The term thermal conductivity is applied to the ability of materials to transmit thermal energy from hot to cold areas. Thermal conductivity is based on the movement of particles within substances and materials. The ability to transfer heat energy in quantitative measurement is the thermal conductivity coefficient. The cycle of thermal energy transfer, or heat exchange, can take place in any substance with an unequal distribution of different temperature sections, but the thermal conductivity coefficient depends on the pressure and temperature in the material itself, as well as on its state - gaseous, liquid or solid.
Physically, the thermal conductivity of materials is equal to the amount of heat that flows through a homogeneous object of established dimensions and area over a certain time period at a specified temperature difference (1 K). In the SI system, a unit indicator, which has a thermal conductivity coefficient, is usually measured in W/(m K).
How to calculate thermal conductivity using Fourier's law
In a given thermal regime, the flux density during heat transfer is directly proportional to the vector of the maximum increase in temperature, the parameters of which vary from one area to another, and modulo with the same rate of increase in temperature in the direction of the vector:
q → = − ϰ x grad x (T), where:
- q → – the direction of the density of an object transmitting heat, or the volume of heat flow that flows through an area for a given time unit through a certain area, perpendicular to all axes;
- ϰ – specific thermal conductivity coefficient of the material;
- T – temperature of the material.
When applying Fourier's law, the inertia of the flow of thermal energy is not taken into account, which means that we mean the instantaneous transfer of heat from any point to any distance. Therefore, the formula cannot be used to calculate heat transfer during processes that have high frequency repetitions. This is ultrasonic radiation, the transfer of thermal energy by shock or pulse waves, etc. There is a solution according to Fourier's law with a relaxation term:
τ x ∂ q / ∂ t = − (q + ϰ x ∇T) .
If relaxation τ is instantaneous, then the formula turns into Fourier’s law.
Approximate table of thermal conductivity of materials:
| The basis | Thermal conductivity value, W/(m K) |
| Hard graphene | 4840 + / – 440 – 5300 + / – 480 |
| Diamond | 1001-2600 |
| Graphite | 278,4-2435 |
| Boron arsenide | 200-2000 |
| SiC | 490 |
| Ag | 430 |
| Cu | 401 |
| BeO | 370 |
| Au | 320 |
| Al | 202-236 |
| AlN | 200 |
| BN | 180 |
| Si | 150 |
| Cu 3 Zn 2 | 97-111 |
| Cr | 107 |
| Fe | 92 |
| Pt | 70 |
| Sn | 67 |
| ZnO | 54 |
| Black steel | 47-58 |
| Pb | 35,3 |
| Stainless steel | Thermal conductivity of steel – 15 |
| SiO2 | 8 |
| High quality heat resistant pastes | 5-12 |
| Granite (consists of SiO 2 68-73%; Al 2 O 3 12.0-15.5%; Na 2 O 3.0-6.0%; CaO 1.5-4.0%; FeO 0.5- 3.0%; Fe 2 O 3 0.5-2.5%; K 2 O 0.5-3.0%; MgO 0.1-1.5%; TiO 2 0.1-0.6% ) | 2,4 |
| Concrete mortar without aggregates | 1,75 |
| Concrete mortar with crushed stone or gravel | 1,51 |
| Basalt (consists of SiO 2 – 47-52%, TiO 2 – 1-2.5%, Al2O 3 – 14-18%, Fe 2 O 3 – 2-5%, FeO – 6-10%, MnO – 0, 1-0.2%, MgO – 5-7%, CaO – 6-12%, Na 2 O – 1.5-3%, K 2 O – 0.1-1.5%, P 2 O 5 – 0.2-0.5%) | 1,3 |
| Glass (consists of SiO 2, B 2 O 3, P 2 O 5, TeO 2, GeO 2, AlF 3, etc.) | 1-1,15 |
| Heat-resistant paste KPT-8 | 0,7 |
| Concrete mortar filled with sand, without crushed stone or gravel | 0,7 |
| The water is clean | 0,6 |
| Silicate or red brick | 0,2-0,7 |
| Oils silicone based | 0,16 |
| Foam concrete | 0,05-0,3 |
| Aerated concrete | 0,1-0,3 |
| Tree | Thermal conductivity of wood – 0.15 |
| Oils petroleum based | 0,125 |
| Snow | 0,10-0,15 |
| PP with flammability group G1 | 0,039-0,051 |
| EPPU with flammability group G3, G4 | 0,03-0,033 |
| Glass wool | 0,032-0,041 |
| Stone wool | 0,035-0,04 |
| Air atmosphere (300 K, 100 kPa) | 0,022 |
| Gel air based | 0,017 |
| Argon (Ar) | 0,017 |
| Vacuum environment | 0 |
The given thermal conductivity table takes into account heat transfer through thermal radiation and particle heat exchange. Since a vacuum does not transfer heat, it flows using solar radiation or other type of heat generation. In a gas or liquid environment, layers with different temperatures mixed artificially or in a natural way.
When calculating the thermal conductivity of a wall, it is necessary to take into account that heat transfer through wall surfaces varies due to the fact that the temperature in the building and outside is always different, and depends on the area of all surfaces of the house and on the thermal conductivity of building materials.
To quantify thermal conductivity, a value such as the thermal conductivity coefficient of materials was introduced. It shows how a particular material is capable of transferring heat. The higher this value, for example the thermal conductivity coefficient of steel, the more efficiently the steel will conduct heat.
- When insulating a house made of wood, it is recommended to choose building materials with a low coefficient.
- If the wall is brick, then with a coefficient value of 0.67 W/(m2 K) and a wall thickness of 1 m and its area of 1 m2, with a difference in external and internal temperatures of 1 0 C, the brick will transmit 0.67 W of energy. With a temperature difference of 10 0 C, the brick will transmit 6.7 W, etc.
Standard value of thermal conductivity coefficient of thermal insulation and others building materials true for a wall thickness of 1 m. To calculate the thermal conductivity of a surface of a different thickness, the coefficient should be divided by the selected value of the wall thickness (meters). 
In SNiP and when carrying out calculations, the term “thermal resistance of the material” appears; it means reverse thermal conductivity. That is, with a thermal conductivity of a foam sheet of 10 cm and its thermal conductivity of 0.35 W/(m 2 K), the thermal resistance of the sheet is 1 / 0.35 W/(m 2 K) = 2.85 (m 2 K)/W.
Below is a table of thermal conductivity for popular building materials and thermal insulators:
| Construction materials | Thermal conductivity coefficient, W/(m 2 K) |
| Alabaster slabs | 0,47 |
| Al | 230 |
| Asbestos-cement slate | 0,35 |
| Asbestos (fiber, fabric) | 0,15 |
| Asbestos cement | 1,76 |
| Asbestos-cement products | 0,35 |
| Asphalt | 0,73 |
| Asphalt for flooring | 0,84 |
| Bakelite | 0,24 |
| Concrete with crushed stone filler | 1,3 |
| Sand filled concrete | 0,7 |
| Porous concrete - foam and aerated concrete | 1,4 |
| Solid concrete | 1,75 |
| Thermal insulating concrete | 0,18 |
| Bitumen mass | 0,47 |
| Paper materials | 0,14 |
| Loose mineral wool | 0,046 |
| Heavy mineral wool | 0,05 |
| Cotton wool is a cotton-based heat insulator | 0,05 |
| Vermiculite in slabs or sheets | 0,1 |
| Felt | 0,046 |
| Gypsum | 0,35 |
| Alumina | 2,33 |
| Gravel aggregate | 0,93 |
| Granite or basalt aggregate | 3,5 |
| Wet soil, 10% | 1,75 |
| Wet soil, 20% | 2,1 |
| Sandstones | 1,16 |
| Dry soil | 0,4 |
| Compacted soil | 1,05 |
| Tar mass | 0,3 |
| Construction board | 0,15 |
| Plywood sheets | 0,15 |
| Hardwood | 0,2 |
| Chipboard | 0,2 |
| Duralumin products | 160 |
| Reinforced concrete products | 1,72 |
| Ash | 0,15 |
| Limestone blocks | 1,71 |
| Mortar on sand and lime | 0,87 |
| Foamed resin | 0,037 |
| Natural stone | 1,4 |
| Cardboard sheets made of several layers | 0,14 |
| Porous rubber | 0,035 |
| Rubber | 0,042 |
| Rubber with fluorine | 0,053 |
| Expanded clay concrete blocks | 0,22 |
| Red brick | 0,13 |
| Hollow brick | 0,44 |
| Solid brick | 0,81 |
| Solid brick | 0,67 |
| Slag brick | 0,58 |
| Silica based slabs | 0,07 |
| Brass products | 110 |
| Ice at a temperature of 0 0 C | 2,21 |
| Ice at a temperature of -20 0 C | 2,44 |
| Deciduous tree at 15% humidity | 0,15 |
| Copper products | 380 |
| Mipora | 0,086 |
| Sawdust for filling | 0,096 |
| Dry sawdust | 0,064 |
| PVC | 0,19 |
| Foam concrete | 0,3 |
| Polystyrene foam brand PS-1 | 0,036 |
| Polystyrene foam brand PS-4 | 0,04 |
| Polystyrene foam grade PVC-1 | 0,05 |
| Polystyrene foam brand FRP | 0,044 |
| PPU brand PS-B | 0,04 |
| PPU brand PS-BS | 0,04 |
| Polyurethane foam sheet | 0,034 |
| Polyurethane foam panel | 0,024 |
| Lightweight foam glass | 0,06 |
| Heavy foam glass | 0,08 |
| Glassine products | 0,16 |
| Perlite products | 0,051 |
| Slabs on cement and perlite | 0,085 |
| Wet sand 0% | 0,33 |
| Wet sand 0% | 0,97 |
| Wet sand 20% | 1,33 |
| Burnt stone | 1,52 |
| Ceramic tile | 1,03 |
| PMTB-2 brand tiles | 0,035 |
| Polystyrene | 0,081 |
| Foam rubber | 0,04 |
| Cement based mortar without sand | 0,47 |
| Natural cork slab | 0,042 |
| Lightweight natural cork sheets | 0,034 |
| Heavy sheets of natural cork | 0,05 |
| Rubber products | 0,15 |
| Ruberoid | 0,17 |
| Slate | 2,100 |
| Snow | 1,5 |
| Coniferous wood with a moisture content of 15% | 0,15 |
| Coniferous resinous wood with a moisture content of 15% | 0,23 |
| Steel products | 52 |
| Glass products | 1,15 |
| Glass wool insulation | 0,05 |
| Fiberglass insulation | 0,034 |
| Fiberglass products | 0,31 |
| Shavings | 0,13 |
| Teflon coating | 0,26 |
| Tol | 0,24 |
| Cement mortar board | 1,93 |
| Cement-sand mortar | 1,24 |
| Cast iron products | 57 |
| Slag in granules | 0,14 |
| Ash slag | 0,3 |
| Cinder blocks | 0,65 |
| Dry plaster mixtures | 0,22 |
| Cement based plaster mortar | 0,95 |
| Ebonite products | 0,15 |
In addition, it is necessary to take into account the thermal conductivity of insulation materials due to their jet heat flows. In a dense environment, it is possible to “transfuse” quasiparticles from one heated building material to another, colder or warmer, through submicron-sized pores, which helps distribute sound and heat, even if there is an absolute vacuum in these pores.
What is thermal conductivity? Not only professional builders need to know about this value, but also ordinary people who decide to build a house on their own.
Each material used in construction has its own indicator of this value. Its lowest value is for insulation materials, the highest for metals. Therefore, you need to know the formula that will help calculate the thickness of both the walls being built and the thermal insulation in order to ultimately get a cozy home.
Comparison of heat conductivity of the most common insulation materials
To have an idea of heat conductivity different materials intended for insulation, you need to compare their coefficients (W/m*K) given in the following table:
As can be seen from the above data, the thermal conductivity index of building materials such as thermal insulation varies from minimum (0.019) to maximum (0.5). All thermal insulation materials have a certain range of readings. SNiPs describe each of them in several forms - dry, normal and wet. The minimum thermal conductivity coefficient corresponds to a dry state, the maximum to a wet state.
If individual construction is planned
When building a house, it is important to consider specifications all components (wall material, masonry mortar, future insulation, waterproofing and steam-removing films, finishing).
To understand which walls the best way will retain heat, you need to analyze the thermal conductivity coefficient not only of the wall material, but also mortar, as can be seen from the table below:
| Order number | Wall material, mortar | Thermal conductivity coefficient according to SNiP |
| 1. | Brick | 0,35 – 0,87 |
| 2. | Adobe blocks | 0,1 – 0,44 |
| 3. | Concrete | 1,51 – 1,86 |
| 4. | Foam concrete and cement-based aerated concrete | 0,11 – 0,43 |
| 5. | Foam concrete and lime-based aerated concrete | 0,13 – 0,55 |
| 6. | Cellular concrete | 0,08 – 0,26 |
| 7. | Ceramic blocks | 0,14 – 0,18 |
| 8. | Cement-sand mortar | 0,58 – 0,93 |
| 9. | Mortar with added lime | 0,47 – 0,81 |
Important . From the data given in the table it can be seen that each building material has a fairly large spread in the thermal conductivity coefficient.
This is due to several reasons:
- Density. All insulation materials are produced or laid (penoizol, ecowool) various densities. The lower the density (more air is present in the insulating structure), the lower the heat conductivity. And, conversely, for very dense insulation materials this coefficient is higher.
- The substance from which it is produced (base). For example, brick can be silicate, ceramic, or clay. The thermal conductivity coefficient also depends on this.
- Number of voids. This applies to bricks (hollow and solid) and thermal insulation. Air is the worst conductor of heat. Its thermal conductivity coefficient is 0.026. The more voids, the lower this figure.
Mortar conducts heat well, so it is recommended to insulate any walls.
If you explain it on your fingers
For clarity and understanding of what thermal conductivity is, you can compare a brick wall, 2 m 10 cm thick, with other materials. Thus, 2.1 meters of brick stacked into a wall on an ordinary cement-sand mortar are equal:
- a 0.9 m thick wall made of expanded clay concrete;
- timber, diameter 0.53 m;
- wall, 0.44 m thick, made of aerated concrete.
If we are talking about such common insulation materials as mineral wool and expanded polystyrene, then only 0.18 m of the first thermal insulation or 0.12 m of the second is required for the thermal conductivity values to be enormous brick wall turned out to be equal to a thin layer of thermal insulation.
Comparative characteristics of thermal conductivity of insulation, construction and finishing materials, which can be done by studying SNiPs, allows you to analyze and correctly compose an insulating pie (base, insulation, finishing). The lower the thermal conductivity, the higher the price. A striking example is the walls of a house made of ceramic blocks or ordinary high-quality bricks. The former have a thermal conductivity of only 0.14 - 0.18 and are much more expensive than any of the best bricks.
Construction business involves the use of any suitable materials. The main criteria are safety for life and health, thermal conductivity, and reliability. This is followed by price, aesthetic properties, versatility of use, etc.
Let's consider one of the most important characteristics building materials - thermal conductivity coefficient, since it is on this property that, for example, the level of comfort in the house largely depends.
Theoretically, and practically too, building materials, as a rule, create two surfaces - external and internal. From a physics point of view, a warm region always tends towards a cold region.
In relation to building materials, heat will tend from one surface (warmer) to another surface (less warm). In fact, the ability of a material to undergo such a transition is called the thermal conductivity coefficient, or in the abbreviation KTP.
Diagram explaining the effect of thermal conductivity: 1 – thermal energy; 2 – thermal conductivity coefficient; 3 – temperature of the first surface; 4 – temperature of the second surface; 5 – thickness of building material
The characteristics of the CTS are usually based on tests, when an experimental specimen measuring 100x100 cm is taken and a thermal effect is applied to it, taking into account the temperature difference of two surfaces of 1 degree. Exposure time 1 hour.
Accordingly, thermal conductivity is measured in Watts per meter per degree (W/m°C). The coefficient is denoted by the Greek symbol λ.
Default, thermal conductivity various materials for construction with a value less than 0.175 W/m°C, equates these materials to the category of insulating.
Modern production has mastered technologies for the production of building materials whose CTP level is less than 0.05 W/m°C. Thanks to such products, it is possible to achieve a pronounced economic effect in terms of energy consumption.
Influence of factors on the level of thermal conductivity
Each individual building material has a specific structure and has a unique physical state.
The basis of this are:
- dimension of crystal structure;
- phase state of matter;
- degree of crystallization;
- anisotropy of thermal conductivity of crystals;
- volume of porosity and structure;
- direction of heat flow.
All these are influencing factors. The level of CTP also has a certain influence chemical composition and impurities. The amount of impurities, as practice has shown, has a particularly pronounced effect on the level of thermal conductivity of crystalline components.
Insulating building materials are a class of products for construction, created taking into account the properties of PTS, close to optimal properties. However, achieving ideal thermal conductivity while maintaining other qualities is extremely difficult.
In turn, the PTS is influenced by the operating conditions of the building material - temperature, pressure, humidity level, etc.
Building materials with minimal package transformer
According to research, dry air has a minimum thermal conductivity value (about 0.023 W/m°C).
From the point of view of using dry air in the structure of a building material, a structure is needed where dry air resides inside numerous closed spaces of small volume. Structurally, this configuration is represented in the form of numerous pores inside the structure.
Hence the logical conclusion: a building material whose internal structure is a porous formation should have a low level of CFC.
Moreover, depending on the maximum permissible porosity of the material, the thermal conductivity value approaches the value of the thermal conductivity of dry air.
The creation of a building material with minimal thermal conductivity is facilitated by a porous structure. The more pores of different volumes are contained in the structure of the material, the better CTP can be obtained
IN modern production Several technologies are used to obtain the porosity of a building material.
In particular, the following technologies are used:
- foaming;
- gas formation;
- water sealing;
- swelling;
- introduction of additives;
- creating fiber scaffolds.
It should be noted: the thermal conductivity coefficient is directly related to properties such as density, heat capacity, and temperature conductivity.
The thermal conductivity value can be calculated using the formula:
λ = Q / S *(T 1 -T 2)*t,
- Q- The amount of heat;
- S– material thickness;
- T1, T2– temperature on both sides of the material;
- t- time.
The average value of density and thermal conductivity is inversely proportional to the value of porosity. Therefore, based on the density of the structure of the building material, the dependence of thermal conductivity on it can be calculated as follows:
λ = 1.16 √ 0.0196+0.22d 2 – 0.16,
Where: d– density value. This is the formula of V.P. Nekrasov, demonstrating the influence of the density of a particular material on the value of its CFC.
The influence of moisture on the thermal conductivity of building materials
Again, judging by the examples of the use of building materials in practice, it turns out Negative influence moisture on the PTS of building materials. It has been noticed that the more moisture the building material is exposed to, the higher the CTP value becomes.
In various ways they strive to protect the material used in construction from moisture. This measure is fully justified, given the increase in the coefficient for wet building materials
It is not difficult to justify this point. The effect of moisture on the structure of a building material is accompanied by humidification of the air in the pores and partial replacement of the air environment.
Considering that the thermal conductivity parameter for water is 0.58 W/m°C, a significant increase in the thermal conductivity of the material becomes clear.
It should also be noted that there is a more negative effect when water entering the porous structure is additionally frozen and turns into ice.
One of the reasons for refusing winter construction In favor of construction in the summer, it is precisely the factor of possible freezing of some types of building materials and, as a consequence, an increase in thermal conductivity that should be considered
From here it becomes obvious construction requirements regarding the protection of insulating building materials from moisture. After all, the level of thermal conductivity increases in direct proportion to the quantitative humidity.
Another point seems no less significant - the opposite, when the structure of the building material is subjected to significant heating. Excessively heat also provokes an increase in thermal conductivity.
This happens due to an increase in the kinematic energy of the molecules that make up the structural basis of the building material.
True, there is a class of materials whose structure, on the contrary, acquires best properties thermal conductivity in high heating mode. One such material is metal.
If, under strong heating, most of the widely used building materials change their thermal conductivity towards an increase, strong heating of the metal leads to the opposite effect - the thermal conductivity of the metal decreases
Methods for determining the coefficient
Different techniques are used in this direction, but in fact all measurement technologies are united by two groups of methods:
- Stationary measurement mode.
- Non-stationary measurement mode.
The stationary technique involves working with parameters that remain unchanged over time or change to a small extent. This technology, according to practical applications, allows us to count on more accurate results of QFT.
The stationary method allows for actions aimed at measuring thermal conductivity to be carried out in a wide temperature range – 20 – 700 °C. But at the same time, stationary technology is considered a labor-intensive and complex technique that requires large quantity execution time.
An example of a device designed to measure thermal conductivity. This is one of the modern digital designs that provides fast and accurate results.
Another measurement technology, non-stationary, seems to be more simplified, requiring from 10 to 30 minutes to complete the work. However, in this case the temperature range is significantly limited. However, the technique has found wide application in the manufacturing sector.
Table of thermal conductivity of building materials
It makes no sense to measure many existing and widely used building materials.
All these products, as a rule, have been tested repeatedly, on the basis of which a table of thermal conductivity of building materials has been compiled, which includes almost all materials needed at a construction site.
One of the options for such a table is presented below, where KTP is the thermal conductivity coefficient:
| Material (building material) | Density, m 3 | KTP dry, W/mºC | % humidity_1 | % humidity_2 | KTP at humidity_1, W/mºC | KTP at humidity_2, W/mºC | |||
| Roofing bitumen | 1400 | 0,27 | 0 | 0 | 0,27 | 0,27 | |||
| Roofing bitumen | 1000 | 0,17 | 0 | 0 | 0,17 | 0,17 | |||
| Roofing slate | 1800 | 0,35 | 2 | 3 | 0,47 | 0,52 | |||
| Roofing slate | 1600 | 0,23 | 2 | 3 | 0,35 | 0,41 | |||
| Roofing bitumen | 1200 | 0,22 | 0 | 0 | 0,22 | 0,22 | |||
| Asbestos cement sheet | 1800 | 0,35 | 2 | 3 | 0,47 | 0,52 | |||
| Asbestos-cement sheet | 1600 | 0,23 | 2 | 3 | 0,35 | 0,41 | |||
| Asphalt concrete | 2100 | 1,05 | 0 | 0 | 1,05 | 1,05 | |||
| Construction roofing felt | 600 | 0,17 | 0 | 0 | 0,17 | 0,17 | |||
| Concrete (on gravel bed) | 1600 | 0,46 | 4 | 6 | 0,46 | 0,55 | |||
| Concrete (on a slag bed) | 1800 | 0,46 | 4 | 6 | 0,56 | 0,67 | |||
| Concrete (on crushed stone) | 2400 | 1,51 | 2 | 3 | 1,74 | 1,86 | |||
| Concrete (on a sand bed) | 1000 | 0,28 | 9 | 13 | 0,35 | 0,41 | |||
| Concrete (porous structure) | 1000 | 0,29 | 10 | 15 | 0,41 | 0,47 | |||
| Concrete (solid structure) | 2500 | 1,89 | 2 | 3 | 1,92 | 2,04 | |||
| Pumice concrete | 1600 | 0,52 | 4 | 6 | 0,62 | 0,68 | |||
| Construction bitumen | 1400 | 0,27 | 0 | 0 | 0,27 | 0,27 | |||
| Construction bitumen | 1200 | 0,22 | 0 | 0 | 0,22 | 0,22 | |||
| Lightweight mineral wool | 50 | 0,048 | 2 | 5 | 0,052 | 0,06 | |||
| Mineral wool is heavy | 125 | 0,056 | 2 | 5 | 0,064 | 0,07 | |||
| Mineral wool | 75 | 0,052 | 2 | 5 | 0,06 | 0,064 | |||
| Vermiculite leaf | 200 | 0,065 | 1 | 3 | 0,08 | 0,095 | |||
| Vermiculite leaf | 150 | 0,060 | 1 | 3 | 0,074 | 0,098 | |||
| Gas-foam-ash concrete | 800 | 0,17 | 15 | 22 | 0,35 | 0,41 | |||
| Gas-foam-ash concrete | 1000 | 0,23 | 15 | 22 | 0,44 | 0,50 | |||
| Gas-foam-ash concrete | 1200 | 0,29 | 15 | 22 | 0,52 | 0,58 | |||
| 300 | 0,08 | 8 | 12 | 0,11 | 0,13 | ||||
| Gas-foam concrete (foam silicate) | 400 | 0,11 | 8 | 12 | 0,14 | 0,15 | |||
| Gas-foam concrete (foam silicate) | 600 | 0,14 | 8 | 12 | 0,22 | 0,26 | |||
| Gas-foam concrete (foam silicate) | 800 | 0,21 | 10 | 15 | 0,33 | 0,37 | |||
| Gas-foam concrete (foam silicate) | 1000 | 0,29 | 10 | 15 | 0,41 | 0,47 | |||
| Construction gypsum board | 1200 | 0,35 | 4 | 6 | 0,41 | 0,46 | |||
| Expanded clay gravel | 600 | 2,14 | 2 | 3 | 0,21 | 0,23 | |||
| Expanded clay gravel | 800 | 0,18 | 2 | 3 | 0,21 | 0,23 | |||
| Granite (basalt) | 2800 | 3,49 | 0 | 0 | 3,49 | 3,49 | |||
| Expanded clay gravel | 400 | 0,12 | 2 | 3 | 0,13 | 0,14 | |||
| Expanded clay gravel | 300 | 0,108 | 2 | 3 | 0,12 | 0,13 | |||
| Expanded clay gravel | 200 | 0,099 | 2 | 3 | 0,11 | 0,12 | |||
| Shungizite gravel | 800 | 0,16 | 2 | 4 | 0,20 | 0,23 | |||
| Shungizite gravel | 600 | 0,13 | 2 | 4 | 0,16 | 0,20 | |||
| Shungizite gravel | 400 | 0,11 | 2 | 4 | 0,13 | 0,14 | |||
| Pine wood cross grain | 500 | 0,09 | 15 | 20 | 0,14 | 0,18 | |||
| Plywood | 600 | 0,12 | 10 | 13 | 0,15 | 0,18 | |||
| Pine wood along the grain | 500 | 0,18 | 15 | 20 | 0,29 | 0,35 | |||
| Oak wood across the grain | 700 | 0,23 | 10 | 15 | 0,18 | 0,23 | |||
| Metal duralumin | 2600 | 221 | 0 | 0 | 221 | 221 | |||
| Reinforced concrete | 2500 | 1,69 | 2 | 3 | 1,92 | 2,04 | |||
| Tufobeton | 1600 | 0,52 | 7 | 10 | 0,7 | 0,81 | |||
| Limestone | 2000 | 0,93 | 2 | 3 | 1,16 | 1,28 | |||
| Lime solution with sand | 1700 | 0,52 | 2 | 4 | 0,70 | 0,87 | |||
| Sand for construction work | 1600 | 0,035 | 1 | 2 | 0,47 | 0,58 | |||
| Tufobeton | 1800 | 0,64 | 7 | 10 | 0,87 | 0,99 | |||
| Lined cardboard | 1000 | 0,18 | 5 | 10 | 0,21 | 0,23 | |||
| Multilayer construction cardboard | 650 | 0,13 | 6 | 12 | 0,15 | 0,18 | |||
| Foam rubber | 60-95 | 0,034 | 5 | 15 | 0,04 | 0,054 | |||
| Expanded clay concrete | 1400 | 0,47 | 5 | 10 | 0,56 | 0,65 | |||
| Expanded clay concrete | 1600 | 0,58 | 5 | 10 | 0,67 | 0,78 | |||
| Expanded clay concrete | 1800 | 0,86 | 5 | 10 | 0,80 | 0,92 | |||
| Brick (hollow) | 1400 | 0,41 | 1 | 2 | 0,52 | 0,58 | |||
| Brick (ceramic) | 1600 | 0,47 | 1 | 2 | 0,58 | 0,64 | |||
| Construction tow | 150 | 0,05 | 7 | 12 | 0,06 | 0,07 | |||
| Brick (silicate) | 1500 | 0,64 | 2 | 4 | 0,7 | 0,81 | |||
| Brick (solid) | 1800 | 0,88 | 1 | 2 | 0,7 | 0,81 | |||
| Brick (slag) | 1700 | 0,52 | 1,5 | 3 | 0,64 | 0,76 | |||
| Brick (clay) | 1600 | 0,47 | 2 | 4 | 0,58 | 0,7 | |||
| Brick (triple) | 1200 | 0,35 | 2 | 4 | 0,47 | 0,52 | |||
| Metal copper | 8500 | 407 | 0 | 0 | 407 | 407 | |||
| Dry plaster (sheet) | 1050 | 0,15 | 4 | 6 | 0,34 | 0,36 | |||
| Mineral wool slabs | 350 | 0,091 | 2 | 5 | 0,09 | 0,11 | |||
| Mineral wool slabs | 300 | 0,070 | 2 | 5 | 0,087 | 0,09 | |||
| Mineral wool slabs | 200 | 0,070 | 2 | 5 | 0,076 | 0,08 | |||
| Mineral wool slabs | 100 | 0,056 | 2 | 5 | 0,06 | 0,07 | |||
| Linoleum PVC | 1800 | 0,38 | 0 | 0 | 0,38 | 0,38 | |||
| Foam concrete | 1000 | 0,29 | 8 | 12 | 0,38 | 0,43 | |||
| Foam concrete | 800 | 0,21 | 8 | 12 | 0,33 | 0,37 | |||
| Foam concrete | 600 | 0,14 | 8 | 12 | 0,22 | 0,26 | |||
| Foam concrete | 400 | 0,11 | 6 | 12 | 0,14 | 0,15 | |||
| Foam concrete on limestone | 1000 | 0,31 | 12 | 18 | 0,48 | 0,55 | |||
| Foam concrete on cement | 1200 | 0,37 | 15 | 22 | 0,60 | 0,66 | |||
| Expanded polystyrene (PSB-S25) | 15 – 25 | 0,029 – 0,033 | 2 | 10 | 0,035 – 0,052 | 0,040 – 0,059 | |||
| Expanded polystyrene (PSB-S35) | 25 – 35 | 0,036 – 0,041 | 2 | 20 | 0,034 | 0,039 | |||
| Polyurethane foam sheet | 80 | 0,041 | 2 | 5 | 0,05 | 0,05 | |||
| Polyurethane foam panel | 60 | 0,035 | 2 | 5 | 0,41 | 0,41 | |||
| Lightweight foam glass | 200 | 0,07 | 1 | 2 | 0,08 | 0,09 | |||
| Weighted foam glass | 400 | 0,11 | 1 | 2 | 0,12 | 0,14 | |||
| Glassine | 600 | 0,17 | 0 | 0 | 0,17 | 0,17 | |||
| Perlite | 400 | 0,111 | 1 | 2 | 0,12 | 0,13 | |||
| Perlite cement slab | 200 | 0,041 | 2 | 3 | 0,052 | 0,06 | |||
| Marble | 2800 | 2,91 | 0 | 0 | 2,91 | 2,91 | |||
| Tuff | 2000 | 0,76 | 3 | 5 | 0,93 | 1,05 | |||
| Concrete on ash gravel | 1400 | 0,47 | 5 | 8 | 0,52 | 0,58 | |||
| Fibreboard (chipboard) | 200 | 0,06 | 10 | 12 | 0,07 | 0,08 | |||
| Fibreboard (chipboard) | 400 | 0,08 | 10 | 12 | 0,11 | 0,13 | |||
| Fibreboard (chipboard) | 600 | 0,11 | 10 | 12 | 0,13 | 0,16 | |||
| Fibreboard (chipboard) | 800 | 0,13 | 10 | 12 | 0,19 | 0,23 | |||
| Fibreboard (chipboard) | 1000 | 0,15 | 10 | 12 | 0,23 | 0,29 | |||
| Polystyrene concrete on Portland cement | 600 | 0,14 | 4 | 8 | 0,17 | 0,20 | |||
| Vermiculite concrete | 800 | 0,21 | 8 | 13 | 0,23 | 0,26 | |||
| Vermiculite concrete | 600 | 0,14 | 8 | 13 | 0,16 | 0,17 | |||
| Vermiculite concrete | 400 | 0,09 | 8 | 13 | 0,11 | 0,13 | |||
| Vermiculite concrete | 300 | 0,08 | 8 | 13 | 0,09 | 0,11 | |||
| Ruberoid | 600 | 0,17 | 0 | 0 | 0,17 | 0,17 | |||
| Fibrolite board | 800 | 0,16 | 10 | 15 | 0,24 | 0,30 | |||
| Metal steel | 7850 | 58 | 0 | 0 | 58 | 58 | |||
| Glass | 2500 | 0,76 | 0 | 0 | 0,76 | 0,76 | |||
| Glass wool | 50 | 0,048 | 2 | 5 | 0,052 | 0,06 | |||
| Fiberglass | 50 | 0,056 | 2 | 5 | 0,06 | 0,064 | |||
| Fibrolite board | 600 | 0,12 | 10 | 15 | 0,18 | 0,23 | |||
| Fibrolite board | 400 | 0,08 | 10 | 15 | 0,13 | 0,16 | |||
| Fibrolite board | 300 | 0,07 | 10 | 15 | 0,09 | 0,14 | |||
| Plywood | 600 | 0,12 | 10 | 13 | 0,15 | 0,18 | |||
| Reed slab | 300 | 0,07 | 10 | 15 | 0,09 | 0,14 | |||
| Cement-sand mortar | 1800 | 0,58 | 2 | 4 | 0,76 | 0,93 | |||
| Metal cast iron | 7200 | 50 | 0 | 0 | 50 | 50 | |||
| Cement-slag mortar | 1400 | 0,41 | 2 | 4 | 0,52 | 0,64 | |||
| Complex sand solution | 1700 | 0,52 | 2 | 4 | 0,70 | 0,87 | |||
| Dry plaster | 800 | 0,15 | 4 | 6 | 0,19 | 0,21 | |||
| Reed slab | 200 | 0,06 | 10 | 15 | 0,07 | 0,09 | |||
| Cement plaster | 1050 | 0,15 | 4 | 6 | 0,34 | 0,36 | |||
| Peat stove | 300 | 0,064 | 15 | 20 | 0,07 | 0,08 | |||
| Peat stove | 200 | 0,052 | 15 | 20 | 0,06 | 0,064 | |||
Modern insulation materials have unique characteristics and are used to solve problems of a certain range. Most of them are designed for treating the walls of a house, but there are also specific ones designed for arranging doors and window openings, places where the roof meets load-bearing supports, basements and attic spaces. Thus, when comparing thermal insulation materials, it is necessary to take into account not only their operational properties, but also their scope of application.
Main parameters
The quality of a material can be assessed based on several fundamental characteristics. The first of these is the thermal conductivity coefficient, which is denoted by the symbol “lambda” (ι). This coefficient shows how much heat passes through a piece of material 1 meter thick and 1 m² in area in 1 hour, provided that the difference between the ambient temperatures on both surfaces is 10°C.
The thermal conductivity of any insulation depends on many factors - humidity, vapor permeability, heat capacity, porosity and other characteristics of the material.
Sensitivity to moisture
Humidity is the amount of moisture contained in the insulation. Water conducts heat well, and a surface saturated with it will help cool the room. Therefore, waterlogged thermal insulation material will lose its qualities and will not give the desired effect. And vice versa: the more water-repellent properties it has, the better.
Vapor permeability is a parameter close to humidity. In numerical terms, it represents the volume of water vapor passing through 1 m2 of insulation in 1 hour, subject to the condition that the difference in potential vapor pressure is 1 Pa and the temperature of the medium is the same.
At high vapor permeability the material may become damp. In this regard, when insulating the walls and ceilings of a house, it is recommended to install a vapor barrier coating.
Water absorption is the ability of a product to absorb liquid when it comes into contact. The water absorption coefficient is very important for the materials that are used for the arrangement. external thermal insulation. High humidity air, precipitation and dew can lead to a deterioration in the characteristics of the material.
Density and heat capacity
Porosity is the number of air pores expressed as a percentage of the total volume of the product. There are closed and open pores, large and small. It is important that they are distributed evenly in the structure of the material: this indicates the quality of the product. Porosity can sometimes reach 50%; in the case of some types of cellular plastics, this figure is 90-98%.
Density is one of the characteristics that affects the mass of a material. A special table will help you determine both of these parameters. Knowing the density, you can calculate how much the load on the walls of the house or its ceiling will increase.
Heat capacity is an indicator demonstrating how much heat the insulation is ready to accumulate. Biostability is the ability of a material to resist the effects of biological factors, for example, pathogenic flora. Fire resistance is resistance to fire insulation, and this parameter should not be confused with fire safety. There are also other characteristics, which include strength, bending endurance, frost resistance, and wear resistance.
Also, when performing calculations, you need to know the coefficient U - the resistance of structures to heat transfer. This indicator has nothing to do with the qualities of the materials themselves, but you need to know it in order to make right choice among a variety of insulation materials. The U-factor is the ratio of the temperature difference on the two sides of the insulation to the volume of heat flow passing through it. To find the thermal resistance of walls and ceilings, you need a table that calculates the thermal conductivity of building materials.
You can make the necessary calculations yourself. To do this, the thickness of the material layer is divided by its thermal conductivity coefficient. The last parameter - if we are talking about insulation - should be indicated on the packaging of the material. In the case of house structural elements, everything is a little more complicated: although their thickness can be measured independently, the thermal conductivity coefficient of concrete, wood or brick will have to be looked up in specialized manuals.
At the same time, materials are often used to insulate walls, ceilings and floors in one room. different types, since for each plane the thermal conductivity coefficient must be calculated separately.
Thermal conductivity of the main types of insulation
Based on the U coefficient, you can choose which type of thermal insulation is best to use and what thickness the layer of material should have. The table below contains information about the density, vapor permeability and thermal conductivity of popular insulation materials:
Advantages and disadvantages
When choosing thermal insulation, you need to consider not only its physical properties, but also such parameters as ease of installation, the need for additional maintenance, durability and cost.
Comparison of the most modern options
As practice shows, the easiest way to install polyurethane foam and penoizol, which are applied to the surface to be treated in the form of foam. These materials are plastic; they easily fill cavities inside the walls of a building. The disadvantage of foaming substances is the need to use special equipment to spray them.
As the table above shows, extruded polystyrene foam is a worthy competitor to polyurethane foam. This material is supplied in the form of solid blocks, but with the help of a regular carpenter's knife it can be cut into any shape. Comparing the characteristics of foam and solid polymers, it is worth noting that foam does not form seams, and this is its main advantage compared to blocks.
Comparison of cotton materials
Mineral wool is similar in properties to foam plastics and expanded polystyrene, but it “breathes” and does not burn. It also has better resistance to moisture and practically does not change its qualities during operation. If you have a choice between solid polymers and mineral wool, it is better to give preference to the latter.
U stone wool comparative characteristics the same as the mineral one, but the cost is higher. Ecowool has a reasonable price and is easy to install, but it has low compressive strength and sags over time. Fiberglass also sags and, in addition, crumbles.
Bulk and organic materials
Sometimes used for thermal insulation of houses. bulk materials– perlite and paper granules. They repel water and are resistant to pathogenic factors. Perlite is environmentally friendly, it does not burn and does not settle. However, bulk materials are rarely used to insulate walls; it is better to use them to equip floors and ceilings.
From organic materials it is necessary to highlight flax, wood fiber and cork covering. They are safe for environment, but are susceptible to burning if not impregnated with special substances. In addition, wood fiber is susceptible to biological factors.
In general, if we take into account the cost, practicality, thermal conductivity and durability of insulation, the best materials for finishing walls and ceilings are polyurethane foam, penoizol and mineral wool. Other types of insulation have specific properties, as they are designed for non-standard situations, and it is recommended to use such insulation only if there are no other options.
How thick should the insulation be, comparison of the thermal conductivity of materials.
- January 16, 2006
- Published: Construction technologies and materials
The need to use WDVS thermal insulation systems is caused by high economic efficiency.
Following the countries of Europe, in Russian Federation adopted new standards for thermal resistance of enclosing and load-bearing structures, aimed at reducing operating costs and energy saving. With the release of SNiP II-3-79*, SNiP 02/23/2003 " Thermal protection buildings" the previous standards of thermal resistance are outdated. The new standards provide for a sharp increase in the required heat transfer resistance of enclosing structures. Now the previously used approaches in construction do not correspond to the new ones regulatory documents, it is necessary to change the principles of design and construction, introduce modern technologies.
As calculations have shown, single-layer structures do not economically meet the accepted new standards of building heating engineering. For example, in the case of using high load-bearing capacity of reinforced concrete or brickwork, in order for the same material to withstand thermal resistance standards, the thickness of the walls must be increased to 6 and 2.3 meters, respectively, which is contrary to common sense. If you use materials with best performance according to thermal resistance, then their load bearing capacity is very limited, for example, like aerated concrete and expanded clay concrete, and expanded polystyrene and mineral wool, effective insulation materials, are not construction materials at all. At the moment there is no absolute building material that would have a high load-bearing capacity in combination with high coefficient thermal resistance.
In order to meet all construction and energy saving standards, it is necessary to build a building according to the principle multilayer structures, where one part will perform a load-bearing function, the second - thermal protection of the building. In this case, the thickness of the walls remains reasonable, and the normalized thermal resistance of the walls is observed. In terms of their thermal performance, WDVS systems are the most optimal of all façade systems on the market.
Table required thickness insulation to meet the requirements of current standards for thermal resistance in some cities of the Russian Federation: 
Table where: 1
- geographical point 2
- average temperature heating season 3
- duration of the heating period in days 4
- degree-day of the heating period Dd, °С * day 5
- normalized value of heat transfer resistance Rreq, m2*°C/W of walls 6 - required insulation thickness
Conditions for performing calculations for the table:
1. The calculation is based on the requirements of SNiP 02/23/2003
2. Group of buildings 1 - Residential, medical and preventive care and children's institutions, schools, boarding schools, hotels and hostels was taken as an example of the calculation.
3. For load-bearing wall the table assumes brickwork 510 mm thick from ordinary clay bricks on cement-sand mortar l = 0.76 W/(m * °C)
4. The thermal conductivity coefficient is taken for zones A.
5. Estimated indoor air temperature + 21 ° C " living room during the cold season" (GOST 30494-96)
6. Rreq is calculated using the formula Rreq=aDd+b for a given geographical location
7. Calculation: Formula for calculating the total heat transfer resistance of multi-layer fencing:
R0= Rв + Rв.п + Rн.к + Ro.к + Rн Rв - heat transfer resistance at the inner surface of the structure
Rн - heat transfer resistance outer surface designs
Rv.p - thermal conductivity resistance air gap(20 mm)
Rн.к - thermal conductivity resistance load-bearing structure
Rо.к - thermal conductivity resistance of the enclosing structure
R = d/l d - thickness of homogeneous material in m,
l - thermal conductivity coefficient of the material, W/(m * °C)
R0 = 0.115 + 0.02/7.3 + 0.51/0.76 + dу/l + 0.043 = 0.832 + dу/l
dу - thickness of thermal insulation
R0 = Rreq
Formula for calculating insulation thickness for given conditions:
dу = l * (Rreq - 0.832)
a) - the average thickness of the air gap between the wall and the thermal insulation is taken to be 20 mm
b) - thermal conductivity coefficient of polystyrene foam PSB-S-25F l = 0.039 W/(m * °C) (based on the test report)
c) - thermal conductivity coefficient of facade mineral wool l = 0.041 W/(m * °C) (based on the test report)
* The table shows the average values for the required thickness of these two types of insulation.
Approximate calculation of the thickness of walls made of a homogeneous material to meet the requirements of SNiP 23-02-2003 “Thermal protection of buildings”.
* For comparative analysis Data from the climate zone of Moscow and the Moscow region are used.
Conditions for performing calculations for the table: 
1. Standardized value of heat transfer resistance Rreq = 3.14
2. Thickness of homogeneous material d= Rreq * l
Thus, from the table it is clear that in order to build a building from a homogeneous material that meets modern requirements thermal resistance, for example, from traditional brickwork, even from perforated brick, the thickness of the walls must be at least 1.53 meters.
To clearly show what thickness of material is needed to meet the requirements for thermal resistance of walls made of a homogeneous material, a calculation was performed taking into account design features application of materials, the following results were obtained:
This table shows calculated data on thermal conductivity of materials.
According to the table data, for clarity, the following diagram is obtained:
Page under construction
Insulated Swedish Plate
Insulated Swedish slab (USP) is one of the types of shallow foundation. The technology came from Europe. This type of foundation has two main layers. The bottom, heat-insulating layer prevents the ground from freezing under the house. Upper layer…
Film - step-by-step instructions on SFTK technology ("wet facade")
With the support of SIBUR, the Association of Manufacturers and Sellers of Expanded Polystyrene, as well as in cooperation with the companies KREIZEL RUS, TERMOKLIP and ARMAT-TD, a unique educational film was created on the production technology of plaster heat-insulating facades...
In February 2015, another training video on facade systems was released. How to properly make decorative elements for decorating a cottage - this is explained step by step in the video.
With the support of SIBUR, the 1st practical conference “Polymers in Thermal Insulation” was held
On May 27, the 1st practical conference “Polymers in Thermal Insulation” was held in Moscow, organized by the information and analytical center Rupec and the Oil and Gas Vertical magazine with the support of SIBUR. The main topics of the conference were trends in the field of regulatory…
Directory - weight, diameter, width of ferrous metal products (reinforcement, angle, channel, I-beam, pipes)
1. Directory: diameter, weight linear meter reinforcement, section, steel class
The BOLARS TVD-1 and BOLARS TVD-2 systems are absolutely fireproof!
The BOLARS TVD-1 and BOLARS TVD-2 systems are absolutely fireproof! Experts came to this conclusion after conducting fire tests on façade thermal insulation systems TM "BOLARS". Systems are assigned a class fire danger K0 - the safest. Huge...
Prev Next