Thermal conductivity of various materials table. Calculation of the thermal conductivity of the wall

To properly organize and premises, you need to know certain features and properties of materials. The thermal stability of your home directly depends on the quality selection of the necessary values, because if you make a mistake, in the initial calculations you risk making the buildings defective. A detailed thermal conductivity table is provided to help you. building materials described in this article.

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What is thermal conductivity and its significance?

Thermal conductivity is the quantitative property of substances to transmit heat, which is determined by the coefficient. This indicator is equal to the total amount of heat that passes through a homogeneous material having a unit of length, area and time at a single temperature difference. The SI system converts this value into the coefficient of thermal conductivity, this is letter designation looks like this - W / (m * K). Thermal energy spreads through the material through rapidly moving heated particles, which, when colliding with slow and cold particles, transfer a fraction of the heat to them. The better the heated particles are protected from the cold ones, the better the accumulated heat in the material will be retained.

Detailed table of thermal conductivity of building materials

The main feature of thermal insulation materials and building parts is the internal structure and compression ratio of the molecular basis of the raw materials that make up the materials. The values ​​of the thermal conductivity coefficients of building materials are tabularly described below.

Important! To achieve more effective insulation need to compose different materials... The compatibility of surfaces with each other is indicated in the instructions from the manufacturer.

Explanations of indicators in the table of thermal conductivity of materials and insulation: their classification

Depending on the design features the structure that needs to be insulated, the type of insulation is selected. So, for example, if the wall is erected in two rows, then 5 cm thick foam is suitable for complete insulation.

Thanks to a wide range of density of foam sheets, they can perfectly produce thermal insulation of walls from OSB and plaster on top, which will also increase the efficiency of the insulation.

You can familiarize yourself with the level of thermal conductivity, tabularly presented in the photo below.

Thermal insulation classification

By the way of heat transfer thermal insulation materials are divided into two types:

• Insulation that absorbs any effect of cold, heat, chemical attack, etc .;
• Insulation that can reflect all types of impact on it;

According to the value of the thermal conductivity coefficients of the material from which the insulation is made, it is distinguished by classes:

• A class. Such insulation has the lowest thermal conductivity, maximum value which is 0.06 W (m * C);
• B class. It has an average SI parameter and reaches 0.115 W (m * C);
• To the class. Endowed with high thermal conductivity and demonstrates an indicator of 0.175 W (m * C);

Note! Not all insulation materials are resistant to high temperatures... For example, ecowool, straw, chipboard, fiberboard and peat need reliable protection from external conditions.

The main types of heat transfer coefficients of the material. Table + examples

Calculation of the necessary, if applicable outer walls the house comes from the regional placement of the building. To clearly explain how it happens, in the table below, the figures given will relate to the Krasnoyarsk Territory.

Type of material	Heat transfer, W / (m * ° С)	Wall thickness, mm	Illustration
3D		5500
Deciduous tree species with 15%	0,15	1230
Expanded clay concrete	0,2	1630
Foam block with a density of 1 thousand kg / m³	0,3	2450
Conifers along the grain	0,35	2860
Oak lining	0,41	3350
on a mortar of cement and sand	0,87	7110
Reinforced concrete

Each building has a different resistance to heat transfer of materials. The table below, which is an excerpt from SNiP, clearly demonstrates this.

Examples of building insulation depending on thermal conductivity

V modern construction Walls consisting of two or even three layers of material have become the norm. One layer consists of, which is selected after certain calculations. Additionally, you need to find out where the dew point is.

To organize it is necessary to comprehensively use several SNIPs, GOSTs, manuals and SP:

• SNiP 23-02-2003 (SP 50.13330.2012). "Thermal protection of buildings". Edition of 2012;
• SNiP 23-01-99 (SP 131.13330.2012). "Construction climatology". Edition of 2012;
• SP 23-101-2004. "Design of thermal protection of buildings";
• Benefit. E.G. Malyavin “Heat loss of a building. Reference manual ";
• GOST 30494-96 (replaced by GOST 30494-2011 since 2011). “Residential and public buildings. Indoor microclimate parameters ";

Making calculations on these documents, determine thermal features building material, enclosing the structure, resistance to heat transfer and the degree of coincidence with regulatory documents. The calculation parameters based on the thermal conductivity table of the building material are shown in the photo below.

1. Do not be lazy to spend time studying technical literature on the properties of thermal conductivity of materials. This step will minimize financial and heat losses.
2. Don't ignore the climate in your area. Information about GOSTs in this regard can be easily found on the Internet.

   
   Climate peculiarity Mold on the walls Tightening of foam plastic with waterproofing

Today the question is very acute rational use Fuel and energy resources. Ways of saving heat and energy are constantly being worked out in order to ensure energy security for the development of the economy of both the country and each individual family.

The creation of efficient power plants and thermal insulation systems (equipment providing the greatest heat exchange (for example, steam boilers) and, conversely, from which it is undesirable (melting furnaces)) is impossible without knowledge of the principles of heat transfer.

Approaches to thermal protection of buildings have changed, requirements for building materials have increased. Any house needs insulation and a heating system... Therefore, at heat engineering calculation of enclosing structures, the calculation of the thermal conductivity index is important.

Thermal conductivity concept

Thermal conductivity - it is physical property material, in which the thermal energy inside the body passes from the hottest part to the colder one. The value of the thermal conductivity index shows the degree of heat loss in living quarters. Depends on the following factors:

Quantify the property of items to skip thermal energy it is possible by means of the thermal conductivity coefficient. It is very important to make the right choice of building materials, insulation to achieve the greatest resistance to heat transfer. Miscalculations or unreasonable savings in the future can lead to a deterioration of the indoor climate, dampness in the building, wet walls, stuffy rooms. And most importantly - high heating costs.

For comparison, below is a table of thermal conductivity of materials and substances.

Table 1

The highest values ​​are for metals, the lowest for heat-insulating items.

Classification of building materials and their thermal conductivity

The thermal conductivity of reinforced concrete, brickwork, expanded clay concrete blocks, usually used for the construction of enclosing structures, is distinguished by the highest standard indicators. In the construction industry wooden structures are used much less frequently.

Depending on the thermal conductivity values, building materials are divided into classes:

• structural and thermal insulation (from 0.210);
• thermal insulation (up to 0.082 - A, from 0.082 to 0.116 - B, etc.).

Efficiency of sandwich structures

Density and thermal conductivity

Currently there is no such building material, high load bearing capacity which would be combined with low thermal conductivity. Construction of buildings on the principle of multilayer structures allows:

Combination construction material and thermal insulation allows you to ensure strength and reduce the loss of thermal energy to an optimal level. Therefore, when designing walls, each layer of the future enclosing structure is taken into account in the calculations.

It is also important to take into account the density when building a house and when insulating it.

The density of a substance is a factor affecting its thermal conductivity, the ability to retain the main heat insulator - air.

Calculation of the thickness of walls and insulation

The calculation of the wall thickness depends on the following indicators:

• density;
• calculated thermal conductivity;
• heat transfer resistance coefficient.

According to the established standards, the value of the heat transfer resistance index of the outer walls must be at least 3.2λ W / m ° C.

Payment thickness of walls made of reinforced concrete and other structural materials is presented in Table 2. Such building materials are characterized by high load-bearing characteristics, they are durable, but as thermal protection they are ineffective and require irrational wall thickness.

table 2

Structural and thermal insulation materials are capable of being subjected to sufficiently high loads, while significantly increasing the thermal and acoustic properties of buildings in wall enclosing structures (Table 3.1, 3.2).

Table 3.1

Table 3.2

Thermal insulation building materials can significantly increase the thermal protection of buildings and structures. The data in Table 4 show that the smallest values ​​of the coefficient of thermal conductivity have polymers, mineral wool, plates from natural organic and inorganic materials.

Table 4

The values ​​of the tables of thermal conductivity of building materials are used in calculations:

The task of choice optimal materials for construction, of course, implies more A complex approach... However, even such simple calculations make it possible to determine the most suitable materials and their number.

Methodological material for self-calculation of the thickness of the walls of the house with examples and theoretical part.

Part 1. Resistance to heat transfer - the primary criterion for determining the thickness of the wall

To determine the thickness of the wall, which is necessary to comply with energy efficiency standards, calculate the resistance to heat transfer of the designed structure, in accordance with section 9 "Methodology for designing thermal protection of buildings" SP 23-101-2004.

Resistance to heat transfer is a property of a material that indicates how much a given material is capable of retaining heat. This is a specific value that shows how slowly heat is lost in watts when a heat flow passes through a unit volume with a temperature difference on the walls of 1 ° C. The higher the value of this coefficient, the “warmer” the material.

All walls (opaque enclosing structures) are considered for thermal resistance according to the formula:

R = δ / λ (m 2 ° С / W), where:

δ - material thickness, m;

λ - specific thermal conductivity, W / (m · ° С) (can be taken from the passport data of the material or from tables).

The resulting value of R total is compared with the table value in SP 23-101-2004.

To target normative document it is necessary to calculate the amount of heat required to heat the building. It is performed according to SP 23-101-2004, the resulting value is "degree · day". The rules recommend the following ratios.

The results obtained must be verified with the norms of clause 5. SNiP 23-02-2003 "Thermal protection of buildings".

You should also take into account the climatic conditions of the zone where the building is being erected: for different regions different requirements due to different temperature and humidity conditions. Those. the thickness of the wall from the gas block should not be the same for the seaside region, middle lane Russia and the Far North. In the first case, it will be necessary to adjust the thermal conductivity taking into account humidity (upward: high humidity reduces thermal resistance), in the second - you can leave it "as is", in the third - be sure to take into account that the thermal conductivity of the material will increase due to the greater temperature difference.

Part 2. Coefficient of thermal conductivity of wall materials

The coefficient of thermal conductivity of wall materials is a value that shows the thermal conductivity of the wall material, i.e. how much heat is lost when the heat flow passes through a conditional unit volume with a temperature difference on its opposite surfaces of 1 ° C. The lower the value of the coefficient of thermal conductivity of the walls - the warmer the building will turn out, the higher the value - the more power will have to be put into the heating system.

In fact, this is the reciprocal of the thermal resistance considered in part 1 of this article. But this only applies to specific values ​​for ideal conditions. The real coefficient of thermal conductivity for a particular material is influenced by a number of conditions: the temperature difference on the walls of the material, the internal heterogeneous structure, the level of humidity (which increases the level of density of the material, and, accordingly, increases its thermal conductivity) and many other factors. As a rule, the tabular thermal conductivity must be reduced by at least 24% to obtain optimal design for temperate climates.

Part 3. Minimum permissible wall resistance for different climatic zones.

The minimum allowable thermal resistance is calculated to analyze the thermal properties of the designed wall for different climatic zones. This is a normalized (base) value that shows what the thermal resistance of the wall should be, depending on the region. First, you choose the material for the structure, calculate the thermal resistance of your wall (part 1), and then compare it with the tabular data contained in SNiP 23-02-2003. In the event that the obtained value is less than the established by the rules, then it is necessary either to increase the thickness of the wall, or to insulate the wall insulating layer(for example, mineral wool).

According to clause 9.1.2 of SP 23-101-2004, the minimum allowable resistance to heat transfer R o (m 2 ° C / W) of the enclosing structure is calculated as

R about = R 1 + R 2 + R 3, where:

R 1 = 1 / α vn, where α vn is the heat transfer coefficient of the inner surface of the enclosing structures, W / (m 2 × ° С), taken according to table 7 of SNiP 23-02-2003;

R 2 = 1 / α ext, where α ext is the heat transfer coefficient of the outer surface of the enclosing structure for the conditions of the cold period, W / (m 2 × ° C), taken according to table 8 of SP 23-101-2004;

R 3 - total thermal resistance, the calculation of which is described in part 1 of this article.

If there is a layer ventilated with outside air in the enclosing structure, the layers of the structure located between the air gap and the outer surface are not taken into account in this calculation. And on the surface of the structure facing the air-ventilated layer outside, the heat transfer coefficient α external should be taken to be 10.8 W / (m 2 ° C).

Table 2. Standardized values ​​of thermal resistance for walls according to SNiP 23-02-2003.

The adjusted values ​​of the degree-day of the heating period are shown in table 4.1. reference manual to SNiP 23-01-99 * Moscow, 2006.

Part 4. Calculation of the minimum permissible wall thickness on the example of aerated concrete for the Moscow region.

When calculating the thickness of the wall structure, we take the same data as indicated in Part 1 of this article, but we rebuild the basic formula: δ = λ R, where δ is the wall thickness, λ is the thermal conductivity of the material, and R is the thermal resistance norm according to SNiP.

Calculation example the minimum wall thickness of aerated concrete with a thermal conductivity of 0.12 W / m ° С in the Moscow region with average temperature inside the house during the heating season + 22 ° С.

1. We take the normalized thermal resistance for walls in the Moscow region for a temperature of + 22 ° C: R req = 0.00035 5400 + 1.4 = 3.29 m 2 ° C / W
2. Thermal conductivity coefficient λ for aerated concrete grade D400 (dimensions 625x400x250 mm) with a moisture content of 5% = 0.147 W / m ∙ ° С.
3. The minimum wall thickness of aerated concrete stone D400: R λ = 3.29 0.147 W / m ∙ ° С = 0.48 m.

Conclusion: for Moscow and the region for the construction of walls with given parameter heat resistance is needed aerated concrete block with a width of at least 500 mm, or a block with a width of 400 mm and subsequent insulation (mineral wool + plastering, for example), to ensure the characteristics and requirements of SNiP in terms of energy efficiency wall structures.

Table 3. The minimum thickness of walls erected from various materials, corresponding to the norms of thermal resistance according to SNiP.

Part 5. The principle of determining the value of heat transfer resistance in a multilayer wall.

If you plan to build a wall from several types of material (for example, building stone + mineral insulation + plaster), then R is calculated for each type of material separately (using the same formula), and then it is summed up:

R total = R 1 + R 2 + ... + R n + R a.l where:

R 1 -R n - thermal resistance of different layers

R a.l - closed loop resistance air gap if it is present in the construction ( table values are taken in SP 23-101-2004, p. 9, tab. 7)

An example of calculating the thickness of a mineral wool insulation for a multilayer wall (cinder block - 400 mm, mineral wool-? mm, facing brick- 120 mm) with a heat transfer resistance value of 3.4 m 2 * Grad C / W (Orenburg).

R = Rslag block + Rbrick + Rvat = 3.4

R slag block = δ / λ = 0.4 / 0.45 = 0.89 m 2 × ° С / W

Rbrick = δ / λ = 0.12 / 0.6 = 0.2 m 2 × ° С / W

R slag block + R brick = 0.89 + 0.2 = 1.09 m 2 × ° С / W (<3,4).

Rvata = R- (Rslag block + Rbrick) = 3.4-1.09 = 2.31 m 2 × ° С / W

δvat = Rvata λ = 2.31 * 0.045 = 0.1 m = 100 mm (we take λ = 0.045 W / (m × ° C) - the average value of thermal conductivity for various types of mineral wool).

Conclusion: in order to comply with the requirements for heat transfer resistance, expanded clay concrete blocks can be used as the main structure with its lining with ceramic bricks and an interlayer of mineral wool with a thermal conductivity of at least 0.45 and a thickness of 100 mm or more.

Questions and answers on the topic

One of the most important indicators of building materials, especially in the Russian climate, is their thermal conductivity, which is generally defined as the ability of a body to heat exchange (that is, to distribute heat from a hotter environment to a colder one).

In this case, the colder environment is the street, and the hotter one is the interior space (in summer it is often the other way around). Comparative characteristics are shown in the table:

The coefficient is calculated as the amount of heat that will pass through a material 1 meter thick in 1 hour with a temperature difference between inside and outside of 1 degree Celsius. Accordingly, the unit of measurement for building materials is W / (m * oC) - 1 Watt, divided by the product of a meter and a degree.

Comparison of thermal conductivity of building materials, as well as their density and vapor permeability is presented in the table.

The most effective materials used in the construction of houses are highlighted in bold.

Below is a pictorial diagram from which it is easy to see how thick a wall of different materials should have in order for it to hold the same amount of heat.

Obviously, according to this indicator, there is an advantage over artificial materials (for example, expanded polystyrene).

Roughly the same picture can be seen if you draw a diagram of the building materials that are most often used in work.

In this case, environmental conditions are of great importance. Below is a table of thermal conductivity of building materials that are used:

• under normal conditions (A);
• in conditions of high humidity (B);
• in an arid climate.

The data was taken on the basis of the relevant building codes and regulations (SNiP II-3-79), as well as from open Internet sources (web pages of the manufacturers of the relevant materials). If there are no data on specific operating conditions, then the field in the table is not filled.

The higher the indicator, the more heat it passes, all other things being equal. So, for some types of expanded polystyrene, this indicator is 0.031, and for polyurethane foam - 0.041. On the other hand, concrete has an order of magnitude higher coefficient - 1.51, therefore, it transmits heat much better than artificial materials.

Comparative heat losses through different surfaces of the house can be seen in the diagram (100% - total losses).

Obviously, most of it leaves the walls, so finishing this part of the room is the most important task, especially in a northern climate.

Video for reference

The use of materials with low thermal conductivity in the insulation of houses

Mainly today artificial materials are used - polystyrene, mineral wool, polyurethane foam, expanded polystyrene and others. They are very effective, affordable and easy enough to install without requiring any special work skills.

• when erecting walls (their smaller thickness is required, since it is the heat-insulating materials that take the main load to save heat);
• when servicing the house (less resources are spent on heating).

Styrofoam

It is one of the leaders in its category, which is widely used in wall insulation both outside and inside. The coefficient is approximately 0.052-0.055 W / (оС * m).

How to choose a quality insulation

When choosing a specific sample, it is important to pay attention to the marking - it is it that contains all the basic information that affects the properties.

For example, PSB-S-15 means the following:

Mineral wool

Another fairly common insulation that is used both in interior and exterior decoration of premises is mineral wool.

The material is quite durable, inexpensive and easy to install. At the same time, unlike foam, it absorbs moisture well, therefore, when using it, it is necessary to use waterproofing materials, which increases the cost of installation work.

Accurate data will allow you to obtain a table of thermal conductivity of building materials. Correct construction of buildings contributes to optimal climatic parameters in the room.

It is better to start the construction of each object with the planning of the project and a careful calculation of the heat engineering parameters. Accurate data will allow you to obtain a table of thermal conductivity of building materials. Correct construction of buildings contributes to optimal climatic parameters in the room. And the table will help you choose the right raw materials that will be used for construction.

Appointment of thermal conductivity

Thermal conductivity is a measure of the transfer of thermal energy from heated objects in a room to objects with a lower temperature. The heat exchange process is carried out until the temperature indicators equalize. To designate thermal energy, a special coefficient of thermal conductivity of building materials is used. The table will help you see all the required values. The parameter denotes how much heat energy is passed through a unit of area per unit of time. The larger this designation, the better the heat transfer will be. When erecting buildings, it is necessary to use a material with a minimum value of thermal conductivity.

The coefficient of thermal conductivity is such a value that is equal to the amount of heat passing through a meter of material thickness per hour. The use of such a characteristic is imperative to create better thermal insulation. Thermal conductivity should be taken into account when selecting additional insulation structures.

What influences the thermal conductivity index?

Thermal conductivity is determined by such factors:

Porosity determines the heterogeneity of the structure. When heat is passed through such materials, the cooling process is negligible;

An increased density value affects close contact of particles, which contributes to faster heat transfer;

High humidity increases this indicator.

Using the values ​​of the thermal conductivity coefficient in practice.

Materials are presented in structural and heat-insulating varieties. The first type has high thermal conductivity. They are used for the construction of floors, fences and walls.

Using the table, the possibilities of their heat transfer are determined. In order for this indicator to be low enough for a normal microclimate in the room, walls made of some materials must be especially thick. To avoid this, it is recommended to use additional thermal insulating components.

Thermal conductivity indicators for finished buildings. Types of insulation.

When creating a project, you need to take into account all the methods of heat leakage. It can exit through walls and roofs, as well as through floors and doors. If you incorrectly carry out the design calculations, then you will have to be content with only the thermal energy received from the heating devices. Buildings built from standard raw materials: stone, brick or concrete must be additionally insulated.

Additional thermal insulation is carried out in frame buildings. At the same time, the wooden frame gives the structure rigidity, and the insulating material is laid in the space between the posts. In buildings made of bricks and cinder blocks, insulation is carried out outside the structure.

When choosing heaters, you need to pay attention to factors such as the level of humidity, the effect of high temperatures and the type of structure. Consider certain parameters of insulating structures:

The thermal conductivity index affects the quality of the heat-insulating process;

Moisture absorption is of great importance when insulating external elements;

Thickness affects the reliability of insulation. Thin insulation helps to preserve the useful area of ​​the room;

Flammability is important. High-quality raw materials have the ability to self-extinguish;

Thermal stability reflects the ability to withstand temperature changes;

Environmental friendliness and safety;

Sound insulation protects against noise.

The following types are used as heaters:

Mineral wool is fire resistant and environmentally friendly. Important characteristics include low thermal conductivity;

Polyfoam is a lightweight material with good insulation properties. It is easy to install and is moisture resistant. Recommended for use in non-residential buildings;

Basalt wool, in contrast to mineral wool, is distinguished by the best indicators of resistance to moisture;

Penoplex is resistant to humidity, high temperatures and fire. Has excellent thermal conductivity, is easy to install and durable;

Polyurethane foam is known for such qualities as incombustibility, good water repellency and high fire resistance;

Extruded polystyrene foam undergoes additional processing during production. Has a uniform structure;

Penofol is a multilayer insulating layer. The composition contains foamed polyethylene. The surface of the plate is covered with foil to provide reflection.

Bulk types of raw materials can be used for thermal insulation. These are paper pellets or perlite. They are resistant to moisture and fire. Organic varieties include wood fiber, flax, or cork. When choosing, pay special attention to indicators such as environmental friendliness and fire safety.

NOTE! When designing thermal insulation, it is important to consider the installation of a waterproofing layer. This will avoid high humidity and increase the resistance to heat transfer.

Thermal conductivity table of building materials: features of indicators.

The table of thermal conductivity of building materials contains indicators of various types of raw materials that are used in construction. Using this information, you can easily calculate the thickness of the walls and the amount of insulation.

How to use the table of thermal conductivity of materials and insulation?

The most popular materials are presented in the table of resistance to heat transfer of materials. When choosing a specific option for thermal insulation, it is important to take into account not only physical properties, but also characteristics such as durability, price and ease of installation.

Did you know that the easiest way is to install foam insulation and polyurethane foam. They spread over the surface in the form of foam. Such materials easily fill the cavities of structures. When comparing hard versus foam options, it should be emphasized that the foam does not form joints.

The values ​​of the heat transfer coefficients of materials in the table.

When making calculations, you should know the coefficient of resistance to heat transfer. This value is the ratio of the temperatures on both sides to the amount of heat flow. In order to find the thermal resistance of certain walls, a thermal conductivity table is used.

You can do all the calculations yourself. For this, the thickness of the heat insulator layer is divided by the thermal conductivity coefficient. This value is often indicated on the packaging if it is insulation. Household materials are measured independently. This concerns the thickness, and the coefficients can be found in special tables.

The coefficient of resistance helps to select a specific type of thermal insulation and the thickness of the material layer. Information on vapor permeability and density can be found in the table.

With the correct use of tabular data, you can choose high-quality material to create a favorable indoor climate. published by