Insulating materials for pipes. Pipeline insulation

Every technological process is based on economic efficiency which is influenced by a combination of many factors. One of these points, important for many industries (chemical, oil refining, metallurgical, food, housing and communal services and many others), is the thermal insulation of equipment and pipelines. On an industrial scale, it is used on horizontal and vertical 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. Additional quality, which the thermal insulation of pipelines has, is to ensure the requirements applied in the field of energy saving. Competent insulation of pipelines, performed according to all standards, reduces heat losses in the process of 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, the allowable load that 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 that have key value 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

Norms fire safety 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 the framework of which specific technological processes with increased requirements for sterility and cleanliness must take place (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. Pipeline insulation is carried out in strict accordance with established norms while ensuring reliability and safety of use.

Domestic manufacturers of protective materials

The market for thermal insulation materials is diverse and able to satisfy 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

In the market of thermal insulation materials, products are also presented 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.

Thermal insulation is of great importance in the construction of a heat pipe. Not only heat losses depend on the quality of the insulating structure of the heat pipe, but, no less important, its durability. With the appropriate quality of materials and manufacturing technology, thermal insulation can simultaneously play the role of anti-corrosion protection of the outer surface of the steel pipeline. Such materials, in particular, include polyurethane and derivatives based on it - polymer concrete and bion.

Thermal insulation is arranged on pipelines, fittings, flange connections, compensators and supports for the following purposes:

reduction of heat losses during its transportation, which reduces the installed capacity of the heat source and fuel consumption;

reducing the temperature drop of the heat carrier supplied to consumers, which reduces the required heat carrier flow and improves the quality of heat supply;

lowering the temperature on the surface of the heat pipe and the air in the places of maintenance (chambers, channels), which eliminates the risk of burns and facilitates the maintenance of heat pipes.

The main requirements for thermal insulation structures are as follows:

1) low thermal conductivity both in a dry state and in a state of natural humidity;

2) low water absorption and small height of capillary rise of liquid moisture;

3) low corrosivity;

4) high electrical resistance;

5) alkaline reaction of the medium (pH > 8.5);

6) sufficient mechanical strength!

It is not allowed to use materials subject to combustion and decay, as well as containing substances capable of releasing acids, strong alkalis, harmful gases and sulfur.

The most severe conditions for the operation of heat pipelines occur during underground channel and especially channelless laying due to the moistening of thermal insulation by soil and surface waters and the presence of stray currents in the ground. In this regard, the most important requirements for heat-insulating materials include low water absorption, high electrical resistance, and with channelless laying, high mechanical strength.

As thermal insulation in heating networks, currently used mainly products made from inorganic materials (mineral and glass wool), lime-silica, sovelite, volcanic, as well as compositions made from asbestos, concrete, asphalt, bitumen, cement, sand or other components for channelless laying: bitumen perlite, asphaltoizol, armo foam concrete, asphalt expanded clay concrete, etc.

Depending on the type of products used, thermal insulation is divided into wrapping (mats, strips, cords, bundles), piece (slabs, blocks, bricks, cylinders, half-cylinders, segments, shells), pouring (monolithic and cast), mastic and backfill.

Wrapping and piece products are used for all elements of heating networks and can be either removable - For equipment requiring maintenance (gland expansion joints, flange connections), or fixed. They are fastened with bandages, wire, screws, etc., made of galvanized, cadmium or corrosion-resistant materials, and a cover layer. Filling and filling insulation is usually used for elements of heating networks that do not require maintenance. Mastic insulation may be used for shut-off and drainage valves and stuffing box expansion joints, provided that removable structures are made for branch pipes of stuffing box expansion joints and stuffing boxes for sealing fittings.

Thermal insulation structures steel pipes wires for above-ground and underground channel laying, as well as for channelless laying in a monolithic shell, usually consist of three main layers: anti-corrosion, heat-insulating and cover. The anti-corrosion layer is superimposed on the outer; the surface of a steel pipe and is made of coating and wrapping materials in several layers (isol or brizol on insulating mastic, epoxy or organosilicate enamels and paints, glass enamel, etc.). On top of it, the main heat-insulating layer of wrapping, piece or monolithic products is laid. It is followed by a protective layer thermal insulation layer from exposure to moisture and air and from mechanical damage. It is carried out with underground laying of two or three layers of isol or brizol on insulating mastic, asbestos-cement plaster on a metal mesh, lacquered fiberglass with various impregnations, foil isol, and with above-ground laying - from sheets of galvanized steel, aluminum, aluminum alloys, glass cement, glass roofing material, fiberglass etc.

Channel heat pipes. In channels with an air gap, the insulating layer can be made in the form of a suspended or monolithic structure. On fig. 8.25. an example of a suspended insulating structure is shown. It consists of three main elements:

a) anti-corrosion protective layer 2 in the form of several layers of enamel or isol, superimposed at the factory on the steel pipeline 1, having sufficient mechanical strength and having high electrical resistance and the necessary temperature resistance;

b) thermal insulation layer 3, made of a material with a low thermal conductivity, such as mineral wool or foam glass, in the form of soft mats or hard blocks laid on top of a protective anti-corrosion layer;

in) protective mechanical coating 4 in the form of a metal mesh acting as a supporting structure for the heat-insulating layer.

To increase the durability of the heat pipeline, the supporting structure of the suspension insulation (knitting wire or metal mesh) is covered on top with a sheath of non-corrosive materials or asbestos-cement plaster.

Rice. 8.25. Heat conductor in an impassable channel with an air gap

1 - pipeline; 2 - anti-corrosion coating; 3 - heat-insulating layer; 4 - protective mechanical coating

Channelless heat pipes. They find justified application in the case when, in terms of reliability and durability, they are not inferior to heat pipes in impassable channels and even surpass them, being more economical compared to the latter in terms of initial cost and labor costs for construction and operation.

The requirements for the insulating structures of channelless heat pipelines are the same as for the insulating structure of heat pipelines in channels, namely, high and stable heat, moisture, air and electrical resistance under operating conditions.

Channelless heat pipelines in monolithic shells. The use of channelless heat pipelines in monolithic shells is one of the main ways to industrialize the construction of heat networks. In these heat pipelines, a shell is applied to the steel pipeline at the factory, combining heat and waterproofing structures. Links of such elements of the heat pipeline up to 12 m long are delivered from the factory to the construction site, where they are laid in a prepared trench, butt welding of individual links between themselves and the application of insulating layers to the butt joint. In principle, heat pipes with monolithic insulation can be used not only without channels, but also in channels.

Modern requirements for reliability and durability are quite fully met by heat pipes with monolithic thermal insulation made of cellular polymeric material such as polyurethane foam with closed pores and an integral structure made by molding on a steel pipe in a polyethylene sheath (“pipe in pipe” type).

At the same time, pre-insulated pipelines are made with a polyethylene sheath. high pressure. The space between the shell and the pipe is filled with rigid polyurethane foam. Copper conductors are embedded in polyurethane foam to control the presence of moisture in the thermal insulation of the pipeline.

Due to the good adhesion of the peripheral layers of insulation to the contact surface, i.e. to the outer surface of the steel pipe and inner surface polyethylene sheath, the long-term strength of the insulating structure is significantly increased, since during thermal deformation the steel pipeline moves in the ground together with the insulating structure and there are no end gaps between the pipe and the insulation, through which moisture can penetrate to the surface of the steel pipe.

The average thermal conductivity of polyurethane foam thermal insulation, depending on the density of the material, is 0.03 - 0.05 W / (m ∙ K), which is approximately three times lower than the thermal conductivity of most widely used thermal insulation materials for heating networks (mineral wool, reinforced concrete, bitumen perlite, etc.).

Due to the high thermal and electrical resistance and low air permeability and moisture absorption of the outer polyethylene sheath, which creates additional waterproofing protection, the thermal waterproofing structure protects the heat pipeline not only from heat losses, but, no less important, from external corrosion. Therefore, when using this insulation design, there is no need for special anti-corrosion protection of the surface of the steel pipeline.

The use of pipelines with polyurethane foam insulation makes it possible to reduce thermal energy losses by 3-5 times compared to existing types of thermal insulation (bitumperlite, expanded clay bitumen, foam concrete, etc.) and obtain annual savings of about 700.0 Gcal/year per 1 km.

The construction of heat networks with polyurethane foam insulation is carried out several times faster compared to channel ones and the cost is 1.3-2 times lower, and the service life is 30 years, while the durability of commonly used structures is 5-12 years.

Bitumoperlite, bitumen expanded clay and other similar insulating materials based on bituminous binder have significant technological advantages that make it relatively easy to industrialize the production of monolithic shells on pipelines. But along with this, the specified technology for manufacturing shells needs to be improved to ensure a uniform density and homogeneity of the bitumen-perlite mass both along the perimeter of the pipe and along its length.

In addition, bitumen-perlite insulation, like many other materials based on a bituminous binder, loses water resistance during prolonged heating at a temperature of 150 ° C due to the loss of light fractions, which leads to a decrease in the corrosion resistance of these heat pipes. To increase the anticorrosion resistance of bitumen-perlite, polymer additives are introduced into Portland cement during the production of hot molding mass, which increases the temperature resistance, moisture resistance, strength and durability of the structure.

Channelless heat pipes in bulk powders. These heat pipelines are mainly used for pipelines of small diameter - up to 300 mm.

The advantage of channelless heat pipes in bulk powders compared to heat pipes with monolithic shells lies in the ease of manufacturing the insulating layer. The construction of such heat pipelines does not require the presence of a plant in the construction area of ​​heat networks, to which steel pipes must first be supplied to apply a monolithic insulating shell. Insulating bulk powder in appropriate packaging, such as polyethylene bags, is easily transported over long distances by rail or road.

Self-sintering foam concrete, perlite concrete, asphalt or asphalt concrete are used as such powders.

As is known, in two-pipe heating networks, the temperature regimes, and, consequently, the temperature deformations of the supply and return pipelines are not the same. Under these conditions, adhesion of the thermal insulation layer to the outer surface of steel pipelines is unacceptable. To protect the outer surface of steel pipelines from adhesion with the insulating mass, they are covered on the outside with a layer of anti-corrosion mastic material, such as asphalt mastic, before pouring with a liquid foam-cement mortar.

Cast structures for thermal insulation of channelless pipelines. Of the cast structures of channelless heat pipelines, heat pipelines in a foam concrete mass have received some use; perlite concrete can be used as a material for the construction of such heat pipelines. Mounted in trenches steel pipelines are filled with a liquid composition prepared directly on the track or delivered in a container from the production base. After setting, the concrete or perlite concrete array is covered with soil.

test questions

1. What are the main requirements for the design of modern heat pipelines? Name the assortment of pipelines of the heating network and the types of fittings used.

2. Compare underground heat pipelines in through channels, impassable and channelless. Name the advantages and disadvantages of each type of gasket and the main areas of their appropriate application.

3. Name the designs of modern compensators for thermal deformations of pipelines of heating networks. How is the calculation and selection of U - shaped expansion joints?

4. Describe the construction of supports for pipelines of heating networks. Give the calculation formula for determining the resulting force acting on the fixed support of the heat pipe.

5. What are the main features and requirements for heat-insulating structures of heat pipelines?

The insulation of heating pipes is important aspect in the creation of energy-saving technologies, and this issue is acute today.

Currently developed a large number of insulating materials and ways of their optimal use in various industrial fields.

But, it is necessary to rationally use energy not only in industry, but also in everyday life. Insulation of heating lines is not only desirable, but also turns into a vital necessity.

In general, the process of thermal insulation is aimed not only at maintaining the temperature regime at a stable level, but also at protecting the heat carrier from freezing during the cold period.

Thermal insulation materials are of the following types:

• piece;
• in rolls;
• combined;
• for filling;
• casing.

Depending on the technical characteristics and insulation parameters, these materials are used in the following networks:

• ventilation;
• supply of cold and hot water;
• technical equipment;
• steam heating.

The choice of protective material must be approached with great responsibility, because it is a guarantee of warmth and comfort in people's homes.

The types of the most effective insulating material are as follows:

1. Thermal insulation paint. It is attributed to the achievements of Russian science. One layer of this coating can be a replacement for several centimeters of polystyrene foam and mineral wool. At the same time, this material does not harm the environment and is resistant to high temperatures. This type of pipeline insulation is used in difficult production conditions.
2. . This material is characterized by low heat conductivity and fire resistance. For these reasons, it has found extensive use in the protection of heating systems. But, this type of protection refers to expensive building materials.
3. Insulation with polyurethane foam. They began to use it for thermal insulation recently, but they have already managed to evaluate its practicality.
4. Styrofoam. This is practically the same pinoplast. This option is distinguished by affordable cost and simple fasteners.
5. . It is a shell resembling a pipe in shape.

Choice of insulating material

When choosing a heater for heating installed on the street, opt for those samples that are not afraid of moisture. The heater that is selected must have:

• minimum thermal conductivity;
• do not react to acids, alkalis and other chemically active components;
• resistance to oxidation and corrosion;
• long service life;
• fire resistance;
• safety for human life;
• ease of installation process.

Why is outdoor insulation needed?

The answer to this question is simple. It's about rather than about insulation, but about the thermal insulation of heating systems on the street. The overall efficiency of all heating will depend on the quality of the insulation.

The main thing is not what materials the insulation was carried out, but how well the installation was done!

Insulation will help smooth out the shortcomings during installation or some of the disadvantages of the physical and chemical properties of the insulation from which the heating itself is made.

Thermal insulation should close the entire pipeline from negative natural phenomena and mechanical damage. The insulation will protect pipes located in the open air from premature destruction and the negative effects of ultraviolet rays.

Polymer samples are resistant to corrosion, but they require good frost protection, as they are prone to freezing, mechanical damage and abrasion, while metal samples, which are more rigid and reliable at first glance, quickly oxidize and become unusable.

Another disadvantage of metal is its high thermal conductivity, which is not very good for heating systems. Proper heat and waterproofing (insulation) will eliminate the above disadvantages without wasting heat.

Everyone chooses the choice of insulation according to their own parameters, based on personal preferences and wishes.

Examples of thermal insulation materials

The process of high-quality thermal insulation or heating insulation is carried out by many companies. Although this process is now established for high level, the majority of people prefer to carry out thermal insulation on their own.

Naturally, to carry out this type of work, you will need to stock up on some knowledge in order to properly carry out the procedure without the involvement of professionals.

Foamed insulation. Today, such an inexpensive material as foamed polyethylene foam is often preferred. It is sold in rolls and is worn directly on the pipe as a cover, keeping it as warm as possible even outdoors.

At the same time, foamed polyethylene foam is resistant to high temperatures, is environmentally friendly and easy to install right on the street. The main thing, after the cover is dressed, do not forget to glue its ends together.

. It can be of two types:

• basalt wool- works with temperature regime up to 650˚С and at the same time does not emit toxic substances. The material is made from rock with a maximum composition of basalt.
• fiberglass wool - made from quartz sand and glass. Works well at temperatures up to 180˚С.

The following types of thermal insulation are used in parallel with waterproofing:

• in the process of insulation with mineral wool, aluminum foil is wound over the base layer, which is fastened with a metal wire;
• for engineering structures, foam molds can be made that allow you to insulate the pipeline on your own.

Due to the fact that the foam is not 100% water repellent, it is not the most the best option for outdoor heating.

Manufacturers produce this insulation in rolls and packs in the form of mats. It does not melt or deform under the influence of high temperatures, therefore it is often used for thermal insulation of heating systems.

The disadvantage of mineral wool is that it absorbs water and loses its thermal insulation properties. Therefore, the insulation of a large system with this material is not economically viable, since along with it it will be necessary to purchase protective equipment against moisture penetration.

Innovative insulation - penofol

Today, penofol is increasingly used for thermal insulation of highways on the street. This insulation is made of polyethylene foam covered on one side with aluminum foil for protection and maximum thermal insulation.

The material is sold in rolls and. Penofol is flexible and during installation it fits snugly, well covering the places of sharp turns and bends.

Its high thermal insulation properties and low price make foam insulation the most commonly used method when working with large heating systems.

This is the most optimal choice for those who wish to do their own work on the insulation on the plot.

Today, a huge number of thermal insulation materials are presented on the construction market, the use of which does not require special tools and skills.

Description and technical characteristics of polyurethane foam

Insulation with polyurethane foam is suitable for both metal and plastic heating systems located outdoors.

This material is suitable for outdoor insulation of pipes of various diameters and is also called "shell". The material is also coated on one side with aluminum foil to reduce the overall thermal conductivity of the coating.

However, it is worth noting that, compared with other types, insulation with polyurethane foam occurs by winding pipes not even in three layers, but at least five, and preferably eight.

Although it looks aesthetically pleasing, which is naturally important for heating systems that are located in the open air, such an expense is not justified.

You will have to wrap at least five layers to achieve the desired result, and this will lead to additional expenses.

Another disadvantage of polyurethane foam– minimal protection against frost and heat loss.

Everyone has the right to choose a suitable, in his opinion, insulation, the main thing is not to save money and take the issue seriously so that the heat reaches the recipient, and does not go to heat the air outside.

Note that properly selected outdoor pipe insulation can significantly extend the life of the pipe. heating system and its efficiency!

Thickness of thermal insulation of heating systems

The thickness of the insulation of heating pipelines is determined by calculation, which is based on the requirements of regulatory documentation.

It is not easy to make these calculations. To get the right result, you need to be patient and attentive. The most common method is the heat loss calculation.

At the same time, the SNIP rules indicate that the insulation of all heating pipelines must be calculated so that heat losses do not exceed the values ​​\u200b\u200bspecified in the SNIP.

In addition to SNIP, the insulation thickness is regulated by the Code of Rules, and it provides more a simple technique. These are the simplifications:

1. the heat loss during heating of the pipeline walls by the flowing medium is not as large as in the outer protection layer; for these reasons, they can be ignored.
2. most structures are made of steel, and its resistance to heat conduction is small, so the resistance of the walls of a metal structure can also be ignored.

The thickness of the insulation of a single-layer structure is calculated using complex formulas, they can be easily found on the Internet. At the same time, SNIP standards suggest different formulas to determine the calculation for round pipes and for a flat surface.

The thickness of the insulation in several layers is calculated by formulas, and this is done for each layer separately.

When calculating the thickness of the insulation, it must be borne in mind that SNIP establishes the exact values ​​\u200b\u200bof heat losses for pipelines of different volumes, and for various ways their pads.

All these calculations are difficult to carry out, and in order to save time, many use a personal computer and special software. At the same time, the desired result is quickly and successfully obtained. We offer to download free program for windows.

Protecting outdoor systems

Insulation of external heating pipelines is necessary so that the heat carrier retains heat for as long as possible. It is especially relevant for outdoor heating lines.

It takes a large amount of heat to warm up the water, and if you do not insulate the external systems, then a significant part of it will simply be wasted on the way to the destination.

Pipeline insulation in buildings

Insulation of existing heating pipelines in the room does not lose its relevance. It is clear that in those areas where the pipeline must give up its thermal energy, it is not worth isolating it.

But, the areas in the room where the pipes pass, for example, in the wall, need to be insulated. Otherwise, the heat will go to heat the wall.

Such protection in the room is not used very often, and it should be noted that without it the quality of heating suffers.

For a system located in the floor, high-density protective materials must be used. For example, any type of foam insulation will be effective indoors. They are great for insulation, and for ease of use, it is better to take tubular options.

These are soft and flexible tubes equipped with a longitudinal slit. They are easy to put on and are fixed with a special clip. If the installation of such a heater in the room is done correctly, then it will last a very long time.

Thermal protection on the street

Insulation of heating pipelines on the street requires a special approach. First of all, during such work, the possible influence of moisture should be calculated. Outside, it's snowing or raining. Also, when laying thermal insulation on the street, it is necessary to provide a waterproof layer.

The generally accepted options for thermal protection of the heat supply network on the street are as follows:

• Winding, which is made up of silk threads.
• Ruberoid.
• Winding from corrosion-resistant wire.

Outdoor protection options must meet the following requirements:

• Slight thermal conductivity.
• Moisture resistant. Moisture should not accumulate in the protection, this is especially important for the highway running in the ground.
• Resistant to aggressive environments. It should not collapse from the influence of low temperature and wind.
• Long time use.
• Simple padding.

Warming rules

The rules for insulating heating pipelines are quite numerous, here are some important points from them:

1. First of all, it is necessary to study the rules and norms of SNIP.
2. Insulation materials should be purchased from official suppliers. They manufacture products, observing all the rules and requirements of standards.
3. It is necessary to carry out thermal protection of pipelines in order to concentrate thermal energy in the area of ​​\u200b\u200bradiators. If you ignore the rules for insulating the central heating pipeline, then the heat will be directed to the walls and window openings.
4. Designers who are engaged in the arrangement of premises can ennoble the appearance of thermal insulation. But, to perform such work, you also need to follow your own rules. For example, when sewing with drywall, we must not forget about the holes for accessing the fittings.
5. Some heaters for the heating pipeline just need to be sawn. But some will need additional material for protection.

Requirements for the choice of thermal insulation of heating

When looking for thermal insulation for a heat network located in the open air, in addition to the above nuances, the following requirements must be followed:

1. An indicator of the thermal conductivity of a material.
2. Ability to withstand the environment.
3. Temperature range for work.
4. The duration of the period of use.
5. Ease of material installation.

Video: outdoor pipe insulation

Thermal insulation in the basement

Having completed the construction of the house, its owner must find out how to insulate pipes for the heating network.

After all, the decision in this situation is directly dependent on the type of premises where they pass. Therefore, thermal insulation for heating pipes in the basement should also be carried out after studying the options intended for such actions.

Video: thermal insulation in the basement

If there is increased ventilation in the attic, then high humidity this space does not exist.

The basement is completely different. For the preparation of the heating system, this place is called the most critical.

Despite the fact that the highway passes below the freezing point of the soil, this does not exempt from such an event.

And from the place where the heating system enters the basement to the location of the plumbing, it still needs to be thermally insulated.

ADVICE! Regardless of the type of product chosen to protect pipelines passing in the ground, they are additionally covered with a layer of waterproofing.

A lot of time to solve the issue of how to insulate pipes in this room does not go away. Experts are convinced that from the perspective of the best ratio of quality and cost, the most a good choice- It's polystyrene.

This product is produced for products of different volumes, and each inhabitant can independently cope with the installation.

The use of mineral wool involves the completion of work in two stages:

1. First stage. This is a dense winding of the workpiece with a cloth and fasteners with a cord.
2. Second phase. A protective waterproofing is formed from the roofing material. Pre-cut, it is superimposed on mineral wool. All this is fixed with a nylon cord.

When doing work in the basement, we must not forget that the correct selection of the structure and the correct laying become the key to a long service life and effective operation of the heating network.

Features of the heating pipeline passing underground

Thermal insulation for pipes in the ground is indispensable in the cold winter. Without good insulation the heat energy of the heat carrier will simply be spent on heating the air, soil, and more. Accordingly, the efficiency of the network in such conditions decreases.

In order for a heating system located in the ground, to reduce heat losses, the following is necessary.

According to the norms of SNiP, the material for heating pipes that are laid in the ground must be characterized by a density of almost 400 kg / m3.

Additionally, these documents indicate that the structures for insulation should not contain flammable compounds.

So far, only mineral and glass wool have been used to insulate pipes in the ground. It can be found in thermal networks even now, but this option has some drawbacks.

They become the reason for the adoption of other heaters with better characteristics. A significant disadvantage in this case is the high hygroscopicity, which leads to a decrease in the protection of blanks in the ground.

Also, mineral wool, after prolonged use, suffers violations of its structural integrity, and this reduces its ability to retain heat.

IMPORTANT! A significant advantage of glass wool is its ability to work at high temperatures. This also includes excellent tolerance to chemical influences, excellent refractory properties and low price.

The latest technologies have brought insulation based on expanded polystyrene, foamed rubber with the addition of refractory additions.

They are hygroscopic, but ease of installation and low cost have led to the fact that they are laid most often.

Foamed polyethylene, which is currently very popular with consumers, deserves special attention.

The advantage of this product is its environmental safety. A large number of positive characteristics put it in a leading position in the ranking of the best products.

A little less often, the thermal insulation of pipes in the ground is carried out with synthetic rubber. This material also has a large number of positive qualities, but it has a higher price.

Heating pipes and insulation in the apartment

Many people mistakenly believe that thermal insulation of the heating system in the apartment is not needed. This is explained by the fact that the outgoing heat remains in the same room.

In reality, everything happens in such a way that the main source of heat in the apartment is radiators, but not the pipes that supply the coolant.

This problem is especially acute in a situation where the pipeline is hidden in the walls or in the floor, or is covered with a plasterboard building.

Such channels heat not only the apartment, but also the walls. Therefore, heat is lost when going outside. Similarly, everything happens with a concrete screed. The heat just goes into the ground.

From the above, the conclusion suggests itself that the system running in the apartment needs thermal insulation.

To date, most often plastic is taken for wiring the heating system. It does not conduct heat well, but, nevertheless, they do not fall to a minimum.

When producing this insulation in an apartment, the foamed polyethylene foam is cut lengthwise. So it fits comfortably on ecoplastic.

Each stick of such a product contains a drawn line along which an incision is made. After attachment to the workpiece, this thermal insulation takes its former shape.

In order for the laying to turn out to be dense and not contain gaps, the cut must be made with particular accuracy.

IMPORTANT! The topic of warming the heating system in the apartment is raised regularly. But, during discussions, regional features are not always remembered. If in some southern regions If you can afford to do without the insulation of the heating system, which is hidden in the wall, then in any northern region such actions are tantamount to sabotage.

Thermal insulation in the apartment without loss, thanks to modern materials can be done without much difficulty.

Video: Stenoflex 400 insulation

And, speaking of such measures, one cannot help but recall liquid thermal insulation, which is an alternative to other methods. This composition is characterized by a particularly stable heat transfer.

This paint is applied in a thin layer on the pipe. One such layer replaces polyurethane or polyethylene protection up to 5 cm thick.

How much protection is needed for the heating line

There are a certain number of people who question this question. They ask: “Why lay thermal protection on an already warm heating network?”.

You need to understand that thermal protection not only improves the efficiency of the heating operation, retaining heat. It also prevents Negative influence external environment on the pipeline, does not allow structures to overheat or form condensate.

To what has been said, it must be added that effective thermal protection is important point financial savings, and quite on a large scale.

IMPORTANT! Thermal protection itself High Quality may become ineffective if unprofessional installation steps are carried out by the craftsmen.

Choose desired material not difficult. The construction market offers a lot of options for these purposes, and all of them are affordable and of good quality.

Entries

If you are equipping a water supply system country house with your own hands, then pipe insulation must be used. And this applies not only to pipelines passing on the street, but also to water supply systems inside the house. For water supply communications, several types of insulation are used, which differ in purpose and materials used for its manufacture. Each type of insulation performs its own functions. In our article, we will consider in detail what kind of insulation is required for hot and cold water pipelines, how this insulation is performed, and what materials can be used for these purposes.

To begin with, many isolation methods are applicable to different systems: water supply, sewerage, heating and ventilation. But in our article we will consider only those methods that are applicable to water pipes hot and cold water supply.

Piping insulation is divided into two types:

• thermal insulation measures;
• waterproofing.

The purpose of each type of isolation measures is as follows:

1. Thermal insulation of the external cold water supply pipeline is needed to protect the system from freezing during the cold season. If the water in the pipe freezes in frost, then it will not be able to get into the house, and it will be quite difficult to find an ice plug and eliminate it.
2. Thermal insulation of external hot water pipes is needed so that hot water does not cool down during transportation to the consumer. In addition, such protection helps to increase the service life of the system.
3. Also, thermal insulation of hot water pipelines is carried out, which will be located in strobes - channels cut in the wall. In this case, these pipe protection methods are needed for the reason that the water temperature in pipes in contact with cold brick or concrete walls, may decrease.
4. Waterproofing of external pipes for hot and cold water supply is needed to protect them from corrosion. The thing is that the moisture present in the soil can cause rusting of steel pipes. However, this does not apply to plastic products.
5. Various types of waterproofing are used to protect pipeline joints from leakage.
6. As for cold water supply systems inside the house, their waterproofing is carried out in order to protect against condensate, which, collecting on pipes, can cause them to corrode. Again, this does not apply to plastic pipelines that are not subject to corrosion.

Exist different types and methods of hydro- and thermal insulation of pipelines and their joints. Let's consider them in more detail.

Pipe insulation

The following methods of thermal insulation of water supply pipes are commonly used:

• The most efficient and in a reliable way protection of water supply pipelines from freezing in winter is the creation of high pressure in the system. Due to this, the liquid moves through the pipes at high speed and does not have time to freeze. But such methods are not suitable for domestic water supply, because when the tap is closed, the liquid will not move in the pipes.
• A fairly effective method of thermal insulation of external pipes is the laying of a heating cable in the same trench with communications. Such methods are used if the bottom of the trench cannot be buried below the freezing point of the soil. In this case, a ditch is dug with a depth of no more than 40 cm, and a special heating cable is wound around the pipeline. The disadvantage of the method is energy dependence and the cost of paying for electricity.

Important: for these purposes, it is worth purchasing a cable with a power of 10-20 W / m. It can be used both outside and inside communications.

• The simplest and cheapest way of thermal insulation is the use of special materials that will protect the pipeline from the cold.

Tip: it is very important to create something like an arch from these materials in the upper part of the pipeline, protecting from the cold coming from the surface. The lower part of the element can be heated by heat coming from the ground.

Classification

The following means of isolation are commonly used:

• pouring;
• roll;
• piece;
• combined;
• casing.

Materials for thermal insulation of hot water pipes

Insulation can be internal and external. The following finished products can be used to perform insulation:

1. PPU. This material increases the service life of the pipeline, increases the waterproofing of the system. The material withstands temperature fluctuations and its limit values. Heat loss is no more than 5%.
2. PPMI is used only for hot water communications. This is a monolithic three-layer construction. The density of the material in the cross section is different on different layers. The composition of the product has an anti-corrosion layer, thermal protection and moisture protection. The product increases the service life of the network, does not allow condensate to collect. The material is resistant to temperature extremes and mechanical damage.
3. VUS is a two-layer coating with anti-corrosion characteristics.

Thermal insulation materials for cold water pipes

Pipe insulation can be made using the following materials:

Waterproofing measures

Waterproofing of pipes and joints is carried out using the following materials:

1. PVC tape. This material is used to protect the surface of steel pipelines from corrosion. It is also suitable for insulating joints, threaded connections and in case of repair work on water supply networks.
2. Rubber sheeting was previously used to isolate only underground engineering networks, but now it is also used to protect elements passing in the basement of houses. This durable, oil and alkali resistant material has an impressive service life. The product does not change its performance characteristics at high temperatures and is easy to install due to good elasticity.
3. Waterproofing of pipelines with the help of gluing materials (isola) is characterized by high strength and temperature stability. This elastic material stretches well during installation. Its only drawback is its low resistance to impact. organic compounds and solvents. The material is suitable for corrosion protection of external water supply pipelines.
4. Heat-shrinkable tape is used to seal the joints of steel and plastic products. The tape consists of a thermofusible layer and polyethylene film. This material is not suitable for pipelines that will be operated at high temperatures. Special heat-shrinkable sleeves are used to protect joints.
5. Self-adhesive tape made of polymeric material. Its second name is fluoroplastic sealant. This material is used to protect against leaks in threaded joints. The product withstands exposure to high temperatures without changing its performance characteristics.

Heat-insulating materials and structures are designed to reduce heat losses by pipelines and equipment of heating networks, maintain a predetermined temperature of the heat carrier, and also prevent high temperatures on the surface of heat pipelines and equipment.

The reduction of transport heat losses is main means fuel economy Considering comparatively small costs for thermal insulation of pipelines (5 ... 8% of investments in the construction of heating networks), it is very important in matters of conservation of heat transported through pipelines to cover them with high-quality and effective thermal insulation materials.

Thermal insulation materials and structures are in direct contact with environment, characterized by fluctuations in temperature, humidity, and with underground laying - aggressive actions ground water in relation to the pipe surface

Thermal insulation structures are made of special materials, the main property of which is low thermal conductivity. There are three groups of materials depending on thermal conductivity: low thermal conductivity up to 0.06 W / (mV ° C) at an average temperature of the material in the structure of 25 ° C and not more than 0.08 W/(m*°C) at 125°C; average thermal conductivity 0.06.. 0.115 W/(m-°С) at 25°С and 0.08.. .0.14 W/(mv°С) at 125°С; increased conductivity 0.115...OD75 W/(m-°C) at 25°C and 0.14...0.21 W/(m-°C) at 125°C.

In accordance with for the main layer of heat-insulating structures for all types of gaskets except wireless, materials with an average density of not more than 400 kg / m3, and thermal conductivity of not more than 0.07 W / (m * ° C) at a material temperature of 25 ° C should be used. With channelless laying - respectively, no more than 600 kg / m3 and 0.13 W / (mv ° C)

Other important property thermal insulation materials is their resistance to temperatures up to 200 ° C, while they do not lose their physical properties and structure. Materials must not decompose with release harmful substances, as well as substances that contribute to corrosion of the surface of pipes and equipment (acids, alkalis, aggressive gases, sulfur compounds, etc.)

For this reason, the use of boiler slag containing sulfur compounds in its composition is not allowed for the manufacture of thermal insulation.

Another important property is water absorption and hydrophobicity (water repellency). Humidification of thermal insulation sharply increases its coefficient of thermal conductivity due to the displacement of air by water. In addition, oxygen and carbon dioxide dissolved in water contribute to corrosion of the outer surface of pipes and equipment.

The air permeability of the heat-insulating material must also be taken into account when designing and manufacturing a heat-insulating structure, which must have appropriate tightness, preventing the penetration of moist air.

Thermal insulation materials must also have increased electrical resistance, preventing stray currents from reaching the surface of pipelines, especially with channelless laying, which causes electrical corrosion of pipes.

Thermal insulation materials must be sufficiently bio-resistant, they are not subject to decay, rodent action and changes in structure and properties over time.

Industriality in the design of heat-insulating structures is one of the main characteristics of heat-insulating materials. Coating pipelines with thermal insulation, but if possible, should be carried out at factories in a mechanized way. This significantly reduces labor costs, installation time and improves the quality of the heat-insulating structure. Insulation of butt joints, equipment, branches and stop valves must be made in previously prepared parts with mechanized assembly at the installation site.

The thermal properties of heat-insulating materials deteriorate with an increase in their density, therefore, mineral wool products should not be subjected to excessive compaction. The fastening parts of thermal insulation (bandages, mesh, wire, ties) should be used from aggressively resistant materials or with an appropriate coating that resists corrosion.

And, finally, heat-insulating materials and structures should have a low cost, their use should be economically justified.

THERMAL INSULATION MATERIALS, PRODUCTS AND STRUCTURES FOR OVERGROUND AND UNDERGROUND HEAT NETWORKS IN CHANNELS

Thermal insulation materials

The main heat-insulating material at present for the thermal insulation of pipelines and heating system equipment is mineral wool and products made from it. Mineral wool is a fine-fibre material obtained from a melt rocks, metallurgical slags or mixtures thereof. In particular, basalt wool and products made from it are widely used.

Mineral wool is made by compacting and adding synthetic or organic (bitumen) binders or stitching various mats, plates, half-cylinders, segments and cords with synthetic threads.

Mineral wool mats are made without linings and with linings of asbestos fabric, fiberglass, fiberglass canvas, corrugated or roofing cardboard; wrapping or sack paper.

Depending on the density, rigid, semi-rigid and soft products are distinguished. Cylinders with a section along the generatrix, half-cylinders for insulating pipes of small diameters (up to 250 mm) and segments for pipes with a diameter of more than 250 mm are made from rigid materials. To insulate pipes of large diameters, vertically layered mats are used, glued to the cover material, as well as embroidered mats made of mineral wool on a metal mesh.

For thermal insulation at the installation site of pipeline joints, as well as compensators, valves, a heat-insulating cord is made of mineral wool, which is a mesh tube, usually made of fiberglass, densely filled with mineral wool. The thermal conductivity of products made of mineral wool depends on the brand (in terms of density) and ranges from 0.044 ... 0.049 W / (m * ° C) at a temperature of 25 ° C and 0.067. ..0.072 W/(m*°C) at 125°C

Glass wool is a fine-fiber material obtained from molten glass charge by continuous drawing of glass fibers, as well as by centrifugal-spunbond-blowing method. Rigid, semi-rigid and soft plates and mats are made from glass wool by molding and gluing with synthetic resins. We also produce mats and slabs without a binder, stitched with glass or synthetic thread.

The value of the coefficient of thermal conductivity of glass wool products also depends on the density and ranges from 0.041 ... 0.074 W / (m - ° C)

Fiberglass canvas (non-woven roll material on a synthetic binder) and canvas stitched from waste glass fiber, which is mhoi layered canvas stitched with glass fibers, are widely used as a wrapping and covering material.

Vulcanite products are obtained by mixing diatomite, quicklime and asbestos, molding and autoclaving. Manufacture of plates, semi-cylinders and segments for insulation of pipelines DN 50 ..400 Thermal conductivity of products from 0.077 W/(m*°C) at 25°C to 0.1 W/(m-°C) at 125°C - a fine mixture of quicklime, siliceous material (diaumite, tripoli, quartz sand) and asbestos. Products are also produced in the form of plates, segments and half-cylinders for insulating pipelines Du 200.. .400. Thermal conductivity of the material from 0.058 Vg/(m-°C) at 25°C to 0.077 W/(m*°C) at 125°C

Perlite is a porous material obtained by heat treatment volcanic glass with inclusions of feldspars, quartz, plagioclases Other silicate rocks of volcanic origin (obsidian, pumice, tuffs, etc.) are used as raw materials for the production of expanded perlite. In the form of crushed stone and sand, perlite is used as a filler for the preparation of heat-insulating concrete and other heat-insulating products e.g. bitumen perlite.

By mixing perlite sand with cement and asbestos, perlite-cement products are obtained in the form of semi-cylinders, slabs and segments by molding. Thermal conductivity coefficient from 0.058 W/(m*°C) at 25°C to 128 W/(m*°C) at 300°C.

Foam plastics are increasingly being used as the main heat-insulating layer. Foam plastics are porous gas-filled polymeric material. The technology of their manufacture is based on the foaming of polymers with gases resulting from chemical reactions between individual mixing components. Foam plastics allowed for use for insulation of heat pipelines include phenol-formaldehyde foam plastics FRP-1 and resopen, made from resole resin FRV-1A or resocel and foaming component VAG-3. Cylinders, semi-cylinders, segments, insulated fittings of the FRP-1 and Resopen brands are made from this material. Thermal conductivity is 0.043...0.046 at 20°C.

Also promising is the use of polyurethane foam materials obtained by mixing various polyesters, isocyanates and foaming additives.

Foam insulation is applied at factories by pouring into molds or spraying onto the surface of pipes. Insulation of joints, fittings, fittings, etc. is possible at the installation site of the pipeline by pouring liquid foam mass into the formwork or into shells, followed by rapid hardening of the foam insulation.

For example, the polyurethane thermal and waterproofing insulation PPU 308 N developed by VNIPIenergoprom has a thermal conductivity coefficient of 0.032 W/(m*°C) at a density of 40.. .90 kg/m3, and is applied to pipes mechanically, without the need for an anti-corrosion coating. The outer layer with a density of 150...400 kg/m3 with a compressive strength of 50 kg/cm2 is used as a cover layer

Thermal insulation structures

Thermal insulation structures include a protective coating of the pipe surface against corrosion, the main insulation layer (several layers) and a protective coating (covering layer) that protects the main thermal insulation layer from mechanical damage, exposure to atmospheric precipitation and aggressive environments. The protective coating also includes the means and details of fastening the cover layer and insulation as a whole.

Choice protective coating pipe surface from corrosion is carried out depending on the method of laying, on the type of aggressive effects on the surface and on the design of thermal insulation (Appendix 5).

The most common are oil-bitumen coatings on the ground, as well as coatings with isol or brizol on insulating mastic.

Very effective is the glass enamel coating, consisting of a mixture of quartz sand, feldspar, alumina, borax and soda. To increase adhesion with metal, oxides of nickel, chromium, copper and other additives are introduced into the composition. An aqueous thick composition is applied to the pipe surface, dried and melted on the pipe surface in an annular electromagnetic inductor at a temperature of about 800 ° C. Butt joints of pipes can be coated with enamel using mobile units. An inexpensive anti-corrosion agent is EFAJS paint coating on epoxy resin Other epoxy enamels are used For heat pipelines in severe temperature and humidity conditions, surface metallization with aluminum by a gas-pressure method is very effective. flow-mechanized line for thermal insulation of pipes

Before applying an anti-corrosion coating, the surface of the pipes is cleaned from corrosion and scale with mechanical brushes or sandblasters and, if necessary, degreased with organic solvents

Prefabricated heat-insulating structures - the most industrial type of insulation - are manufactured at the factory with anti-corrosion treatment of pipes and with fastening of the cover layer over the main insulation layer. Insulation of joints, fittings, fittings, compensators, etc. products.

Prefabricated complete heat-insulating structures are a complete set of heat-insulating products, coating elements and fasteners in size and diameter.

Appendix 4 shows heat-insulating, prefabricated and complete structures for heating networks.

Suspended heat-insulating structures are the main method of thermal insulation of heat pipelines of above-ground and underground channel laying. It is made of mineral wool, glass wool, volcanic products, lime-silicon and other materials. Appendices 1 and 2 list the permitted materials for the main insulation layer, depending on the method of laying the heating network.

Currently, the manufacture of suspended heat-insulating structures, as a rule, is carried out by assembling piece blanks with fixing with a cover layer and fastening details. The assembly of insulating structures at the installation site from prefabricated elements (segments, strips, mats, shells and half-cylinders) is associated with a large amount of manual labor.

When installing thermal insulation soft materials(plates, mats) when applying the cover layer, the sealing of the material of the heat-insulating layer is inevitable. This must be taken into account when calculating required amount material compaction factor (Appendix 8).

For isolation of stop valves, removable structures of stuffed insulation in the form of mattresses filled with mineral or glass wool, perlite and other heat-insulating material are used. The shell of the mattresses is made of fiberglass.

The cover layer during above-ground laying in the open air, as a rule, performs the functions of a protective coating against the penetration of atmospheric moisture. Folgoizol, foil-roofing material, armored plastic materials, fiberglass, fiberglass, carbon steel sheet and galvanized sheet steel, sheets, tapes and foil from aluminum alloys are used (Appendix 6 and 7).

When laying in impassable channels, cheaper armored plastic materials, fiberglass, fiberglass, glass ruberoid, roofing material are used. In tunnels, it is also allowed to use folgoizol, folgorubsroid and duplicated aluminum foil.

When choosing a material for a protective coating, depending on the method of laying heat pipes, one should be guided by the standards.

The fastening of the cover layer from sheet metal is carried out with self-tapping screws, strips or bandages from a packing tape or bands from an aluminum alloy, a shell made of fiberglass, foil and other materials, fastened with bandages from an aluminum or packing tape, galvanized steel tape and wire. Roofing steel roofing painted with weatherproof paints.

On fig. 1 shows an example of the thermal insulation of a pipeline with soft wool boards.

Wrapping structures are made of stitched mats or soft plates on a synthetic binder, which are sewn with transverse and longitudinal seams. The cover layer is attached in the same way as in suspension insulation.

Wrapping structures in the form of heat-insulating bundles of mineral or glass wool, after being applied to the surface, are also covered protective layer. Isolate joints, fittings, fittings.

Mastic insulation is also used for thermal insulation at the installation site of fittings and equipment. Powdered materials are used: asbestos, asbestos, sovelite. The mass mixed with water is applied to the preheated insulated surface by hand. Mastic insulation is used rarely, as a rule, during repair work.