Stable water supply of residential buildings is a prerequisite for the normal residence of people in them. However, owners of private households during the onset of frost often face the problem of freezing the water supply, especially at the entrances to the building and the unheated underground. The formation of an ice plug completely blocks the flow of water into the house, and the expansion of the freezing liquid leads to ruptures of the water pipes and damage to the valves. Such troubles can be avoided only if the insulation of water pipes in a private house is ensured.
Important groundwater installation conditions
Prerequisites for freezing water in pipes arise even at the stage of installation of an external water supply. The construction rules directly indicate that the depth of the underground water lines should be below the standard freezing point of the soil.
For our northern country in most regions, this value exceeds 1.2 meters. It is usually not desirable to dig such a deep trench and is taken for the truth (hope) that the soil does not freeze to such a depth, and as a result, the water supply is laid at a depth of half a meter, thereby making a gross mistake. One of the winters, the water in it will surely freeze. And to dig frozen ground in winter ... Make a conclusion yourself.
Attention! It must be said here that the concept of soil freezing is not the annual formation of permafrost to a depth of one and a half meters, but a temporary decrease in soil temperature to a negative value.
Methods of insulation of water pipes
If during the underground laying of the pipeline the depth of the line was maintained correctly and there is no danger of freezing water in this section, then when entering the house, the water supply rises closer to the surface and enters the freezing zone of the soil.
After that, he enters the building and passes some distance through the basement (underground). If the rooms below the zero mark of the house are warm, then it is necessary to isolate only the underground section of the pipe lift and the input unit. Otherwise, the work on the thermal insulation device is divided into two stages:
- insulation of water pipes in the ground;
- thermal insulation of open-laying pipes in the basement.
This separation is due to the different technologies used for each case. The insulation of the underground gasket must be rigid, waterproof and not attracting rodents and insects. The requirements for open pipe laying in the basement of a building are less stringent and make it easier.
Thermal insulation materials used
Solving the issue of how to insulate a water pipe in the ground and inside the house, it is necessary to ensure the following thermal insulation requirements are met:
- minimum coefficient of thermal conductivity of the material;
- sustainable shape retention under mechanical stress;
- inability to absorb moisture or the presence of protection from it;
- simple installation work.
Especially for the insulation of pipelines, manufacturers of building materials make assembly heat-insulating elements in the form of tubular shells, half cylinders and segments. As a traditional material, sheet heaters are still considered, with which the pipes are simply wrapped.
Glass wool
Fiberglass thermal insulation is used to insulate water pipes only in dry rooms. The durability of this material, good thermal insulation properties and low cost lose their significance due to the ability of glass wool to actively absorb moisture. Therefore, the insulation of the water supply in a private house requires the obligatory presence of a waterproofing layer, which increases the cost of insulation and complicates installation.
Basalt heaters
They are made in the form of flat mats, half cylinders and segments. The ability to absorb moisture is present, but it is much lower than that of glass wool. Recommended for insulation of pipes in dry rooms. Basalt heaters are not used for the insulation of underground pipelines.
To isolate pipelines, manufacturers make products with a protective layer already applied from foil isol or glassine. Sophisticated manufacturing technology of the material increases its cost. As a result, insulation of small diameter pipes often becomes economically disadvantageous.
Expanded polystyrene
Dense, strong and durable material with excellent thermal insulation properties, is best suited for insulation of water pipes in the ground. Available in the form of split tubes and half cylinders. A surface protective coating of polymer materials or foil is possible.
Polyurethane foam
This type of insulation is used for the manufacture of pre-insulated pipes PPU in the factory. Such systems are considered the best protected from heat loss and all types of external influences. But the main drawback for private developers is the need to attract specialists for installation work.
Foamed polyethylene and artificial rubber
Especially for the insulation of pipelines, tubular casings of various diameters are made from these materials. They are worn on the pipe during installation work or on already installed pipelines. To do this, a longitudinal incision is provided along the length of the casing, which allows you to open the shell and put it on the pipe, doing the installation yourself.
Tubular insulation made of foamed polyethylene and artificial rubber:
- has good thermal insulation properties;
- does not pass and does not absorb moisture;
- easy to install;
- durable and affordable.
However, the low mechanical strength of these materials does not allow their use in underground installation. The weight and pressure of the soil will lead to compaction of the layer and loss of thermal insulation properties. Therefore, use is allowed only with open pipe laying.
Heat insulating paint
This innovative material is a thick, pasty composition that is applied to the surface of the pipeline. The paint layer with a thickness of 4 mm in its properties corresponds to 8 mm mineral wool insulation.
The coating is characterized by high strength, wear resistance and high resistance to moisture. The main disadvantage is the high cost - more than $ 150 per bucket of 10 liters.
Alternative ways to protect your water pipe from freezing
It is possible to protect the water supply in a private house not only with the help of thermal insulation, but also in other ways. These include:
- pipe heating with electric heating cable;
- creating excessive pressure;
- using an air shell.
These three protection technologies are widely used in practice and therefore deserve more detailed consideration.
Using a heating cable
This method involves direct heating of the pipeline using a special electric cable. It can be on the surface of the pipe or inside it. The average consumed heating power is 20 W per linear meter of water supply, but the exact value is determined by the location of the wire and the diameter of the pipeline.
The use of external heating technology allows you to lay water pipes at a depth of less than 1 meter, and also once and for all to solve the issue of how to insulate a water pipe in the street. However, the additional energy consumption in the cold season makes you think about the appropriateness of this method.
When installing the heating pipe with a cable, it can simply be wound along the surface of the pipe or located inside it. In the first case, a significant part of the heat will not go to the water supply, but to the environment. In the second case, specialists have to be invited to perform installation work.
A good option would be to share a heating cable and thermal insulation. In this case, it is placed under the heat-insulating layer along the pipes along the surface. Heat losses will be minimal and energy consumption will be significantly reduced.
Air insulation
This frost protection technology is only used for underground water pipelines. The essence of the method is the presence of an air gap between the surface of the pipeline and the soil. It is created using a plastic corrugated pipe worn on top, the diameter of which is 20-25 mm larger than the diameter of the water supply.
The result is a pipe-in-pipe system with an air gap of sufficient size. Tap water, having a positive temperature, heats the air and provides itself with protection against freezing. However, such a system requires a water intake, and if 3-4 days are not used in the house, the air will cool and the insulating effect will disappear. Therefore, this technology is not suitable for a summer residence.
High pressure
This method is based on the physical property of water to lower the temperature of the freezing point at elevated pressure, similar to the property of boiling at a temperature of less than 100 ° C in highlands.
Overpressure is generated by the pump and receiver. However, there are technical difficulties. The fact is that the folding valves in the house are not designed to work with high water pressure. So, for example, the standard pressure for a shower mixer is 0.1 MPa. Therefore, it is necessary to create a rather complex engineering system:
- a receiver is installed in the pit at the wellhead, in which a high pressure in the water supply is created using a powerful deep-well pump with a check valve;
- the applied pipe material must withstand the created load;
- a water pressure regulator is installed inside the building in a warm room, which will ensure the operation of the internal system in normal operating conditions;
- after the pressure regulator, it is necessary to install a safety valve with water discharge into the drain pipe in the event of a valve failure.
As a result, the system is quite complex, which means that the level of its reliability and safe operation is reduced.
Automation of water supply control
Today on sale you can find a variety of immersion and surface temperature sensors. By installing such devices on the underground part of the water supply, you can receive timely information about the approaching time of a possible emergency. After that, open the water taps and warm up the water supply, since the water coming from the well always has a positive temperature.
Signals from sensors can be sent through a microprocessor to a sound siren, and in more complex systems send messages to a phone or email. If you have a heating cable, you can automate its inclusion when the critical temperature is reached.
Installation instructions for heating cable for underground pipe laying
When installing a single-core wire, it should be noted that in order to be able to connect it, it must go through the pipeline, and then go back. Thus, you will have two ends that can be connected to a power source.
Work should be carried out in the following sequence:
- lay the cable along the pipe from beginning to end, temporarily fixing it with tape;
- transfer the cable to the back of the pipeline and pull it in the opposite direction;
- stick foil adhesive tape over both threads, which will ensure complete fixation of the wire and reflection of the heat flux towards the pipe;
- mount the selected insulation throughout the water supply;
- wrap the surface with waterproofing plumbing tape or waterproof the surface in another reliable way.
Before laying the pipe in the ground, it is necessary to test the installed heating system. To do this, connect the cable to the power source and make sure that heating occurs on the visible end segments.
Finally
Providing reliable protection of the water supply will ensure a continuous supply of water to the house and save you from possible problems with water supply in the cold season. The choice of protection method depends on the actual operating conditions and your financial capabilities. But to prevent freezing of water in the pipes is necessary in any case.