Technologies for installing thermal insulation of pipelines. Thermal insulation of pipelines, pipe insulation, pipeline insulation, thermal insulation of pipelines
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 is used more often in conditions of independent construction. 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 the already almost always hot pipes of the 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 true for production or laboratory installations, where the 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 for both heating mains and hot water pipes - no one is completely immune from emergency situations with boiler equipment.
The cylindrical shape of the pipes itself 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 of 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 it is enough thick layer 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 sunlight, which has a detrimental effect on them. Thirdly, we should not forget about the 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 home is probably not indifferent to aspects of aesthetic appearance laid 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 external laying– big enough. They come in roll type or in the form of mats; they can be given a cylindrical or other shape that is convenient for installation. curly shape, 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.
This structure becomes reliable barrier for moisture - at correct installation neither water nor water vapor will be able to penetrate through it to the walls of the pipe.
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 finish 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, most often, this temperature is sufficient, although on the verge, and for central heating, 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 a variety of types of thermal insulation work. 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 are equipped with a tongue-and-groove locking connection for assembly into a single structure. 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. There are many types of it available, for different outer diameters of insulated pipes and different thickness thermal insulation layer. Typically the length of the parts is 1000 or 2000 mm.
For production, polystyrene foam type PSB-S is used. various brands– 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 fit right 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. It also has a negative effect on him ultraviolet radiation. 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 the impact 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 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 covered with metal sheets on top - exactly by analogy with a polystyrene foam shell. 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 apparent inexpensive price 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 - thin layer foil will not protect against accidental or intentional mechanical impact.
Insulation of heating mains with polyurethane foam
One of the most efficient and safest modern insulation materials- This 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 forms.
- PPU shells are widely used, usually having an outer foil coating. It can be dismountable, consisting of half-cylinders with tongue-and-groove locks, or, for small-diameter pipes, with a cut along the length and a special valve with a self-adhesive rear 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. 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.
— External covering– 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 carrying out 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 thickness its walls (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
Thermal insulation materials and products made from synthetic foam rubber have recently become very popular. This material has a number of advantages that bring it to the forefront leadership positions in matters of insulation of pipelines, including not only heating mains, but also more responsible ones - on complex technological lines, in machine, 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 a moderately cold climate 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 | °C | from - 60 to + 260 |
Such coverage will not require additional protective layers– it is strong enough to cope with all impacts on its own.
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 - with a roller and brush. The number of layers depends on the operating conditions of the heating main, climate region, pipe diameter, 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 insulation material or product | Average density in the finished structure, kg/m3 | Thermal conductivity thermal insulation material(W/(m×°С)) for surfaces with temperature (°С) | 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 provide the 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 Central region 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 about one 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 at medium density 23 kg/m3 | 2 |
| ̶ the same, with an average density of 50-60 kg/m3 | 1,5 |
| Mats made of glass staple fiber on a synthetic binder brand: | |
| M-45, 35, 25 | 1.6 |
| M-15 | 2.6 |
| Mats made 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.
Mats with one-sided lining can be used, in which case the mats are installed with the lining towards the frame (inside the structure). Fully prefabricated structures based on mats stitched into facings can also be used. 4.6. Thermal insulation of cold storage tanks drinking water in water supply systems. For thermal insulation of cold water storage tanks in water supply systems, it is recommended, first of all, to use stitched mats covered with fiberglass on both sides. The design of thermal insulation is similar to that given in paragraphs 4.5.4 - 4.5.5 (with a frame made of wooden blocks) and is distinguished by the presence of a vapor barrier layer. Wiring mats produced by ISOROK CJSC are installed in one or two layers, depending on the calculated insulation thickness, between the posts of a wooden frame, secured with pins and tied with galvanized wire along the pins (Fig. 59 - 64).
Technologies for installing thermal insulation of pipelines
FIELD OF APPLICATION OF THERMAL INSULATING MINERAL WOOL MATS PRODUCED BY IZOROK CJSC 1.1. Thermal insulation mats pierced with mineral wool are intended for use in industrial thermal insulation at temperatures of insulated surfaces from minus 180°C to plus 700°C and in accordance with the recommendations of sections 2 and 3. It should be taken into account that at a temperature of the insulated surface above 600°C the period The service life of stitched mats is significantly reduced.
1.2. Stitched mats can be used for insulation industrial equipment industrial and housing and communal services facilities, including:
- vertical and horizontal cylindrical technological devices of chemical, oil refining, gas, metallurgical, etc. enterprises.
Stitched mats made of mineral wool - to make pipes last longer!
Info
CUTWOOL®MP tufted mats are made of mineral basalt wool on a synthetic binder with fiberglass roving lining the carpet, lined with fiberglass on both sides of the mat, in accordance with TU 5762-002-89646568-2013. Marking: CUTWOOL®MP2 M50-2400.100.1000, TU 5762-002-89646568-2013, where: MP – symbol stitched mats; 2 — fiberglass lining on both sides; M50 – product brand; 2400 – mat length (mm); 100 – mat thickness (mm); 1000 – mat width (mm). Specifications: Length (mm) 2400 Width (mm) 1000 Thickness (mm) from 50 to 120; Density, kg/m3 from 30 to 100; Compressibility, % no more than 20 Humidity, % no more than 0.5 Thermal conductivity, W/mK 0.033 Flammability group NG Application temperature* from -180 to +600; * standard application temperature is +4000C, more on special order.
Advantages of tufted mineral wool mats
They are characterized by low smoke generation and also effectively prevent the spread of fire, providing additional time to rescue personnel and equipment.
- Excellent sound insulation. Stitched mats guarantee excellent sound insulation for both residential premises and industrial workshops.
- Ability to withstand high temperatures. Mineral wool pierced mats are a material that can withstand loads of up to 700°C! And some types of material, for example, having a combined composition with the addition of mullite silica, work at temperatures up to 1100°C!
- Chemical resistance.
Mineral wool mats pierced are not afraid of the effects of such organic matter, such as oils, alkalis, solvents. - Low water absorption. An important ability of tufted mineral wool mats is to resist the influence of moisture.
Thermal insulation products of Isorok JSC. part 2
To compensate for temperature deformations, crimping of coating elements or other design solutions can be used. 4.3.14. The design of the protective coating of the vertical apparatus is shown in Fig. 47 and 48. The protective coating of vertical devices is also secured with self-tapping screws 4x12 with anti-corrosion coating or rivets.
Attention
Screw (rivet) installation pitch: vertically 150 - 200 mm, horizontally - no more than 300 mm. 4.3.15. The height of the protective coating of the device must include expansion joints, in which the elements of the protective coating rest on unloading devices or hinged brackets (Fig. 79) and are not fastened horizontally (circumferentially). Hinged brackets can be installed on the covering sheets of the previous row.
Unloading devices are installed along the height of the apparatus in height increments of no more than 3-4 meters.
403 forbidden
In terms of density, mats are produced in grades 100. 2.3. The maximum application temperature is determined by the temperature resistance of mineral wool and lining materials. The maximum temperature for using mats depending on the type of covering material is given in Table 2.1. Table 2.1. Temperature of application of stitching mats.
Name of lining material Without lining material or with fiberglass lining on one side (install with the fabric facing out) 600-700 (see clause 1.1.) Fabric, mesh, fiberglass canvas (with lining material sewn on both sides) 450 2.4. Stitched mineral wool mats grade 100 with and without linings belong to the group of non-combustible materials (NG) according to GOST 30244. 2.5. The nominal dimensions of the mats indicating the maximum deviations are given in Table 2.2. Table 2.2.
Permissible temperature difference (to - tк) Air temperature, t0, °С Relative air humidity, φ, % 50 60 70 80 90 Estimated difference, (to - tк) °С 10 9.8 7.3 5.1 3.1 1.5 12 9.9 7.3 5.1 3.1 1.5 14 10.1 7.4 5.2 3.2 1.5 16 10.2 7.6 5.3 3.3 1, 5 18 10.4 7.7 5.4 3.3 1.5 20 10.5 7.8 5.4 3.4 1.5 22 10.7 7.9 5.5 3.4 1.5 24 10.9 8.0 5.6 3.5 1.6 26 11.0 8.2 5.7 3.5 1.6 28 11.2 8.3 5.8 3.6 1.6 30 11, 4 8.4 5.9 3.6 1.6 5.3.4. The heat transfer coefficient, (αн), should be taken in accordance with Appendix 2.1. 5.3.5. When designing, the thickness of thermal insulation in the structure should be taken as a multiple of 10 mm, taking into account the current range of pierced mats mineral wool production CJSC "ISOROC", in this case, you should only round up.
5.3.6.
Unloading devices are also installed at the upper and lower bottoms of the devices. To impart rigidity to the structure of the protective coating, the coating elements can be zided. 4.4. Thermal insulation of flues and air ducts rectangular section. 4.4.1. Thermal insulation mats are recommended to be used for insulating gas ducts of thermal power plants, ferrous and non-ferrous metallurgy facilities, etc., and air ducts of rectangular cross-section. A variant of the design of thermal insulation of a rectangular gas duct is shown in Fig. 49. Fastening of the heat-insulating layer is provided using pins (welded, plug-in) and bandages. At the corners of thermal insulation of rectangular gas ducts for bandages or replacing them wire rings install metal linings from the coating material.
Thermal insulation of pipelines with stitched mats
Temperature conditions of water heating networks, ºС 95-70 150-70 180-70 Pipeline Design coolant temperature, ™ ºС Supply 65 90 110 Return 50 50 50 b) design temperature of the external environment, at a laying depth to the top of the channel of 0.7 m or less : — for year-round operation of the heating network — average annual outside air temperature; - when operating only during the heating period - average for the heating period; c) if the depth of the top of the channel is more than 0.7 m - the average annual soil temperature at the depth of the pipeline axis. 5.4.3. The recommended thickness of insulation from heat-insulating pierced mineral wool mats of grade 100, which meets the heat flux density standards for pipelines of heating networks of two-pipe underground channel installations located in the European region of Russia, is given in Table 5.4.2.
Thermal insulation of pipelines with stitched mats
The calculated thickness of thermal insulation made of pierced mineral wool mats produced by ISOROC CJSC at an indoor air temperature of 20ºC and relative humidity of 60, 70 and 80% is given in Table 5.3.2. 5.3.7. When the temperature and humidity of the air in the room differ from those indicated, the thickness of the insulation should be determined using formulas (6) or (7), since with an increase in the relative humidity of the air in the absence of ventilation, the thickness of the insulation increases significantly. Table 5.3.2. Recommended thickness of thermal insulation made of pierced mineral wool mats, preventing condensation of moisture from the air on the surface of the insulation of pipelines and equipment located in the room.
Outer diameter, mm Relative humidity of ambient air.
process of installing thermal insulation of pipelines
It doesn’t matter whether a high-rise building or a small wooden house is being prepared, if it has communications, they must be installed and installed according to the rules.
While there are no big problems with electrical, telephone and other wires, errors in the process of installing heating pipes, water supply and sewerage lead to not the most pleasant consequences.
Errors in the installation of the pipeline itself can cause leaks at the connecting points and can be removed very simply. But errors when installing thermal insulation of pipelines lead to freezing of the pipes, and, as a rule, their rupture in the most immediate suitable places. So, the first and most definite advantage that the owner receives after correctly organizing the process of installing thermal insulation of pipelines is the absence of stressful circumstances associated with accidents in the operation of the pipeline.
Plus, thermal insulation performs the following functions:
- interferes with the action of an aggressive environment;
- minimizes heat exchange with the external environment, reducing heat loss;
- maintains the functionality of the system.
Materials used when installing thermal insulation of pipelines.
thermal insulation materials for pipelines
Having realized the need for thermal insulation, the owner of a privatized house (brick, log house, foam concrete blocks, etc.) begins to select materials from which the installation process will be carried out.
Let us discuss in detail, as far as the volume of the publication allows, all types of materials for thermal insulation and the specifics of their installation process.
- Heat insulators made of fiberglass.
Very popular among installers. A very light, non-flammable material that does not rot, it is also popularly known under the names “fiberglass wool”, “mineral wool”. Can be supplied as rolls or as pressed slabs. Due to my own fibrous structure perfectly absorbs moisture. When installing, it is necessary to take this specificity into account and insulated pipes should be covered with moisture-repellent material (rolled roofing material, polyethylene, fiberglass).
Fiberglass-based wool is not suitable for insulating underground pipes. Plus, when installing it, it is necessary to take into account the compaction indicator (heat insulators made of fiberglass are compacted over a period of time).
- Basalt mineral wool.
They are plates and cylinders that are molded and special. Very durable, they, like fiberglass-based wool, are non-flammable, durable, at the same time do not absorb moisture and are excellent for installing both underground and above-ground communications.
Most manufacturers use aluminum foil in the form of additional moisture and thermal insulation.
Due to the rather high price, basalt seals are not as popular as fiberglass-based wool, but with their help it is convenient to install the thermal insulation of pipelines in problem areas(tees, expanders, and so on).
Installation work using basalt forms does not require great skills and is carried out without outside help.
- Expanded polystyrene (expanded polystyrene).
Just imagine a pipe that is made of polystyrene foam and sawn in two, while each half of the resulting pipe is equipped with a groove and a tenon for good reliability of the joints and you will get a complete picture of these so-called “shells”.
Taking into account the properties of polystyrene foam, it must be stated that such insulation is well suited for thermal insulation of both above-ground and underground pipelines.
To install such thermal insulation, it is very simple to combine the two halves of the shell into one, and tie them together using special glue or regular tape. Qualified installers suggest moving the pipe halves slightly apart by 10-15 cm relative to each other. This will give the so-called “overlap”. To bypass difficult areas (turns, expanders, tees), special shaped shells are used.
- Polyurethane foam.
If the thermal insulation of pipelines is carried out correctly, this will significantly increase the service life of the system and ensure maximum efficient operation. The thermal insulation of heating pipelines itself must be carried out in accordance with all established standards and standards.
Basic rules of thermal insulation
So, in general, there are several basic requirements (recommendations, rules) that should be observed when installing thermal insulation:- For thermal insulation, materials should be used High Quality, the characteristics of which are suitable for operating conditions.
- Installation of thermal insulation is carried out exclusively by specialists; this is the only way to guarantee the correct and high-quality execution of all work.
- Completion of all metalwork and welding work;
- Checking the density and strength of the surface;
- Coating of the pipeline with anti-corrosion agents.
Installation of thermal insulation: cylinder design
Thermal insulation process pipelines will be most effective if it is a prefabricated or fully prefabricated system. In other words it will be a cylindrical structure. The essence of the work is quite simple: laying thermal insulation on the pipe with its further adjustment and strengthening.When performing work, some requirements for thermal insulation of pipelines must be observed:
- Installation should begin from the flange connections, while the thermal insulation cylinders should be mounted as tightly as possible;
- The seams should not form one continuous horizontal line;
- Special bandages are used as fastening: two per cylinder (in increments of 40-50 cm);
- The bandage is attached using buckles, which are made of aluminum or packing tape.
It should be noted that insulation materials such as perlite cement, foam diatomite and siliceous lime segments are often used as thermal insulation. After the volume of thermal insulation of the pipeline has been calculated, the material in the form of mats should be laid in such a way that all seams are covered; then the insulation is fixed to the pipes using wire hangers in increments of 50 cm.
What is noteworthy is that in the event of a thermal insulation element of the structure failing, you can easily selectively dismantle the thermal insulation of pipelines and replace the damaged element with a new one.
Thermal insulation and temperature of the structure features
It should be remembered that the calculation of the thickness of pipeline insulation depends on some important factors, for example, as the temperature of the substance transported through pipes. If a substance has very high temperature, then thermal insulation is carried out using cylinders that are laminated with aluminum foil. No protective coating is used for this type of thermal insulation. It is recommended to use aluminum-based material as a bandage.In the event that water passes through the pipeline, the temperature of which does not exceed 12 ° C, the thickness of the thermal insulation of the pipelines can be increased, and hydrofibized cylinders are used as an insulator. As additional protection, a vapor barrier is installed, and the seams of the structure must be properly insulated (taped).
Attention! If the vapor barrier layer is damaged, it should be properly glued or completely replaced with a new one.
In general, it becomes clear that the calculation of thermal insulation of pipelines is made depending on the type of insulation, climatic factors and the liquid that is transmitted through the pipes.
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 exchange 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 an autonomous heating system. Only in a few northern regions private houses are 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 the presence of heat-reflecting 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 the thermal insulation of pipelines must comply with safety and environmental protection requirements. 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; The operating temperature range is 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 an 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 they 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 two-pipe system heating supply, 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 well (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
Temperature range at which the use of foamed polyethylene is allowed high pressure, from -70 to +70 °C. The upper limit is not compatible with the maximum temperature of the heating pipe, usually accepted 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- 2 meters. Color varies from white to dark gray. There may be a coating of aluminum foil that reflects IR radiation. The differences concern 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 universal material to preserve heat and cold. Designed for a temperature range from -200 to +150 °C. Meets all environmental safety requirements.
It is used as insulation of cold water pipelines, insulation of heating pipes, and is 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.