Specialization: master of interior and exterior decoration (plaster, putty, tile, drywall, wall paneling, laminate, and so on). In addition, plumbing, heating, electrical, conventional cladding and balcony extensions. That is, repairs in an apartment or house were done on a turnkey basis with all the necessary types of work.
To begin with, the thermal insulation of pipelines of heating networks according to
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, on the way...
We heat pipes
Pipes can be heated not only with passive heaters, 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 offered and advertised option that you can find on the Internet is shells that are made from mineral wool, polystyrene foam or extruded polystyrene foam.
- Further in popularity, one can distinguish mineral (basalt) wool with waterproofing from roofing material 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 pillows are dry.
- The best option for pipe insulation is a warm room - a basement, a room in an apartment, or just a closed box.
- A heating cable that can be led directly into the pipe or wrapped around it from above - the effect, in fact, will 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 the best is to use liquid foam- and the price suits, and it's easy to do.
| Insulation material | Thermal conductivity (W/m⁰C) | Application temperature (⁰C) | Flammability group |
| Stitched mineral mats | 0,041-0,032 | From -180⁰C to +450⁰C for a fabric base and up to +700⁰C for a metal mesh base | non-combustible |
| Mats and wool from basalt thin fiber without binding elements | 0,031-0,24 | From – 180⁰C to +600⁰C | non-combustible |
| Extruded polystyrene materials | 0,032 | From – 180⁰C to +70⁰C | G3, G4 |
| From foam polymer minerals | 0,044 | From – 180⁰C to +150⁰C | G2 |
| From armored concrete | 0,05 | From – 180⁰C to +180⁰C | G2 |
| From armored concrete | 0,029-0,024 | From – 180⁰C to +130⁰C | G2-G4 |
| Made of polyethylene foam | 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, this does not 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, which rust when dampness enters, which leads to material subsidence.
I usually use two options for thermal insulation of pipes - polyethylene foam and mineral (basalt) wool. Of course, you can buy shells from this material in the store, and even with a foil surface, but it will be quite expensive.
It is much easier to use roll material, the thickness of which can be from 20 mm to 200 mm. You need to choose this parameter depending on the region of residence, that is, on the possible decrease in soil temperature in winter.
For underground pipe laying, of course, it is best to use the method of deepening, rather than insulation. If the pipeline runs 50 cm below the freezing point, then you do not need any insulation.
But there can be a real problem here - in the northern regions of Russia, the depth of soil freezing sometimes reaches more than 2m, so this option will not always be convenient.
As you understand, moisture in any case will be an excellent conductor of cold, therefore, without waterproofing, insulation of pipelines is only allowed indoors, as in the photo above. It can be either basements, but even there, in some cases, waterproofing is indispensable due to the same condensate.
Ruberoid is an excellent waterproofing
In order to insulate a pipeline with underground or air laying, 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 in winter.
To fix the material, it is very convenient to use a nylon thread - such a coil can be purchased, probably, in any store that sells building materials. But roofing material is best wrapped with any soft wire - the cheapest is steel knitting, but if you have stocks, then it can be aluminum or even copper.
In addition, it is best to make a sand cushion for underground laying of the pipeline and also fill it with sand 50-60 mm from above. Such a 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 very 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 carrier transported through them with the environment. Thermal insulation of pipelines is used not only in heating systems and hot water supply, but also where technology requires the 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 by means of 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. Only 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 an autonomous heating system. Only in a few northern regions, private houses are connected to the central heating main with heating pipes placed outside.
For some types of boilers, for example, powerful gas or diesel ones, the requirements of the set of rules SP 61.13330.2012 “Thermal insulation of equipment and pipelines” require a separate location from the building - in a boiler room several meters away from the heated object. In their case, the strapping fragment passing through the street necessarily needs to be insulated.
On the street, insulation of heating pipelines is required both for open ground placement and for hidden laying underground. The latter method is channel - a reinforced concrete gutter is first laid in the trench, and pipes are already placed in it. Channelless placement - directly in the ground. The insulating materials used differ not only in thermal conductivity, but also in vapor and water resistance, durability and installation methods.
The need to insulate cold water pipes is not so obvious. However, it cannot be dispensed with in the case when the water supply is laid in an open ground way - the pipes must be protected from freezing and subsequent damage. But inside buildings, it is also necessary to insulate water pipes - to prevent moisture condensation on them.
Glass wool, mineral wool
Proven insulating materials. They 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, similar in structure to crystals.
Glass wool is made from waste glass production, mineral wool from silicon-containing slag and silicate metallurgy waste. The differences in their properties are insignificant. They are produced in the form of rolls, stitched mats, plates and pressed cylinders.
It is important to be careful with materials and be able to handle them correctly. Any manipulations should be performed in protective overalls, gloves and a respirator.
Installation
The pipe is wrapped or lined with cotton wool, ensuring a uniform filling density over the entire surface. Then the insulation, without too much pressure, is fixed with a tie wire. The material is hygroscopic and easily gets wet, therefore, the 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 cover layer is placed on top of it, which prevents the penetration of precipitation - a casing made of roofing sheet, galvanized iron or sheet aluminum.
Basalt (stone) wool
Thicker than glass wool. The fibers are made from a melt of gabbro-basalt rocks. Absolutely non-combustible, briefly withstands temperatures up to 900 ° C. Not all insulating materials can, like basalt wool, be in long-term contact with surfaces heated to 700 ° C.
The thermal conductivity is comparable to polymers, ranging from 0.032 to 0.048 W/(m K). High performance indicators make it possible to use its thermal insulation properties not only for pipelines, but also for the arrangement of hot chimneys.
Available in several versions:
- like glass wool, rolls;
- in the form of mats (stitched rolls);
- in the form of cylindrical elements with one longitudinal slot;
- in the form of pressed cylinder fragments, the so-called shells.
The last two versions have different modifications, differing in density and presence heat reflective film. The slot of the cylinder and the edges of the shells can be made in the form of a spike connection. 
SP 61.13330.2012 contains an indication that the thermal insulation of pipelines must comply with safety and protection requirements environment. By itself, basalt wool fully complies with this indication.
Manufacturers often resort to tricks: to improve consumer performance - to give it hydrophobicity, greater density, 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 hygiene certificate.
Installation
Insulation fibers are stronger than those of glass wool, so the ingress of its particles into the body through the lungs or skin is almost impossible. However, when working, it is still recommended to use gloves and a respirator.
The installation of a roll web does not differ from the way in which glass wool heating pipes are insulated. Thermal protection in the form of shells and cylinders is attached to pipes using mounting tape or a wide bandage. Despite some hydrophobicity of basalt wool, pipes insulated with it also require a waterproof vapor-permeable sheath made of polyethylene or roofing material, and additional, 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, maximum withstand for a short time - 150 °C.
The main brands of PPU belong to the combustibility group G4 (highly combustible). When changing the composition with the help of the addition of fire retardants, they are assigned G3 (normally combustible).
Although polyurethane foam is great as insulating material for heating pipes, keep in mind that SP 61.13330.2012 allows the use of such thermal insulation only in single-apartment residential buildings, and SP 2.13130.2012 limits their height to two floors.
The heat-insulating 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 protective sheath made of polyethylene.
Installation
The shells are fixed on the heating pipe with the help of ties, clamps, plastic or metal bandage. Like many polymers, the material does not tolerate long-term exposure to sunlight, therefore, an open above-ground pipeline, when using PU foam shells, needs a cover layer, for example, from galvanized steel.
For underground channelless placement, heat-insulating products are laid on waterproof and temperature-resistant mastics or adhesives, and are insulated from the outside with a waterproof coating. It is also necessary to take care of the anti-corrosion surface treatment. metal pipes– even glued shell joints are not tight enough to prevent condensation of water vapor from the air.
Expanded polystyrene (polyfoam, PPS)
It is produced in the form of shells, outwardly practically no different from polyurethane foam - the same dimensions, the same tongue-and-groove locking connection. But the temperature range of application, from -100 to +80 ° C, with all this external similarity, makes it impossible or limited to use it for thermal insulation of a heating pipeline.
SNiP 41-01-2003 "Heating, ventilation and air conditioning" states that in the case of two-pipe system heating supply, the maximum supply temperature can reach 95°C. As for the return risers of heating, everything is not so simple here: 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 over other insulations with a higher allowable temperature applications.
The material has a number of disadvantages: it is highly combustible (even with the addition of fire retardants), it does not tolerate chemical influences (it dissolves in acetone), it crumbles with balls during prolonged exposure to solar radiation.
There are other, non-polystyrene foams - formaldehyde, or shortly, phenolic. In fact, this is a completely different material. It is devoid of these shortcomings, is successfully used as thermal insulation of pipelines, but is not so widespread.
Installation
The shells are fixed on the pipe with a bandage or foil tape, it is allowed to glue them to the pipe and to each other.
Foamed polyethylene
The temperature range at which the use of foamed high-pressure polyethylene is allowed is from -70 to +70 °С. The upper limit is not combined with the maximum temperature of the heating pipe, usually taken into account in the calculations. This means that the material is of little use as a thermal insulation of pipelines, but can be used as an insulating layer over a heat-resistant one.
Polyethylene foam insulation has found practically no alternative application 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. The standard length is 2 meters. The color varies from white to dark gray. An IR reflective aluminum foil coating may be available. The differences relate to internal diameters (from 15 to 114 mm), wall thickness (from 6 to 30 mm).
The application ensures that the temperature on the pipe is above the dew point, which means it prevents the formation of condensate.
Installation
An easy way with worse vapor barrier results is to cut the foam material into a small indentation along the side surface, open the edges and put it on the pipe. Then wrap along the entire length with mounting tape.
A more complicated solution (and by no means always feasible) is to turn off the water, completely disassemble the insulated sections of the water supply and put on solid sections. Then put everything back together. Secure the polyethylene with zip ties. In this case, only the junction of the segments will become a weak point. It can be glued or also wrapped with tape.
foamed rubber
Foamed synthetic rubber with a closed cell structure is the most versatile material for keeping warm and cold. Designed for temperature range from -200 to +150 °C. Conforms to all requirements of ecological safety.
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.
Outwardly similar to polyethylene foam, it is also available in the form of sheets and flexible thick-walled pipes. Installation is also practically the same, except that such thermal insulation of pipes can be attached to glue.
Liquid heaters
A technology has been successfully applied that allows self-spraying 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 need insulation: foundation, walls, roofing. The coating, in addition to thermal protection, provides hydro, vapor barrier, provides anti-corrosion resistance.
Conclusion
Properly performed installation of thermal insulation is a guarantee that the pipe will not lose heat, and the consumer will not freeze. Freezing of the cold water supply pipeline invariably leads to its rupture. Until recently, in hidden and open heating mains, glass wool was the usual insulating material. Its shortcomings stem from one another. Such coverage requires constant monitoring.
Even with a slight damage to the protective surface layer, vapor permeability and hygroscopicity nullify all savings. Moisture causes low thermal resistance and premature failure. Modern insulating materials with a cellular structure that are inert to the effects of steam and water will help to significantly improve the situation: polyurethane foam, foamed rubber, polyethylene foam.
When performing work on equipment and installation of pipelines, it is necessary to comply with the norms of SNiP. What is SNiP? These are building norms and rules for the organization of construction production, for compliance with standards, specifications and regulatory departmental acts.
Basic norms and rules for thermal insulation
Heating network is one of the main elements of district heating. It is necessary to strictly adhere to the rules and regulations when drafting the thermal insulation of pipelines. Subject to SNiP, thermal insulation of pipelines will be carried out qualitatively 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, industrial buildings requires strict compliance with design standards and a fire safety system.
The quality of materials must comply with SNiP, thermal insulation of pipelines must 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 pipelines with hot water supply. The main function of the insulation is to prevent 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 provide a certain temperature on the surface of the insulation, and in case of stagnant water, protect it from freezing and icing in the winter.
Insulation of pipelines also increases the life of pipes.
According to the norms of SNiP, thermal insulation of pipelines is used both for centralized heating and reduces heat losses from in-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, semi-cylinders or soft mats in rolls. Insulation of pipes of small diameter is mainly carried out using cylinders and half-cylinders.
- Heat carrier temperature.
- The conditions under which the pipes will be operated.
Types of heaters
Consider the most popular and commonly used materials for thermal insulation:
- Fiberglass. Glass fiber materials are often used for above ground pipelines 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. Thermal insulation of pipelines with mineral wool is a very effective heat insulator. This insulating material will be 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 are preserved. Mineral wool does not lose its shape, has a high resistance to chemical attack, 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 with mineral wool is mainly used in residential buildings, public and domestic premises, as well as to protect surfaces that are heated.
- Polyurethane foam has a wide range of applications, but is a rather expensive material. According to the norms of SNiP, 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.
- Styrofoam. In some areas of industry, foam 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, the insulation of pipelines can also be carried out using other less well-known, but no less practical heaters, such as foam glass and penoizol. These materials are strong, safe and are close relatives of Styrofoam.
Corrosion protection and high thermal insulation of pipes can also be provided by heat-insulating paint.
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 differences.
dom-data.com
Features of thermal insulation of pipelines for heating networks: standards, materials, technology
When laying pipelines, a prerequisite is the performance of work on the thermal insulation of networks. This applies to all pipelines - not only water supply, but also sewage systems. The need for this is due to the fact that winter time water passing through pipes can freeze. And if a coolant circulates through the communications, then this leads to a decrease in its temperature. To minimize heat loss, when laying pipelines, they resort to the device of 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
It is possible to provide effective protection for piping systems from environmental factors, mainly from the temperature of the outside air, if the following measures are taken:
Since the latter method is most often used, it makes sense to talk about it in more detail.
Norms for thermal insulation of pipelines
Requirements for thermal insulation of equipment pipelines are formulated in SNiP. The regulations contain detailed information about the materials 
which can be used for thermal insulation of pipelines, and besides this, methods of work. In addition, the regulatory documents indicate standards for thermal insulation circuits, which are often used to insulate pipelines.
- regardless of what temperature the coolant has, any piping system must be insulated;
- both ready-made and prefabricated structures can be used to create a heat-insulating layer;
- corrosion protection shall be provided for metal parts of pipelines.
It is desirable to use a multilayer circuit design for pipeline insulation. 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 deformation of the pipes.
Note that most of the requirements contained in regulatory documents relate to the insulation of main pipelines high power. But even in the case of installation of household systems, it would be useful to familiarize yourself with them and take them into account when installing sewage water supply systems on your own.
Materials for thermal insulation of pipelines
At the moment, the market offers a large selection of materials that can be used to insulate pipelines. Each of them has its own advantages and disadvantages, and besides this, and application features. To choose the right heat insulator, you need to know all this.
Polymer heaters
When the task is to create an effective system of thermal insulation of pipelines, most often attention is paid to foam-based polymers. A large assortment allows you to choose the right material, thanks to which you can provide effective protection from the external environment and eliminate heat loss.
If we talk in more detail about polymeric materials, then the following can be distinguished from those available on the market.
Polyethylene foam.
The main characteristic of the material is its 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 performed even by people who are far from the sphere of thermal insulation of pipelines. However, this material is characterized by one drawback: structures made of polyethylene foam have rapid wear and, in addition, have poor heat resistance.
If polyethylene foam cylinders are chosen for the 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 the design of insulation, it is possible to exclude spontaneous removal of casings from polyethylene foam.
Styrofoam.
The main feature of this material is elasticity. It is also characterized by high strength indicators. Protective products for thermal insulation of pipelines from this material are produced in the form of segments that resemble shells in their appearance. Special locks are used to connect parts. They have spikes and grooves, which ensure the speed of installation of these products. The use of a shell made of expanded polystyrene 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 mainly used for pre-installed thermal insulation of pipelines of heating networks. However, it can also be used for warming domestic piping systems. This material is available in the form of foam or shell, which consists of two or four segments. Insulation by spraying provides reliable thermal insulation with a high degree of tightness. The use of such insulation is most suitable for communication systems that have a complex configuration.
Using polyurethane foam in the form of foam for thermal insulation of pipelines of heating networks, it is necessary to know that it is destroyed under the influence of ultraviolet rays. Therefore, in order for the insulating layer to serve for a long time, it is necessary to ensure its protection. To do this, a layer of paint is applied over the foam or a non-woven fabric with good permeability is laid.
Fiber materials
Heaters of this type are mainly represented by mineral wool and its varieties. At the moment, among consumers, they are most popular as a heater. Materials of this type are also in high demand, as well as polymeric materials.
For thermal insulation, performed using fibrous insulation, certain advantages are characteristic. These include the following:
- low coefficient of thermal conductivity;
- resistance of the heat-insulating material to the effects of such aggressive substances as acids, alkalis, oil;
- material in a state without additional frame maintain a given shape;
- the cost of insulation is quite acceptable and affordable for most consumers.
Please note that during work on the thermal insulation of pipelines with such materials, it is necessary to exclude compression of the fiber when laying the insulation. It is also important to ensure that the material is protected from moisture.
Products for thermal insulation made from polymer and mineral wool insulation can in some cases be covered with aluminum or steel foil. The use of such screens reduces heat dissipation.
Laminated structures for protecting pipelines
Often, for the insulation of pipelines, thermal insulation is arranged according to the "pipe in pipe" method. When using this scheme, a heat shield is installed. The main task of the specialists who install such a circuit is to correctly connect all the parts into a single structure.
At the end of the work, a structure is obtained that looks like this:
- a pipe made of metal or polymer material acts as the basis of the heat-protective circuit. She happens to be bearing element the entire device;
- the heat-insulating layers of the structure are made of foamed polyurethane foam. The application of the material is carried out according to the pouring technology, a specially created formwork is filled with the molten mass;
- protective cover. Pipes made of galvanized steel or polyethylene are used for its manufacture. The first are used for laying networks in open space. The latter are used in cases where pipeline systems are laid in the ground using channelless technology. In addition, often when creating this type of protective casing, copper conductors are laid in polyurethane foam insulation, the main purpose of which is remote control the state of the pipeline, including the integrity of the thermal insulation layer;
- if the pipes are delivered to the installation site assembled, then the welding method is used to connect them. Experts use special heat-shrink cuffs to assemble a heat-protective circuit. Or overhead sleeves made from mineral wool, which are covered with a layer of foil, can be used.
Do-it-yourself thermal insulation device for pipelines
There are a number of factors on which the technology of creating a heat-insulating layer on pipelines may depend. One of the most important is how the collector is laid - outside or its installation is carried out 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 the outer pipeline
In accordance with existing regulations, pipelines located on the surface of the earth are thermally insulated as follows:
- insulation work begins with the fact that all parts are cleaned of rust;
- then the pipes are treated with an anti-corrosion compound. After that, they proceed to the installation of a polymer shell, followed by pipe wrapping roll insulation from mineral wool;
- please note that a layer of polyurethane foam can be used to cover the structure, or it is possible to cover the structure with several layers thermal insulation paint;
- the next step is to wrap the pipe as in the previous version.
Along with fiberglass, other materials can be used, for example, foil film with polymer reinforcement. When this work is done, the structures are fixed 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, it is necessary to adhere to the technology of work. In this case, heat loss will be minimal, and in addition, the pipeline structure will be protected from various factors, which will positively affect 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 the normal operation of networks in the winter, since the likelihood of freezing and failure of pipes is quite high and, moreover, dangerous.
According to existing norms, as well as the rules for the safe operation of steam and hot water pipes, for pipeline elements with a wall temperature of more than 55 degrees and at the same time they are in accessible places, it is recommended to use additional thermal insulation in such a way as to reduce their heating. In view of this, during calculations of the thickness of the protective coating laid in the room, the norms of the heat flux density 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, it is quite realistic to significantly reduce heat losses, as well as make the operation of systems reliable and absolutely safe.
Figure #1. Thermal insulation of pipes with foam plastic
What to pay attention to when calculating:
- - the difference in ambient temperatures where communications are used;
- - the temperature of the surface to be insulated;
- - possible loads falling on the pipes;
- - mechanical influences from external influences, whether it be pressure, vibration, etc.;
- - the value of the coefficient of thermal conductivity of the applied insulation;
- - impact and corresponding magnitude from traffic and soil;
- - the ability of the insulator to resist various kinds of deformation.
It should be noted that SNiP 41-03-2003 is considered the main document on the basis of which materials for insulation are selected, their thickness, according to specific operating conditions. The same SNiP says that for networks in which the operating temperature of the pipes is less than 12 degrees, it is necessary to additionally lay vapor barrier during surface treatment.
Thermal insulation of pipes can be calculated in two ways, while each option can be called reliable and convenient for specific conditions. We are talking about the engineering (formula) and online version.
In the first case, the actual thickness of the optimal insulation layer is determined by a technical and economic calculation, in which the main parameter is the temperature resistance. The corresponding value should be within 0.86ºC m²/W for pipes up to 25mm in diameter, and not less than 1.22ºC m²/W for 25mm and above. SNiP provides for special formulas, according to 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 acceptable. Otherwise, a situation may arise when the amount of certain actions may be more costly in terms of money than doing everything from scratch.
At self-fulfillment works, it should also be understood that all calculations of the thickness of pipe insulation are made under certain operating conditions, which take into account the materials themselves, and temperature changes, and humidity.
The second method is implemented through online calculators, which today are countless. 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 the calculation. All calculations are carried out quickly and accurately. Understanding how to use the calculator will turn out without much difficulty.
Initially, the required task is selected:
- 1. Prevention of freezing of the liquid of the pipeline of engineering networks.
- 2. Ensuring a constant operating temperature of the protective insulation.
- 3. Warming of communications of water heating networks of two-pipe underground channel laying.
- 4. Protection of the pipeline from the formation of condensate on the insulator.
Then you need to enter the main parameters, through which the calculation is carried out:
- 1. Outer diameter of the pipe.
- 2. Preferred insulation component.
- 3. The time during which water crystallizes in an inert state.
- 4. Temperature indicator of the surface to be insulated.
- 5. The value of the coolant temperature.
- 6. Type of coating used (metal or non-metal).
After entering all the data, the result of the calculations appears, which can be taken as a basis in the subsequent construction and selection of materials.
Figure #2. Thermal insulation of central heating pipes
Choosing the right heater
The main reason for the 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. That is why thermal insulation of networks is essential.
Particular attention should be paid to this aspect in pipelines that operate periodically, whether it is water supply from a well or country water heating. In order not to have to subsequently restore working systems, it is better, after all, to perform their timely thermal insulation.
Until recently, insulation work was carried out using a single technology, while as protective element fiberglass was used. At present, a huge selection of various heat insulators is offered, designed for a certain type of pipes, having various specifications and composition.
In view of their direction of application, 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;
- - pouring
- - casing;
- - combined.
By area of use:
- - for water and sewerage;
- - for supply networks of steam, heating, hot and cold water;
- - for ventilation pipelines and freezing units.
Any thermal insulation is characterized by resistance to fire and its thermal conductivity.
- 1. Shell. Its advantage is ease of installation, optimal performance and high quality workmanship. Differs in low heat conductivity, fire resistance, the minimum level of moisture absorption. Suitable for protection of heating networks and water supply systems.
Figure #3. Insulation for pipes shell
- 2. Mineral wool. It is usually supplied in rolls and is used to process pipes whose coolant has a very high temperature. This option is advisable only for small areas of processing, since mineral wool is a rather expensive material. Its laying is carried out by winding communications with fixation in a given position with stainless steel wire or twine. Additionally, it is recommended to perform waterproofing, since cotton wool easily absorbs moisture.
Figure #4. Insulation mineral wool cylinder
- 3. Styrofoam. The design of this type of thermal insulation is more like two halves, or a shell, through which the pipeline is insulated. The option can be safely called high-quality and convenient in terms of installation. Due to minimal moisture absorption and low thermal conductivity, high fire resistance, minimal thickness, expanded polystyrene is excellent for protecting heating and water supply networks.
Figure #5. Insulation foam
- 4. Penoizol. Thermal insulation has similar parameters with polystyrene foam, although with a significant difference in installation. The application is carried out by means of 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, which reliably maintains the temperature of the coolant. A significant advantage is the absence of the need to use additional fasteners to fix the material. The downside is, perhaps, its high cost.
Figure #6. Insulation of pipes with foam insulation
- 5. Penofol with a foil base. An innovative product that is becoming more and more popular every day. It consists of polyethylene foam and aluminum foil. The two-layer design allows both to keep the temperature of the networks and to heat the space, since the foil is able to reflect and accumulate heat. We especially pay attention to low combustion ability, high environmental data, ability to withstand high humidity and significant temperature fluctuations.
Figure #7. Pipe insulated with foil foam
- 6. Foamed polyethylene. Thermal insulation of this type is very common, and it is often found on water mains. A feature is the ease of installation, for which it is enough to cut off the desired size of the material and wrap it around the technological line, with fixation with adhesive tape. Often foamed polyethylene is supplied in the form of a pipe wrap for a certain diameter with a technological cut, which is put on the desired section of the system.
Figure #8. Foamed polyethylene
It is important to know that when insulating pipelines, all heaters, except for penoizol, require the additional use of waterproofing and adhesive tape for fixing.
From the foregoing, it can be seen that there are 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, a competent thermal insulation calculation also plays an important role, which will allow you to be confident in the work performed.
Video #1. Thermal insulation of pipes. Mounting example
Ways of thermal insulation of pipelines
SNiP specifications and many professionals recommend following the following trunk line protection options:
- 1. Air insulation. Usually, communication systems passing in the ground are protected by thermal insulation. certain thickness. However, the factor that the freezing of the earth goes from the top point 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 minimum thickness, the rising heat is also insulated. It is more rational in this case to install a heater above the upper part of the line, so that a thermal layer is formed.
- 2. Use of a heater and a heating element. Great as an alternative to traditional options. In this case, the moment is taken into account that the protection of the lines is seasonal, and it is not rational to lay them in the ground for financial reasons, as well as to use a large thickness of the insulator. According to the rules of SNiP and manufacturers' instructions, the cable can be located both inside the pipes and outside them.
- 3. Laying a pipe in a pipe. Here, in polypropylene pipes additional pipes are installed. A feature of the method is that it is practically always possible to warm up the systems, including using the principle of suction of warm air masses. In addition, if necessary, an emergency hose can be easily laid in the existing gap.
Conclusion
Summing up 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. Not the last role is played by the option of its installation, 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, in the end, can lead to minimal cost and reduce 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 #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 spread across the premises of the main house, but also stretched to other nearby buildings. These can be residential outbuildings, outbuildings, summer kitchens, utility or agricultural buildings, for example, used for keeping pets or birds. The option is not excluded when, on the contrary, the autonomous boiler house itself is located in separate building, at some distance from the main residential building. It happens that the house is connected to the central heating main, from which pipes are stretched to it.
The laying of heating pipes between buildings is possible in two ways - underground (channel or channelless) and open. The process of installing a local heating main above the ground seems to be less time-consuming, and this option, under conditions self construction come running more often. One of the main conditions for the efficiency of the system is a properly planned and well-executed thermal insulation for heating pipes on outdoors. This is the question that will be considered in this publication.
Why do we need thermal insulation of pipes and the basic requirements for it
It would seem nonsense - why insulate the already almost always hot pipes of the heating system? Perhaps someone can be misled by a kind of "play on words." In the case under consideration, of course, it would be more correct to conduct a 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 the reduction of heat losses, maintaining the required temperature of the pumped liquid comes to the fore. The same principle is also valid for industrial or laboratory installations, where the technology requires maintaining a certain temperature of the substance transferred through the pipes.
- For pipelines of cold water supply or sewer communications, it is insulation that becomes the main factor, 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 for both heating mains and hot water pipes - no one is completely immune from emergencies on boiler equipment.
Herself cylindrical shape pipes predetermines a very considerable area of constant heat exchange with the environment, which means significant heat losses. And they, of course, grow as the diameter of the pipeline increases. The table below clearly shows how the value of heat loss changes depending on the temperature difference inside and outside the pipe (column Δt °), on the diameter of the pipes and on the thickness of the thermal insulation layer (data are given taking into account the use of insulation material with an average coefficient of thermal conductivity 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 running 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 total heat loss 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 insulating materials with the lowest possible coefficient of thermal conductivity - this is one of the main requirements for thermal insulation of pipelines.
Sometimes a pipe heating system is also required!
When laying water or sewer communications, it happens that, due to the peculiarities of 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 of our portal.
- The material that is used for thermal insulation of pipes, if possible, should have hydrophobic qualities. There will be little current from a heater soaked with water - it will not prevent heat loss either, and it 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 a heater is used that can actively absorb water. Secondly, materials should be protected from exposure to the ultraviolet spectrum of sunlight, which is detrimental to them. Thirdly, one should not forget about the wind load that can violate the integrity of 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, for any owner of a private house, for sure, the moments of the aesthetic appearance of the laid heating main are also not indifferent.
- Any thermal insulation material used on heating mains must have a range of operating temperatures corresponding to the actual conditions of use.
- An important requirement for the insulation material and its outer lining is the 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, and in any position and in any complex area. Fortunately, in this regard, manufacturers do not get tired of pleasing user-friendly developments.
- An important requirement for thermal insulation is that its materials must themselves be chemically inert and not enter into any reactions with the pipe surface. Such compatibility is the key to the duration of trouble-free operation.
The issue of cost is also very important. But in this regard, the range of prices for specialized ones is very large.
What materials are used to insulate aboveground heating mains
The choice of thermal insulation materials for heating pipes for their external laying is quite large. They are of a roll type or in the form of mats, they can be given a cylindrical or other figured shape convenient for installation, there are heaters that are applied in liquid form and acquire their properties only after solidification.
Insulation with polyethylene foam
Foamed polyethylene is rightly referred to as a very effective thermal insulator. And more importantly, the cost of this material is one of the lowest.
The coefficient of thermal conductivity of foamed polyethylene is usually in the region of 0.035 W / m × ° C - this is a very good indicator. The smallest gas-filled bubbles isolated from each other create an elastic structure, and with such material, if its rolled version is purchased, it is very convenient to work on pipe sections with complex configurations.
Such a structure becomes a reliable barrier to moisture - with proper installation, neither water nor water vapor can penetrate through it to the pipe walls.
The density of polyethylene foam is low (about 30 - 35 kg / m³), and thermal insulation does not make the pipes heavier.
The material, with some assumption, can be categorized 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 fades. Moreover, combustion products, unlike many other thermal insulators, do not pose any serious toxic hazard to humans.
Rolled polyethylene foam for insulating external heating mains will be both inconvenient and unprofitable - you will have to wind several layers in order to achieve the required thermal insulation thickness. It is much more convenient to use material in the form of sleeves (cylinders), in which an internal channel is provided that corresponds to the diameter of the insulated pipe. For putting on pipes, usually an incision is made along the length of the cylinder on the wall, which, after installation, can be sealed with reliable adhesive tape.
Putting insulation on the pipe is not difficult A more effective type of polyethylene foam is penofol, which has 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 profiled cylindrical elements - especially for thermal insulation of pipes for various purposes.
And all foamed polyethylene for thermal insulation of heating mains is used infrequently. It is more suitable for other communications. The reason for this is a rather low temperature range of operation. So. if you look at physical characteristics, then the upper limit balances somewhere on the verge of 75 ÷ 85 degrees - higher, violations of the structure and the appearance of deformations are possible. For autonomous heating, most often, such a temperature is enough, however, on the verge, and for the central one, thermal stability is clearly not enough.
Expanded polystyrene insulation elements
The well-known expanded polystyrene (in everyday life it is often called polystyrene foam) is very widely used for the most different types thermal insulation work. Pipe insulation is no exception - for this, special parts are made of foam plastic.
Usually these are semi-cylinders (for pipes of large diameters there may be segments of a third of the circumference, 120 ° each), which are equipped with a tongue-and-groove lock for assembly into a single structure. This configuration allows you to completely, over the entire surface of the pipe, provide reliable thermal insulation, without the remaining "cold bridges".
In everyday speech, such details are called "shells" - for their clear resemblance to it. Many types of it are produced, for different outer diameters of insulated pipes and different thicknesses of the thermal insulation layer. Usually the length of the parts is 1000 or 2000 mm.
For the manufacture of polystyrene foam type PSB-S 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 | Styrofoam brand | ||||
|---|---|---|---|---|---|
| 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 than) | 0.08 | 0.12 | 0.17 | 0.36 | 0.35 |
| Dry thermal conductivity 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 |
The advantages of polystyrene foam as an insulating material have long been known:
- It has a low thermal conductivity.
- The low weight of the material greatly simplifies the 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 fungus.
- Moisture absorption is negligible.
- The material is easy to cut, fit to the desired size.
- Polyfoam is chemically inert, absolutely safe for pipe walls, no matter what material they are made of.
- One of the key advantages - polystyrene is one of the most inexpensive heaters.
However, it also has many disadvantages:
- First of all, it is a low level of fire safety. The material cannot be called non-combustible and does not spread flame. That is why when using it for warming 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 the pipe. True, you can find special curly details.
- Polyfoam does not belong to durable materials - it is easily destroyed under external influence. Ultraviolet radiation also has a negative effect on it. In a word, the above-ground sections of the pipe, insulated with polystyrene foam shells, will definitely require additional protection in the form of a metal casing.
Usually, in stores that sell foam shells, they also offer galvanized sheets, cut into the desired size, corresponding to the diameter of the insulation. An aluminum shell can also be used, although it is certainly much more expensive. Sheets can be fixed 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 even this is not the main thing. The upper limit of normal temperatures for operation is only around 75 ° C, after which linear and spatial deformation of parts can begin. Like it or not, this value may not be enough for heating. Perhaps it 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 with the use of mineral wool. By the way, it is also the most budgetary, 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 wool is the least preferred: firstly, it most actively absorbs moisture, and secondly, its residual acidity can be very destructive to steel pipes. Even the cheapness of this cotton wool does not at all justify the risks of its use.
But mineral wool based on basalt or glass fibers is fully suitable. It has good indicators of thermal resistance to heat transfer, high chemical resistance, the material is elastic, and it is easy to lay it even on complex sections of pipelines. Another advantage - you can be, in principle, completely calm in terms of fire safety. It is almost impossible to heat up mineral wool to the degree of ignition in the conditions of an external heating main. Even exposure to an open flame will not cause the spread of fire. That is why mineral wool is used to fill fire gaps when using other pipe insulation.
The main disadvantage of mineral wool is its high water absorption (basalt is less susceptible to this “ailment”). This means that any pipeline will require mandatory protection from moisture. In addition, the structure of wool is not resistant to mechanical stress, it is easily destroyed, and it should be protected with a strong casing.
Usually, a strong polyethylene film is used, which is securely wrapped with a layer of insulation, with the obligatory overlap of the strips by 400 ÷ 500 mm, and then all this is closed from above metal sheets- exactly by analogy with the polystyrene shell. Roofing material can also be used as a waterproofing - in this case, 100 ÷ 150 mm of overlap of one strip on another will be enough.
The existing GOSTs define the thickness of the protective metal coatings for open sections of pipelines with any type of thermal insulation materials used:
| Cover material | The minimum thickness of the metal, with the outer diameter of the 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 |
| Sheet steel, galvanized or color coated | 0.5 | 0.8 | 0.8 |
| Sheets of aluminum or aluminum alloys | 0.3 | 0.5 | 0.8 |
| Tapes made of aluminum or aluminum alloys | 0.25 | - | - |
Thus, despite the seemingly inexpensive price of the insulation itself, its full installation will require considerable additional costs.
Mineral wool for pipeline insulation can also act in a different 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 turns, tees, etc.
Typically, such insulating parts are made of the most dense - basalt mineral wool, have an external foil coating, which immediately removes 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 against accidental or intentional mechanical impact.
Warming of the heating main with polyurethane foam
One of the most effective and safest modern insulation materials in operation is polyurethane foam. He 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 insulation of pipelines can be used in various types.
- PPU-shell is widely used, usually having an external foil coating. It can be collapsible, consisting of half-cylinders with tongue-and-groove locks, or, for pipes of small diameter, 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 insulate a heating main with polyurethane foam is to spray it in liquid form using special equipment. The resulting foam layer after complete hardening becomes an excellent insulation. This technology is especially convenient at complex interchanges, pipe bends, in nodes with shut-off and control valves, etc.
The advantage of this technology is also that due to the excellent adhesion of polyurethane foam spraying to the pipe surface, excellent waterproofing and corrosion protection are created. True, 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 best choice would be to use pre-insulated (pre-insulated) pipes.
In fact, such pipes are a multilayer structure assembled at the factory:
- The inner layer is, in fact, the steel pipe itself of the required diameter, through which the coolant is pumped.
- External coating - protective. It can be polymeric (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 assembly section was left at both ends of the pipe for welding during the assembly of the heating main. Its length is calculated in such a way that the heat flux from the welding arc will not damage the polyurethane foam layer.
After the installation, the remaining non-insulated areas are primed, covered with a polyurethane foam shell, and then with metal belts, comparing the coating with the common outer casing of the pipe. Often, it is in such areas that fire breaks are organized - they are densely filled with mineral wool, then they are waterproofed with roofing material and still covered with a steel or aluminum casing from above.
The standards establish a certain assortment of such sandwich pipes, that is, it is possible to purchase products of the desired nominal diameter with optimal (normal or reinforced) thermal insulation.
| Steel pipe outer diameter and minimum wall thickness (mm) | Dimensions of galvanized sheet steel sheath | Estimated thickness of the thermal insulation layer of polyurethane foam (mm) | |
|---|---|---|---|
| nominal outside 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 with their purchase and installation, a whole range of problems is solved at once. So these costs seem to be quite justified.
Video: production process of pre-insulated pipes
Insulation - foamed rubber
very popular in Lately become thermal insulation materials and products made of synthetic foam rubber. This material has whole line advantages that bring it to a leading position in the issues of insulation of pipelines, including not only heating mains, but also more responsible ones - on complex technological lines, in machine, aircraft and shipbuilding:
- Foamed rubber is very elastic, but at the same time it has a large margin of tensile strength.
- The density of the material is only from 40 to 80 kg / m³.
- The low thermal conductivity 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, it never contains any foci of mold or fungus, or nests of insects or
- The most important quality is almost absolute water and vapor impermeability. Thus, the insulation layer immediately becomes an excellent waterproofing for the pipe surface.
Such thermal insulation can be produced in the form of hollow tubes with an internal diameter of 6 to 160 mm and a layer thickness of insulation from 6 to 32 mm, or in the form of sheets, which are often given the function of "self-adhesive" 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 °С |
| Thermal conductivity, W / (m × ° С): | λ≤0.036 at 0°C |
| λ≤0.039 at +40°C | |
| Vapor permeability coefficient: | μ≥7000 |
| Degree of fire hazard | Group G1 |
| Permissible length change: | ±1.5% |
But for outdoor heating mains, ready-made insulation elements made using the Armaflex ACE technology, with a special protective coating ArmaChek, are especially convenient.
Coating "ArmaChek" can be of several types, for example:
- Arma-Chek Silver is a multi-layered PVC-based shell with a silver reflective coating. This coating provides excellent insulation protection against both mechanical stress and ultraviolet rays.
- The black "Arma-Chek D" finish has a high strength fiberglass backing that retains excellent flexibility. This is an excellent protection against all possible chemical, weather, mechanical influences, which will keep the heating pipe intact.
Typically, such products using ArmaChek technology have self-adhesive valves that hermetically “seal” the insulating cylinder on the pipe body. Figured elements are also produced, allowing installation on difficult sections of the heating main. Skillful use of such thermal insulation allows you to quickly and reliably mount it without resorting to the creation of an additional external protective casing - there is simply no need for it.
Probably the only thing that hinders the widespread use of such thermal insulation products for pipelines is the still prohibitively high price for real, "brand" products.
Prices for thermal insulation for pipes
Thermal insulation for pipes
A new direction in insulation - heat-insulating paint
Can't miss another one modern technology insulation. And it is 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, without any doubt, is an "alien" from the field of space technology. It is in this scientific and technical branch that the issues of thermal insulation from critically low (in open 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 look.
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 qualities.
| Names of indicators | Unit | Value |
|---|---|---|
| paint color | white (can be customized) | |
| Appearance after application and complete curing | matt, even, uniform surface | |
| Flexural elasticity of the film | mm | 1 |
| Adhesion of the coating according to the force of separation from the painted surface | ||
| - to the concrete surface | MPa | 1.28 |
| - to the brick surface | MPa | 2 |
| - to steel | MPa | 1.2 |
| Coating resistance to temperature difference from -40 °С to + 80 °С | without changes | |
| Resistance of the coating to the effects of temperature +200 °C for 1.5 hours | no yellowing, cracks, peeling or blisters | |
| Durability for concrete and metal surfaces in a moderately cold climatic region (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 | °С | from - 60 to + 260 |
Such a coating does not require additional protective layers - it is strong enough to cope with all the impacts on its own.
Such a liquid insulation is implemented in plastic jars (buckets), as well as regular paint. There are several manufacturers, and among the domestic brands, the brands "Bronya" and "Korund" can be especially noted.
Such 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, the climatic region, the diameter of the pipes, the average temperature of the pumped coolant.
Many experts believe that such heaters will eventually replace the usual thermal insulation materials on a mineral or organic basis.
Video: presentation of ultra-thin thermal insulation brand "Korund"
Thermal insulation paint prices
Thermal insulation paint
What thickness of heating mains insulation is required
Summing up the review of the materials used for thermal insulation of heating pipes, you can see the performance indicators of the most popular of them in the table - for clarity of comparison:
| Thermal insulation material or product | Average density in 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 pierced plates | 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-combustible |
| 150 | 0,05 | 0.048 ÷ 0.037 | |||
| Heat-insulating slabs of mineral wool on a synthetic binder | 65 | 0.04 | 0.039 ÷ 0.03 | From - 60 to + 400 | non-combustible |
| 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 | Slightly combustible |
| Semi-cylinders and mineral wool cylinders | 50 | 0,04 | 0.039 ÷ 0.029 | From - 180 to + 400 | non-combustible |
| 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-combustible, the rest are slightly combustible |
| Glass staple fiber mats with synthetic binder | 50 | 0,04 | 0.039 ÷ 0.029 | From - 60 to + 180 | non-combustible |
| 70 | 0,042 | 0.041 ÷ 0.03 | |||
| Mats and wool made of superfine glass fiber without binder | 70 | 0,033 | 0.032 ÷ 0.024 | From - 180 to + 400 | non-combustible |
| Mats and wool made of super-thin basalt fiber without a binder | 80 | 0,032 | 0.031 ÷ 0.024 | From - 180 to + 600 | Non-combustible |
| Perlite sand, expanded, fine | 110 | 0,052 | 0.051 ÷ 0.038 | From - 180 to + 875 | non-combustible |
| 150 | 0,055 | 0.054 ÷ 0.04 | |||
| 225 | 0,058 | 0.057 ÷ 0.042 | |||
| Thermal insulation products made of expanded polystyrene | 30 | 0,033 | 0.032 ÷ 0.024 | From - 180 to + 70 | combustible |
| 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 | combustible |
| 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 | combustible |
But for sure, an inquisitive reader will ask: where is the answer to one of the main questions that arise - what should be the thickness of the insulation?
This question is quite complex, and there is no single answer to it. If you wish, 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 down the required thickness, calculated for a particular region. And if mineral wool insulation is used, then you can use the data of the tables that are given in a special Code of Rules, which is designed specifically for thermal insulation of pipelines and process equipment. This document is easy to find on the web by entering a search query "SP 41-103-2000".
Here, for example, is a table from this handbook regarding the above-ground placement of the pipeline in the Central region of Russia, using mats made of glass staple fiber grade M-35, 50:
| Outer diameter pipeline, mm | Type of heating pipe | |||||
|---|---|---|---|---|---|---|
| innings | return line | innings | return line | innings | return line | |
| Average temperature regime coolant, °С | ||||||
| 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 |
Similarly, you can find the desired 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 insulation layer for pipelines are also determined:
| Outer diameter of the pipeline, mm | Maximum thickness of the 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 about one important nuance. The fact is that any insulation with a fibrous structure inevitably shrinks over time. And 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 amendment for shrinkage.
To calculate, you can apply the following formula:
H = ((D + h) : (D + 2 h)) × h× Kc
H- the thickness of the mineral wool layer, taking into account the correction for compaction.
D- outer diameter of the pipe to be insulated;
h- the required thickness of insulation according to the table of the Code of Practice.
Ks- coefficient of shrinkage (compaction) of fibrous insulation. It is a calculated constant whose value can be taken from the table below:
| Thermal insulation materials and products | Compaction factor Kc. |
|---|---|
| Mineral wool mats | 1.2 |
| Heat-insulating mats "TEHMAT" | 1.35 ÷ 1.2 |
| Mats and canvases made of super-thin basalt fiber when laying on pipelines and equipment with nominal diameter, mm: | |
| Doo | 3 |
| 1,5 | |
| DN ≥ 800 at 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 |
| Glass staple fiber mats "URSA" brand: | |
| M-11: | |
| ̶ for pipes with DN up to 40 mm | 4,0 |
| ̶ for pipes with DN from 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 boards on a synthetic binder brand: | |
| 35, 50 | 1.5 |
| 75 | 1.2 |
| 100 | 1.10 |
| 125 | 1.05 |
| Glass staple fiber board grades: | |
| P-30 | 1.1 |
| P-15, P-17 and P-20 | 1.2 |
To help the interested reader, a special calculator is placed below, in which the indicated ratio is already included. It is worth entering the requested parameters - and immediately get the required thickness of mineral wool insulation, taking into account the amendment.
At the heart of each technological process is 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 apparatuses, tanks for storing various liquids, in various exchangers and pumps. Particularly high requirements for thermal insulation are distinguished by the use of cryogenic and low-temperature equipment. 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 the SNiP. Thermal ensures the preservation of the invariance of the set parameters, at which they occur, as well as their safety, 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 choice of material and installation. They are collected in SNiP. The insulation of pipelines must comply with the norms, since the normal functioning of many systems depends on this. Almost all requirements listed in the documentation are mandatory. In most cases, the thermal insulation of heat pipelines is a key factor for the smooth operation and functioning of energy, housing and communal services and industry facilities. An additional quality that the thermal insulation of pipelines has is to meet the requirements applied in the field of energy saving. Competent, performed according to all standards, pipeline insulation reduces heat losses during its transfer from the supplier to the final consumer (for example, when providing hot water services in the housing and communal services system), which in turn reduces overall energy costs.
Building requirements
The installation and operation of thermal insulation structures directly depend on their purpose and installation site. There are a number of factors that affect them. 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, accounting for them is basic in the construction of structures. These include, in particular:
Safety in relation to the environment;
Fire hazard, reliability and durability of the materials from which the structure is made;
Thermal performance indicators.
The parameters characterizing the operational properties of thermal insulation materials include some physical quantities. These are thermal conductivity, compressibility, elasticity, density, vibration resistance. Equally important are flammability, resistance to aggressive factors, the thickness of pipeline insulation and a number of other parameters.
Thermal conductivity of the material
The coefficient of thermal conductivity 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 from the side of the heat insulator on the object. When calculating the value of the coefficient, the entire set of factors that directly affect it is taken into account. The final value affects the choice of material, the way it is laid, the required thickness to achieve maximum effect. It also takes into account temperature resistance, the degree of deformation under 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 directly affecting it. These, in particular, should include the location of the object and weather conditions, the presence / absence of mechanical influence on the heat-insulating structure. These factors, which are of key importance, affect the durability of the structure. An additional special coating helps to increase the service life, which significantly reduces the level of environmental impact.
fire safety requirements
Fire safety standards are defined for each of the industries. For example, for the gas, petrochemical, chemical industries, the use of slow-burning or non-combustible materials as part of heat-insulating structures is allowed. At the same time, the choice is influenced not only by the indicated indicators of the selected substance, but also by the behavior of the heat-insulating structure during a general fire. The increase in 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 paramount importance. It is important for such premises to use materials that do not affect the situation. The situation is similar for housing and communal services. Insulation of pipelines 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 meet the needs of any buyer. Here is the product
action 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 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);
On a synthetic basis;
Products based on glass staple synthetic fibers.
The largest manufacturers of heat-insulating materials are: JSC "Termosteps", Nazarovsky ZTI, "Mineralnaya vata" (CJSC), JSC "URSA-Eurasia".
Foreign manufacturers of materials
The market of heat-insulating materials also includes products of foreign companies. Among them stand out: "Partek", "Rockwool" (Denmark), "Paroc" (Finland), "Izomat" (Slovakia), "Saint-Gobain Izover" (Finland). All of them specialize in various types and combinations of fibrous heat-insulating materials. The most common are mats, cylinders and plates, which can be uncoated or coated on one side (for example, aluminum foil can be used as it).
Rubber and foam materials
Filling polyurethane foam has received the greatest distribution from foam plastic heat-insulating materials. 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 Scientific Research Institute of Synthetic Resins (in Vladimir), and its subsidiary, Izolan CJSC. Pipeline insulation is also made with synthetic-based materials. In this case, equipment operating in conditions of negative and positive ambient temperatures is subjected to protection. The main suppliers of such materials are L'ISOLANTE K-FLEX and Armacell. Such thermal insulation looks like tubes (cylinders) or plate and sheet products.
