Specialization: master of interior and exterior finishing (plaster, putty, tiles, drywall, lining, laminate, etc.). In addition, plumbing, heating, electrical, conventional cladding and balcony extensions. That is, the renovation of an apartment or house was done on a turnkey basis with all the necessary types of work.
Let me start with the fact that the thermal insulation of heating network pipelines
SNiP does not have any clear characteristics, and, perhaps, this is at least strange. However, this is not the point - I want to tell you how to insulate pipes and not freeze in winter in a private house. I will support my words with the help of a visual video in this article. So, let's go...
Warming the pipes
Pipes can be heated not only with passive insulation, but also with active devices. But I will talk about this below.
6 types of insulation
Now we will briefly look at 5 types that SNiP allows for thermal insulation equipment and pipelines:
- The most proposed and advertised option that you can find on the Internet are shells that are made from mineral wool, polystyrene foam or extruded polystyrene foam.
- Next in popularity is mineral (basalt) wool with waterproofing made of roofing felt or dense polyethylene.
- In addition, thermal insulation of equipment and pipelines can be made with materials such as sand or expanded clay - the main thing is that such pads are dry.
- The best option for insulating pipes is a warm room - a basement, a room in an apartment, or just a closed box.
- A heating cable that can be inserted directly into the pipe or wrapped around it from above - the effect will essentially be the same as in the case described in paragraph 4.
- And finally, liquid insulation and paints that simply cut off cold air to the pipes. There can be many options here, but in my opinion it is best to use liquid foam- and the price will suit you, and it’s easy to do.
| Insulation material | Thermal conductivity (W/m⁰C) | Temperature for application (⁰C) | Flammability group |
| Stitched mineral mats | 0,041-0,032 | From -180⁰C to +450⁰C for fabric base and up to +700⁰C for metal mesh base | Non-flammable |
| Mats and wool made of thin basalt fiber without binding elements | 0,031-0,24 | From - 180⁰C to +600⁰C | Non-flammable |
| Extruded polystyrene foam materials | 0,032 | From - 180⁰C to +70⁰C | G3, G4 |
| Made from foam minerals | 0,044 | From - 180⁰C to +150⁰C | G2 |
| Made from reinforced foam concrete | 0,05 | From - 180⁰C to +180⁰C | G2 |
| Made from reinforced foam concrete | 0,029-0,024 | From - 180⁰C to +130⁰C | G2-G4 |
| Made from foamed polyethylene | 0,05 | From - 70⁰C to +95⁰C | G3, G4 |
Various pre-insulated pipes for heating networks
My best option
Double insulation - polyethylene foam and mineral wool
So, this is not an instruction, but just my opinion, but, nevertheless, I have used this method for more than one year - mineral (basalt) wool. Let's start with the definition of mineral wool - it can be glass, slag or stone (basalt). The packing density directly depends on your efforts, and, in fact, it doesn’t really matter (unless, of course, you compress the cotton wool).
There are three types of mineral wool - glass, slag and stone or basalt. In our case, it is best to use the latter option - such products are made from melts of volcanic rocks.
It is very inconvenient to work with glass wool, but iron particles remain in the slag wool, which rust when exposed to dampness, which leads to subsidence of the material.
I usually use two options for thermal insulation of pipes - foamed polyethylene and mineral (basalt) wool. Of course, you can buy shells made of this material in the store, and even with a foil surface, but this will be quite expensive.
It is much easier to use rolled material, the thickness of which can be from 20 mm to 200 mm. You need to choose this parameter depending on your region of residence, that is, on a possible decrease in ground temperature in winter.
For underground pipe laying, of course, it is best to use the burial method rather than insulation. If the pipeline runs 50 cm below the freezing point, then you do not need any insulation.
But there may be a real problem here - in the northern regions of Russia, the depth of soil freezing sometimes reaches more than 2 m, so this option will not always be convenient.
As you understand, moisture will in any case be an excellent conductor of cold, therefore, without waterproofing, insulation of pipelines is only allowed indoors, as in the photo above. These could be basements, but even there, in some cases, it is impossible to do without waterproofing due to the same condensation.
Ruberoid is an excellent waterproofing
In order to insulate a pipeline with underground or overhead installation, I wrap it with basalt wool, trying not to compress the material too much. The looser the material, the better the protection from the cold and the warmer it is in winter.
To fix the material, it is very convenient to use a nylon thread - such a spool can probably be purchased at any store that sells building materials. But it is best to wrap roofing felt with any soft wire - the cheapest is steel knitting wire, but if you have supplies, it can be aluminum or even copper.
In addition, it is best to lay the underground pipeline with a sand cushion and also cover it with 50-60 mm of sand on top. This measure will protect the shell from sharp stones of various objects that may be in the ground - glass, wire, and so on.
Conclusion
In conclusion, I want to say that it is quite simple to insulate any pipeline (water supply, sewerage) with your own hands - the main thing is not to compress the material too much. When compressed, the density increases, therefore, the thermal conductivity also increases. If you have other suggestions on how to insulate the pipeline so as not to freeze in the cold, write about it in the comments.
Thermal insulation of pipelines is a set of measures aimed at preventing the heat exchange of the medium transported through them with the environment. Thermal insulation of pipelines is used not only in heating and supply systems hot water, but also where technology requires transportation of substances with a certain temperature, for example, refrigerants.
The meaning of thermal insulation is the use of means that provide thermal resistance to heat transfer of any kind: contact and carried out through infrared radiation.
The greatest application, expressed in numbers, is the thermal insulation of pipelines of heating networks. Unlike Europe, centralized system heating dominates throughout the post-Soviet space. In Russia alone, the total length of heating networks is more than 260 thousand kilometers.
Much less often, insulation for heating pipes is used in private households with autonomous system heating. Only in a few northern regions are private houses connected to the central heating main with heating pipes placed on the street.
For some types of boilers, for example, powerful gas or diesel boilers, the requirements of the set of rules SP 61.13330.2012 “Thermal insulation of equipment and pipelines” are required to be placed separately from the building - in a boiler room several meters away from the heated object. In their case, a fragment of the piping passing through the street necessarily needs insulation.
On the street, insulation of heating pipelines is required both when installed above ground and when laid hidden - underground. The latter method is a channel method - a reinforced concrete trench is first laid in the trench, and pipes are already placed in it. Channelless placement method - directly in the ground. The insulating materials used differ not only in thermal conductivity, but also in steam and water resistance, durability and installation methods.
The need to insulate cold water supply pipes is not so obvious. However, you cannot do without it when the water supply is laid open above ground - the pipes must be protected from freezing and subsequent damage. But inside buildings, water supply pipes also have to be insulated - to prevent moisture condensation on them.
Glass wool, mineral wool
Insulating materials proven by practice. Meet the requirements of SP 61.13330.2012, SNiP 41-03-2003 and fire safety standards for any installation method. They are fibers with a diameter of 3-15 microns, close to crystals in structure.
Glass wool is made from waste from glass production, mineral wool from silicon-containing slag and silicate waste from metallurgy. The differences in their properties are insignificant. Available in the form of rolls, stitched mats, plates and pressed cylinders.
It is important to be careful with materials and know how to handle them correctly. Any manipulations must be performed in protective overalls, gloves and a respirator.
Installation
The pipe is wrapped or lined with cotton wool, ensuring uniform filling density over the entire surface. Then the insulation, without too much pressure, is fixed using a knitting wire. The material is hygroscopic and easily gets wet, so insulation of external pipelines made of mineral or glass wool requires the installation of a vapor barrier layer made of a material with low vapor permeability: roofing felt or polyethylene film.
A covering layer is placed on top of it to prevent the penetration of precipitation - a casing made of roofing tin, galvanized iron or sheet aluminum.
Basalt (stone) wool
More dense than glass wool. The fibers are made from the melt of gabbro-basalt rocks. Absolutely non-flammable, can withstand temperatures up to 900° C for a short time. Not all insulating materials, like basalt wool, can be in long-term contact with surfaces heated to 700° C.
Thermal conductivity is comparable to polymers, ranging from 0.032 to 0.048 W/(m K). High performance indicators allow it to be used thermal insulation properties not only for pipelines, but also when installing hot chimneys.
Available in several versions:
- like glass wool, in rolls;
- in the form of mats (stitched rolls);
- in the form of cylindrical elements with one longitudinal slot;
- in the form of pressed fragments of a cylinder, the so-called shells.
The last two versions have different modifications, differing in density and presence heat reflective film. The cylinder slot and the edges of the shells can be made in the form of a tenon joint. 
SP 61.13330.2012 contains instructions that thermal insulation of pipelines must meet safety and protection requirements environment. Basalt wool itself fully complies with this instruction.
Manufacturers often resort to tricks: to improve consumer performance - to give it hydrophobicity, greater density, and vapor permeability, they use impregnations based on phenol-formaldehyde resins. Therefore, it cannot be called 100% safe for humans. Before using basalt wool in a residential area, it is advisable to study its hygienic certificate.
Installation
The insulation fibers are stronger than glass wool, so it is almost impossible for its particles to enter the body through the lungs or skin. However, it is still recommended to use gloves and a respirator when working.
Installation of rolled sheets is no different from the method of insulating heating pipes with glass wool. Thermal protection in the form of shells and cylinders is attached to the pipes using mounting tape or a wide bandage. Despite some hydrophobicity of basalt wool, pipes insulated with it also require a waterproof, vapor-permeable shell made of polyethylene or roofing felt, and an additional one made of tin or dense aluminum foil.
Foamed polyurethane (polyurethane foam, PPU)
Reduces heat loss by more than half compared to glass wool and mineral wool. Its advantages include: low thermal conductivity, excellent waterproofing properties. The service life declared by the manufacturers is 30 years; Range operating temperature from -40 to +140 °C, the maximum withstandable for a short time is 150 °C.
The main brands of polyurethane foam belong to the flammability group G4 (highly flammable). When the composition is changed by adding fire retardants, they are assigned G3 (normally flammable).
Although polyurethane foam is excellent as insulating material for heating pipes, keep in mind that SP 61.13330.2012 allows the use of such thermal insulation only in single-family houses residential buildings, and SP 2.13130.2012 limits their height to two floors.
Thermal insulation coating is produced in the form of shells - semicircular segments with tongue and groove locks at the ends. Ready-made steel pipes insulated from polyurethane foam with a protective sheath made of polyethylene.
Installation
The shells are secured to the heating pipe using ties, clamps, plastic or metal bandage. Like many polymers, the material does not tolerate prolonged exposure to sunlight, so an open ground pipeline when using PPU shells requires a covering layer, for example, galvanized steel.
For underground ductless placement, thermal insulation products are laid on waterproof and temperature-resistant mastics or adhesives, and the outside is insulated with a waterproof coating. It is also necessary to take care of anti-corrosion surface treatment metal pipes– even the glued interlocking joint of the shells is not tight enough to prevent condensation of water vapor from the air.
Expanded polystyrene (foam plastic, EPS)
It is produced in the form of shells, practically no different in appearance from polyurethane foam - the same dimensions, the same tongue-and-groove locking connection. But the application temperature range, from -100 to +80 °C, with all this external similarity, makes its use for thermal insulation of heating pipelines impossible or limited.
SNiP 41-01-2003 “Heating, ventilation and air conditioning” states that in the case of a two-pipe heat supply system, the maximum supply temperature can reach 95°C. As for the return heating risers, not everything is so simple: it is believed that the temperature in them does not exceed 50 °C.
Foam insulation is more often used for cold water and sewer pipes. However, it can be used on top of other insulation materials with a higher permissible temperature applications.
The material has a number of disadvantages: it is highly flammable (even with the addition of fire retardants), does not tolerate chemical influences (dissolves in acetone), and crumbles into balls during prolonged exposure to solar radiation.
There are other non-polystyrene foams - formaldehyde, or phenolic for short. In fact, it is a completely different material. It is devoid of these disadvantages and is successfully used as thermal insulation for pipelines, but is not so widespread.
Installation
The shells are secured to the pipe using a bandage or foil tape; they can be glued to the pipe and to each other.
Foamed polyethylene
The temperature range at which the use of high-density polyethylene foam is allowed is from -70 to +70 °C. The upper border does not match with maximum temperature heating pipes, usually taken in calculations. This means that the material is of little use as thermal insulation for pipelines, but can be used as an insulating layer over a heat-resistant one.
Polyethylene foam insulation has found virtually no alternative use as protection against freezing of water pipes. Very often it is used as a vapor barrier and waterproofing.
The material is produced in the form of sheets or in the form of a flexible thick-walled pipe. The latter form is more often used, as it is more convenient for insulating water pipes. Standard length is 2 meters. Color varies from white to dark gray. There may be a coating of aluminum foil that reflects IR radiation. The differences relate to internal diameters (from 15 to 114 mm), wall thickness (from 6 to 30 mm).
The application ensures the temperature on the pipe is above the dew point, which means it prevents the formation of condensation.
Installation
A simple way with worse vapor barrier results is to cut the foam material along a small depression along the side surface, open the edges and put it on the pipe. Then wrap it along the entire length with mounting tape.
A more complex solution (and not always feasible) is to turn off the water, completely disassemble the insulated sections of the water supply system and put on solid sections. Then put everything back together. Secure the polyethylene with ties. In this case, only the junction of the segments will become a vulnerable point. It can be glued or also wrapped with tape.
Foam rubber
Foamed synthetic rubber with a closed-cell structure is the most versatile material for preserving heat and cold. Designed for a temperature range from -200 to +150 °C. Meets all environmental safety requirements.
Used as pipeline insulation cold water, heating pipe insulation, often found in refrigeration and ventilation systems. Heating pipes laid inside buildings and insulated with rubber do not require the installation of a vapor barrier layer.
Externally similar to foamed polyethylene, it is also available in the form of sheets and flexible thick-walled pipes. Installation is also practically no different, except that such thermal insulation of pipes can be attached with glue.
Liquid insulation
A technology has been successfully used that allows you to independently spray foam from a polyurethane composition onto ready-made structures. Excellent adhesive properties allow it to be used not only for insulating pipelines, but also applied to other elements that require insulation: foundations, walls, roofs. The coating, in addition to thermal protection, provides hydro, vapor barrier, and provides anti-corrosion resistance.
Conclusion
Proper installation of thermal insulation is a guarantee that the pipe will not lose heat and the consumer will not freeze. Freezing of a cold water supply pipeline invariably leads to its rupture. Until recently, glass wool was the usual insulating material for hidden and open heating mains. Its shortcomings stem from one another. This coating requires constant monitoring.
Even with slight damage to the protective surface layer, vapor permeability and hygroscopicity reduce all savings to nothing. Moisture causes low thermal resistance and premature failure. Modern insulating materials with a cellular structure, inert to the effects of steam and water: polyurethane foam, foam rubber, polyethylene foam will help to significantly improve the situation.
When carrying out work on equipment and installation of pipelines, it is necessary to comply with SNiP standards. What is SNiP? These are building codes and rules for organizing construction production, compliance with standards, technical specifications and regulatory departmental acts.
Basic norms and rules for thermal insulation
Heating network- this is one of the main elements district heating. You should strictly adhere to the rules and regulations when drawing up a pipeline thermal insulation project. Subject to compliance with SNiP, thermal insulation of pipelines will be carried out efficiently without violating standards. Thermal insulation of pipelines SNiP is provided for linear sections of pipelines, heating networks, compensators and pipe supports. Insulation of pipelines in residential buildings and industrial buildings requires strict compliance with design standards and fire safety systems.
The quality of materials must comply with SNiP, thermal insulation of pipelines should be aimed at reducing heat loss.
The main tasks of thermal insulation, features of the choice of materials
The main purpose of thermal insulation is to reduce heat loss in heating systems or hot water pipelines. The main function of insulation is aimed at preventing condensation. Condensation can form both on the surface of the pipe and in the insulating layer. In addition, according to safety standards, the insulation of pipelines must ensure a certain temperature on the insulation surface, and in case of stagnation of water, protect it from freezing and icing in the winter.
Insulation of pipelines also increases the service life of pipes.
According to SNiP standards, thermal insulation of pipelines is used both for centralized heating and reduces heat loss from intra-house heating networks. What to consider when choosing thermal insulation:
- Pipe diameter. It depends on what type of insulator will be used. Pipes can be cylindrical, half-cylinders or soft mats in rolls. Insulation of small diameter pipes is mainly carried out using cylinders and half-cylinders.
- Coolant temperature.
- Conditions in which the pipes will be operated.
Types of insulation
Let's consider the most popular and frequently used materials for thermal insulation:
- Fiberglass. Glass fiber materials are often used for above-ground piping because they have long term operation. Fiberglass has a low application temperature and is characterized by low density. High-quality fiberglass has high vibration, chemical and biological resistance.
- Mineral wool. Insulation of pipelines with mineral wool is a very effective heat insulator. This insulating material is used in different conditions. Unlike fiberglass, which has a low application temperature (up to 180ºC), mineral wool can withstand temperatures up to 650ºC. At the same time, its heat-insulating and mechanical properties. Mineral wool does not lose its shape and is highly resistant to chemicals and acid. This material is non-toxic and has a low degree of moisture absorption.
In turn, mineral wool comes in two forms: stone and glass.
Insulation of pipelines using mineral wool is used mainly in residential buildings, public and domestic premises, as well as to protect surfaces that are subject to heating.
- Polyurethane foam has a wide range of applications, but is a fairly expensive material. According to SNiP standards, thermal insulation of pipelines is environmentally friendly and does not affect human health. Polyurethane foam is resistant to external factors, non-toxic and quite durable.
- Expanded polystyrene. In some areas of industry, foam plastic is an indispensable material, as it has low thermal conductivity and moisture absorption and long term services. Expanded polystyrene is difficult to ignite and is an excellent sound insulator.
- In addition to the above materials, pipeline insulation can be carried out using other less well-known, but no less practical insulation materials, such as foam glass and penoizol. These materials are durable, safe and are close relatives of polystyrene foam.
Thermal insulating paint can also provide protection against corrosion and high thermal insulation of pipes.
This is a relatively new material, the main advantage of which is that it penetrates into hard to reach places and is able to withstand high temperature changes.
dom-data.ru
Features of thermal insulation of pipelines for heating networks: standards, materials, technology
When laying pipelines, a prerequisite is to perform work on thermal insulation of the networks. This applies to all pipelines - not only water supply, but also sewerage systems. The need for this is due to the fact that winter time Water passing through pipes may freeze. And if coolant circulates through the communications, this leads to a decrease in its temperature. To minimize heat loss, when laying pipelines they resort to installing a heat-insulating layer. What materials and methods can be used for thermal insulation of networks - this will be discussed in this article.
Thermal insulation of pipelines: ways to solve the problem
Effective protection for pipeline systems from environmental factors, mainly from outside air temperature, can be achieved by taking the following measures:
Since the last method is most often used, it makes sense to talk about it in more detail.
Standards for thermal insulation of pipelines
Requirements for thermal insulation of equipment pipelines are formulated in SNiP. The regulatory documents contain detailed information about materials, 
which can be used for thermal insulation of pipelines, and in addition methods of work. In addition, the regulatory documents indicate standards for thermal insulation circuits, which are often used to insulate pipelines.
- regardless of the temperature of the coolant, any pipeline system must be insulated;
- Both ready-made and prefabricated structures can be used to create a thermal insulation layer;
- Corrosion protection must be provided for metal parts of pipelines.
It is desirable to use a multilayer circuit design when insulating pipelines. It must include the following layers:
- insulation;
- vapor barrier;
- protection made of dense polymer, non-woven fabric or metal.
In some cases, reinforcement can be built that eliminates the collapse of materials and, in addition, prevents pipe deformation.
Note that most of requirements contained in regulatory documents relate to insulation main pipelines high power. But even in case of installation household systems, it would be useful to familiarize yourself with them and take them into account when installing water supply and sewerage systems on your own.
Materials for thermal insulation of pipelines
Currently, the market offers a large selection of materials that can be used for pipeline insulation. Each of them has its own advantages and disadvantages, and in addition, application features. For the right choice heat insulator needs to know all this.
Polymer insulation
When the task is to create an effective thermal insulation system for pipelines, attention is most often paid to foam-based polymers. A large assortment allows you to choose suitable material, thanks to which it is possible to provide effective protection from the external environment and eliminate heat loss.
If we talk in more detail about polymer materials, the following can be distinguished from those available on the market.
Polyethylene foam.
The main characteristic The material is low density. In addition, it is porous and has high mechanical strength. This insulation is used for the manufacture of cylinders with a cut. Their installation can be carried out even by people far from the field of thermal insulation of pipelines. However, this material has one drawback: structures made of polyethylene foam wear out quickly and, in addition, have poor heat resistance.
If polyethylene foam cylinders are chosen for thermal insulation of pipelines, then special attention must be paid to their diameter. It must match the diameter of the collector. Taking this rule into account when choosing an insulation design, it is possible to exclude spontaneous removal of polyethylene foam casings.
Expanded polystyrene.
The main feature of this material is elasticity. It is also characterized by high strength indicators. Protective products for thermal insulation of pipelines made from this material are produced in the form of segments that resemble a shell in appearance. Special locks are used to connect parts. They have tongues and grooves, which ensure quick installation of these products. The use of polystyrene foam shells with technical locks eliminates the occurrence of “cold bridges” after installation. In addition, during installation there is no need to use additional fasteners.
Polyurethane foam.
This material is used mainly for pre-installed thermal insulation of heating network pipelines. However, it can also be used to insulate household pipeline systems. This material is available in the form of foam or shell, which consists of two or four segments. Spray insulation provides reliable thermal insulation with a high degree of tightness. The use of such insulation is most suitable for communication systems with a complex configuration.
When using polyurethane foam in the form of foam for thermal insulation of pipelines of heating networks, you need to know that it is destroyed under the influence of ultraviolet rays. Therefore, in order for the insulating layer to last a long time, it is necessary to ensure its protection. To do this, apply a layer of paint on top of the foam or lay a non-woven fabric with good permeability.
Fibrous materials
Insulation materials of this type are mainly represented by mineral wool and its varieties. Currently, they are most popular among consumers as insulation. Materials of this type are also in high demand, like polymer materials.
Thermal insulation made using fiber insulation has certain advantages. These include the following:
- low thermal conductivity coefficient;
- resistance of the thermal insulation material to aggressive substances such as acids, alkalis, oil;
- material is in condition without additional frame maintain a given shape;
- the cost of insulation is quite reasonable and affordable for most consumers.
Please note that during work on thermal insulation of pipelines with such materials, it is necessary to prevent compression of the fiber when laying the insulation. It is also important to ensure that the material is protected from moisture.
Products made from polymer and mineral wool insulation for thermal insulation in some cases can be covered with aluminum or steel foil. The use of such screens reduces heat dissipation.
Multilayer structures for pipeline protection
Often, to insulate pipelines, thermal insulation is installed using the “pipe-in-pipe” method. When using this scheme, a heat-protective casing is installed. the main task The task of specialists installing such a circuit is to correctly connect all the parts into a single structure.
Upon completion of the work, the result is a design that looks like this:
- the basis of the heat-protective circuit is a pipe made of metal or polymer material. She happens to be load-bearing element the entire device;
- The thermal insulation layers of the structure are made of foamed polyurethane foam. The material is applied using pouring technology; the molten mass is filled into a specially created formwork;
- protective casing. Pipes made of galvanized steel or polyethylene are used for its manufacture. The first ones are used for laying networks in open space. The latter are used in cases where pipeline systems are laid in the ground using ductless technology. In addition, often when creating this type of protective casing, copper conductors are placed in insulation based on polyurethane foam, the main purpose of which is remote control condition of the pipeline, including the integrity of the thermal insulation layer;
- If the pipes arrive at the installation site in assembled form, then the welding method is used to connect them. Specialists use special heat-shrinkable cuffs to assemble the heat-protective circuit. Or, overhead couplings made from mineral wool, which are covered with a layer of foil, can be used.
Do-it-yourself thermal insulation of pipelines
There are a number of factors on which the technology for creating a thermal insulation layer on pipelines may depend. One of the most important is how the collector is laid - outside or in the ground.
Insulation of underground networks
To solve the problem of ensuring thermal protection of buried communications, insulation work is carried out in the following order:
Thermal insulation of external pipeline
In accordance with existing standards, pipelines located on the surface of the earth are thermally insulated as follows:
- insulation work begins with all parts being cleaned of rust;
- Next, the pipes are treated with an anti-corrosion compound. After this, they proceed to installing a polymer shell followed by wrapping the pipes roll insulation from mineral wool;
- Please note that to cover the structure you can use a layer of polyurethane foam or you can cover the structure with several layers thermal insulation paint;
- The next step is to wrap the pipe as in the previous option.
Along with fiberglass, other materials can be used, for example, foil film with polymer reinforcement. When this work is completed, the structures are secured using steel or plastic clamps.
Thermal insulation of pipelines is an important task that must be carried out when laying communications. There are many materials and technologies for its implementation. Having chosen the appropriate method of thermal insulation, you must adhere to the work technology. In this case, heat loss will be minimal, and in addition, the pipeline structure will be protected from various factors, which will have a positive effect on their service life.
kotel.guru
Today, thermal insulation of pipelines is necessary both to reduce heat losses of the corresponding systems and to lower the temperature of communications for their safe use. In addition, without it it is difficult to ensure normal operation of networks in winter, since the likelihood of freezing and failure of pipes is quite high and also dangerous.
According to existing standards, as well as rules for the safe operation of steam and hot water supply pipes, for pipeline elements with a wall temperature of more than 55 degrees and at the same time they are located in accessible places, it is recommended to use additional thermal insulation in such a way as to reduce their heating. In view of this, when calculating the thickness of the protective coating laid in a room, heat flux density standards are taken as a basis. In some cases, the temperature of the outer part of the insulation itself is also taken into account.
How to calculate insulation?
The choice of the required insulation is carried out on the basis of mathematical calculations, from which it is clear which material is better to take, its thickness, composition and other characteristics. If everything is done correctly, then it is quite possible to significantly reduce heat losses, as well as make the operation of systems reliable and absolutely safe.
Figure No. 1. Thermal insulation of pipes with foam plastic
What to pay attention to during calculations:
- - difference in ambient temperatures where communications are used;
- - the temperature of the surface that is supposed to be insulated;
- - possible loads on the pipes;
- - mechanical impacts from external influences, be it pressure, vibration, etc.;
- - the value of the thermal conductivity coefficient of the insulation used;
- - impact and corresponding magnitude from transport and soil;
- - the ability of the insulator to resist various types of deformation.
It should be noted that SNiP 41-03-2003 is considered the main document on the basis of which materials for insulation and their thickness are selected, according to specific operating conditions. The same SNiP states that for networks in which the operating temperature of the pipes is less than 12 degrees, it is necessary to additionally lay a vapor barrier when treating the surface.
Thermal insulation of pipes can be calculated in two ways, and each option can be called reliable and convenient for specific conditions. We are talking about an engineering (formula) and online version.
In the first case, the actual thickness of the optimal insulating layer is determined by a technical and economic calculation, in which the main parameter is temperature resistance. The corresponding value should be within 0.86ºC m²/W in the case of pipes with a diameter of up to 25mm, and at least 1.22ºC m²/W - from 25mm and above. SNiP provides special formulas by which the total temperature resistance of the insulating composition of cylindrical pipes is calculated.
Please note that if you have any doubts about the correctness of the calculation, it is better to seek help and advice from specialists who will carry out the work reliably and efficiently, especially since the prices for their services are quite reasonable. Otherwise, a situation may arise where the scope of certain actions may be more costly in terms of money than doing everything from scratch.
At independent execution work, it should also be understood that all calculations of the thickness of pipe insulation are made under certain operating conditions, where the materials themselves, temperature changes, and humidity are taken into account.
The second method is implemented through online calculators, of which there are countless today. Such an assistant is usually free, simple and convenient. Often it also takes into account all the norms and requirements of SNiP, according to which professionals perform calculations. All calculations are carried out quite quickly and accurately. Figuring out how to use the calculator will be easy.
Initially, the required task is selected:
- 1. Preventing liquid freezing of utility pipelines.
- 2. Ensuring a constant operating temperature of protective insulation.
- 3. Insulation of communications of water heating networks of two-pipe underground channel gaskets.
- 4. Protection of the pipeline from the formation of condensation on the insulator.
Then you need to enter the main parameters by which the calculation is carried out:
- 1. Pipe outer diameter.
- 2. Preferred insulating component.
- 3. The time during which water crystallizes in an inert state.
- 4. Temperature indicator of the surface to be insulated.
- 5. Coolant temperature value.
- 6. Type of coating used (metal or non-metal).
After entering all the data, the calculation result appears, which can be used as a basis for subsequent construction and selection of materials.
Figure No. 2. Thermal insulation of central heating pipes
The right choice of insulation
The main reason for freezing of pipes is the low circulation rate of working fluids in them. A negative factor is the freezing process, which can lead to irreversible and catastrophic consequences. This is why thermal insulation of networks is extremely necessary.
Particular attention should be paid to this aspect in pipelines that operate periodically, be it water supply from a well or a country house. water heating. In order not to have to restore working systems in the future, it is still better to carry out their timely thermal insulation.
Until recently, insulation work was carried out using a single technology, while protective element fiberglass was used. Currently, we offer a huge selection of all kinds of heat insulators designed for a specific type of pipe, having different specifications and composition.
Due to their intended use, it would be wrong to compare materials and say that one is better than the other. For this reason, below we will reveal the insulators that exist today.
According to the component representation option:
- - sheet;
- - roll;
- - filling
- - casing;
- - combined.
By area of use:
- - for water drainage and sewerage;
- - for steam, heating, hot and cold water supply networks;
- - for ventilation pipelines and freezing units.
Any thermal insulation is characterized by its resistance to fire and its thermal conductivity.
- 1. Shell. Its advantage is ease of installation, optimal characteristics and high quality workmanship. It has low thermal conductivity, fire resistance, and a minimal level of moisture absorption. Suitable for protecting heating networks and water supply systems.
Figure No. 3. Shell pipe insulation
- 2. Mineral wool. It is usually supplied in rolls and is used for processing pipes whose coolant has a very high temperature. This option is only advisable for small processing areas, since mineral wool is quite an expensive material. Its installation is carried out by winding communications and fixing them in a given position with stainless steel wire or twine. Additionally, it is recommended to carry out waterproofing, since cotton wool easily absorbs moisture.
Figure No. 4. Insulation mineral wool cylinder
- 3. Expanded polystyrene. The design of thermal insulation of this type is more like two halves, or a shell, through which the pipeline is insulated. The option can safely be called high-quality and convenient in terms of installation. Due to minimal moisture absorption and low thermal conductivity, high fire resistance, minimal thickness, polystyrene foam is excellent for protecting heating and water supply networks.
Figure No. 5. Foam insulation
- 4. Penoizol. Thermal insulation has similar parameters to polystyrene foam, although with a significant difference in installation. Application is carried out using an appropriate sprayer, since the material is in a liquid state. After complete drying, the entire treated surface of the pipe acquires a dense and durable hermetic structure that reliably maintains the temperature of the coolant. A significant advantage is that there is no need to use additional fasteners to secure the material. The only downside is that it is expensive.
Figure No. 6. Insulation of pipes with foam insulation
- 5. Penofol with foil base. An innovative product that is becoming more popular every day. It consists of polyethylene foam and aluminum foil. The two-layer design allows both maintaining the temperature of the networks and heating the space, since the foil is able to reflect and accumulate heat. We especially pay attention to the low combustion ability, high environmental data, ability to withstand high humidity and significant temperature changes.
Figure No. 7. Pipe insulated with foil penofol
- 6. Foamed polyethylene. Thermal insulation of this type is very common, and it is often found on water mains. A special feature is the ease of installation, for which it is enough to cut the required size of the material and wrap it around the production line, fixing it with tape. Foamed polyethylene is often supplied in the form of a wrap for a pipe of a certain diameter with a technological cut, which is put on the desired section of the system.
Figure No. 8. Foamed polyethylene
It is important to know that when insulating pipelines, all insulation materials, except penoizol, require the additional use of waterproofing and adhesive tape for fixation.
From all of the above, it is clear that there are quite a lot of options for processing pipes, and the choice is very large. Experts advise paying attention to the conditions in which each material will be used, its characteristics and installation method. Naturally, competent thermal insulation calculations also play an important role, which will allow you to be confident in the work done.
Video No. 1. Thermal insulation of pipes. Installation example
Methods of thermal insulation of pipelines
SNiP specifications and many professionals recommend following the following options for protecting trunk lines:
- 1. Air insulation. Typically, underground communication systems are protected by thermal insulation. certain thickness. However, the factor that the freezing of the ground goes from the top to the bottom is often not taken into account, while the heat flow from the pipes tends to the top. Since the pipeline is protected on all sides by a component of minimal thickness, the rising heat is also insulated. In this case, it is more rational to install insulation over the upper part of the line, so that a thermal layer is formed.
- 2. Use of insulation and heating element. Great as an alternative to traditional options. In this case, the point is taken into account that the protection of lines is seasonal, and laying them in the ground is not rational for financial reasons, as is the use of a large thickness of insulator. According to SNiP rules and manufacturers' instructions, the cable can be located both inside and outside the pipes.
- 3. Laying a pipe in a pipe. Here, in polypropylene pipes additionally separate pipes are installed. The peculiarity of the method is that it is possible to warm up the systems almost always, including using the principle of suction of warm air masses. In addition, if necessary, an emergency hose can easily be laid in the existing gap.
Conclusion
Summarizing all of the above, we can say that there are a lot of important points and nuances for processing and protecting the pipeline. In any situation, it is always better to start by calculating the required insulation, choosing its type, thickness and cost. The option of its installation also plays an important role, since the most problematic conditions will require additional significant cash injections into the construction of the necessary systems.
A perfect approach to the choice of thermal insulation can ultimately lead to minimum costs and reducing the complexity of the work performed. High-quality selection of the required insulating components will effectively maintain the temperature of the coolant in the pipes, as well as significantly increase their service life.
Video No. 2. Universal thermal insulation for pipes
In the practice of private construction, it is not so common, but there are still situations when heating communications need to be not only distributed throughout the premises of the main house, but also extended to other nearby buildings. These can be residential outbuildings, extensions, summer kitchens, utility or agricultural buildings, for example, used for keeping domestic animals or poultry. The option cannot be ruled out when, on the contrary, the autonomous boiler room itself is located in a separate building, at some distance from the main residential building. It happens that a house is connected to a central heating main, from which pipes are extended to it.
There are two options for laying heating pipes between buildings - underground (ducted or ductless) and open. The process of installing a local heating main above the ground seems less labor-intensive, and this option in conditions self-construction come running more often. One of the main conditions for the efficiency of the system is properly planned and high-quality thermal insulation for heating pipes on outdoors. It is this issue that will be addressed in this publication.
Why do you need thermal insulation of pipes and the basic requirements for it?
It would seem nonsense - why insulate already almost always hot pipes? heating system? Perhaps someone may be misled by a peculiar “play on words”. In the case under consideration, of course, it would be more correct to conduct the conversation using the concept of “thermal insulation”.
Thermal insulation work on any pipelines has two main goals:
- If pipes are used in heating or hot water supply systems, then reducing heat losses and maintaining the required temperature of the pumped liquid comes to the fore. The same principle is also true for industrial or laboratory installations, where technology requires maintaining a certain temperature of the substance transmitted through pipes.
- For cold water supply pipelines or sewer communications, the main factor is insulation, that is, preventing the temperature in the pipes from falling below a critical level, preventing freezing, leading to failure of the system and deformation of the pipes.
By the way, such a precaution is required both for heating mains and for hot water supply pipes - no one is completely immune from emergency situations on boiler equipment.
Herself cylindrical shape pipes predetermines a very large area of constant heat exchange with the environment, which means significant heat loss. And they naturally increase as pipeline diameters increase. The table below clearly shows how the amount of heat loss changes depending on the temperature difference inside and outside the pipe (Δt° column), on the diameter of the pipes and on the thickness of the thermal insulation layer (data given taking into account the use of insulation material with an average thermal conductivity coefficient λ = 0.04 W/m×°C).
| The thickness of the thermal insulation layer. mm | Δt.°С | Pipe outer diameter (mm) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 15 | 20 | 25 | 32 | 40 | 50 | 65 | 80 | 100 | 150 | ||
| The amount of heat loss (per 1 linear meter 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 | 8.31 | 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 | |
As the thickness of the insulation layer increases, the overall heat loss rate decreases. However, please note that even a fairly thick layer of 40 mm does not completely eliminate heat loss. There is only one conclusion - it is necessary to strive to use insulation materials with the lowest possible thermal conductivity coefficient - this is one of the main requirements for thermal insulation of pipelines.
Sometimes a pipeline heating system is also required!
When laying water supply or sewer lines, it happens that due to the local climate or specific installation conditions, thermal insulation alone is clearly not enough. We have to resort to forced installation of heating cables - this topic is discussed in more detail in a special publication on our portal.
- The material used for thermal insulation of pipes, if possible, should have hydrophobic properties. There will be little current from insulation soaked in water - it will not prevent heat loss, and itself will soon collapse under the influence of negative temperatures.
- The thermal insulation structure must have reliable external protection. Firstly, it needs protection from atmospheric moisture, especially if insulation is used that can actively absorb water. Secondly, materials should be protected from exposure to the ultraviolet spectrum of sunlight, which has a detrimental effect on them. Thirdly, we should not forget about wind load, which can damage the integrity of the thermal insulation. And fourthly, there remains the factor of external mechanical impact, unintentional, including from animals, or due to banal manifestations of vandalism.
In addition, any owner of a private house is probably not indifferent to the aesthetic appearance of the installed heating main.
- Any thermal insulation material used on heating mains must have an operating temperature range that corresponds to the actual conditions of use.
- An important requirement for insulating material and its external cladding is durability of use. No one wants to return to the problems of thermal insulation of pipes even once every few years.
- From a practical point of view, one of the main requirements is the ease of installation of thermal insulation, in any position and in any difficult area. Fortunately, in this regard, manufacturers never tire of delighting with easy-to-use developments.
- An important requirement for thermal insulation is that its materials themselves must be chemically inert and not enter into any reaction with the surface of the pipes. Such compatibility is the key to long-term trouble-free operation.
The issue of cost is also very important. But in this regard, the range of prices among specialized ones is very large.
What materials are used for insulation of above-ground heating mains
The choice of thermal insulation materials for heating pipes when they are laid externally is quite large. They come in roll type or in the form of mats; they can be given a cylindrical or other shaped shape that is convenient for installation; there are insulation materials that are applied in liquid form and acquire their properties only after hardening.
Insulation using foamed polyethylene
Foamed polyethylene is rightly classified as a very effective thermal insulator. And what is also very important, the cost of this material is one of the lowest.
The thermal conductivity coefficient of foamed polyethylene is usually around 0.035 W/m×°C - this is a very good indicator. The smallest bubbles, isolated from each other, filled with gas, create an elastic structure, and with such material, if you purchase a roll version, it is very convenient to work on sections of pipes with complex configurations.
Such a structure becomes a reliable barrier to moisture - if installed correctly, neither water nor water vapor will be able to penetrate through it to the pipe walls.
The density of polyethylene foam is low (about 30 - 35 kg/m³), and thermal insulation will not make the pipes heavier.
The material, with some assumption, can be classified as low-hazard in terms of flammability - it usually belongs to class G-2, that is, it is very difficult to ignite, and without an external flame it quickly extinguishes. Moreover, combustion products, unlike many other thermal insulators, do not pose any serious toxic danger to humans.
Rolled foam polyethylene for insulation of external heating mains will be both inconvenient and unprofitable - you will have to wind it in several layers to achieve the required thickness of thermal insulation. Much more convenient to use is material in the form of sleeves (cylinders), which have an internal channel corresponding to the diameter of the insulated pipe. To put it on pipes, an incision is usually made along the length of the cylinder on the wall, which after installation can be sealed with reliable tape.
Putting insulation on a pipe is not difficult A more effective type of polyethylene foam is penofol, which has on one side. This shiny coating becomes a kind of thermal reflector, which significantly increases the insulating qualities of the material. In addition, it is an additional barrier against moisture penetration.
Penofol can also be of a roll type or in the form of profile cylindrical elements - especially for thermal insulation of pipes for various purposes.
And foamed polyethylene is rarely used for thermal insulation of heating mains. It is more likely to be suitable for other communications. The reason for this is the rather low operating temperature range. So. if you look at physical characteristics, then the upper limit balances somewhere on the verge of 75 ÷ 85 degrees - above that, structural disturbances and the appearance of deformations are possible. For autonomous heating, more often than not, this temperature is sufficient, although on the edge, and for the central temperature, thermal stability is clearly not enough.
Insulation elements made of polystyrene foam
The well-known expanded polystyrene (in everyday life it is more often called polystyrene foam) is very widely used for the most different types thermal insulation works. The insulation of pipes is no exception - special parts are made from foam plastic for this purpose.
Usually these are half-cylinders (for pipes of large diameters there may be segments of a third of the circumference, 120° each), which for assembly into a single structure are equipped with a tongue-and-groove type locking connection. This configuration makes it possible to provide reliable thermal insulation completely over the entire surface of the pipe, without remaining “cold bridges.”
In everyday speech, such details are called “shells” for their obvious resemblance to it. Many types are produced, for different outer diameters of insulated pipes and different thicknesses of the thermal insulation layer. Typically the length of the parts is 1000 or 2000 mm.
For production, polystyrene foam of the PSB-S type of various grades is used - from PSB-S-15 to PSB-S-35. The main parameters of this material are shown in the table below:
| Estimated material parameters | Brand of expanded polystyrene | ||||
|---|---|---|---|---|---|
| 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 |
| Bending strength (MPa, not less) | 0.08 | 0.12 | 0.17 | 0.36 | 0.35 |
| Thermal conductivity in dry condition at a temperature of 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 |
The advantages of polystyrene foam as an insulating material have long been known:
- It has a low thermal conductivity coefficient.
- The light weight of the material greatly simplifies insulation work, which does not require any special mechanisms or devices.
- The material is biologically inert - it will not be a breeding ground for the formation of mold or mildew.
- Moisture absorption is negligible.
- The material can be easily cut and adjusted to the desired size.
- Polystyrene foam is chemically inert and absolutely safe for pipe walls, no matter what material they are made of.
- One of the key advantages is that polystyrene foam is one of the most inexpensive insulation materials.
However, it also has many disadvantages:
- First of all, this low level fire safety. The material cannot be called non-flammable and does not spread flame. That is why, when using it to insulate above-ground pipelines, fire breaks must be left.
- The material does not have elasticity, and it is convenient to use it only on straight sections of pipe. True, you can also find special figured parts.
- Polystyrene foam is not a durable material - it is easily destroyed under external influence. Ultraviolet radiation also has a negative effect on it. In a word, above-ground sections of the pipe, insulated with polystyrene foam shells, will definitely require additional protection in the form of a metal casing.
Usually, stores that sell foam shells also offer galvanized sheets, cut to the required size, corresponding to the diameter of the insulation. An aluminum shell can also be used, although it is of course much more expensive. The sheets can be secured with self-tapping screws or clamps - the resulting casing will simultaneously create anti-vandal, anti-wind, waterproofing protection and a barrier from sunlight.
- And yet this is not even the main thing. The upper limit of normal operating temperatures is only around 75°C, after which linear and spatial deformation of parts may begin. Whatever one may say, this value may not be enough for heating. It probably makes sense to look for a more reliable option.
Insulation of pipes with mineral wool or products based on it
The most “ancient” method of thermal insulation of external pipelines is using mineral wool. By the way, it is also the most budget-friendly, if it is not possible to purchase a foam shell.
For thermal insulation of pipelines, various types of mineral wool are used - glass wool, stone (basalt) and slag. Slag is the least preferable: firstly, it absorbs moisture most actively, and secondly, its residual acidity can have a very destructive effect on steel pipes. Even the cheapness of this cotton wool does not in any way justify the risks of its use.
But mineral wool based on basalt or glass fibers is fully suitable. It has good thermal resistance to heat transfer, high chemical resistance, the material is elastic, and it is easy to install even on complex pipeline sections. Another advantage is that you can, in principle, be completely calm in terms of fire safety. It is almost impossible to heat mineral wool to the point of ignition in the conditions of an external heating main. Even exposure to an open flame will not cause a fire to spread. That is why mineral wool is used to fill fire gaps when using other pipe insulation materials.
The main disadvantage of mineral wool is its high water absorption (basalt wool is less susceptible to this “disease”). This means that any pipeline will require mandatory protection from moisture. In addition, the structure of the wool is unstable to mechanical stress, is easily destroyed, and should be protected with a durable casing.
Usually they use a durable polyethylene film, which is securely wrapped in a layer of insulation, with the obligatory overlap of the strips by 400 ÷ 500 mm, and then the whole thing is closed on top metal sheets- exactly by analogy with polystyrene foam shells. Roofing felt can also be used as waterproofing - in this case, 100 ÷ 150 mm of overlap of one strip over another will be sufficient.
Existing GOST standards determine the thickness of protective metal coatings for open sections of pipelines with any type of thermal insulation materials used:
| Protective cover layer material | Minimum metal thickness, with outer diameter of insulation | ||
|---|---|---|---|
| 350 or less | Over 350 and up to 600 | Over 600 and up to 1600 | |
| Stainless steel strips and sheets | 0.5 | 0.5 | 0.8 |
| Sheets made of thin sheet steel, galvanized or polymer coated | 0.5 | 0.8 | 0.8 |
| Aluminum or aluminum alloy sheets | 0.3 | 0.5 | 0.8 |
| Aluminum or aluminum alloy tapes | 0.25 | - | - |
Thus, despite the seemingly inexpensive price of the insulation itself, its full installation will require considerable additional costs.
Mineral wool for insulation of pipelines can also act in another capacity - it serves as a material for the manufacture of finished thermal insulation parts, by analogy with polyethylene foam cylinders. Moreover, such products are produced both for straight sections of pipelines and for bends, tees, etc.
Typically, such insulating parts are made from the densest material - basalt mineral wool, and have an external foil coating, which immediately eliminates the problem of waterproofing and increases the efficiency of insulation. But you still won’t be able to get away from the outer casing - a thin layer of foil will not protect you from accidental or intentional mechanical impact.
Insulation of heating mains with polyurethane foam
One of the most effective and safest modern insulation materials is polyurethane foam. It has a lot of various advantages, so the material is used on almost any structure that requires reliable insulation.
What are the features of polyurethane foam insulation?
Polyurethane foam for pipeline insulation can be used in various types.
- PPU shells are widely used, usually having an outer foil coating. It can be collapsible, consisting of half-cylinders with tongue-and-groove locks, or, for small-diameter pipes, with a cut along the length and special valve with a self-adhesive back surface, which greatly simplifies the installation of insulation.
- Another way to thermally insulate a heating main with polyurethane foam is to spray it in liquid form using special equipment. The resulting layer of foam, after complete hardening, becomes an excellent insulation material. This technology is especially convenient at complex junctions, pipe turns, in units with shut-off and control valves, etc.
The advantage of this technology is that, thanks to the excellent adhesion of polyurethane foam spraying to the surface of the pipes, excellent waterproofing and anti-corrosion protection is created. True, the polyurethane foam itself also requires mandatory protection - from ultraviolet rays, so again it will not be possible to do without a casing.
- Well, if you need to lay a sufficiently long heating main, then, probably, the most optimal choice will be the use of pre-insulated (pre-insulated) pipes.
In fact, such pipes are a multilayer structure assembled in a factory:
— The inner layer is, in fact, the steel pipe itself of the required diameter, through which the coolant is pumped.
— The outer coating is protective. It can be polymer (for laying a heating main in the thickness of the soil) or galvanized metal - what is required for open sections of the pipeline.
— Between the pipe and the casing, a monolithic, seamless layer of polyurethane foam is poured, which performs the function of effective thermal insulation.
An installation section is left at both ends of the pipe for welding work when assembling the heating main. Its length is designed in such a way that the heat flow from the welding arc will not damage the polyurethane foam layer.
After installation, the remaining uninsulated areas are primed, covered with a polyurethane foam shell, and then with metal belts, comparing the coating with the overall outer casing of the pipe. It is often in such areas that fire breaks are organized - they are tightly filled with mineral wool, then waterproofed with roofing felt and still covered on top with a steel or aluminum casing.
The standards establish a certain range of such sandwich pipes, that is, it is possible to purchase products of the required nominal diameter with optimal (regular or reinforced) thermal insulation.
| Outer diameter of steel pipe and minimum wall thickness (mm) | Dimensions of galvanized sheet steel shell | Estimated thickness of the thermal insulation layer of polyurethane foam (mm) | |
|---|---|---|---|
| nominal outer diameter (mm) | minimum thickness of steel sheet (mm) | ||
| 32×3.0 | 100; 125; 140 | 0.55 | 46,0; 53,5 |
| 38×3.0 | 125; 140 | 0.55 | 43,0; 50,5 |
| 45×3.0 | 125; 140 | 0.55 | 39,5; 47,0 |
| 57×3.0 | 140 | 0.55 | 40.9 |
| 76×3.0 | 160 | 0.55 | 41.4 |
| 89×4.0 | 180 | 0.6 | 44.9 |
| 108×4.0 | 200 | 0.6 | 45.4 |
| 133×4.0 | 225 | 0.6 | 45.4 |
| 159×4.5 | 250 | 0.7 | 44.8 |
| 219×6.0 | 315 | 0.7 | 47.3 |
| 273×7.0 | 400 | 0.8 | 62.7 |
| 325×7.0 | 450 | 0.8 | 61.7 |
Manufacturers offer such sandwich pipes not only for straight sections, but also for tees, bends, expansion joints, etc.
The cost of such pre-insulated pipes is quite high, but their acquisition and installation solves a whole range of problems at once. So such costs seem quite justified.
Video: the production process of pre-insulated pipes
Insulation – foam rubber
Very popular in Lately become thermal insulation materials and products made from synthetic foam rubber. This material has whole line advantages that bring it to a leadership position in matters of insulation of pipelines, including not only heating mains, but also more responsible ones - on complex technological lines, in mechanical engineering, aircraft and shipbuilding:
- Foam rubber is very elastic, but at the same time has a large margin of tensile strength.
- The density of the material is only from 40 to 80 kg/m³.
- The low thermal conductivity coefficient provides very effective thermal insulation.
- The material does not shrink over time, completely retaining its original shape and volume.
- Foamed rubber is difficult to ignite and has the property of rapid self-extinguishing.
- The material is chemically and biologically inert; there are no pockets of mold or mildew, no nests of insects or
- The most important quality is almost absolute water and vapor tightness. Thus, the insulating layer immediately becomes an excellent waterproofing for the surface of the pipe.
Such thermal insulation can be produced in the form of hollow tubes with an internal diameter from 6 to 160 mm and an insulation layer thickness from 6 to 32 mm, or in the form of sheets, which are often given a “self-adhesive” function on one side.
| The name of indicators | Values |
|---|---|
| Length of finished tubes, mm: | 1000 or 2000 |
| Color | black or silver, depending on the type of protective coating |
| Temperature range of application: | from - 50 to + 110 °C |
| Thermal conductivity, W/(m ×°C): | λ≤0.036 at 0°C |
| λ≤0.039 at a temperature of +40°C | |
| Vapor permeation resistance coefficient: | μ≥7000 |
| Fire hazard level | Group G1 |
| Allowable length change: | ±1.5% |
But for heating mains located in the open air, ready-made insulation elements made using the Armaflex ACE technology, which have a special protective covering"ArmaChek".
ArmaChek coating can be of several types, for example:
- "Arma-Chek Silver" is a multi-layer PVC-based shell with a silver reflective coating. This coating provides excellent protection of the insulation from both mechanical stress and ultraviolet rays.
- The black Arma-Chek D coating has a fiberglass base that is highly durable but retains excellent flexibility. This is excellent protection against all possible chemical, weather, and mechanical influences, which will keep the heating pipe intact.
Typically, such products using the ArmaChek technology have self-adhesive valves that hermetically “seal” the insulating cylinder on the pipe body. Curved elements are also produced that allow installation on difficult sections of the heating main. Skillful use of such thermal insulation allows you to quickly and reliably install it, without resorting to creating an additional external protective casing - there is simply no need for it.
The only thing, probably, that is hindering the widespread use of such thermal insulation products for pipelines is the still prohibitively high price for real, “branded” products.
Prices for thermal insulation for pipes
Thermal insulation for pipes
A new direction in insulation - thermal insulation paint
You can't miss another one modern technology insulation. And it’s all the more pleasant to talk about it, since it is the development of Russian scientists. We are talking about ceramic liquid insulation, which is also known as heat-insulating paint.
This is, without any doubt, an “alien” from the sphere of space technology. It is in this scientific and technical field that the issues of thermal insulation from critically low (in outer space) or high (during the launch of ships and landing of descent vehicles) are especially acute.
The thermal insulation qualities of ultra-thin coatings seem simply fantastic. At the same time, such a coating becomes an excellent hydro- and vapor barrier, protecting the pipe from all possible external influences. Well, the heating main itself takes on a well-groomed, pleasing appearance.
The paint itself is a suspension of microscopic, vacuum-filled silicone and ceramic capsules suspended in a liquid state in a special composition, including acrylic, rubber and other components. After applying and drying the composition, a thin elastic film is formed on the surface of the pipe, which has outstanding thermal insulation properties.
| Names of indicators | Unit | Magnitude |
|---|---|---|
| Paint color | white (can be customized) | |
| Appearance after application and complete hardening | matte, smooth, homogeneous surface | |
| Film elasticity when bending | mm | 1 |
| Coating adhesion based on pull-off force from the painted surface | ||
| - to the concrete surface | MPa | 1.28 |
| - to a brick surface | MPa | 2 |
| - to steel | MPa | 1.2 |
| Resistance of the coating to temperature changes from -40 °C to + 80 °C | without changes | |
| Resistance of the coating to temperatures of +200 °C for 1.5 hours | no yellowing, cracks, peeling or bubbles | |
| Durability for concrete and metal surfaces in cold-temperate climates (Moscow) | years | at least 10 |
| Thermal conductivity | W/m °C | 0,0012 |
| Vapor permeability | mg/m × h × Pa | 0.03 |
| Water absorption in 24 hours | % by volume | 2 |
| Operating temperature range | °C | from - 60 to + 260 |
Such a coating will not require additional protective layers - it is strong enough to independently cope with all impacts.
This liquid insulation is sold in plastic cans (buckets), just like regular paint. There are several manufacturers, and among the domestic ones we can particularly note the brands “Bronya” and “Korund”.
This thermal paint can be applied by aerosol spraying or in the usual way- roller and brush. The number of layers depends on the operating conditions of the heating main, climatic region, pipe diameter, and average temperature of the pumped coolant.
Many experts believe that such insulation materials will eventually replace conventional thermal insulation materials on a mineral or organic basis.
Video: presentation of ultra-thin thermal insulation of the Korund brand
Prices for thermal insulation paint
Thermal insulation paint
What thickness of heating main insulation is required?
To summarize the review of materials used for thermal insulation of heating pipes, we can put the performance indicators of the most popular ones in the table - for clarity of comparison:
| Thermal insulating material or product | Average density in the finished 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 | 0,05 | 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 - 180 + 400 | ||
| 180 | 0,052 | 0.051 ÷ 0.038 | |||
| Thermal insulation products made of foamed ethylene-polypropylene rubber "Aeroflex" | 60 | 0,034 | 0,033 | From - 55 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 ÷ 0.024 | 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 |
But surely an inquisitive reader will ask: where is the answer to one of the main questions that arises - what should be the thickness of the insulation?
This question is quite complex, and there is no clear answer to it. If desired, you can use cumbersome calculation formulas, but they are probably understandable only to qualified heating engineers. However, not everything is so scary.
Manufacturers of finished thermal insulation products (shells, cylinders, etc.) usually lay required thickness, calculated for a specific region. And if mineral wool insulation is used, then you can use the data from the tables that are given in a special Code of Rules, which was developed specifically for thermal insulation of pipelines and process equipment. This document is easy to find on the Internet by entering a search query "SP 41-103-2000".
Here, for example, is a table from this reference book regarding the above-ground placement of a pipeline in the Central region of Russia, when using mats made of glass staple fiber grade M-35, 50:
| Outer diameter pipeline, mm | Heating pipe type | |||||
|---|---|---|---|---|---|---|
| innings | return | innings | return | innings | return | |
| Average temperature regime coolant, °C | ||||||
| 65 | 50 | 90 | 50 | 110 | 50 | |
| Required insulation thickness, mm | ||||||
| 45 | 50 | 50 | 45 | 45 | 40 | 40 |
| 57 | 58 | 58 | 48 | 48 | 45 | 45 |
| 76 | 67 | 67 | 51 | 51 | 50 | 50 |
| 89 | 66 | 66 | 53 | 53 | 50 | 50 |
| 108 | 62 | 62 | 58 | 58 | 55 | 55 |
| 133 | 68 | 68 | 65 | 65 | 61 | 61 |
| 159 | 74 | 74 | 64 | 64 | 68 | 68 |
| 219 | 78 | 78 | 76 | 76 | 82 | 82 |
| 273 | 82 | 82 | 84 | 84 | 92 | 92 |
| 325 | 80 | 80 | 87 | 87 | 93 | 93 |
In a similar way, you can find the necessary parameters for other materials. By the way, the same Code of Rules does not recommend significantly exceeding the specified thickness. Moreover, the maximum values of the insulating layer for pipelines have been determined:
| Pipeline outer diameter, mm | Maximum thickness of thermal insulation layer, mm | |
|---|---|---|
| temperature 19 ° C and below | temperature 20 ° C or more | |
| 18 | 80 | 80 |
| 25 | 120 | 120 |
| 32 | 140 | 140 |
| 45 | 140 | 140 |
| 57 | 150 | 150 |
| 76 | 160 | 160 |
| 89 | 180 | 170 |
| 108 | 180 | 180 |
| 133 | 200 | 200 |
| 159 | 220 | 220 |
| 219 | 230 | 230 |
| 273 | 240 | 230 |
| 325 | 240 | 240 |
However, do not forget one thing important nuance. The fact is that any insulation with a fibrous structure inevitably shrinks over time. This means that after a certain period of time its thickness may become insufficient for reliable thermal insulation of the heating main. There is only one way out - even when installing insulation, immediately take into account this correction for shrinkage.
To calculate, you can use the following formula:
N = ((D + h) : (D + 2 h)) × h× Kc
N– thickness of the mineral wool layer, taking into account the correction for compaction.
D– outer diameter of the pipe to be insulated;
h– required insulation thickness according to the table of the Code of Rules.
KS– shrinkage (compaction) coefficient of fiber insulation. It is a calculated constant, the value of which can be taken from the table below:
| 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 with an average density of 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 from glass staple fiber "URSA" brand: | |
| M-11: | |
| ̶ for pipes with DN up to 40 mm | 4,0 |
| ̶ for pipes with DN 50 mm and above | 3,6 |
| M-15, M-17 | 2.6 |
| M-25: | |
| ̶ for pipes with DN up to 100 mm | 1,8 |
| ̶ for pipes with DN from 100 to 250 mm | 1,6 |
| ̶ for pipes with DN over 250 mm | 1,5 |
| Mineral wool slabs with synthetic binder brand: | |
| 35, 50 | 1.5 |
| 75 | 1.2 |
| 100 | 1.10 |
| 125 | 1.05 |
| Glass staple fiber slabs brand: | |
| P-30 | 1.1 |
| P-15, P-17 and P-20 | 1.2 |
To help the interested reader, below is a special calculator, which already contains the indicated ratio. You just need to enter the requested parameters and immediately get the required thickness of mineral wool insulation, taking into account the correction.
Each technological process is based on economic efficiency, which is influenced by a combination of many factors. One of these points, important for many industries (chemical, oil refining, metallurgical, food, housing and communal services and many others), is the thermal insulation of equipment and pipelines. On an industrial scale, it is used on horizontal and vertical devices, tanks for storing various liquids, in various exchangers and pumps. The processes using cryogenic and low-temperature equipment have particularly high requirements for thermal insulation. The energy industry uses insulating elements in the operation of all types of boilers and turbines, storage tanks and various. Depending on the area of application, they are subject to certain requirements that are included in SNiP. Thermal ensures the preservation of the unchanged parameters at which they occur, as well as their safety, and reduces losses.
General information
Thermal insulation is one of the most common types of protection, which has found its application in almost all industries. Thanks to it, trouble-free operation of most objects that pose a threat to human health or the environment is ensured. There are certain requirements for the selection of material and installation. They are collected in SNiP. Pipeline insulation must comply with standards, since the normal functioning of many systems depends on it. Almost all the requirements listed in the documentation are mandatory. In most cases, thermal insulation of heat pipelines is a key factor for the uninterrupted operation and functioning of energy facilities, housing and communal services and industry. An additional quality that thermal insulation of pipelines has is that it meets the requirements applied in the field of energy saving. Proper insulation of pipelines, carried out according to all standards, allows to reduce heat losses during its transfer from the supplier to the final consumer (for example, when providing hot water supply services in the housing and communal services system), which in turn reduces overall energy costs.
Requirements for structures
The installation and operation of thermal insulation structures directly depend on their purpose and installation location. There are a number of factors that influence These include temperature, humidity, mechanical and other influences. To date, certain requirements have been adopted and approved, in accordance with which the calculation of pipeline insulation and subsequent installation is carried out. They are considered basic, and taking them into account is basic during the construction of structures. These include, in particular:
Environmental safety;
Fire hazard, reliability and durability of the materials from which the structure is made;
Thermal performance indicators.
The parameters characterizing the performance properties of thermal insulation materials include some physical quantities. These are thermal conductivity, compressibility, elasticity, density, vibration resistance. Flammability, resistance to aggressive factors, pipeline insulation thickness and a number of other parameters are also important.
Thermal conductivity of the material
The thermal conductivity coefficient of the raw materials from which the insulation is made determines the efficiency of the entire structure. Based on its value, the required thickness of the future material is calculated. This in turn affects the amount of load that will be exerted by the heat insulator on the object. When calculating the value of the coefficient, the entire set of factors that directly influence it is taken into account. The final value affects the choice of material, the method of laying it, and the required thickness to achieve maximum effect. Also taken into account is temperature resistance, degree of deformation at a given load, permissible load, which the material will add to the insulated structure, and much more.
Life time
The operational period of thermal insulation structures is different and depends on many factors that directly influence it. These, in particular, should include the location of the object and weather conditions, the presence/absence of mechanical influence on the thermal insulation structure. These key factors influence the durability of the structure. The application of an additional special coating, which significantly reduces the level of environmental impact, helps to increase the service life.
Fire safety requirements
Fire safety standards are defined for each industry. For example, for the gas, petrochemical, and chemical industries, the use of low-burning or non-combustible materials as part of thermal insulation structures is allowed. In this case, the choice is influenced not only by the indicated indicators of the selected substance, but also by the behavior of the thermal insulation structure during a general fire. Increased fire resistance is achieved by applying an additional coating that is resistant to high temperatures.
Sanitary and hygienic requirements for structures
When designing objects within which specific technological processes with increased requirements for sterility and cleanliness (for example, for the pharmaceutical industry), certain standards are of leading importance. It is important for such premises to use materials that do not affect the housing and communal services. The situation is similar for housing and communal services. Pipeline insulation is carried out in strict accordance with established standards, while reliability and safety of use must be ensured.
Domestic manufacturers of protective materials
Market thermal insulation materials diverse and able to satisfy the needs of any buyer. Products presented here
tion of both imported and domestic manufacturers. Russian companies are engaged in the production of the following types of thermal insulation materials:
Mats, which are fiberglass fabric stitched on both sides, lined with mineral wool or kraft paper;
Mineral wool products based on a corrugated structure (with its help, industrial insulation of pipelines is carried out);
Synthetic based;
Products based on glass staple synthetic fibers.
The largest producers of thermal insulation materials are: Termosteps OJSC, Nazarovo ZTI, Mineral Wool (CJSC), URSA-Eurasia OJSC.
Foreign manufacturers of materials
The products of foreign companies are also represented on the market of thermal insulation materials. Among them, the following stand out: "Partek", "Rockwool" (Denmark), "Paroc" (Finland), "Izomat" (Slovakia), "San-Gobain Izover" (Finland). They all specialize in various types and combinations of fibrous thermal insulation materials. The most common are mats, cylinders and slabs, which can be uncoated or coated on one side (for example, aluminum foil can be used as it).
Rubber and foam materials
The most widely used foam thermal insulation material is polyurethane foam. It is used in two forms: in the form of tile products and spraying, it is used mainly for protection in low-temperature production. Its developer is the Research Institute of Synthetic Resins (in Vladimir), and its subsidiary is ZAO Izolan. Pipeline insulation is also made with synthetic-based materials. In this case, equipment operating in conditions of negative and positive ambient temperatures is protected. The main suppliers of such materials are L’ISOLANTE K-FLEX and Armacell. Thermal insulation looks like tubes (cylinders) or plate-sheet products.
