The purpose of building insulation work is to retain heat in winter, save energy resources and reduce the cost of heating a home. Years of practice have shown that the most effective way insulate a private house, is to sheathe the outside with one of the insulation materials. The question is which one to choose, because the construction market offers a large assortment new materials.
Table indicators
The table below will help you avoid making mistakes in choosing a thermal insulation material. It indicates not only the thermal conductivity coefficient, but also the degree of vapor permeability, which plays a significant role important role in the use of insulation in outdoor work.
|
Material |
Density |
Vapor permeability |
Thermal conductivity |
|
Expanded polystyrene |
150kg/m 3 |
0,05 |
0,05 |
|
Expanded polystyrene |
100kg/m 3 |
0,05 |
0,041 |
|
Minvata |
200kg/m 3 |
0,49 |
0,07 |
|
Minvata |
100kg/m 3 |
0,56 |
0,056 |
|
Polyurethane foam |
80kg/m 3 |
0,05 |
0,041 |
|
Polyurethane foam |
60kg/m 3 |
0,05 |
0,035 |
|
Foam glass |
400kg/m 3 |
0.02 |
0,11 |
About additional properties construction insulation materials, which determine the reaction of materials to various physical influences, such as water absorption, thermal expansion, heat capacity can be found from reference books building materials.
The table shows that mineral (basalt) wool has the greatest vapor permeability. In addition, it has a fairly low thermal conductivity, which makes it possible to use thinner slabs for insulation.
Foam glass has the lowest heat saving coefficient, so it is better to use it when the question is how to insulate the foundation of a house from the outside.
If we compare mineral wool with polystyrene foam and other types of insulation listed in the table, then they have lower vapor permeability, having approximately the same thermal conductivity. Consequently, walls covered with these materials will “breathe” less.
What to look for when choosing
The first thing you should be interested in when buying insulation is its thermal insulation performance, and the lower the thermal conductivity figure, the better it will keep the house warm in winter and cool in summer.
The heat capacity of a material depends on its ability to accumulate and retain heat. The greater its density, the more energy the insulation can accumulate, therefore the best insulation materials those in the structure of which there are many bubble formations or microscopic cavities isolated from each other.
The next indicator is vapor permeability. The higher it is, the better it will be removed from the building excess moisture and accumulate less in the walls of the house. Materials with low vapor permeability properties reduce the building’s ability to retain heat, and it is necessary to install improved forced ventilation, and these are extra costs.
Low-weight insulation is easier to transport, install, and is always cheaper. But most importantly, hanging it requires fewer fastening devices, and there is no need to strengthen the walls and foundation. The flammability of materials also plays an important role, especially when insulating. wooden buildings. The most fire-resistant are foam glass and basalt wool.
Scientists from the independent laboratory of the All-Russian Scientific Research Institute of Physical, Technical and Radio Engineering Measurements (VNIIFTRI) conducted thermal conductivity tests at different temperatures four of the most popular insulation materials in construction: modified PIR polyurethane foam, polystyrene (extruded XPS and foamed EPS) and mineral wool insulation (MV).
Purpose of testing- establish the dependence of the thermal conductivity of materials on temperature in the range from -190 to +80 C.
VNIIFTRI is one of the leading metrological institutes in Russia, state science Center Russian Federation. It is this institute that is responsible for the unity of measurements and is the custodian of standards.
Based on the measurement results, scientists revealed the following facts:
Fact 1: The thermal conductivity of all studied materials increases when the temperature rises, and vice versa, decreases when the temperature decreases.
Fact 2: PIR thermal insulation has the best resistance to heat transfer due to the structure of the material: closed cells, filled with gas with extremely low thermal conductivity.
Fact 3: deviations in the thermal conductivity of materials from those declared by manufacturers were discovered. The minimum deviations are for EPS, the maximum for mineral wool.
Test method
The tests were carried out on a thermal conductivity measuring installation “TAU-5” (photo 1). This installation is a reference device of the second category with a permissible basic error in thermal conductivity measurements of 2%.
The installation implements the non-stationary heated circle method and is a reservoir with liquid nitrogen into which the samples under study are immersed with a heater - a thermal conductivity sensor.
Photo 1. Installation "TAU-5"
From the presented materials (EPS/XPS/PIR/MB), 2 measuring samples were prepared in the form of cylinders with a diameter of 30 mm and a thickness of 15 mm (photo 2). A heater sensor was installed between the samples. Thus, actual thermal conductivity measurements were carried out on surfaces located in the middle of the slab.
Photo 2. Appearance samples
Photo 3. Installation of the first half of the sample, sensor-heater, installation of the sensor, installation of the second half of the sample.
Measurements and comparisons of thermal conductivity were carried out in an air atmosphere at room temperature 295 K (22C) and in a nitrogen atmosphere in the temperature range from 80 to 360 K (-193/87C) in several series: from 80 to 360K in steps of 5-10K and from 360 to 80K in similar steps. Measurements at each point, at a certain temperature, were carried out in several stages, until the standard deviation was established close to or equal to zero (Fig. 1).
Figure 1. Results of measurement convergence for one point at a temperature of 300K/26C.
General test results
The test results showed that the thermal conductivity of all analyzed insulation increases with increasing temperature, see fig. 2.
Figure 2. Thermal conductivity of TIM at temperatures in the range -190/+80C.
Test results for individual materials
XPS and EPS
The results of measurements of XPS and EPS samples (Fig. 3, 4) showed that the thermal conductivity values in air and nitrogen at the beginning of the first series were the same and only after heating to 330K (57C) in the first series they decreased by 2 and 2.5%, respectively. This was followed by stabilization, and the temperature dependence of thermal conductivity was relatively smooth.
The large range of values, as well as the concavity of the temperature dependence graph, indicate the presence in the pores of light gases with high thermal conductivity, freezing at the temperatures of the phase transition of water vapor into ice.
What is noteworthy is that the temperature dependence of the thermal conductivity of EPS intersects the dependences of XPS (Figure 2). At -80 o C it is lower, when defrosting gases it is higher).
Figure 3. Thermal conductivity of XPS in the temperature range -190/+80C.
Figure 4. Thermal conductivity of EPS in the temperature range -190/+80C.
Mineral wool
When measuring mineral wool samples, the thermal conductivity values of open-porous material, in contrast to closed-porous ones, in air and in nitrogen practically coincided (Fig. 5) even after heating to 360K (87C) in the first nitrogen series.
Moreover, the temperature dependence of thermal conductivity is relatively smooth, and some scatter is explained by the fragility and heterogeneity of wool. The large range of thermal conductivity values, as well as the convexity of the temperature dependence, indicate the presence of one gas in the pores of cotton wool - nitrogen. All other gases were sorbed into nitrogen immediately after immersion.
Figure 5. Thermal conductivity of mineral wool in the temperature range -190/+80C.
PIR insulation
The results of measurements of PIR insulation samples showed that the temperature dependence of thermal conductivity is not smooth and has two minima or inflection points at -33 and -13C (Fig. 6).
This indicates the presence in the pores of the material of at least two gases (pentane and CO2), which condense below these temperatures, thereby increasing thermal conductivity by increasing the proportion of light molecules in the gas phase. However, the increase in the indicator is insignificant and more closely resembles stabilization of the thermal conductivity value with decreasing temperature.
Figure 6. Thermal conductivity of PIR insulation at a temperature range of -78/+42C.
The presented materials become more effective in the critical zone negative temperatures(less than -15C): the decrease in the thermal conductivity coefficient takes on the character of a rapid drop.
Such a sharp decrease in thermal conductivity is explained by the very small contact patch of the liquid phase of heavy gases formed in the pores with solid walls Due to this, the proportions of light molecules in the gas phase change and a vacuum is formed, replacing the gas phase of the foaming agent, but these factors do not participate in the transfer of heat. As it turned out, the vacuum reliably performs a compensatory function.
|
Temperature |
Thermal conductivity W/m*K |
||||
Real and declared thermal conductivity indicators
It is interesting that during the study, deviations in the thermal conductivity of materials from the figures stated by manufacturers were discovered (Fig. 7).
The minimum and maximum values for the range of declared thermal conductivity values were determined for TIM of the same density as the measured samples. The analysis of the declared indicators was carried out on the basis of information from open sources in the Internet.
Figure 7. Deviations of thermal conductivity of building materials from the declared ones at 25C.
Results
All materials studied in the independent laboratory of VNIIFTRI showed a steady increase in thermal conductivity with increasing temperature. Each has its own limit, determined by the structure of the material. If for XPS the increase was from 0.011 to 0.044, for MV - 0.015-0.051, then for PIR - 0.010-0.029.
As you can see, modern thermal insulation made from fire-resistant polyisocyanurate foam PIR, modified polyurethane foam, has proven itself best. The results of Russian independent studies confirm data obtained in other countries: PIR really insulates better.
Preface. On modern market there is simply huge selection materials that differ in price and other characteristics. Let's try to compare insulation materials based on thermal conductivity and understand this diversity in order to make an informed decision in favor of a particular insulation material. Let's consider which parameters are more important when choosing - thermal conductivity or other characteristics.
Main characteristics of insulation
Let us first provide the characteristics of the most popular thermal insulation materials, which you should first pay attention to when choosing. Comparison of insulation materials by thermal conductivity should be made only on the basis of the purpose of the materials and the conditions in the room (humidity, presence open fire etc.). We have further arranged in order of importance the main characteristics of insulation.
Thermal conductivity. The lower this indicator, the less thermal insulation layer is required, which means that insulation costs will also be reduced.
Moisture permeability. Less permeability of the material to moisture vapor reduces during operation negative impact for insulation.
Fire safety. Thermal insulation should not burn or emit toxic gases, especially when insulating a boiler room or chimney.
Durability. The longer the service life, the cheaper it will cost you during operation, since it will not require frequent replacement.
Environmental friendliness. The material must be safe for humans and surrounding nature.
Economical. The material must be accessible to a wide range of consumers and have an optimal price/quality ratio.
Easy to install. This property for thermal insulation material is very important for those who want to do repairs themselves.
Thickness and weight of material. The thinner and lighter the insulation, the less heavy the structure will be when installing thermal insulation.
Soundproofing. The higher the sound insulation value of the material, the better the protection in the living room from extraneous noise from the street.
Expanded polystyrene (foam)
This is the most popular thermal insulation material in Russia, due to its low thermal conductivity, low cost and ease of installation. Polystyrene foam is produced in slabs with a thickness of 20 to 150 mm by foaming polystyrene and consists of 99% air. The material has different densities, has low thermal conductivity and is resistant to humidity.
Due to its low cost, polystyrene foam is in great demand among companies and private developers for insulation. various rooms. But the material is quite fragile and ignites quickly, releasing toxic substances when burned. Because of this, polystyrene foam is preferable to use in non-residential premises and for thermal insulation of non-loaded structures - insulation of facades under plaster, basement walls, etc.
Extruded polystyrene foam
Extrusion (technoplex, penoplex, etc.) is not exposed to moisture and rotting. This is a very durable and easy-to-use material that can be easily cut with a knife into required sizes. Low water absorption ensures high humidity minimal change in properties, the slabs have high density and compression resistance. Extruded polystyrene foam is fireproof, durable and easy to use.
All these characteristics, along with low thermal conductivity in comparison with other insulation materials, make Technoplex, URSA XPS or Penoplex slabs ideal material for insulation of strip foundations of houses and blind areas. According to the manufacturers, an extrusion sheet 50 millimeters thick replaces 60 mm of foam block in terms of thermal conductivity, while the material does not allow moisture to pass through and you can do without additional waterproofing.
Mineral wool
Izover mineral wool slabs in packaging
Mineral wool (for example, Izover, URSA, Tekhnoruf, etc.) is made from natural natural materials– slag, rocks and dolomite according to special technology. Mineral wool has low thermal conductivity and is absolutely fireproof. The material is produced in slabs and rolls different hardness. For horizontal planes, less dense mats are used, for vertical structures use rigid and semi-rigid slabs.
However, one of the significant disadvantages this insulation, like basalt wool, has low moisture resistance, which requires additional moisture and vapor barrier devices when installing mineral wool. Experts do not recommend using mineral wool for insulation of wet rooms - basements of houses and cellars, for thermal insulation of steam rooms from the inside in baths and dressing rooms. But even here it can be used with proper waterproofing.
Basalt wool
This material is produced by melting basalt rocks and blowing the molten mass with the addition of various components to obtain a fibrous structure with water-repellent properties. The material is non-flammable, safe for human health, has good performance on thermal insulation and sound insulation of premises. Can be used for both internal and external external thermal insulation.
When installing basalt wool, you should use protective equipment (gloves, a respirator and goggles) to protect the mucous membranes from cotton wool microparticles. The most famous brand of basalt wool in Russia is materials under the Rockwool brand. During operation, the thermal insulation slabs are not compacted or caked, which means excellent properties The low thermal conductivity of basalt wool remains unchanged over time.
Penofol, isolon (foamed polyethylene)
Penofol and isolon are roll insulation materials with a thickness of 2 to 10 mm, consisting of polyethylene foam. The material is also available with a layer of foil on one side to create a reflective effect. The insulation is several times thinner than previously presented insulation materials, but at the same time retains and reflects up to 97% of thermal energy. Foamed polyethylene has long term operation and environmentally friendly.
Isolon and foil penofol are lightweight, thin and very easy to use thermal insulation materials. Use roll insulation for thermal insulation of wet rooms, for example, when insulating balconies and loggias in apartments. Also, the use of this insulation will help you save usable area indoors, with insulation inside. Read more about these materials in the section “Organic thermal insulation”.
Comparison of insulation materials. Thermal conductivity table
It is possible based on several fundamental characteristics.
Main characteristics of thermal insulation materials
Thermal conductivity. The lower the thermal conductivity, the less insulation layer is required, which means your insulation costs will be reduced.
Moisture permeability. Lower moisture permeability reduces the negative impact of moisture on the insulation during subsequent use.
Fire safety. The material should not support combustion and emit toxic fumes, but should be self-extinguishing.
Economical. Insulation must be affordable for a wide range of consumers.
Durability. The longer the period of use of the insulation, the cheaper it is for the consumer during operation and does not require frequent replacement or repair.
Environmental friendliness. The material for thermal insulation must be environmentally friendly, safe for human health and the environment. This characteristic is important for residential premises.
Material thickness. The thinner the insulation, the less the living space of the room will be “eaten up”.
Material weight. Less weight of the insulation will result in less weighting of the insulated structure after installation.
Soundproofing. The higher the sound insulation, the better protection residential premises from noise from the street.
Easy to install. The moment is quite important for those who like to do home renovations with their own hands.
Comparison of the characteristics of popular insulation materials
Foam plastic (expanded polystyrene)
This insulation is the most popular due to its ease of installation and low cost.
Polystyrene foam is made by foaming polystyrene, has very low thermal conductivity, is resistant to moisture, is easy to cut with a knife and is convenient during installation. Due to its low cost, it is in great demand for insulating various rooms. However, the material is quite fragile and also supports combustion, releasing toxic substances into the atmosphere. It is preferable to use polystyrene foam in non-residential premises.
Penoplex (extruded polystyrene foam)
The insulation is not subject to rotting or moisture, is very durable and easy to use - it can be easily cut with a knife. Low water absorption ensures minor changes in the thermal conductivity of the material in conditions of high humidity; the slabs have high compression resistance and do not decompose. Thanks to this, extruded polystyrene foam can be used for insulation strip foundation and blind areas. Penoplex is fireproof, durable and easy to use.
Basalt wool
The material is made from basalt rocks by melting and blowing with the addition of components to obtain a fibrous structure of the material with water-repellent properties. During operation, basalt wool is not compacted, which means its properties do not change over time. The material is fireproof and environmentally friendly, has good sound insulation and thermal insulation. Used for internal and external insulation. In damp rooms requires additional vapor barrier.
Mineral wool
Mineral wool is produced from natural materials - rocks, slag, dolomite using special technology. Mineral has low thermal conductivity, is fireproof and absolutely safe. One of the disadvantages of insulation is its low moisture resistance, which requires the installation of additional moisture and vapor barrier when using it. The material is not recommended for insulation of basements and foundations, as well as in wet rooms - steam rooms, baths, dressing rooms.
Penofol, isolon (foil heat insulator made of polyethylene)
The insulation consists of several layers of foamed polyethylene, having different thicknesses and porous structures. The material often has a layer of foil for a reflective effect and is available in rolls and sheets. The insulation is several millimeters thick (10 times thinner than conventional insulation), but reflects up to 97% of thermal energy; it is a very light, thin and easy-to-use material. Used for thermal insulation and waterproofing of premises. It has a long service life and does not emit harmful substances.
The first of them is coefficient of thermal conductivity, 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 coefficient of any insulation depends on many factors - from humidity, vapor permeability, heat capacity, porosity and others 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. Consequently, an over-moistened 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 materials that are used for 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.
Resistance coefficient
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 where it is calculated
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 of various thermal insulations
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, then the best materials for finishing walls and ceilings - these 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.
The ability of bodies and substances to transfer internal energy, defined in macroprocesses by the term “ thermal energy" is called thermal conductivity. In technology and construction, thermal conductivity external structures– one of the most important standardized criteria.
The formula for thermal conductivity (Fourier's Law), which is discussed below in more detail, relates the amount of thermal energy transferred per unit time through a unit area through the thermal conductivity coefficient, which serves basic characteristic building structures based on their heat transfer.
The thermal conductivity of some thermal insulation materials makes them unsuitable for use in home construction, although their other indicators are quite acceptable. The thermal conductivity of mixtures and composite materials used for the construction of houses is usually higher than that of other substances, since this property is taken into account when developing their compositions.
The thermal conductivity coefficient of a material can be determined numerically using special instruments and techniques, which are mandatory to comply with existing architectural standards in Russia.
Construction thermal insulation materials and their thermal conductivity
The thermal conductivity of a structure is a function not only of the components included in its composition; the porosity of the insulation plays an important role, since air is a good heat insulator. The heat transfer of porous materials is significantly lower than that of monolithic ones.
Comparison of the range of properties of structural products, which includes: strength characteristics, permissible loads, thermal conductivity of materials and required thicknesses to comply with thermal conductivity standards leads to the conclusion that for the construction of high-quality modern house the use of thermal insulation materials with high insulating capacity per unit volume and mass is required.
A separate area in the creation of thermal insulation materials is the insulation of pipelines. Pipes have a significant impact on useful volume living space, therefore, a significant reduction in the thickness of their thermal insulation, required for the normal functioning of the system, is one of important requirements modern design.
Environmental properties and heat transfer
Heat transfer in building structures depends not only on the properties of thermal insulation materials and temperature differences, but also on environmental parameters. The lower the dew point, that is, the less water in the air, the lower its thermal conductivity. At the same time, cold air always has a lower dew point.
Therefore, in order to improve the thermal insulation of living space, they use vapor barrier materials, the action of which is based on the principle of membranes. They separate the moist air on one side of the insulating materials from the air at their surface, thus significantly reducing the thermal conductivity of the wall.
Comparison of the thicknesses of thermal insulation materials required to ensure acceptable architectural standards of a house being built using vapor barrier and without it leads to a clear conclusion about the clear need to use the proposed membrane fabrics together with thermal insulation in wall and roofing thermal insulation layers.
Thermal insulation materials used for arranging pipes of heating systems and water supply systems are mainly products made of porous materials with low thermal conductivity, having continuous films on their surfaces obtained by extrusion, which in turn ensures a constant dew point inside the pores. Therefore, the diameter of products for reliable pipe insulation is significantly smaller than would be required without the presence of such surfaces.
Thermal conductivity table
The thermal conductivity of some materials is given in the table below. Information on other building products in construction can be found in the directory.
| Material | Coefficient of thermal conductivity | Required thickness | |
| 1 | Expanded polystyrene PSB-S-25 | 0,042 | 124 |
| 2 | Mineral wool Rockwool Facade Batts | 0,046 | 135 |
| 3 | Glued wooden beams or solid wood | 0,18 | 530 |
| 4 | Ceramic blocks Proterm | 0,17 | 575 |
| 5 | Gas foam concrete blocks 400 kg/m3 | 0,18 | 610 |
| 6 | Polystyrene concrete blocks 500 kg/m3 | 0,19 | 643 |
| 7 | Aerated concrete blocks 600 kg/m3 | 0,29 | 981 |
| 8 | Expanded clay concrete blocks 800 kg/m3 | 0,31 | 1049 |
| 9 | Expanded clay hollow brick 1000 kg/m3 | 0,52 | 1530 |
| 10 | Clay building brick | 0,52 | 1530 |
| 11 | Sand-lime building brick | 0,76 | 2236 |
| 12 | Reinforced concrete (GOST 26633) 2500 kg/m3 | 0,87 | 2560 |
| Name of material | Thermal conductivity, W/m*K | Vapor permeability, mg/m*h*Pa | Moisture absorption,% | Flammability group |
| Minvata | 0,037-0,048 | 0,49-0,6 | 1,5 | NG |
| Styrofoam | 0,036-0,041 | 0,03 | 3 | G1-G4 |
| PPU | 0,023-0,035 | 0,02 | 2 | G2 |
| Penoizol | 0,028-0,034 | 0,21-0,24 | 18 | G1 |
| Ecowool | 0,032-0,041 | 0,3 | 1 | G2 |
Expanded polystyrene
Foamed insulation based on styrene and styrene-butadiene compositions. It has good heat-insulating properties and is used for insulating walls and pipes.
Extrusion plates
Various in base (mainly polyurethane foam and polystyrene foam). The plates have joint grooves, which does not require sealing them together. This modern materials, used for insulating any large and flat surfaces.
Penofol
Foamed foil polyethylene. It has a number of advantages: it is elastic, does not allow air to pass through, and has a reflective surface. It is used for thermal insulation of walls, pipes, floors, has good thermal insulation properties, but at the same time “does not breathe”, in other words, moisture can condense on its surface at a large temperature difference.
Mineral wool
Fiber insulation made from mineral fibers. Widely used for insulation of walls, ceilings and roofs, indispensable for insulation of complex non-flat surfaces. Can be used as pipe wrapping large diameter. More elastic than basalt wool and lighter in weight. Other characteristics are slightly worse, with the exception of price.
Basalt wool
One of the most modern premium sheet elastic insulation materials. Somewhat less elastic compared to mineral wool. Has a larger specific gravity, large transport dimensions, higher cost.
Styrofoam
Foamed polyurethane foam. Used in the form of slabs mounted “butt joint”. It is used for insulating walls, floors and ceilings, and roofing.
Bulk and organic materials
Bulk and organic materials(expanded clay, slag, sawdust, shavings) are used for filling cavities (hollow walls, ceilings). They have a number of disadvantages: hygroscopicity, compaction over time, low vapor barrier ability. The main advantages are availability and cost.
Comparison of vapor permeability of insulation materials
Name of material Thermal conductivity, W/m*K Vapor permeability, mg/m*h*Pa Moisture absorption, %
Flammability group
Mineral wool 0.037-0.048 0.49-0.6 1.5 NG
Foam plastic 0.036-0.041 0.03 3 G1-G4
PPU 0.023-0.035 0.02 2 G2
Penoizol 0.028-0.034 0.21-0.24 18 G1
Ecowool 0.032-0.041 0.3 1 G2
The thermal conductivity of the walls of a house, equal to the sum of the thermal conductivities of all layers of their structure, divided by their thickness, shows how much this design can keep warm.
A comparative analysis of the data from the table of thermal conductivity of materials and insulation materials allows one to make calculations about their applicability in certain cases. The thermal conductivity of the building materials of a house, as mentioned above, also depends on the dew point of the environment between its surfaces.
Fourier's law of thermal conductivity
In conclusion, a few words about theoretical basis phenomena of heat transfer and thermal conductivity. To calculate the thermal conductivity coefficient of materials, Fourier's law is used, which describes the relationship between the rate of passage of thermal energy through a unit section.
Thermal conductivity through the coefficient λ is related to the physical parameters of the body. If we consider a parallelepiped as a heat-conducting body, then the amount of heat passing through it per unit time can be described by the following formula (Fourier’s law):
P=λ ×S∆T/l, where P is the heat loss power, S is the cross-sectional area of the parallelepiped, T is the temperature difference between the faces, l is the length of the parallelepiped (the distance between the faces).
In other words, the coefficient determined by measuring the temperature difference is equal to the amount of heat that passes through square centimeter cross sections of material per unit time.