethane foam, foam glass, but perfectly deal with basalt wool. Her and similar materials for external insulation of water supply pipes must be protected from rodents, if they are located at a depth of less than 2 meters. Earthen ants do not penetrate below 1 meter, and forest at the same time build a large anthill, the above-ground part of which is impossible not to notice.
To protect against rodents, you can wrap the insulation with a metallic fine-meshed mesh. To prevent the access of not only mice, but also ants, it is necessary to wrap aluminum material. foil, reinforced with adhesive tape or plastic pipes or trays of any forms.
The shell of polyurethane foam or foam glass can withstand the pressure of the soil, the impact of moisture in the ground, and can not be damaged by rodents and insects
Heating of external water systems
If we consider any system, then warming is just a way to increase the time to reduce its temperature to the value corresponding to the environment. Therefore, sometimes it is necessary to resort to another option to prevent freezing of the water supply system - heating.
Going on heating water due to external sources of energy and there are several ways to organize this process.
Water circulation organization
The simplest source of additional thermal energy is water, the temperature of which is higher than in the insulated portion of the water supply system. If warmer water constantly replaces chilled water, then the system does not freeze. For this reason, the “ajar tap” method works when the slow but constant movement of fluid through pipes is organized.
For cold water supply of individual housing, it is possible to organize periodic replacement of water in the outer branch to a warmer one. In the case of supply from the main water supply system, it is often necessary to produce a small amount of discharge, which ensures the replacement of fluid.
It is rational to use a special tank located in the house for this purpose, which also performs the functions of a septic tank, from which you can later take water for your needs.
Drainage of water to prevent freezing may be at a time when it is not necessary. Use it later will allow storage tank
If the supply is organized from wells in which the water temperature is usually from 7 to 10 degrees Celsius, then it is necessary to turn on the pump more often. For storage of water, you can also use the usual cumulative capacity or hydraulic tank.
You can use the second pipe and three-way valve to organize the circulation of fluid with its discharge back into the well. At one time, it is sufficient to pump 1.5 to 2 volumes of a section of water supply located in the ground between the wellhead and the entrance to the house.
When water intake from a well there is also the option of draining it back by gravity after stopping the pump. This method is inappropriate to use in the case of metal elements of the water supply system. The constant change of fluid and air leads to intense corrosion of the inner surface of pipes and deterioration of water quality.
In stand-alone well-based water systems, water source insulation as well as the insulation of the pipeline itself. We recommend to read the article on the methods of thermal insulation of water wells.
If there is a possibility of long idle water and, as a result, its freezing, then despite the insulation, it is necessary to use other methods of heating.
Use of electrical cable
Most often, as an additional source of heat for an individual water supply system located in the ground, they use electrical cables. They can be placed inside the pipe that supplies water, and on its outer surface. The principle of heating is the conversion of electrical energy into heat.
The electric cable heats the elements of the water supply, the heat from which is transferred to the water. External insulation prevents the heat from leaving in the ground
The cables located inside the system have higher efficiency than the external ones due to the direct heating of the liquid.
The disadvantages of this type of cable placement include:
- higher price per meter due to compliance with environmental requirements;
- the complexity and sometimes the impossibility of carrying through the curved sections of the water supply;
- strong recommendations of experts to make the connection through the RCD, despite the certificates of compliance with the increased requirements of electrical protection
Installation of both options is approximately equal in complexity. The cable passing inside the pipe is sold complete with a special terminal sleeve. Its connection is made through a standard tee. The external cable is fixed with aluminum tape, and from above it is necessary to impose a warming shell so that the energy does not go to the ground.
Image Gallery
A photo of
The heating cable is laid in two ways: outside and inside the water pipe. The first method is easier to implement
To lay the cable inside the pipe, it is pulled into the cavity so that there are no "folds" and sags
In open areas, it is acceptable to close the water supply system with the heating cable by thermal insulation capable of absorbing moisture.
When using hygroscopic insulation materials for laying in the ground, it is necessary to construct a box with waterproofing properties.
Installation of heating cable outside the pipe
Specific installation of the cable inside the pipe
Insulation of water supply in open areas
Laying pipe with cable in the ground
Complete with a resistive cable that emits a constant amount of heat, to save electricity, it is better to use a thermostat to automatically turn the heating on and off. When using a self-regulating cable variant, it is necessary to choose the right parameters for it, then there is no need to use a temperature control device.
There are ready-made integrated solutions that, in addition to the water pipe, insulation and a rigid waterproof sheath, have an embedded cable for heating. These kits significantly reduce the time of installation of the system, but the purchase of all the elements separately will be much cheaper.
Ready-made solutions for underground pipelines may contain a cable for heating, which virtually eliminates the possibility of the system freezing.
The heating cable can be used to heat both part of the system and the entire outer section of the pipeline, which makes it unnecessary to lay the pipeline below the seasonal freezing mark soils.
Application of warm air
Another effective way to protect water pipe laid in the ground from freezing is to heat it with warm air from home. There are two options - with natural and forced air circulation and for both the installation of an additional closed tray or pipe of larger diameter.
In the case of natural air circulation to the water supply, they put on the pipe and warm it outside. It has access to a warm room and, therefore, there is a slow circulation of the surrounding air supply system with the transfer of heat from the basement or first floor of the house to it.
In the second case, along the entire length of the aqueduct, two channels (U-shaped profiles) are fastened along which air passes. They are wrapped with insulation and covered with an outer tube to prevent the insulation and profiles from being squeezed by the ground.
At the end of the heated section, these profiles are connected, thus obtaining a closed system with an entrance and an exit indoors. The air supply is forced with a hair dryer.
Schematic representation of the insulated underground water supply structure in case of its heating with warm air from the room. The version with forced circulation includes the use of a hair dryer, which directs a stream of air into one of the profiles.
Conclusions and useful video on the topic
Video # 1. Laying the pipeline in the ground from the well to the house with its insulation and the nuance of freezing around the foundation:
Video # 2. Insulation of a water supply system implemented on the basis of a plastic pipe and a method for insulating a knee using a larger diameter cylinder:
Video # 3. Detailed instructions for mounting the external heating cable, taking into account the proper bypass of fasteners and cranes:
High-quality insulation or heating of the water supply system, located underground, will ensure its uninterrupted flow in the winter period. In case of neglect of the rules of installation and protection against cold, a complicated procedure of defrosting and expensive repair of the water supply system can follow.
Want to talk about your own experience in the device insulation of water pipes in a suburban area? Would you like to share useful information with us and site visitors? Please write comments in the block below, ask questions, post photos on the topic.
