Thermal insulation for plastic water supply pipes. How to insulate the water supply in a private house with your own hands. Types of insulation materials
Master of Architecture, graduated from Samara State University of Architecture and Civil Engineering. 11 years of experience in design and construction.
Stable water supply to residential buildings is prerequisite for normal living of people in them. However, when frost sets in, owners of private households are often faced with the problem of freezing water pipes, especially at the entrances to the building and 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 water pipes and damage to shut-off valves. Such troubles can only be avoided if the water supply pipes in a private home are insulated.
Important conditions for laying underground water supply
Prerequisites for water freezing in pipes arise even at the stage of installation of external water supply. Construction rules directly indicate that the depth of underground water supply lines must be below the standard freezing point of the soil.
For our northern country in most regions this value exceeds 1.2 meters. You usually don’t want to dig such a deep trench and take it as a truth (hope) that the soil does not freeze to such a depth, and as a result, the water supply is placed at a depth of half a meter, thereby making a grave mistake. One winter, the water in it will definitely freeze. And digging frozen soil in winter... Draw your own conclusion.
Freezing depth by region. Attention! Here it must be said 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 for insulating water pipes
If, when laying a pipeline underground, the depth of the line was maintained correctly and there is no danger of water freezing in this area, then when entering the house, the water supply rises closer to the surface and enters the soil freezing zone.
After this, he enters the building and walks some distance through the basement (underground). If the rooms below the zero level of the house are warm, then only the underground section of the pipe rise and the input unit need to be insulated. Otherwise, work on installing thermal insulation is divided into two stages:
- insulation of water pipes in the ground;
- thermal insulation of pipes laid openly in the basement.
This division is due to the different technologies used for each case. The insulation of the underground installation must be rigid, moisture-proof and not attractive to rodents and insects. The requirements for open pipe laying in the basement of a building are less stringent and it is easier to do.
Thermal insulation materials used
When deciding how to insulate a water pipe in the ground and inside the house, it is necessary to ensure that the following requirements for thermal insulation are met:
- minimum thermal conductivity coefficient of the material;
- stable shape retention under mechanical influence;
- inability to absorb moisture or the presence of protection against it;
- easy execution installation work.
Manufacturers specifically for pipeline insulation building materials produce assembly heat-insulating elements in the form of tubular shells, half-cylinders and segments. Traditional material Sheet insulation, which is simply wrapped around pipes, is still considered.
Glass wool
Thermal insulation made of fiberglass is used to insulate water pipes only in dry rooms. The durability of this material is good thermal insulation properties and low cost lose their significance due to the ability of glass wool to actively absorb moisture. Therefore, insulating a water supply system in a private house requires the presence of a waterproofing layer, which increases the cost of insulation and complicates installation.
Basalt insulation
They are manufactured in the form of flat mats, half-cylinders and segments. The ability to absorb moisture is present, but it is significantly lower than that of glass wool. Recommended for insulating pipes in dry rooms. For insulation of underground pipeline lines basalt insulation do not apply.
To insulate pipelines, manufacturers make products with a protective layer of foil insulation or glassine already glued on. Complex technology for manufacturing the material increases its cost. As a result, insulation of small-diameter pipes often becomes economically unprofitable.
Selection of the diameter of thermal insulation for pipes. Expanded polystyrene
Dense, strong and durable material with excellent thermal insulation properties, the best way Suitable for insulating water pipes in the ground. Available in the form of split tubes and half-cylinders. It is possible to have a surface protective coating made of polymer materials or foil.
Polyurethane foam
This type of insulation is used for the manufacture of pre-insulated polyurethane foam pipes in the factory. Such systems are considered the best protection against heat losses and all types external influences. But the main disadvantage for private developers is the need to attract specialists to carry out installation work.
Foamed polyethylene and artificial rubber
Tubular casings are made from these materials especially for thermal insulation of pipelines various diameters. They are put on the pipe during installation work or on already installed pipelines. To do this, a longitudinal cut 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 polyethylene foam and artificial rubber:
- has good thermal insulation properties;
- does not allow or absorb moisture;
- easy to install;
- durable and affordable.
However, the low mechanical strength of these materials does not allow their use for 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 only permitted when pipes are laid open.
Thermal conductivity of materials. Thermal insulation paint
This innovative material is a thick paste-like composition that is applied to the surface of the pipeline. A layer of paint 4 mm thick corresponds in its properties 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 for a 10-liter bucket.
Alternative ways to protect water pipes from freezing
You can protect the water supply in a private home not only with the help of thermal insulation, but also in other ways. These include:
- heating the pipe using an electric heating cable;
- creation of excess 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 heating power consumption is 20 W per linear meter of water supply, but the exact value is determined by the way the wire is positioned and the diameter of the pipeline.
The use of external heating technology makes it possible to lay water pipes at a depth of less than 1 meter, and also to once and for all solve the issue of how to insulate a water pipe on the street. However, the additional energy consumption in the cold season makes us think about the feasibility of this method.
When installing pipe heating 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 go not to the water supply, but to the environment. In the second case, you have to invite specialists to perform installation work.
A good option may be to use a heating cable and thermal insulation together. In this case, it is placed under the heat-insulating layer along the pipes along the surface. Heat loss will be minimal and energy consumption will be significantly reduced.
Air insulation
This freeze protection technology is only used for underground water pipes. The essence of the method is the presence of an air gap between the surface of the pipeline and the ground. It is created using a plastic corrugated pipe placed 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 from freezing. However, such a system requires water supply, and if water is not used in the house for 3-4 days, then the air will cool down and the insulating the effect will disappear. Therefore, this technology is not suitable for a dacha.
Creating high pressure
This method is based on the physical property of water to lower the freezing point temperature at high blood pressure, similar to the property of boiling at temperatures below 100°C at high altitudes.
Excessive pressure is created using a pump and receiver. However, technical difficulties arise here. The fact is that the water fittings in the house are not designed to operate at high water pressure. For example, the standard pressure for shower mixer is the value of 0.1 MPa. Therefore, we have to create a rather complex engineering system:
- a receiver is installed in a pit at the wellhead, in which high pressure is created in the water supply using a powerful deep-well pump with a check valve;
- the pipe material used must withstand the load created;
- a water pressure regulator is installed inside the building in a warm room, which will ensure the operation of the internal system in normal conditions operation;
- installation required after the pressure regulator safety valve with water discharge into the drain pipeline in case of valve failure.
As a result, the system turns out to be quite complex, which means its level of reliability and safe operation decreases.
Automation of water pipeline operation control
Today you can find a variety of immersion and surface-type temperature sensors on sale. By installing such devices on the underground part of the water supply system, you can receive timely information about the approaching time of a possible emergency situation. After this, 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 annunciator, and in more complex systems send messages to your phone or email. If you have a heating cable, you can automate its switching on when the critical temperature is reached.
Instructions for installing a heating cable for underground pipe installation
When installing a single-core wire, it should be taken into account that in order to be able to connect it, it must go through the pipeline and then return back. This way 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 securing it with tape;
- move the cable to the opposite side of the pipeline and pull it in the opposite direction;
- stick foil tape over both threads, which will ensure complete fixation of the wire and reflection of the heat flow towards the pipe;
- install the selected insulation throughout the water supply;
Spiral laying of heating cable. - wrap the surface with waterproofing plumber's 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 at the visible end sections.
Finally
Ensuring 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 during the cold season. The choice of protection method depends on the actual operating conditions and your financial capabilities. But it is necessary to prevent water from freezing in pipes in any case.
Video on the topic
September 2, 2016
Specialization: Capital construction work (laying a foundation, erecting walls, constructing a roof, etc.). Internal construction work (laying internal communications, rough and fine finishing). Hobbies: mobile communications, high technology, computer equipment, programming.
I once told you about how you need to thaw water that froze in the pipes in winter. My neighbor in the dacha, who was going to celebrate his anniversary there, asked me to do this.
And recently, remembering the advice that I gave him then, he asked me to insulate the water pipes in the ground outside and inside the cottage. He probably doesn’t want to face similar troubles next winter. This is correct, because insulated pipes are a guarantee of the availability of water in the home at any time of the day and at any time of the day.
Naturally, he had to pay me a considerable fee, although the price was quite consistent with the labor intensity of the work performed. And you have the opportunity to do everything with your own hands and “absolutely free of charge,” as the wise owl said in the famous cartoon. The one I compiled will help with this. instructions, which I present below.
The need to insulate the water transport system (Article 1)
I think even those readers who do not know about my winter adventures (we are talking about the time when I defrosted my neighbor’s pipes) understand the need to insulate the pipes through which water flows from a well or well into the house.
Insulation may not be carried out only in one case: when utility lines are sufficiently buried in the ground, that is, they are below the soil freezing level. Insulation in the ground may only be needed if the pipes are buried shallowly.
Therefore, I recommend, if you have not already done so, that you protect your pipes from the cold. Moreover, the length of engineering communications on any private plot of land is not that great, and they are buried very shallowly.
In addition to underground water pipes, you need to take care of utilities laid in unheated rooms at home (especially basements and attics). There, too, water may freeze, which will lead to the inoperability of the system as a whole.
Well, I hope I have convinced you of the need to carry out insulation work, it’s time to decide what material to use for this. We'll talk about this in the next section.
Materials used
When I was little, my grandfather and I insulated a piece of pipeline (3 meters) that went from the well to the storage room. At that time, old military pea coats, soldiers' blankets and other similar things were perfect for this (I think you guessed what my grandfather worked for).
However, nowadays there are many modern building materials that will cope with the tasks assigned to them much better, and their purchase will not make a bottomless hole in your family budget.
On the other hand, some people find it difficult to know what to choose. Before giving specific advice, I want to list the requirements that the insulation must meet so that you can use it for finishing pipes:
- have good heat-retaining properties that do not change under the influence external conditions(humidity, temperature, mechanical stress, deformation, damage, and so on);
- have long term operation, resistance to impact chemical substances and biocorrosion;
- have hydrophobic functions, do not change their technical characteristics and performance properties when wet;
- It is good to withstand exposure to high temperatures without changing the thermal conductivity coefficient and service life.
I’ll tell you about the most common options, and you can choose for yourself:
- Glass fiber insulation(glass wool). Most suitable for metal finishing plastic pipes wires I worked with such insulation materials as Izover, URSA, Knauf Insulation and others. They differ slightly from each other in certain parameters, but they do not affect the efficiency of operation.
Considering that glass wool has a low density, when wrapping it around pipes that you are then going to bury in the ground, you need to figure out how to protect it from mechanical stress. In my practice, I used roofing felt, geotextiles or large sewer pipes.
In general, not the best convenient option, which requires a lot of time and effort.
- Basalt heat insulator. The material is produced in the form of ready-made shells for a certain diameter of water or sewer pipes. Thanks to this, they are very easy to install on utility lines.
Suitable for insulating pipelines in a private home , and underground, since it can withstand strong mechanical stress and high load. In some cases, in addition to a layer of basalt fiber, manufacturers protect their products with foil insulation or glassine on top, which further increases the performance properties of the material.
However, as you understand, we have to pay for all these advantages. The cost of the considered insulation cannot be called affordable.
- Expanded polystyrene. This is the material I worked with most often. It differs from other products in its affordable price and considerable assortment. There are varieties with and without an external protective layer, for installation on large and small diameter pipes, and so on.
I insulated pipes with polystyrene foam in a ditch and in unheated rooms country houses. In both cases, the result was fully consistent with expectations. None of the customers remembered any more freezing.
This material is designed for reusable use. If for some reason you need to disassemble the water supply system, you can dismantle the polystyrene foam shells without damaging their integrity, and then reinstall them. The main thing is that the diameter of the parts matches.
- Thermal insulating paint. It is a thick mass of white color (although it can be tinted), which in its own way appearance and performance properties are very similar to conventional coloring compounds. Except that even a thin layer of it significantly reduces the thermal conductivity of the pipes.
This material is produced on the basis of varnish or water, as well as acrylic and a special filler. The latter is a microscopic hollow ceramic sphere containing air inside. It is thanks to them that the beauty protects the pipes from freezing.
I used paint and am quite pleased with the result. It is, of course, better to do this with a special sprayer, although you can also use a brush. The more layers you apply, the more reliably you will protect your water supply from freezing in severe frost.
Paint has other advantages:
- perfectly tolerates strong temperature fluctuations, so it is also suitable for heating pipes;
- has anti-corrosion properties, as a result of which it can be used for processing metal water pipes;
- has a long service life and can act as a decorative material if coloring pigments are added to it.
I would, of course, advise you to use only paint, but its cost is quite high, so for household use buy yourself polystyrene foam shells. Although, there are other ways to prevent pipes from freezing, which I will discuss further.
Insulation of underground water pipelines
Naturally, one of the simplest ways to insulate a water supply is to use heat-insulating materials. But that doesn't mean he's the only one. And, by the way, it’s not always the most effective.
In my many years of practice, I had to resort to other methods. Some of you may find them easier to implement. Especially if the pipes are laid very deep to dig the ditch again, but not deep enough to avoid freezing in winter.
I have made a small table to make it easier for you to navigate.
| Way insulation |
Description |
| Heating cable | In this case, you need not only to insulate, but also to heat the pipe through which the water flows. For this purpose, special heating cables are used, which can be purchased in specialized stores. The power of such products ranges between 10 and 20 W per meter. It can be installed inside and outside pipes. Using a heating cable, you can bury water pipes in the ground no deeper than 50 cm from the surface. As for power consumption, you don’t have to worry too much. The heating is turned on only in the coldest months, and, fortunately, we don’t have many of them. Unless, of course, you live in the Far North, but then it is better to choose another method of heating the water supply. |
| Air insulation | Here you can use heat insulating materials listed in the previous section. However, they do not wrap the pipe, but install a kind of thermal barrier on top, which prevents the penetration of cold air to the utilities. And the pipes themselves are heated by warm air from below. We also often used a technique such as “pipe in pipe.” That is, a part of a smaller diameter through which water should flow is placed in a product of a larger diameter to create a heat-insulating air layer. |
| Pressure insulation | In this case, a special receiver is needed, with the help of which the pressure in the main engineering systems is increased (that is, the part that goes underground and in unheated rooms). The technology has proven itself well in cases where the water supply is organized using a submersible water pump, which is capable of providing the required water pressure (more than 5 atmospheres). Naturally, part of the system should be check valves, protecting system parts from damage until pressure is released. |
I’ve made a brief overview, now I’ll tell you about everything in more detail, so that you can insulate the pipes yourself and not be afraid of ice forming in the water supply system.
Method 1 - Using thermal insulation materials
In my practice, glass wool or materials based on it were most often used to insulate water pipes. And although I don’t consider this option the most effective and convenient, I’ll tell you about it first.
The work flow is as follows:
- We dig out pipes buried in the ground. You need to act carefully so as not to damage the engineering system with a shovel. It is necessary to free not only the pipeline itself, but also remove a small amount of earth from below so that you can work comfortably.
- Then we wrap the pipes with glass wool insulation. Try to make sure that there are no gaps through which the plastic or metal of the pipe can be seen. Otherwise, a cold bridge will form in this place, which will certainly cause the pipe to freeze.
- The insulation material can be secured with adhesive tape, or plastic ties, or other suitable means.
- After this, we protect the heat insulator with more durable material. Roofing felt is most often used. It is the most accessible and has hydrophobic properties, that is, it does not allow the insulation to get wet.
In principle, everything is simple. But personally, I would not recommend resorting to this finishing method. I will justify my position with the following considerations:
- By doing this kind of insulation, you are doing the same job twice. First install the glass wool, then protective layer. This takes too long and is quite tedious.
- After backfilling the soil (especially with layer-by-layer compaction, which avoids soil movement), the insulation, due to its low density, contracts. This negatively affects its heat-retaining properties, that is, the pipes will be worse insulated than you think.
- Glass wool does not tolerate moisture well, which will constantly seep into the insulation through the ground. Moistened glass wool does not retain heat so well and protect the engineering system from the cold. And it will be even worse if the insulator, wet after the autumn rains, also freezes.
I said all this to the point that I advise you to choose ready-made thermal insulation cylinders made of polystyrene foam or mineral fiber. You don't need to be an expert plumber to install them. Connect the two halves of the cylinder on the pipe and snap it into place.
Just make sure there are no joints. The cylinder parts need to be connected to each other with a slight offset (from 10 to 20 cm). If you are afraid that your pipeline will be damaged by some stray mole, you can additionally strengthen the parts with adhesive tape.
To insulate fittings, valves, inspection holes and other protrusions on pipes, use polystyrene foam shells specially made for this purpose.
As a result, your pipes will be insulated in the most reliable way. This is especially true for strength and water absorption. Backfilling of soil does not in any way affect the insulation, and the parts themselves absorb only 2% of the liquid from the volume of material per day. That is, the insulation, one might say, does not get wet at all.
And the best thing is that similar material can be used for finishing pipelines running inside a building in unheated rooms.
Method 2 - Installation of heating cable
Let's say for some reason you don't want to use thermal insulation. Then I can recommend installing a heating cable. I’ll say right away that it itself is not cheap and requires additional costs during operation (payment for electricity).
But in this way it is possible to lay a pipeline with a slight depth. And if it does freeze, you can plug in the cable and wait for the ice to thaw.
I can name two ways to lay a heating cable:
- Inside the pipe. You can understand the essence from the name. At self-production you will have to work hard. So as not to create for yourself unnecessary problems, I advise you to buy water pipes with a heating cable already installed inside or with an empty one cable channel, which will facilitate installation engineering system.
- Outside pipes. In this case, you can buy ordinary water pipes and cables, and then assemble everything into a finished system.
Most often I had to resort to the second method, so I will dwell on it in more detail.
The advantage of this method is that it is not necessary to dig a ditch 2 meters deep. We only need to go 50 cm deeper so that the pipes themselves are not destroyed by vehicles passing on the ground, and the cable will be responsible for the insulation.
In addition, you also need to buy foil adhesive tape and insulation with hydrophobic properties (for example, basalt shells). After this, you can get down to business. The sequence of actions is as follows:
- The pipe through which water flows from the water intake point (well or borehole) to the house must be covered with foil adhesive tape in a spiral. There is no need to place the coils too tightly; there should be a distance of about 10 cm between them.
- Then, clearly follow the resulting line, wrap the pipe with a heating cable. Make sure that you don’t get any intersections anywhere, otherwise the heating element may short out later.
- Then you need to seal the pipe with the same adhesive tape. This will ensure that the heating cable is fixed exactly in the place where you placed it.
- After this, basalt cylinders should be cut and installed on the pipe. Be sure to make overlapping joints to prevent cold bridges from appearing. They are often the cause of excessive consumption of electrical energy when heating pipes.
- We take another adhesive tape, plumber's tape, and wrap the entire pipe over the insulation, firmly securing the heat-insulating material. Additionally, plumber's tape helps prevent water from leaking into the pipe if you leave a gap in the insulation somewhere.
Pay special attention to the area where the pipeline enters a residential building. I advise you to make a good tin box in that place, which, after installing the pipe there, needs to be filled with a heat insulator and carefully protected from water with film.
One more thing. I recommend installing, along with the cable, in several places in the pipeline temperature sensors, which are connected to the heating cable operation control system. In this case, when the temperature of the engineering system drops below permissible level the heating system will turn on on its own or notify you of the need to perform any action.
As I already said, the disadvantage of this solution is the consumption of electricity for heating the pipes. But if you know another method, which I will discuss below, you can heat the pipes with free thermal energy. Don't know how? Listen.
Method 3 - Arranging an air gap
By insulating the pipeline, we kind of protect it from cold from all directions. possible parties- up and down. However, as you know, the deeper the ditch, the more heat can be obtained directly from the ground. This heat can not be wasted, but can be used to heat the water supply.
In this case, it is not necessary to insulate the entire pipe, but only top part, creating a kind of thermal umbrella.
Another method is to lay the working water pipe inside a thicker pipeline. Then a kind of air gap is created between the parts, protecting the engineering system from freezing.
This method of laying, by the way, has several other advantages:
- In the event of an emergency, you can stretch a flexible temporary hose or water pipe through an improvised main collector without any problems. To do this, during installation, I recommend throwing an emergency cable or wire there.
- If a pipe fails, it can be replaced without excavation work. That is, even in winter.
- Possibility of arrangement additional systems heating For example, if the heating cable working in tandem with the insulation fails, you can melt the ice or heat the water supply with warm air supplied to the collector pipe.
There is another air heating circuit that I have installed several times. To do this, you need a house that has a basement or cellar, where all year round positive temperature is maintained. Then we take the thick pipe in which the water supply is laid into the basement at one end, and at the other we equip an exhaust hood with a deflector.
The result is a kind of ventilation. Warm air leaves the basement, passes through a thick pipe, warming the water supply, and is then removed through the deflector. This results in free heating of the engineering system and fresh air in the basement.
Method 4 - Using High Pressure
Now let's turn to high technology. We are not talking about nanorobots that will insulate your pipe, but about ordinary powerful deep well pump pumping water into a home water supply. The essence of this method is that water under pressure in the pipe will not freeze. Which, in fact, is what we will use.
The downside here is that you will have to turn the system on and off every time you come to the country and leave for the city.
I will describe a diagram of such a solution:
- You need to install a receiver into the water pipe, which will help create excess pressure in the area connecting the well to the house. The water itself will be pumped by a submersible pump, the power of which is quite sufficient for this.
- You will also need a check valve.
The procedure is as follows:
- to avoid freezing, you need to close the tap in front of the receiver and pump water into the pipe, reaching a pressure value of 5 atmospheres;
- upon arrival at the dacha, you again need to release excess water from the pipe, bringing the water supply system into working condition.
Insulation of the water supply system inside the building
With works on outdoors We slowly figured it out. Now let's move on to the issue of insulating the water supply inside the house. Everything is much simpler and easier here. You can use the following materials:
- Expanded polystyrene. Buy heat-insulating cylinders suitable diameter and put them on the pipes. It is better to take those varieties that are protected from mechanical stress on top. If there are none, wrap a layer of roofing material or something similar on top.
- Glass wool. This material is mainly used for metal pipes. There is no particular difference between installing insulation in a house and outside, so I will not describe everything in detail.
- Basalt cylinders. Another great way insulation of water supply in unheated rooms. Despite their strength, I still advise you to additionally protect the cylinders with glassine or foil insulation.
I told you all the methods that I once used. I think this is enough to insulate pipes in your dacha or country house. To ensure that the work is carried out as efficiently as possible, I will give you some tips:
- When burying pipes in the ground, do not be lazy to draw up an accurate diagram of the engineering system. Particular attention should be paid to the location of the connecting elements. It is at these points that pipes often fail when the water inside freezes.
- It is necessary to insulate both internal and external communications at the same time. As a last resort, if you need to insulate a short section of the system (50-70 centimeters), cut out a piece of pipe from the sewer, put it on the water supply and fill it with construction foam. Suitable as a temporary option.
Conclusion
In conclusion, I want to tell you that you should never neglect such an important stage in the construction of a water supply system as protecting it from freezing. Otherwise, you will have to thaw the ice later, as described in the video in this article. Do you need it?
In a private house with water supply from your own well, well or from central water supply Some pipes are always laid outdoors - underground or in the air. More often - underground, but any pipes must be insulated, since winters in the Russian Federation always pass with negative temperatures, and the water in the pipes should not freeze for a minute. Therefore, the problem of how to insulate a water pipe on the street always remains relevant, and everyone solves it in their own way. But there are many general points, the implementation of which will help to properly operate the water supply system in extreme conditions. And the main requirement for insulating materials that will be used to insulate pipes is low water absorption and high thermal impermeability.
In the ground, pipes made of metal or plastic come into contact with water and the ground at the same time. The temperature of these materials will always be different, so condensation will form on the surface of the pipes. Due to the extreme operating conditions of the pipes, they must be made of a material that can withstand mechanical stress (soil pressure, impacts during system installation), have a long service life, and resist mold and corrosion. 
Types of insulation and methods of insulating private water supply
The most common and popular insulation materials for plumbing systems:
- Glass wool, basalt, stone, mineral wool:
- Glass wool is sold in rolls. It has a soft structure, which makes it easy to insulate pipelines and pipe sections with complex configuration: valves, valves, turns, branches. Glass wool is used for insulating metal-plastic pipes; in combination with glass wool, it is recommended to use roofing material or fiberglass. Basalt wool is produced in cylindrical rolls - “shells”, which are ready-made strips 1 meter long. The cylinders are easily cut into pieces of the required length; Some brands of basalt wool are made coated with aluminum. This coating protects the insulation from damage, extending its service life.
- Polystyrene foam, polystyrene foam:
- Expanded polystyrene is also produced in a “shell”. Popular thanks to easy installation and ready-made shells corresponding to the shapes of standard plumbing fittings with turns. Shaped polystyrene foam blanks can be used many times. Due to its high flammability, insulation material cannot be used in pipeline sections with a high risk of fire;
- Liquid insulation:
- The finely dispersed material, produced in the form of an aerosol, tightly covers the surfaces of pipes of any complexity, encases the pipes in multiple homogeneous layers of high strength, and perfectly protects the surface of the water supply system from heat loss.
In addition to those listed insulation materials, you can thermally insulate water pipes in areas with shallow lines using the following methods:
- Electric cable for heating the pipeline:
- The use of a heating cable completely eliminates thermal insulation materials from the heat maintenance scheme around the main line. The space is perfectly heated by a cable with a power of 10-20 W/lm. The profitability of this method lies in the fact that heating is needed only at negative temperatures, therefore, in warm time years, the cable may not be turned on. The use of this progressive method makes it possible not to deepen the pipes by the 2 meters required by the standards - the pipeline can only be laid to 0.5 m.
- Air insulation:
- Well, the path of movement of the cold air flow creates a heat shield, which is formed from warm air around pipes due to the umbrella effect. The thermal shield is created by inserting it into an insulator cylindrical water pipe. Thus, a “pipe-in-pipe” design is obtained.
- Insulation using high pressure:
- This method uses a receiver in which pressure is created and works effectively when installing submersible water pumps. The pressure is controlled by installing a check valve.
The development of insulating materials for water supply began with the use of wooden boxes in which the water supply was laid and covered with soil, sawdust or ash slag. After the invention of mineral wool and expanded clay, insulation made from these natural materials became popular. And only recently the range of insulation materials has expanded significantly - now any insulation material - from natural or synthetic components - can be bought everywhere. 
To maximize the insulation effect, when purchasing materials, it is necessary to study all their properties and characteristics and link them to the region and operating conditions of the water supply system.
Requirements for insulation
The functional purpose of insulation is to protect the water supply from negative temperatures, and for optimal results the insulation must meet the declared characteristics, such as:
- Low thermal conductivity;
- Water-repellent characteristics of the material - to ensure the tightness of the layer;
- Antifungal and antiseptic properties;
- Immunity to aggressive environments, the influence of which can manifest itself locally on wandering sections of the pipeline;
- Fire resistance;
- Long service life.
Glass wool, mineral wool and polystyrene foam
To insulate a pipe passing through the air, use mineral wool or glass wool in rolls, which simplifies their installation and allows you to carry out the insulation yourself. The workability of these soft materials allows you to insulate the most difficult areas pipelines are much more efficient than when working with other insulation materials. Mineral wool can be used to tightly cover any dimensional valve or valve, pipe distribution corner or tee, or complex horizontal or vertical turn. 
When buying mineral wool based on basalt fiber, you should immediately take care of the presence of special cylinders - “shells” - of certain sizes for insulating shaped parts. The length of such cylinders can be adjusted using a bench cutter or knife. They are also called “shells” in construction circles. The “shell” is often covered with aluminum foil or thin galvanized iron to protect the insulation layer from mechanical damage and improve heat retention around the pipe. Pipes for cold water are most often insulated with expanded polystyrene, since the flammability of the material does not allow it to be used without restrictions in insulating hot water supply. 
When working with mineral wool, it is necessary to use personal protective equipment - goggles, rubber gloves and a respirator, since the wool is made from small glass, basalt or other hard mineral fibers, which will fly apart during work and can damage the skin, eyes, or get into the lungs person.
Installation of insulating cylinders
Installing the “shell” insulation is simple - select the required diameter of the “shell” according to the diameter of the water supply. Since the shell consists of two halves, all that remains is to bury a section of the pipe on both sides, leaving 10-15 cm of the open shell to overlap it with the next cylinder. To improve the thermal insulation properties of the cylinders, a protective layer is applied to the shell. polyethylene film, metal or aluminum foil, roofing felt or membrane insulation. Any modern insulation material contains air bubbles, which retain heat in the space between the pipes and the insulation. 
Heating of underground water supply
A water pipe running under the ground or under the floor is also insulated in most cases with glass wool, which is wrapped around the pipe and secured to it with wire or a synthetic cord. If glass wool is used for insulation in the ground, the insulation layer should be protected with a layer of waterproofing so that under soil pressure the glass wool does not begin to compact and collapse.
Also pipes underground water supply can be heated using a heating cable. Although the method is costly at one time, it works seasonally, so the savings are obvious. 
You can turn on the heating cable only when the outside temperature drops to negative values. This method is also good because it is possible not only to insulate the water pipe running under the floor, but also not to bury the pipes in the ground as deeply as required by building regulations - a ditch 0.5 m deep is enough. The cable for heating the water pipe is laid as follows: inside the pipe and outside – the effect will be equally positive. The only difference is in the fastening - you can fasten the cable on the outside yourself, but it is better to entrust the cable laying inside the pipe to specialists.
Outside, the heating cable can be laid and secured longitudinally or in a spiral. There are special calculations that calculate the distance between the turns of the wire and the total number of turns. 
Another difficulty with this method of heating pipes is that it is necessary to install temperature sensors near the cable to control the temperature. But, despite the difficulties, this insulation option is considered by experts not only to be the most effective and high-quality, but also the most reliable.
Having studied all available insulation methods and materials for implementing these methods, you can choose the most suitable one for your water supply operating conditions. When using a cable for heating pipes with insulation, you can literally install them within 24 hours optimal temperature around pipes even in the most extreme cold. The disadvantage of this solution is the need to connect to the electrical network, so this option should not be the only one - it must be duplicated by other insulation methods, for example, by lining glass wool pipes. 
How to lay and connect the heating wire:
- If the pipes are already laid in the ground, they need to be dug out and the trench expanded;
- Wind the cable around the pipe - in a spiral or longitudinal laying;
- Place glass wool or other soft insulation on the wire, secure it with clamps or wire;
- Connect the cable to voltage;
- Backfill the trench.
In this way, multi-layer protection is installed: electric heating wire, glass wool, soil protection.
Water supply in an apartment building, private house or country cottage is a common occurrence; water should be available at any time of the year. However, temperature fluctuations can make significant adjustments to the water supply process.
Apartment owners think little about how the water supply is organized, and owners of private houses are forced to take steps on their own to ensure that the water in the pipes does not freeze in winter. At the same time, we note that frost does not spare either steel or plastic pipes. The only way to keep water in liquid form and prevent damage to the water supply system is to fully insulate the water pipes. After all, unlike here, there is no warm medium.
Due to the fact that thermal insulation is carried out on your own site, we are not talking about an industrial scale of work, which means it makes sense to study how to insulate water pipes with your own hands.
Do underground water pipes need to be insulated?
If the pipes are laid below the soil freezing level - no, if above - yes.
The depth of the water pipeline is regulated by SNiP 2.04.02-84.
Let’s make a reservation right away that laying pipes at the correct depth neutralizes the effects of low temperatures; the material in this article is focused on those cases where, for certain reasons, the water supply system was buried at a shallow depth.
Methods for insulating water pipes outdoors (in the ground)
- increasing pressure in the water supply system;
- cable for heating a water pipe;
- thermal insulation for water supply pipes.
1. Creating high pressure in the water supply system
The water pipe will not freeze because the water will move at high speed. To implement this method, a pump is used to increase the pressure in the water supply system or a receiver that cuts into the pipe directly next to the pump.
2. Heating cable for water supply
Cable power 10-15 W (average price – 15 USD/m.p.). Excellent for heating pipes in the ground when they are placed at a shallow depth. According to the rules, it is not advisable to place any communications in the soil below the soil freezing level. There are situations in which this requirement is ignored. In this case, simple insulation of pipes will not give the desired result, because... the pipeline will in fact be located in water (in a humid environment that freezes in winter). Most of the insulation materials are not suitable for this mode of operation and do not provide proper thermal insulation.
Using a cable to heat the water supply makes it possible to lay pipes at a depth of up to 500 mm.
The heating cable for insulating water pipes is wound along the pipe or around it with a given pitch. The pitch is determined by the power of the cable. The lower the power, the smaller the step. Methods for laying the heating cable are shown in the diagram.
Craftsmen and users note that insulating a water supply system by heating the pipe with a cable is the most reliable method for protecting pipes laid in the ground freezing zone.
Cable heating makes it possible to avoid freezing of water in the pipe, and, equally important, to quickly defrost frozen pipes. Such a need may arise at a dacha if it is intended for seasonal living. In this case, you can quickly prepare the pipeline for operation, because under natural conditions you can wait until May for complete defrosting (when laying pipes at the level of soil freezing). The cable is located both inside and outside the water supply pipe.
Note. Installing temperature sensors along the cable route will make it possible to monitor the cable temperature and regulate it manually or automatically.
3. Application of thermal insulation materials for pipes
This is the most cost-effective and easiest insulation method from the point of view of independent implementation. Let's look at it in more detail. Let's start with the best way to insulate a water supply system, what materials can be better used depending on specific conditions.
Thermal insulation for water supply pipes
It is not difficult to get confused in the wide range of thermal insulation materials. To choose best option, you need, at a minimum, to know the main types and types, key characteristics and features.
Thermal insulation of water pipes is carried out with various insulation materials, which are grouped below (in the form of a classification) according to the principle of unity of insulation technology.
Materials for insulating water pipes
Types, types, varieties and rules for choosing pipe insulation.
Rigid insulation
Polystyrene foam is an excellent insulator and has a relatively low cost (compared to other materials). However, it is quite difficult to insulate a round pipe with a rigid insulation board. To insulate pipes, special shells (hard boxes) are used - shells in which pipes are placed, and the space is filled with soft insulation.
Roll insulation
This segment includes: polyethylene (as an additional material), foil penofol (50-56 rubles/sq.m.), mineral wool (70-75 rubles/sq.m.) and glass wool (110-125 rubles/sq.m.) ), furniture foam rubber (250-850 rubles/sq.m. depending on thickness).
Insulation of water supply pipes roll thermal insulation is also fraught with difficulties, which lie in the hygroscopicity of the material. Those. insulation loses its properties when exposed to moisture, which means it has a narrower scope of application, or needs additional protection. Plus, you need to think about how to attach the insulation to the pipe.
Segmental (shell) insulation
Pipe insulation casing is the most progressive option for pipeline thermal insulation. The shell for insulating the water pipe ensures maximum tightness and, as a result, creates a reliable thermal insulation layer.
There are types of segmental insulation:
rigid (thermal insulating casing for pipes - (PPU) or foam plastic. Price from 190 rubles/m.p., depends on the thickness and diameter of the cylinder);
soft (pipe insulation made of foamed polyethylene, cost from 28 rubles/m.p. with a thickness of 13 mm); Material prepared for the website www.site
basalt cylinders for pipes (from 15 rubles/m.p. with a thickness of 30 mm. (from 70 rubles/m.p. for foil-coated basalt cylinders). Sprayed insulation (PPU)
The peculiarity of insulation by spraying polyurethane foam is that thermal insulation is applied to the surface of the pipe, ensuring 100% tightness (the cost of components for polyurethane foam filling starts from 3.5 euros per kg). The number of components is determined by the thickness of the fill; work is paid additionally). On average, the cost of insulation with sprayed polyurethane foam is 15-20 dollars/m.p.
Sprayed insulation also includes heat-insulating paint for pipes. You can apply it yourself, because... Thermal paint is sold in aerosol cans. A layer of paint of 20 mm. replaces 50 mm of basalt wool insulation. In addition, this is the only material that is not susceptible to damage from rodents.
When choosing thermal insulation material for insulating water supply pipes, you need to take into account the following factors:
- pipeline installation location. Insulation of pipes laid on the ground and located underground is carried out in different ways, even when using the same materials (it is also important to take into account whether the pipes are laid before or below the freezing level);
- frequency of pipeline operation. For example, in a country house that is not intended for permanent residence, it is enough to simply avoid a pipe rupture. To do this, a receiver is installed or the water supply is insulated with a cable. But in a private house it is necessary to ensure a year-round water supply. Here you need to approach the choice of insulation more carefully;
- thermal conductivity indicator of pipes (plastic, metal);
- resistance to moisture, combustion, biological activity, ultraviolet radiation, etc. determines the need to protect the insulation from these factors;
- ease of installation;
- price;
- life time.
How to insulate a water pipe with your own hands
Pipe laying site, one more important factor, which must be taken into account when choosing insulation. Indeed, depending on where the pipes are located (in the ground, basement, cold attic, unheated room), the temperature and humidity conditions are determined, as well as the ease of installation of the insulation and the need for its additional protection.
Insulation of water pipes on the street
Water pipes are rarely laid by air or on the soil surface. Rather, in this case, the part of the pipeline that runs directly under the house or at the junction of the pipe with the pump, meter, or inside the distribution well needs insulation.
The specificity of insulation in this case is such that the pipe is insulated with any insulation that is capable of ensuring a sufficient tightness of the fit and is not exposed to moisture. As a rule, the thickness of the insulation intended for above-ground insulation of pipes is higher than for underground insulation. At this stage, it is important not only to insulate the pipe, but also to provide protection thermal insulation material, in particular from getting wet.
Note. The most dangerous place from the point of view of freezing is the pipe exiting to the surface. To insulate this unit, it is necessary to use materials with greater thermal insulation capacity or lay it in two or three layers.
Insulation of water pipes in the ground
Such insulation will be needed only if the pipes are laid above the soil freezing level. To insulate a pipeline in the ground, you can use any material, including rigid insulation.
It is worth noting that the insulation of external water supply does not end with the installation of insulation. It is important to protect the insulation from getting wet. To do this, a film, roofing material is wound over the main thermal insulation material, or a plastic box is installed.
How to install a heating cable for heating pipes
For installation, prepare: foil tape, thermal insulation material, heating cable (power 20 W per linear meter).
Technology for insulating water pipes with cable:
- the pipe along its entire length (from the well/well to the house) is glued with foil tape;
- heating cable is laid in a convenient way with the same step. For a 20 W cable, a pitch of 100-150 mm will be optimal. For a less powerful cable, the pitch is reduced. The most convenient way to lay the cable is to wrap the pipe in a spiral;
- the cable is fixed with foil tape;
- Insulation is installed on the pipe. Pipes made of foamed polymers, basalt cylinders or polyurethane foam shells are placed on the pipe. In this case, it is necessary to ensure that the pipe diameter matches internal diameter segment insulation. Before starting work, roll insulation is cut into strips, which are wrapped around the pipe and secured with clamps or wire. Their task is to hold the insulation in a given position.
Note. The main thing when installing insulation is to minimize the number of joints that form cold bridges. Laying the heat insulator in two layers with an offset helps to completely eliminate them.
- the insulation is fixed to the pipe with tape (plumbing tape). The tape is wrapped very tightly. The main task of the winding is waterproofing, i.e. prevent groundwater from entering the insulation;
- additionally insulate the pipe at the point where it reaches the soil surface. The following options are offered: additional winding with insulation or arrangement of a box in which the insulation will be placed.
Advice. To avoid the risk of freezing of the water supply at the entrance to the house, it is advisable to wind the heating cable until it exits the wall in the house.
Installation of cable for heating pipes - video
Conclusion
Regardless of the insulation method, it makes sense to choose only high-quality materials and install them according to the instructions. Of course, this affects the budget of the event, but expenses of this kind pay off in the future. And a frosty winter will not bring unpleasant surprises in the form of a lack of water due to freezing in pipes or a rupture in the water supply system.
Under construction own home More than once we have to face the need to lay underground utilities. This applies to plumbing, domestic or storm sewer, sometimes it is necessary to lay a heating main between two buildings. But it is not enough to lay the pipes themselves correctly, observing, if necessary, their required slope - it is very important to protect them from the effects of low temperatures, eliminating the possibility of freezing in the cold season.
Insulation for pipes in the ground is especially important in regions with harsh winters, where the soil freezes to a considerable depth.
Surely, objections may be heard - why, they say, insulate sewage drains, which are obviously given an appropriate slope, and by definition there cannot be stagnation of water here? Meanwhile, thermal insulation of sewerage is a very responsible matter. There are at least two reasons that can cause water to accumulate in them - a septic tank that was not pumped out on time or clogged pipes. In both cases, freezing of the liquid in an uninsulated pipe will lead to the formation of an ice plug and subsequently to rupture of the walls. But to carry out quick repair or replacing a damaged area in frozen ground conditions is an extremely complex and large-scale problem.
There are quite a lot of thermal insulation materials intended for insulating underground sections of pipes. They differ in the material of manufacture, service life, thickness, quality and, of course, cost.
Criteria for choosing insulation for pipes
Thermal insulators for pipes running at a certain depth into the ground must meet certain requirements, which include:
- The hydrophobicity of the insulation, that is, its resistance to moisture. In addition to thermal insulation, the material must protect the pipe from soil moisture, preventing it from passing through, and without collapsing or losing its thermal insulation qualities.
- Low thermal conductivity for high-quality preservation of natural heat inside the pipes.
In fact, thermal insulation under the conditions under consideration can perform two main tasks:
— If coolant (heating system) or hot water (DHW system) is pumped through a pipe, then minimizing heat loss comes to the fore.
— For cold water supply or sewerage pipes, the main purpose of insulation is to protect against the effects of negative temperatures, that is, from freezing.
The table shows the heat loss of pipes different diameters, depending on the thickness of the thermal insulation layer (with an average thermal conductivity coefficient of 0.04 W/m×° WITH) and the difference between the temperatures of the pumped liquid and the environment (Δt°):
| Thermal insulation thickness, mm | Δт,оС | Pipe diameter in mm | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 15 | 20 | 25 | 32 | 40 | 50 | 65 | 80 | 100 | 150 | ||
| Estimated heat losses per 1 linear pipeline, W. | |||||||||||
| 10 | 20 | 7.2 | 8.4 | 10 | 12 | 13.4 | 16.2 | 19 | 23 | 29 | 41 |
| 30 | 10.7 | 12.6 | 15 | 18 | 20.2 | 24.4 | 29 | 34 | 43 | 61 | |
| 40 | 14.3 | 16.8 | 20 | 24 | 26.8 | 32.5 | 38 | 45 | 57 | 81 | |
| 60 | 21.5 | 25.2 | 30 | 36 | 40.2 | 48.7 | 58 | 68 | 86 | 122 | |
| 20 | 20 | 4.6 | 5.3 | 6.1 | 7.2 | 7.9 | 9.4 | 11 | 13 | 16 | 22 |
| 30 | 6.8 | 7.9 | 9.1 | 10.8 | 11.9 | 14.2 | 16 | 19 | 24 | 33 | |
| 40 | 9.1 | 10.6 | 12.2 | 14.4 | 15.8 | 18.8 | 22 | 25 | 32 | 44 | |
| 60 | 13.6 | 15.7 | 18.2 | 21.6 | 23.9 | 28.2 | 33 | 38 | 48 | 67 | |
| 30 | 20 | 3.6 | 4.1 | 4.7 | 5.5 | 6 | 7 | 8 | 9 | 11 | 16 |
| 30 | 5.4 | 6.1 | 7.1 | 8.2 | 9 | 10.6 | 12 | 14 | 17 | 24 | |
| 40 | 7.3 | 8.3 | 9.5 | 10.9 | 12 | 14 | 16 | 19 | 23 | 31 | |
| 60 | 10.9 | 12.4 | 14.2 | 16.4 | 18 | 21 | 24 | 28 | 34 | 47 | |
| 40 | 20 | 3.1 | 3.5 | 4 | 4.6 | 4.9 | 5.8 | 7 | 8 | 9 | 12 |
| 30 | 4.7 | 5.3 | 6 | 6.8 | 7.4 | 8.6 | 10 | 11 | 14 | 19 | |
| 40 | 6.2 | 7.1 | 7.9 | 9.1 | 10 | 11.5 | 13 | 15 | 18 | 25 | |
| 60 | 9.4 | 10.6 | 12 | 13.7 | 14.9 | 17.3 | 20 | 22 | 27 | 37 | |
Obviously, as the thickness of the insulation increases, the level of heat loss decreases, but even with a thickness of 40 mm it is impossible to achieve complete insulation. In the case of cold water supply or sewerage, sometimes it is necessary to resort to additional measures - installing electric heating.
About the required thickness of insulation for various types pipelines will be discussed below.
- Resistance to external chemical influences - soil is a very aggressive environment in this regard.
- The insulation must have high mechanical strength, be resistant to external mechanical and atmospheric influences, and withstand loads and soil pressure. This also includes durability - since replacing thermal insulation in underground areas will be quite difficult.
- Resistance to high and low temperatures environment and liquid transported through an insulated pipeline.
- The material should be easily mounted on a pipe in any position.
- An important factor is the compatibility of the insulation materials and the pipe, since a reaction between them is unacceptable - it can lead to mutual damage.
Fulfilling all the requirements for insulating material will allow you to avoid significant heat loss and make it possible not to worry about the integrity of the pipes and the likelihood of ice plugs forming in them.
Materials used for insulation of underground pipelines
On modern market building materials there is a fairly wide range of insulation for pipes. Most common materials for their manufacture are polyethylene foam, polyurethane foam, polystyrene foam, and some types of mineral wool.
To insulate pipes, material is used in the form of tapes, rolls, mats, or made into a special shape - cylinders, half-cylinders, segments, etc. Of course, profile insulation is the most convenient to install, since they can be put on a pipe installed in any position.
Polyethylene foam insulation
Foamed polyethylene has very high technical characteristics for pipe insulation. And this — at a very affordable price.
- The thermal conductivity of the material is minimal and amounts to 0.035 W/m×°C.
- This material has a structure consisting of tiny closed cells that help create effective waterproofing, which is especially important for metal pipes. This provides additional protection against corrosion and extends the life of the pipeline.
- Foamed polyethylene can have a density of 25 ÷ 40 kg/m. As a rule, the most popular products are those with this indicator of 30 ÷ 35 kg/m³.
- In addition, the material has excellent elasticity, which does not change even at critical negative temperatures (up to - 55°). This quality makes installing the insulation a very simple matter - the sleeve is easy to cut and put on a pipe located under any bend.
- The tensile load that foamed polyethylene can withstand is 0.3 MPa, and its dynamic elasticity is 0.76 MPa.
- The compression coefficient at a load of 4500 N/m² is 0.2.
- Vapor permeability is 0.001 mg/m×h×Pa, that is, foamed polyethylene is a material that supports natural vapor exchange.
- The hydrophobicity of this insulation was tested by immersing it in water for 24 hours, as a result of which the material absorbed moisture by only 1.3% of its volume. Moreover, it should be noted that in the following hours the absorption of moisture completely stops.
- Operating temperatures of foamed polyethylene vary from - 55 to + 85 degrees. Higher temperatures lead to its spatial deformation, and at negative values below the specified threshold, the insulation loses its elasticity and becomes brittle.
- Fire resistance in this case is not important, since the insulated pipes will be located in the ground. But this material is also used for external thermal insulation, therefore, it has an appropriate classification, and according to this parameter it is designated G2, that is, a moderately flammable material. Polyethylene ignites at a temperature of 300 degrees and only when exposed to direct flame. When burned, polyethylene breaks down into water and carbon dioxide, which is non-toxic and in small concentrations is not hazardous to human health.
Insulation from this foamed polyethylene is produced in different thicknesses, in the form of cylinders (sleeves) 2000 mm long. It is easy to cut and adheres well to the surface of pipes made of different materials.
Prices for polyethylene foam insulation
polyethylene foam insulation
Having compared the characteristics of their material with the requirements for insulation, we can conclude that this foamed polyethylene is ideally suited for thermal insulation of pipelines.
You may be interested in information about what degree of insulation is provided for
Another material that is actively used for pipe insulation is Penofol. This is the same foamed polyethylene, but has a foil coating, which has a reflective property and enhances the thermal insulation properties of polyethylene.
“Penofol” for insulation of pipelines is also produced in sleeves, but some craftsmen prefer to use material made in rolls. The first option is put on the pipe and secured with special tape. The second is cut into strips and overlapped onto the mounted pipes.
Pipe insulated with penofol tapes
Penofol prices
The convenience of tape insulation is that it can thermally insulate a pipeline that has many bends or turns. Due to the elasticity of the material, it will take the desired shape and provide sufficient tightness for thermal insulation.
If cylinders (sleeves) are used to insulate an already installed pipeline, then a cut is made along their entire length, through which they are put on the pipes. This cut is then secured with waterproof adhesive tape. Very often such a cut is already provided by the manufacturer.
Video: comparison of some types of pipe insulation
Insulation for polystyrene foam pipes
Pipe insulation made from polystyrene foam is otherwise called “shell”, as it really resembles an eggshell. This material has its advantages and disadvantages, and it is worth considering its characteristics in more detail before choosing it.
Foam insulation for pipes consists of two half-cylinders (for large-diameter pipes, sometimes three segments), interconnected by side tongue-and-groove locks, which allow you to completely isolate the pipeline from environmental influences while maintaining a positive temperature inside the “shell.” Due to the form of the insulation made from polystyrene foam, it is easy to install on existing lines.
This insulation is produced in the form of detachable pipes one or two meters long. The wall thickness and diameters, external and internal, may be different.
For the manufacture of shell-type pipe insulation, PSB-S÷15, PSB-S÷25 and PSB-S÷35 foam plastics are used. Main characteristics - given in table:
| Name of parameters | PSB-S-15U | PSB-S-15 | PSB-S-25 | PSB-S-35 | PSB-S-50 |
|---|---|---|---|---|---|
| Density kg/m³ | to 10 | up to 15 | 15.1÷25 | 25.1÷35 | 35.1÷50 |
| Compressive strength at 10% linear deformation MPa, not less | 0.05 | 0.06 | 0.08 | 0.16 | 0.2 |
| 0.08 | 0.12 | 0.17 | 0.36 | 0.35 | |
| Thermal conductivity in a dry state at 25°C, W / (m×°K) | 0.043 | 0.042 | 0.039 | 0.037 | 0.036 |
| Water absorption in 24 hours, % by volume, no more. | 3 | 2 | 2 | 2 | 2 |
| Humidity, % no more | 2.4 | 2.4 | 2.4 | 2.4 | 2.4 |
| Bending strength, not less | to 10 | up to 15 | 15.1÷25 | 25.1÷35 | 35.1÷50 |
- Polystyrene foam or expanded polystyrene is a chemically inert, lightweight material that has a structure of closed cells that are not interconnected.
- The insulation has low coefficient thermal conductivity, amounting to 0.037÷0.042 W/m².
- Moisture absorption polystyrene foam per day, as tests have shown, amounts to up to 2% of the total volume of the material, so it can be called moisture resistant.
- The operating temperature range of expanded polystyrene is from -50 to +75 °C. In this limit, it does not deform and does not lose its basic qualities.
- This material is resistant to the formation of mold or mildew, does not rot, and can withstand exposure to alkali, cement and gypsum solutions, salts and other inorganic substances.
The positive qualities of polystyrene foam insulation for pipes include the following:
- Low thermal conductivity.
- High moisture resistance, which allows you to preserve the thermal insulation properties of the material for many years.
- Easy to install.
- Resistance to environmental influences.
- It is compatible with any material from which pipes are made, as it does not react with metal and plastic.
- The insulation has completely affordable price.
The disadvantages of such insulation include:
- Combustibility of the material - it is classified as G4. For underground areas this criterion is not decisive.
- Expanded polystyrene is not elastic and cannot be bent, so it can only be used to insulate smooth pipes. And for turns you will have to select special corner parts.
- When using this insulation for pipes laid in the ground, it is recommended to provide additional protection for it by wrapping it in thick polyethylene.
By following all the installation recommendations, carefully placing the insulating shell on the pipes and protecting it on top with a layer of waterproofing, you can create a hermetic insulation that will protect the pipeline not only from freezing, but also from soil moisture.
Pipe insulation - polyurethane foam
Currently, ready-made versions of sewer and water pipes are already enclosed in a layer of thermal insulation made of polyurethane foam, which is protected on top by a metal or plastic shell. For example, for pipelines passing above the ground, pipes in a galvanized metal sheath are used, and for pipelines laid underground, the option coated with polyethylene is excellent, since this material has a high degree of moisture resistance.
Such ready-made insulated pipes are rapidly replacing the previously widely used thermal insulation made of mineral wool. For comparison, please refer to the table below.
Prices for polyurethane foam insulation
polyurethane insulation
Comparative characteristics of polyurethane foam and mineral wool used for pipe insulation:
| Material parameters | Unit | PPU | Minvata |
|---|---|---|---|
| Coefficient of thermal conductivity | W/m×°С | 0.033 | 0.049 |
| Density | kg/m³ | 60÷80 | 55÷150 |
| Compressive Strength | MPa | 0.3 | Not standardized, load resistance is minimal |
| Water absorption, no more | % | 10 | Not standardized, moisture resistance is minimal, constant humidity included in the calculation is 4% |
| Effective service life, no more | years | 40 | 10 |
| Operating costs (specific damage rate) | damage per year per 100 km of pipeline | 3÷4 | 30÷40 |
Similar pipes insulated with polyurethane foam with an outer polyethylene sheath in accordance with GOST 30732÷200 are produced with a diameter of 57 mm and above. The following release forms are provided:
| Outside diameter steel pipes, d, mm | Type 1 | Type 2 | ||||
|---|---|---|---|---|---|---|
| PPU layer thickness, mm | Outer diameter of polyethylene shell, D, mm | PPU layer thickness, mm | ||||
| nominal | maximum deviation (+) | nominal | maximum deviation (+) | |||
| 57 | 125 | 3.7 | 31.5 | 140 | 4.1 | 38.5 |
| 76 | 140 | 4.1 | 29 | 160 | 4.7 | 39 |
| 89 | 160 | 4.7 | 32.5 | 180 | 5.4 | 42.5 |
| 108 | 180 | 5.4 | 33 | 200 | 5.9 | 43 |
| 133 | 225 | 6.6 | 42.5 | 250 | 7.4 | 54.5 |
| 159 | 250 | 7.4 | 41.5 | 280 | 8.3 | 55.5 |
| 219 | 315 | 9.8 | 42 | 355 | 10.4 | 62 |
| 273 | 400 | 11.7 | 57 | 450 | 13.2 | 81.5 |
| 325 | 450 | 13.2 | 55.5 | 500 | 14.6 | 79.5 |
| 426 | 560 | 16.3 | 58.2 | 630 | 16.3 | 92.5 |
| 530 | 710 | 20.4 | 78.9 | - | - | - |
| 630 | 800 | 23.4 | 72.5 | - | - | - |
| 720 | 900 | 26.3 | 76 | - | - | - |
| 820 | 1000 | 29.2 | 72.4 | 1100 | 32.1 | 122.5 |
| 920 | 1100 | 32.1 | 74.4 | 1200 | 35.1 | 120.5 |
| 1020 | 1200 | 35.1 | 70.4 | - | - | - |
Types 1 and 2 of pipes mean products with regular or reinforced insulation. The advantage of pipes immediately equipped with insulation and a protective shell over any other options is that the heat insulator completely seals the body of the pipe. Non-insulated areas are left at the ends of the pipes for connecting them into a solid pipeline using welded joints with deep weld penetration.
The appearance and quality of the protective polyethylene shell also have its own regulations according to the same GOST:
| Options | Characteristics |
|---|---|
| Surface quality | Shell pipes must have a smooth surface outer surface. Minor longitudinal stripes and waviness are allowed, which do not take the pipe wall thickness beyond the limits of permissible deviations. The inner surface of the pipes must be rough. Bubbles, cracks, cavities, and foreign inclusions are not allowed on the outer, inner and end surfaces of pipes. The color of the pipes is black. |
| Elongation at break, %, not less | 350 |
| Change in the length of shell pipes after heating at 110 °C, %, no more | 3 |
| Resistance at temperature 80 °C and constant internal pressure, hours, no less | 1000 (at an initial stress in the pipe wall of 3.2 MPa) |
Installation of such pipes, as mentioned above, is carried out using welding. The seam must be checked using a special method. Then the pipeline sections without insulation at the points of their connection, after installation, the lines are closed with a heat-shrink sleeve, which is filled polyurethane foam. This ensures complete tightness of the insulating material and the outer shell.
The advantages of using polyurethane foam as insulation include its following qualities:
- Low thermal conductivity.
- High moisture resistance.
- Light weight - density only 45–60 kg/m³.
- If installed correctly, there is a complete absence of cold bridges.
- Ability to give metal pipes additional anti-corrosion protection.
- Duration of the operational period, since the material is not subject to rotting and decomposition, and is also resistant to atmospheric and aggressive influences and temperature changes.
However, it should be noted that ready-made thermally insulated pipes have a fairly high price, so insulation is often used instead by spraying polyurethane foam onto the installed pipeline. But in this case, the heat insulator will be deprived of external protection in the form of an outer shell.
Mineral wool
The most affordable thermal insulation material remains mineral wool, which is divided into three types depending on the material of manufacture - glass wool, basalt and slag wool.
Due to their characteristics, only two options are suitable for insulating pipes running in the ground - glass wool and basalt. Slag wool absorbs moisture abundantly, which means it quickly loses its thermal insulation properties. In addition, it has high residual acidity, which contributes to the activation of corrosion processes, and for insulation metal structures absolutely not suitable. Therefore, this option should be immediately rejected and the technical characteristics of the other two materials should be considered, especially since they have long been successfully used for insulating heating mains.
Glass and basalt wool have a number of identical positive qualities that meet almost all the requirements of insulation for pipelines. These include the following parameters:
- Low thermal conductivity.
- High resistance to alkaline and acidic substances, as well as other chemical compounds.
- Sufficient elasticity, which allows easy installation not only on straight sections of the highway, but also on bends and turns.
A negative quality of mineral wool can be called its hygroscopicity - it absorbs moisture quite well (basalt wool is less susceptible to this drawback). Therefore, if the material is used for thermal insulation of a pipeline running in the ground, it is necessary to provide reliable waterproofing for it. It may consist of roofing felt, aluminum foil or dense polyethylene, which is wound onto the insulation with an overlap of 400 ÷ 500 mm and intercepted on top with metal stainless wire or tape.
Insulation of pipes with mineral wool - mandatory external waterproofing is required
Despite the affordable price of the insulation itself, the need additional use waterproofing material complicates installation and increases total cost works
By the way, mineral wool for pipe insulation is produced only in mats, sheets or slabs. You can also find collapsible mineral wool cylinders on sale, which are perfect for straight sections of pipeline.
You might be interested in information on how to choose
What should be the thickness of the insulation layer for the underground section of the pipe?
So, the main insulating materials that are used for thermal insulation of pipelines were considered. To facilitate the perception of information and make comparisons when choosing, the main characteristics of insulation materials are summarized in a single table:
| Material, product | Average density in the structure, kg/m3 | Thermal conductivity of thermal insulation material (W/(m×°C)) for surfaces with temperature (°C) | Operating temperature range, °C | Flammability group | |
|---|---|---|---|---|---|
| 20 and above | 19 and below | ||||
| Mineral wool slabs pierced | 120 | 0.045 | 0,044-0,035 | From - 180 to + 450 for mats, on fabric, mesh, fiberglass canvas; up to + 700 - on a metal mesh | Non-flammable |
| 150 | 0.049 | 0,048-0,037 | |||
| Thermal insulation slabs made of mineral wool with a synthetic binder | 65 | 0.04 | 0,039-0,03 | From - 60 to + 400 | Non-flammable |
| 95 | 0.043 | 0,042-0,031 | |||
| 120 | 0.044 | 0,043-0,032 | From minus - 180 to + 400 | ||
| 180 | 0,052 | 0,051-0,038 | |||
| Thermal insulation products made of foamed ethylene-polypropylene rubber "Aeroflex" | 60 | 0,034 | 0.033 | From - 57 to + 125 | Low flammable |
| Half-cylinders and mineral wool cylinders | 50 | 0,04 | 0,039-0,029 | From - 180 to + 400 | Non-flammable |
| 80 | 0,044 | 0,043-0,032 | |||
| 100 | 0,049 | 0,048-0,036 | |||
| 150 | 0,05 | 0,049-0,035 | |||
| 200 | 0,053 | 0,052-0,038 | |||
| Thermal insulation cord made of mineral wool | 200 | 0,056 | 0,055-0,04 | From - 180 to + 600 depending on the material of the mesh tube | In mesh tubes made of metal wire and glass thread - non-flammable, the rest are low-flammable |
| Glass staple fiber mats with synthetic binder | 50 | 0,04 | 0,039-0,029 | From - 60 to + 180 | Non-flammable |
| 70 | 0,042 | 0,041-0,03 | |||
| Mats and wadding made of superfine glass fiber without binder | 70 | 0,033 | 0,032-0,024 | From - 180 to + 400 | Non-flammable |
| Mats and wool made of superfine basalt fiber without binder | 80 | 0,032 | 0,031-0,24 | From - 180 to + 600 | Non-flammable |
| Perlite sand, expanded, fine | 110 | 0,052 | 0,051-0,038 | From - 180 to + 875 | Non-flammable |
| 150 | 0,055 | 0,054-0,04 | |||
| 225 | 0,058 | 0,057-0,042 | |||
| Thermal insulation products made of polystyrene foam | 30 | 0,033 | 0,032-0,024 | From - 180 to + 70 | Flammable |
| 50 | 0,036 | 0,035-0,026 | |||
| 100 | 0,041 | 0,04-0,03 | |||
| Thermal insulation products made of polyurethane foam | 40 | 0,030 | 0,029-0,024 | From - 180 to + 130 | Flammable |
| 50 | 0,032 | 0,031-0,025 | |||
| 70 | 0,037 | 0,036-0,027 | |||
| Thermal insulation products made of polyethylene foam | 50 | 0,035 | 0.033 | From - 70 to + 70 | Flammable |
The article still does not answer the key question - what thickness of insulation should be used? It is impossible to answer unambiguously, since this parameter depends on large number source data. There are thermotechnical calculation formulas established by SNiP, but they are quite cumbersome, and only specialists can understand them.
But you can also use the calculated tabular indicators. Similar tables are placed in the “Code of Rules for the Design and Construction of Thermal Insulation of Equipment and Pipelines,” approved by the State Construction Committee of the Russian Federation. Finding them is not difficult - any Internet search engine upon request "SP 41— 103-2000" will lead to this document.
It is simply impossible to place these tables within the framework of this publication, since there are a lot of them - they are compiled for various types of insulation, for pipelines for various purposes, type of laying, temperatures of the pumped liquid, etc. But in this diversity there will certainly be an answer for a specific pipe laid in the ground.
It would seem that everything is, however, there is one more important point. It concerns insulation materials that shrink and become compacted over time, which is accompanied by a decrease in the effectiveness of thermal insulation. We are talking about mineral wool.
The table value determined according to SP 41-103-2000 may, over time, become not enough– the material will become compacted and the quality of thermal insulation will significantly decrease. By the way, this is very common a mistake that can lead to serious consequences. This means that it is necessary to provide a reserve of insulation thickness that compensates for its shrinkage.
To determine this parameter, use the following formula:
N =h× Kc× ((D+ h) / (D + 2 h) )
N– the required thickness of the insulation, taking into account future shrinkage (compaction);
h– table value of the required insulation thickness;
D– outer diameter of the insulated pipe;
KS– coefficient of compaction of thermal insulation material. This is a constant calculated for each type of insulation, which can be taken from the proposed table:
| Thermal insulation materials and products | Compaction coefficient Kc. |
|---|---|
| Stitched mineral wool mats | 1.2 |
| Heat-insulating mats "TEKHMAT" | 1,35-1,2 |
| Mats and canvases made of super-thin basalt fiber when laid on pipelines and equipment with a nominal diameter, mm: | |
| - Du | 3 |
| 1,5 | |
| - DN ≥ 800 at medium density 23 kg/m³ | 2 |
| - the same, with an average density of 50-60 kg/m³ | 1,5 |
| Mats made of glass staple fiber on a synthetic binder brand: | |
| - M-45, 35, 25 | 1.6 |
| - M-15 | 2.6 |
| Mats made of glass spatula fiber "URSA" brand: | |
| - M-11: | |
| a) for pipes with DN up to 40 mm | 4,0 |
| b) for pipes with DN from 50 mm and above | 3,6 |
| - M-15, M-17 | 2.6 |
| - M-25: | |
| a) for pipes with DN up to 100 mm | 1,8 |
| b) for pipes with DN from 100 to 250 mm | 1,6 |
| c) for pipes with DN over 250 mm | 1,5 |
| Mineral wool slabs with synthetic binder brand: | |
| - 35, 50 | 1.5 |
| - 75 | 1.2 |
| - 100 | 1.1 |
| - 125 | 1.05 |
| Glass staple fiber slabs brand: | |
| - P-30 | 1.1 |
| - P-15, P-17 and P-20 | 1.2 |
| Fine expanded perlite sand, grades 75, 100, 150 | 1.5 |
In order not to force the reader to spend independent calculations, we suggest using the capabilities of the built-in calculator.
