Properties of insulation and thermal conductivity table of building materials

Thermal insulation material is a product that is used for thermal insulation of buildings, structures and equipment. In specialized stores, insulators are presented in a wide range. When choosing thermal insulation, it is important to know information about the qualities of the material.

Insulation materials come in household and industrial types. They differ in the form of release, origin, and type of raw materials. They also have distinctive features in their characteristics. Thermal insulation characteristics include hygroscopicity.

Penoplex or mineral wool

Penoplex is a polystyrene derivative and is a product of organic chemistry. Mineral or basalt wool is a product of thermal processing of mineral raw materials. Both materials are successfully used in the creation of heat-insulating layers, but there are peculiarities in the use of each of them, which is explained by some physical indicators. Physical indicators of mineral wool:

• density – varies widely and can be from 10 to 300 kg/m3;
• thermal conductivity (at a density of about 35 kg/m3) – 0.040-0.045 W/m*K;
• moisture absorption – more than 1% (depending on density);
• vapor permeability – 0.4-0.5 mg/hour*m*Pa;
• maximum holding temperature 450 C and above.

Analysis of these values ​​shows that the worse thermal conductivity of mineral wool is compensated by better vapor permeability, resistance to high temperatures and non-flammability. Usage min. cotton wool is justified precisely in those conditions where the listed parameters are important. It is advisable to use glass wool insulation in garages, workshops, industrial facilities, anywhere where there is an increased risk of fire. It is better to insulate wet rooms, such as saunas, baths and swimming pools, also using mineral insulation, since in this case the vapor permeability of the insulator is important.

The environmental safety of insulation based on polystyrene and mineral wool depends on the conditions of use. In case of fires, polystyrene derivatives can support combustion and emit toxic smoke. Mineral heat insulators are resistant to high temperatures and do not decompose, but over time they can age and release dust in the form of microfibers that make up the material. The external method of insulating walls using basalt wool is safe in this regard.

The insulation design must take into account possible exposure to water. Mineral materials are subject to greater fluid accumulation, and their thermal conductivity will be increased.

Other criteria for selecting insulation materials

Thermal insulation coating reduces heat loss by 30-40%, increases the strength of load-bearing structures made of brick and metal, reduces noise levels and does not take up the usable area of ​​the building. When choosing insulation, in addition to thermal conductivity, other criteria must be taken into account.

Volume weight

The weight and density of mineral wool affects the quality of insulation.
This characteristic is related to thermal conductivity and depends on the type of material:

• Mineral wool products have a density of 30-200 kg/m3, so they are suitable for all building surfaces.
• Foamed polyethylene has a thickness of 8-10 mm. The density without foil is 25 kg/m3 with a reflective base - about 55 kg/m3.
• Polystyrene foam has a specific gravity of 80 to 160 kg/m3, and extruded polystyrene foam has a specific gravity of 28 to 35 kg/m3. The latter material is one of the lightest.
• Semi-liquid sprayed penoizol with a density of 10 kg/m3 requires preliminary plastering of the surface.
• Foam glass has a density associated with its structure. The foamed version is characterized by a volumetric weight from 200 to 400 kg/m3. Thermal insulation made of cellular glass - from 100 to 200 m3, which makes it possible to use it on facade surfaces.

The lower the volumetric weight, the less material is consumed.

Ability to keep fit

Plates and polyurethane foam have the same degree of rigidity and hold their shape well.
Manufacturers do not indicate dimensional stability on the packaging, but you can focus on Poisson’s and friction ratios, resistance to bending and compression. The stability of the shape is used to judge the creasing or change in parameters of the heat-insulating layer. In case of deformation, there is a risk of heat leakage by 40% through cracks and cold bridges.

The dimensional stability of building materials depends on the type of insulation:

• Cotton wool (mineral, basalt, eco) is straightened out when laid between the rafters. Due to the rigid fibers, deformation is eliminated.
• Foam types hold their shape at the level of hard stone wool.

The ability of a product to keep its shape is also determined by its elasticity characteristics.

Vapor permeability

Determines the “breathing” properties of the material - the ability to transmit air and steam. This indicator is important for controlling the indoor microclimate - more mold and mildew forms in mothballed rooms. In conditions of constant humidity, the structure may collapse.

Based on the degree of vapor permeability, there are two types of insulation:

• Foams are products for the production of which foaming technology is used. The product does not allow condensation to pass through at all.
• Cotton wool is thermal insulation based on mineral or organic fiber. Materials may allow condensation to pass through.

When installing vapor-permeable wool, a film vapor barrier is additionally laid.

Flammability

The indicator that is used to guide the construction of above-ground parts of residential buildings. The classification of toxicity and flammability is specified in Art. 13 Federal Law No. 123. The technical regulations highlight the following groups:

• NG – non-flammable: stone and basalt wool.
• G – flammable. Materials of category G1 (polyurethane foam) are characterized by low flammability, category G4 (expanded polystyrene, including extruded) are highly flammable.
• B – flammable: chipboards, roofing felt.
• D – smoke-generating (PVC).
• T – toxic (minimum level – paper).

The best option for private construction is self-extinguishing materials.

Soundproofing

Characteristics related to vapor permeability and density. Cotton wool prevents the penetration of extraneous noise into the room; more noise penetrates through the foam.

Dense materials have better sound insulation properties, but installation is complicated by thickness and weight. The best option for independent thermal insulation work would be stone wool with high sound absorption. Similar indicators are found in light glass wool or basalt insulation with twisted long thin fibers.

The normal sound insulation indicator is a density of 50 kg/m3.

Features of thermal conductivity

Expanded polystyrene retains not only heat, but also cold well.
Such possibilities are explained by its structure. The composition of this material structurally includes a huge number of sealed multifaceted cells. Each has a size from 2 to 8 mm. And inside each cell there is air, consisting of 98%. It is this that serves as an excellent heat insulator. The remaining 2% of the total mass of the material is made up of polystyrene cell walls. You can verify this if you take, for example, a piece of foam plastic. 1 meter thick and 1 square meter in area. Heat one side and leave the other side cold. The difference between temperatures will be tenfold. To obtain the thermal conductivity coefficient, it is necessary to measure the amount of heat that transfers from the warm part of the sheet to the cold part.

People are accustomed to constantly asking sellers about the density of polystyrene foam. This is because density and heat are closely related. Today, modern foam plastic does not require checking its density. The production of improved insulation involves the addition of special graphite substances. They make the thermal conductivity coefficient of the material unchanged.

The main parameters on which the thermal conductivity depends

Not all building materials are equally thermally efficient. The following factors influence this:

The porous structure of the material indicates that such a structure is heterogeneous, and the pores are filled with air. Thermal masses, moving through such layers, lose a minimum of their energy. Therefore, foam concrete with closed pores is considered a good heat insulator.

The increased density of the material ensures a closer connection of particles with each other. Accordingly, the balancing of the temperature balance occurs much faster. For this reason, dense material has a high thermal conductivity coefficient. Therefore, reinforced concrete is considered one of the “coldest” materials.

Humidity is a malignant factor that increases the rate of heat transfer

Therefore, it is so important to carry out high-quality waterproofing of the necessary components of the building, properly organize ventilation and use building materials that are as inert to wetness as possible.

“It’s cold, cold and wet. I don’t understand what’s cooled down in us...” Even Sogdiana knows that dampness and cold are eternal neighbors, from which you can’t hide in a warm sweater

Knowing what heat conductivity is and what factors influence it, you can safely try to apply your knowledge to calculate future building structures. To do this, you need to know the coefficients of the materials used.

Comparative analysis of the main technical characteristics of basalt wool and expanded polystyrene

Fire resistance

Compared to expanded polystyrene, basalt wool has higher fire resistance. Basalt wool fibers are sintered at a temperature of about 1500 degrees. However, the maximum permissible temperature for use of this thermal insulation material in the form of mats and slabs is limited due to the binders that were used to form the finished products. At a temperature of about 600 degrees, the binders are destroyed, and the basalt slab or mat loses its integrity. It should be noted that polystyrene foam can withstand temperatures that do not exceed 75 degrees without any consequences.

Flammability

No less important is such an indicator as flammability - the ability of a material to burn. Modern building materials are usually divided into:

• non-flammable (NG) - able to withstand exposure to very high temperatures without ignition, loss of strength, deformation of the structure and changes in other properties.
• flammable (G) - the degree of flammability is determined by such indicators as flammability, smoke generation ability, flame spread, toxicity.

It is important to note that if materials of class NG are not only completely fireproof, but also prevent the spread of fire, then materials of class G always pose a fire hazard.

The flammability of basalt wool, which is based on inorganic materials that by their nature cannot burn, is determined depending on the amount of organic binders used in the production of insulation. High-quality basalt wool (for example, the Beltep brand) contains no more than 4.5% binders, therefore it is assigned the NG group. In the case of a higher content of organic substances, the flammability group of basalt wool changes to group G1 (lowly flammable materials) or G2 (moderately flammable materials).

Expanded polystyrene, regardless of the type of material, always belongs to class G. Moreover, the flammability group of this thermal insulation material can vary from G1 (lowly flammable material) to G4 (highly flammable material).

Water absorption

Basalt wool has open porosity, therefore it is able to absorb moisture (up to 2% by volume, and up to 20% by weight). And since water is an excellent conductor of heat, when moisture gets in, the thermal insulation characteristics of basalt wool significantly deteriorate (up to complete unsuitability). And although manufacturers treat basalt wool with water-repellent additives that prevent moisture absorption, experts recommend reliably protecting this thermal insulation material from moisture with vapor and waterproofing barriers.

Unlike basalt wool, polystyrene foam has a closed closed porosity, therefore it is characterized by high resistance to capillary water absorption (up to 0.4% by volume) and water vapor diffusion.

Strength

Strength characteristics mean such indicators as the strength of the material to peel off layers, compression at 10% deformation, shear/shear, bending, etc.

The strength characteristics of basalt wool depend on the density of the material and the amount of binders. For expanded polystyrene, these indicators depend solely on the density of the material. At the same time, expanded polystyrene is characterized by higher compressive strength at 10% deformation than basalt wool with a lower density (for example, the compressive strength at 10% deformation of expanded polystyrene with a density of 35-45 kg/m3 is about 0.25-0.50 MPa, while for basalt wool with a density of 80-190 kg/m3 this figure ranges from 0.15-0.70 MPa). Note that for basalt wool with a density of 11-70 kg/m3, it is not the strength characteristics that are measured, but the compressibility value under a load of 2000 Pa.

Thermal conductivity

One of the most important indicators of any thermal insulation material is its thermal conductivity. Research has shown that both materials we are considering have almost the same thermal conductivity: for basalt wool - 0.033-0.043 W/m•°C, for expanded polystyrene - 0.028-0.040 W/m•°C. Note, however, that air has the lowest thermal conductivity (0.026 W/m•°C), and both one and the other thermal insulation material are effective insulation.

Types of mineral wool boards

The currently valid GOST 52953-2008 divides mineral wool into three types:

• glass (glass wool);
• stone (basalt) mineral wool;
• slag

Glass wool is primarily a budget type of insulation with high density and elasticity. In this case, the thermal conductivity of mineral wool is 0.03–0.052 W/(m°C). For its production, the same materials are used as for producing ordinary glass - soda, sand, borax, limestone and dolomite. The obvious advantages of choosing glass wool include not only its low thermal conductivity, but also its relatively low cost, while the disadvantages include a harmful effect on the skin and respiratory system.

Blast furnace to make slag wool. At the same time, the thermal conductivity of the material is higher than that of glass wool, but still quite low - at the level of 0.46-0.48 W/(m°C). The advantages of mineral wool can be listed for quite a long time, but the main ones are the relatively low cost, ease of installation and high sound absorption coefficient. Among the disadvantages are the high hygroscopicity of the material, due to which it easily absorbs moisture.

Stone mineral wool is obtained from molten igneous rocks - primarily from basalt. That is why this material is sometimes also called basalt wool. Its thermal conductivity varies over a wider range, compared to other types of mineral wool, from 0.032 to 0.046 W/(m°C), so it is difficult to call this type of wool popular when used as insulation. At the same time, basalt wool is considered the most durable among analogues and is least susceptible to moisture. However, it costs more than other types of mineral wool.

Thermal conductivity concept and theory

Thermal conduction is the process of moving thermal energy from heated parts to cold parts. Metabolic processes occur until the temperature reaches complete equilibrium.

A comfortable microclimate in the house depends on high-quality thermal insulation of all surfaces

The heat transfer process is characterized by a period of time during which temperature values ​​are equalized. The more time passes, the lower the thermal conductivity of building materials, the properties of which are shown in the table. To determine this indicator, a concept called thermal conductivity coefficient is used. It determines how much thermal energy passes through a unit area of ​​a certain surface. The higher this indicator, the faster the building will cool. A thermal conductivity table is needed when designing the protection of a building from heat loss. This can reduce the operating budget.

Heat losses in different areas of the building will differ

Table of thermal conductivity coefficients of different materials

Based on the table with the thermal conductivity coefficients of building materials and popular insulation materials, a comparative analysis can be made. It will ensure the selection of the optimal thermal insulation option for the building.

For thickness parameters, an average value was used.

Thermal conductivity of polystyrene foam from 50 mm to 150 mm is considered thermal insulation

Expanded polystyrene boards, colloquially referred to as polystyrene foam, are an insulating material, usually white. It is made from thermally expanded polystyrene. In appearance, the foam is presented in the form of small moisture-resistant granules; during the melting process at high temperatures, it is smelted into one whole, a slab. The sizes of the granule parts are considered to be from 5 to 15 mm. The outstanding thermal conductivity of 150 mm thick foam is achieved due to a unique structure - granules.

Each granule has a huge number of thin-walled micro-cells, which in turn increase the area of ​​contact with air many times over. We can say with confidence that almost all polystyrene foam consists of atmospheric air, approximately 98%, in turn, this fact is their purpose - thermal insulation of buildings both outside and inside.

Everyone knows, even from physics courses, that atmospheric air is the main insulator of heat in all thermal insulation materials; it is in a normal and rarefied state, in the thickness of the material. Heat-saving, the main quality of polystyrene foam.

As mentioned earlier, polystyrene foam is almost 100% air, and this in turn determines the high ability of polystyrene foam to retain heat. This is due to the fact that air has the lowest thermal conductivity. If we look at the numbers, we will see that the thermal conductivity of polystyrene foam is expressed in the range of values ​​from 0.037 W/mK to 0.043 W/mK. This can be compared with the thermal conductivity of air - 0.027 W/mK.

While the thermal conductivity of popular materials such as wood (0.12 W/mK), red brick (0.7 W/mK), expanded clay (0.12 W/mK) and others used for construction is much higher.

Therefore, polystyrene foam is considered to be the most effective material among the few for thermal insulation of external and internal walls of a building. Residential heating and cooling costs are significantly reduced through the use of polystyrene foam in construction.

The excellent qualities of polystyrene foam boards have found their application in other types of protection, for example: polystyrene foam, which also serves to protect underground and external communications from freezing, due to which their service life increases significantly. Polystyrene foam is also used in industrial equipment (refrigerators, refrigerators) and in warehouses.

Conclusion

Correct use of thermal conductivity, as one of the parameters of mineral wool, allows you to select the thickness of internal or external thermal insulation taking into account the requirements. Correctly selected material characteristics make it possible to maintain optimal microclimatic conditions inside insulated rooms with minimal heating costs. But in order for such protection to last as long as possible, it is necessary not only to use a suitable type of mineral wool board (for external installation - basalt insulation, for internal installation - glass wool or slag wool), but also to prevent moisture from entering the material.

One of the ways to preserve the performance characteristics of mineral wool is to install wind protection, that is, install a special film. It is fixed directly on top of the insulation, creating a ventilation gap between the wind barrier layer and the mineral wool slabs. To increase the level of thermal insulation protection, the individual edges of the film are glued together using a special connecting tape. The result will be increased reliability and durability of thermal insulation, and hence additional savings on heating.

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 by thermal conductivity should be made only on the basis of the purpose of the materials and room conditions (humidity, presence of open fire, etc.)

We have further arranged in order of importance the main characteristics of insulation.

Comparison of building materials

Thermal conductivity. The lower this indicator, the less thermal insulation layer is required, which means that insulation costs will also be reduced.

Moisture permeability. The lower permeability of the material to moisture vapor reduces the negative impact on the insulation during operation.

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.

Environmentally friendly. The material must be safe for humans and the environment.

Selecting insulation density

Before deciding which insulation density to choose, you need to determine where it will be installed.

If you plan to insulate the walls, the type of cladding plays an important role. It determines the type and density of the heat insulator. Thus, for a residential building it is recommended to use basalt wool, which has low thermal conductivity, high fire resistance and environmental friendliness.

For cladding with siding, a basalt heat insulator with values ​​of 40-90 kg/m³ is suitable. The higher the thermal insulation is located, the higher the indicator should be. If the surface will be plastered, then you need to choose special thermal insulation for facade work.

The density should be 140-160 kg/m³. For this work, special elements are used that have high vapor permeability and tear strength. For interior work, low-density thermal insulation material is used.

When doing roofing work, the choice of insulation depends on the type of roof. If the roof is pitched, choose insulation with values ​​of 30-45 kg/m³. To insulate the attic, the indicator must be at least 35-40 kg/m³.

A flat roof must withstand heavy loads caused by snow, wind and other atmospheric phenomena. Therefore, in this case, thermal insulation with a density of 150 kg/m³ should be used if mineral wool is used. For expanded polystyrene, this figure should be no more than 40 kg/m³.

To insulate the floor from the cold, you should choose a material whose mass pressure per unit volume is sufficiently high. However, if you plan to lay material between the joists, you can use loose insulation. The logs take on the entire load, and the thermal insulation is not tasked with withstanding the pressure exerted.

In interior partitions, the thermal insulation material also performs a soundproofing function. Since these partitions are not designed to protect against low temperatures, medium-density thermal insulation can be used. It is desirable that it be presented in the form of slabs.

Comparison of insulation materials by thermal conductivity

Expanded polystyrene (foam)

Expanded polystyrene (foam) slabs

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, expanded polystyrene is in great demand among companies and private developers for insulating various premises. But the material is quite fragile and ignites quickly, releasing toxic substances when burned. Because of this, it is preferable to use polystyrene foam in non-residential premises and for thermal insulation of non-loaded structures - insulation of facades under plaster, basement walls, etc.

Extruded polystyrene foam

Penoplex (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 to the desired size. Low water absorption ensures minimal changes in properties at high humidity; 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 an ideal material for insulating 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 produced from natural materials - slag, rocks and dolomite using special technology. Mineral wool has low thermal conductivity and is absolutely fireproof. The material is produced in slabs and rolls of varying hardness. Less dense mats are used for horizontal planes; rigid and semi-rigid slabs are used for vertical structures.

However, one of the significant disadvantages of this insulation, like basalt wool, is low moisture resistance, which requires additional moisture and vapor barrier installations 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

Rockwool basalt wool slabs in packaging

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, and has good thermal insulation and sound insulation properties. It is used for both internal and 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 do not compact or cake, which means that the excellent properties of low thermal conductivity of basalt wool remain 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 a long service life and is environmentally friendly.

Isolon and foil penofol are lightweight, thin and very easy to use thermal insulation materials. Roll insulation is used 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 useful space in the room when insulating inside. Read more about these materials in the section “Organic thermal insulation”.

Comparison of thermal insulation materials

The most popular materials for installation are polyurethane foam and penoizol. The widespread use of these materials in construction is due to their low cost and excellent thermal insulation.

The waterproofing properties of penoizol allow it to be used as a roofing material.

Only vacuum insulation is more effective than polyurethane foam, and this is very expensive.

Polyurethane foam can be used in ready-made thermal insulation parts - blocks, panels. And it can be used in special compositions that are sprayed onto almost any surface: wood, glass, metal, concrete, brick, paint. As a result, there is no need to make fasteners for insulation.

Expanded polystyrene competes with polyurethane foam. Due to its low weight, even a thick layer of foam does not exert a significant load on the supporting structures. Consists of closed cells, tightly structured.

You can insulate with foam plastic:

• Exterior walls;
• Roofs;
• Floors;
• Pipelines.

To install polystyrene foam on vertical sections, it is not necessary to attach a frame. Rigid sheets of insulation can be glued to the surface or fastened mechanically.

Another one of the most popular modern materials is foil polyethylene. The bottom layer is covered with foamed polyethylene. The top layer is covered with aluminum foil, which reflects heat up to 97%.

This type of insulation is used in the construction of heated floors, for sound insulation of ventilation shafts, pipelines, and expansion tanks. The material does not allow steam and water to pass through. It insulates heat and sound at the same time. In this case, it is laid in a thin layer.

One layer of 4 mm polyethylene can replace 8 cm thick mineral wool.

Distinctive features of PPE insulation

Specifications

Thermal insulation made of foamed polyethylene is a product with a closed-porous structure, soft and elastic, having a shape appropriate for its purpose. They have a number of properties that characterize gas-filled polymers:

• Density from 20 to 80 kg/m3,
• Operating temperature range from -60 to +100 0C,
• Excellent moisture resistance, in which moisture absorption is no more than 2% of the volume, and almost absolute vapor tightness,
• High noise absorption even with a thickness greater than or equal to 5 mm,
• Resistant to most chemically active substances,
• No rotting or fungal damage,
• Very long service life, in some cases reaching more than 80 years,
• Non-toxic and environmentally safe.

But the most important characteristic of polyethylene foam materials is their very low thermal conductivity, due to which they can be used for thermal insulation purposes. As you know, air retains heat best, and there is plenty of it in this material.

The heat transfer coefficient of polyethylene foam insulation is only 0.036 W/m2 * 0C (for comparison, the thermal conductivity of reinforced concrete is about 1.69, plasterboard - 0.15, wood - 0.09, mineral wool - 0.07 W/m2 * 0C).

INTERESTING! Thermal insulation made of foamed polyethylene with a layer thickness of 10 mm can replace a 150 mm thickness of brickwork.

Application area

Foamed polyethylene insulation is widely used in new and reconstructive construction of residential and industrial facilities, as well as in automotive and instrument making:

• To reduce heat transfer by convection and thermal radiation from walls, floors and roofs,
• As reflective insulation to increase the heat output of heating systems,
• To protect pipe systems and pipelines for various purposes,
• In the form of an insulating gasket for various cracks and openings,
• For insulating ventilation and air conditioning systems.

In addition, polyethylene foam is used as packaging material for transporting products that require thermal and mechanical protection.

Is polyethylene foam harmful?

Supporters of the use of natural materials in construction may talk about the harmfulness of chemically synthesized substances. Indeed, when heated above 120 0C, foamed polyethylene turns into a liquid mass, which can be toxic. But under standard living conditions it is absolutely harmless. Moreover, insulation materials made from polyethylene foam are superior to wood, iron and stone in most respects. Building structures using them are light, warm and low cost.

Density and thermal conductivity of thermal insulation in the form of plates and segments

The table shows the density values ​​and temperature dependence of the thermal conductivity of thermal insulation molded in the form of slabs, segments, etc., as well as their maximum operating temperature.

Thermal insulation density, thermal conductivity and temperature are indicated for such thermal insulation as: diatom segments, sovelite segments and shells, newel shells, asbestos cement segments, vulcanite slabs, vermiculite shells, foam concrete segments, foam glass slabs, cork segments, peat segments, mineral wool segments, alfol smooth sheets (segments), corrugated aluminum foil (segments), ball insulation backfilled into segments, rod thermal insulation backfilled into segments (porcelain rods with a diameter of 0.5 mm).

The lightest thermal insulation is alfol; according to the table, it has a density of 200 kg/m3 and a maximum operating temperature of up to 500°C. High-temperature thermal insulation (up to 2000°C) includes ball and rod insulation. However, such thermal insulation has a high density and low thermal conductivity, equal to 0.23...0.39 W/(m deg). The thermal conductivity of thermal insulation depends on temperature. The table presents formulas for the temperature dependence of thermal conductivity of thermal insulation and its maximum operating temperature.

Note: to calculate the thermal conductivity coefficient from the dependencies in the table, it is necessary to enter the temperature in degrees Celsius.

Thermal conductivity of polystyrene foam in comparison

If you compare polystyrene foam with many other building materials, you can draw colossal conclusions.

The thermal conductivity of foam plastic ranges from 0.028 to 0.034 watts per meter/Kelvin. If the density increases, the thermal insulation properties of extruded polystyrene foam without graphite additives decrease.

A 2 cm layer of extruded foam can retain heat like a 3.8 cm layer of mineral wool, like a 3 cm layer of regular polystyrene foam, or like a 20 cm thick wooden board. For brick, these abilities are equivalent to a wall thickness of 37 cm. For foam concrete – 27 cm.

general description

Polystyrene foam is a slab of varying thickness, consisting of foam material - polymer. The thermal conductivity of polystyrene foam is ensured by air, of which it consists of 95-98%, i.e. gas that does not allow heat to pass through.

Since polystyrene foam is basically air, it has an extremely low density and, accordingly, a low specific gravity. Also, foam plastic has very good sound insulation (thin cell partitions filled with air are a very poor conductor of sounds).

Depending on the source raw material (polymer) and manufacturing processes, it is possible to produce foam of different densities, resistance to mechanical factors, and resistance to other types of influence. In connection with the above, the choice of a certain type of foam and its use is determined.

Indicators for different brands of polystyrene foam

From the given simplified formula we can conclude that the thinner the insulation sheet, the less efficient it is. But in addition to the usual geometric parameters, the density of the foam also affects the final result, albeit slightly - only within 1-5 thousandths. For comparison, let’s take two slabs of similar brand:

• PSB-S 25 conducts 0.039 W/m°C.
• PSB-S 35 at a higher density - 0.037 W/m °C.

But with a change in thickness, the difference becomes much more noticeable. For example, the thinnest sheets of 40 mm with a density of 25 kg/m 3 can have a thermal conductivity of 0.136 W/m°C, while 100 mm of the same polystyrene foam transmits only 0.035 W/m°C.

Comparison with other materials

The average thermal conductivity of PSB lies in the range of 0.037-0.043 W/m·°C, and we will focus on it. Here, foam plastic, in comparison with mineral wool made from basalt fibers, seems to benefit slightly - it has approximately the same indicators. True, with twice the thickness (95-100 mm versus 50 mm for polystyrene). It is also customary to compare the conductivity of insulation with the various building materials necessary for the construction of walls. Although this is not very correct, it is very clear:

1. Red ceramic brick has a heat transfer coefficient of 0.7 W/m °C (16-19 times more than foam). Simply put, to replace 50 mm of insulation you will need masonry about 80-85 cm thick. Silicate insulation will need at least a meter.

2. Solid wood is better in this regard compared to brick - here it is only 0.12 W/m °C, that is, three times higher than that of expanded polystyrene. Depending on the quality of the wood and the method of constructing the walls, the equivalent of a 5 cm thick PSB can be a log house up to 23 cm wide.

It is much more logical to compare styrene not with mineral wool, brick or wood, but to consider closer materials - polystyrene foam and Penoplex. Both of them are classified as foamed polystyrene and are even made from the same granules. It’s just that the difference in the technology of “gluing” them gives unexpected results. The reason is that styrene beads for the production of Penoplex with the introduction of blowing agents are simultaneously processed under pressure and high temperature. As a result, the plastic mass acquires greater homogeneity and strength, and air bubbles are evenly distributed in the body of the slab. Polystyrene foam is simply steamed in a mold like popcorn, so the bonds between the expanded granules are weaker.

As a result, the thermal conductivity of Penoplex, an extruded “relative” of PSB, also improves noticeably. It corresponds to 0.028-0.034 W/m °C, that is, 30 mm is enough to replace 40 mm of foam. However, the complexity of production also increases the cost of XPS, so you should not count on savings. By the way, there is one curious nuance here: usually extruded polystyrene foam loses a little in efficiency as its density increases. But when graphite is added to Penoplex, this dependence practically disappears.

Prices for foam plastic sheets 1000x1000 mm (rubles):

Change in thermal conductivity of mineral wool when wet

One of the main disadvantages of any mineral wool is its high level of hygroscopicity. Because of this, when moisture gets on such a material, the thermal conductivity of mineral wool increases noticeably - for example, an increase in humidity by only 5% worsens the thermal insulation characteristics of the material by almost 50 percent. In cases where moisture trapped inside the mineral wool freezes, the insulation can become deformed, thereby reducing its performance characteristics even further.

The thermal conductivity of mineral wool made from basalt and other rocks changes the least with increasing humidity. Minimal hygroscopicity and high vapor permeability of the material (water absorption does not exceed 1% by volume) means that excess moisture does not accumulate inside the mineral wool slabs, but simply evaporates from them. This allows the material to be used for external insulation (on building facades, roofing) and to reduce heat loss through the floors of the first floor.

Glass wool is often used for thermal insulation of pitched roofs, ventilated facades and floors, and to improve the sound insulation of internal walls and partitions. When used as external insulation, this type of mineral wool requires complete isolation from moisture. Slag wool has approximately the same characteristics. Although its water absorption is even higher, it is not suitable for thermal insulation of roofs and facades - the same applies to installation in rooms with high humidity.

What you need to know about the thermal conductivity of foam plastic

The ability of a material to transfer heat, conduct or retain heat flows is usually assessed by the thermal conductivity coefficient. If you look at its dimension - W/m∙C o , it becomes clear that this is a specific value, that is, determined for the following conditions:

• The absence of moisture on the surface of the slab, that is, the thermal conductivity coefficient of polystyrene foam from the reference book, is a value determined in ideally dry conditions, which practically do not exist in nature, except perhaps in the desert or Antarctica;
• The value of the thermal conductivity coefficient is given for a foam thickness of 1 meter, which is very convenient for theory, but somehow not impressive for practical calculations;
• The results of measuring thermal conductivity and heat transfer were carried out for normal conditions at a temperature of 20 o C.

According to a simplified method, when calculating the thermal resistance of a layer of foam insulation, you need to multiply the thickness of the material by the thermal conductivity coefficient, then multiply or divide by several coefficients used to take into account the actual operating conditions of the thermal insulation. For example, strong watering of the material, or the presence of cold bridges, or the method of installation on the walls of the building.

How the thermal conductivity of polystyrene foam differs from other materials can be seen in the comparison table below.

It's actually not that simple. To determine the thermal conductivity value, you can create it yourself or use a ready-made program for calculating insulation parameters. For a small object this is usually done. A private owner or self-builder may not be interested in the thermal conductivity of the walls at all, but rather lay insulation from foam plastic material with a margin of 50 mm, which will be quite enough for the harshest winters.

Large construction companies that insulate walls covering an area of ​​tens of thousands of square meters prefer to act more pragmatically. The calculation of the insulation thickness is used to draw up an estimate, and the actual thermal conductivity values ​​are obtained on a full-scale object. To do this, glue several sheets of foam plastic of different thicknesses onto a section of the wall and measure the actual thermal resistance of the insulation. As a result, it is possible to calculate the optimal thickness of the foam with an accuracy of several millimeters; instead of approximately 100 mm of insulation, you can lay the exact value of 80 mm and save a considerable amount of money.

How beneficial the use of polystyrene foam is in comparison with standard materials can be assessed from the diagram below.

How much lining is needed for finishing - online calculator

When planning to sheathe a room with thin profiled boards - clapboard - it is important to know exactly the required quantity, taking into account. The optimal calculation option includes not only calculating the required area of ​​the facing material (how much lining is needed), but also selecting the length of the lamellas, taking into account the dimensions of the room

Online calculation of lining

An online calculator is used to calculate the required lining area.

Basic data for calculating the area of ​​the surface to be coated and the dimensions of the planks

It is important to take into account some calculation features:

Manual calculation

One of the common uses of the material is the interior decoration of a balcony (loggia). Using a simple sketch as an example, we will calculate how much it costs to cover this room with clapboard, taking into account how much it costs per sq.m. linings of different profiles.

So, only the walls need to be finished. We calculate the perimeter given the known

• lengths – 1200 + 3000 + 1200 +3000 = 8400 mm;
• height 2800 mm;
• the size of the “subtracted” openings - for the balcony block (window and door to the loggia) and the balcony frame (glazing of the loggia itself). Standard size of the opening for a balcony block (dimensions may vary depending on the layout of the house). The size of the opening for the frame is equal to the length of the fence, taking into account its height.

Accordingly, calculating the amount of lining is simple: from the total area of ​​the balcony walls (excluding openings), it is necessary to subtract the area of ​​the openings. For convenience, calculations are carried out in meters.

8.40 x 2.80 = 23.52 sq. m; 1.30 x 1.40 + 0.68 x 2.05 + 3.00 x 1.10 = 1.82 + 1.394 + 3.30 = 6.514 sq. m;

23.52 – 6.514 = 17.006 sq. m.

Next, the selected profile and how much lining fits in 1 m2 are taken into account. If a profile with parameters 140x15x3000 is selected, then one such panel has an area

0.140 x 3.00 = 0.420 sq.m. per square meter

1:0.420 = 2.38 lamellas.

Accordingly, for cladding you will need

17.006:0.420 = 40.5 panels.

You can compare how much a square of lining costs depending on the thickness and number of slats using information from manufacturers’ price lists (the price of lining is indicated there per square meter, per package indicating the number of slats in it, or per piece).

Important: when calculating, it is necessary to include a reserve of 5...10% of the amount of material!

Using thermal conductivity values ​​in practice

Materials used in construction can be structural and thermal insulating.

There are a huge number of materials with thermal insulating properties

The highest thermal conductivity value is for structural materials that are used in the construction of floors, walls and ceilings. If you do not use raw materials with heat-insulating properties, then to retain heat you will need to install a thick layer of insulation for the construction of walls.

Often simpler materials are used to insulate buildings

Therefore, when constructing a building, it is worth using additional materials. In this case, the thermal conductivity of building materials is important; the table shows all the values.

In some cases, insulation from the outside is considered more effective.

Why is thermal insulation needed?

The relevance of thermal insulation is as follows:

• Keeps you warm in winter and cool in summer.

Heat loss through the walls of a typical multi-storey residential building is 30-40% . To reduce heat loss, special thermal insulation materials are needed. The use of electric heaters in winter contributes to additional energy costs. It is more profitable to compensate for these costs by using high-quality thermal insulation material, which ensures heat retention in winter and coolness in the summer heat. At the same time, the cost of cooling the room with air conditioning will also be minimized.

• Increasing the durability of building structures.

What is the thermal conductivity of polystyrene foam Properties and characteristics

Thermal conductivity is a value indicating the amount of heat (energy) passing through 1 m of any body per hour at a certain temperature difference on one side and the other. It is measured and calculated for several initial operating conditions:

• At 25±5 °C - this is a standard indicator enshrined in GOSTs and SNiP.
• “A” – this means dry and normal humidity conditions in the premises.
• “B” – all other conditions are included in this category.

The actual thermal conductivity of polystyrene foam granules pressed into a lightweight slab is not as important in itself as in conjunction with the thickness of the insulation. After all, the main goal is to achieve an optimal level of resistance of all layers of the wall in accordance with the requirements for a particular region. To obtain the initial numbers, it will be enough to use the simplest formula: R = p÷k.

• Heat transfer resistance R can be found in special tables of SNiP 23-02-2003, for example, for Moscow they take 3.16 m ° C / W. And if the main wall, according to its characteristics, does not reach this value, it is the insulation (mineral wool or the same polystyrene foam) that should cover the difference.
• The p index indicates the required thickness of the insulating layer, expressed in meters.
• Coefficient k is precisely what gives an idea of ​​the conductivity of bodies, which we focus on when choosing.

The thermal conductivity of the material itself is checked by heating one side of the sheet and measuring the amount of energy transferred by conduction to the opposite surface per unit time.

Where bulk and organic materials are used

Bulk and organic materials are used in construction. Bulk materials include expanded perlite.

Characteristics:

• Incombustible;
• Environmentally friendly material;
• Not susceptible to water.

It is used for the production of lightweight concrete and thermal insulation products, for insulation of ceilings and floors. More suitable for horizontal surfaces.

Organic materials include flax and cork. They are safe for people, but are flammable materials. Therefore, polyurethane foam, penoizol and mineral wool can be called advantageous in their characteristics for finishing materials. They are affordable to consumers, practical, and have a long service life.

Features of the production of basalt wool and expanded polystyrene

The production of basalt wool is based on the melt of rocks of the gabbro-basalt group. Melting occurs in furnaces at temperatures above 1500 degrees. The resulting melt is transformed into thin fibers, from which a mineral wool carpet is formed. Then the mineral wool carpet is treated with binders and heat treated in a polymerization chamber, resulting in finished products - mats and slabs.

Expanded polystyrene is a lightweight gas-filled polystyrene-based material, which is characterized by a uniform structure consisting of small (0.1-0.2 mm) completely closed cells. Today, the construction market offers two types of this material: regular and extruded polystyrene foam. The main difference between these two types of expanded polystyrene is the production technology, and, as a consequence, the properties of the finished product.

Conventional polystyrene foam is formed by sintering granules under high temperatures.

Extruded polystyrene foam is made by swelling and welding granules under the influence of hot steam or water (temperature 80-100 degrees) and subsequent extrusion through an extruder.

The main difference between extruded polystyrene foam and regular polystyrene is its higher rigidity and lower water absorption. Another difference is due to the production technology - the limitation on the thickness of the slabs (maximum 100 mm) made from extruded polystyrene foam.

Advantages and disadvantages of insulation

Types of polyurethane foam
Advantages: seamless foam installation, durability, better heat and water insulation.

Disadvantages: high cost of material, instability to UV radiation.

Advantages: low thermal conductivity, low cost, ease of installation, water resistance.

Disadvantages: fragility, easy flammability, condensation.

Disadvantages: much more expensive than polystyrene foam, susceptibility to organic solvents, condensation formation.

Advantages: resistance to the formation of fungi, sound insulation, mechanical strength, fire resistance, non-flammability.

Disadvantages: higher cost compared to analogues.

Advantages: sound insulation, environmental friendliness, moisture resistance, affordable cost.

Disadvantages: thermal conductivity increases during operation, the need for special equipment for installation, and the possibility of shrinkage.

Advantages: low thermal conductivity, low vapor permeability, high noise insulation, ease of cutting and installation, environmental friendliness, flexibility, light weight.

Disadvantages: low strength, need for a ventilation gap.

Advantages: environmental friendliness, high ability to reflect heat, high noise insulation, moisture resistance, non-flammability, ease of transportation and installation, reflection of radiation exposure.

Disadvantages: low rigidity, difficulty in fastening the material; penofol alone is not enough as thermal insulation.

Thermal conductivity of foam

The main characteristic due to which expanded polystyrene has gained wide recognition as the No. 1 insulation material is the ultra-low thermal conductivity of foam. The relatively low strength of the material is more than compensated by such advantages as resistance to most aggressive compounds, low weight, non-toxicity and safety during operation. The good thermal insulation properties of polystyrene foam make it possible to insulate a house at a relatively low price, while the durability of such insulation is designed for a period of at least 25 years of service.

Why is it important to correctly calculate insulation indicators?

Thermal insulation is installed to reduce energy loss through the walls, floor and roof of a home. Insufficient insulation thickness will cause the dew point to move inside the building. This means the appearance of condensation, dampness and fungus on the walls of the house. An excess layer of thermal insulation does not significantly change temperature indicators, but requires significant financial costs, and is therefore irrational. This disrupts air circulation and natural ventilation between the rooms of the house and the atmosphere. To save money while ensuring optimal living conditions, an accurate calculation of the thickness of the insulation is required.

The main types of insulation used to reduce heat loss

To carry out thermal insulation measures of any type, the following types of insulators are used:

• extruded polystyrene foam (XPS), refers to polystyrene derivatives (represented by various manufacturing enterprises, has many brands);
• polystyrene foam, its production also involves the processing of polystyrene, but using a different technology (it has a sufficient number of manufacturers, the breakdown by brand is not clear, it is positioned as “foam plastic”).
• mineral or basalt wool is fundamentally different from polystyrene products and acts as the main competitor of foamed polystyrenes (represented on the insulating goods market by a large number of manufacturers).

The number of manufacturing companies, both domestic and foreign, is measured in dozens. When choosing products, you need to rely on the physical properties of each individual product.

Installation and operational efficiency

Installation of polyurethane foam is quick and easy.

Comparison of the characteristics of insulation materials should be carried out taking into account installation, because this is also important. It is easiest to work with liquid thermal insulation, such as polyurethane foam and penoizol, but this requires special equipment. It is also not difficult to lay ecowool (cellulose) on horizontal surfaces, for example, when insulating a floor or attic floor. To spray ecowool on walls using the wet method, special devices are also needed.

Polystyrene foam is laid both over the sheathing and directly onto the work surface. In principle, this also applies to stone wool slabs. Moreover, slab insulation can be laid on both vertical and horizontal surfaces (including under screed). Soft glass wool in rolls is laid only on the sheathing.

During operation, the thermal insulation layer may undergo some undesirable changes:

• absorb moisture;
• shrink;
• become a home for mice;
• collapse from exposure to IR rays, water, solvents, etc.

In addition to all of the above, the fire safety of thermal insulation is important. Comparison of insulation materials, flammability group table:

Styrex or penoplex

Stirex is an extrusive polystyrene foam, like penoplex.
At its core, the applicability of Styrex is justified where the applicability of penoplex is, that is, there are no decisive differences. Preference may be given to one material only if it is convenient to cut slabs of a given size, to reduce waste, and in case of increased strength requirements, since Styrex has better bending strength. Physical properties of Styrex:

• density – 0.35-0.38 kg/m3;
• thermal conductivity – 0.027 W/m*K;
• moisture absorption, no more than – 0.2%;
• compressive strength – 0.25MPa;
• bending strength – 0.4-0.7;
• vapor permeability – 0.019-0.020 mg/hour*m*Pa.

At large deltas of external and internal temperatures, the slightly lower thermal conductivity of Styrex makes this material more advantageous, however, with an average difference of 0.003 W/m*K this will be barely noticeable. The production of insulation under the Stirex brand is located in Ukraine.

Floor

The calculation of thickness is no different from all the above calculations. All layers of materials used in the construction of the building should be taken into account, as well as the presence or absence of a cold basement underneath.

It is not recommended to use mineral wool as insulation inside residential premises. The first two materials are due to their flammability and harmful fumes, and the latter due to their good ability to absorb moisture, which can subsequently lead to mold, mildew and rotting.

A good option for the floor would be. The disadvantages include its rather high price. However, it is also a very good sound insulator, so it can solve two construction problems at once. This material is quite durable and is recommended for use under concrete screed and self-leveling floors. The beautiful texture allows you to leave the material as a finishing coating, treating the top layer with a special varnish.

When choosing cork material for laying on the floor, like any other material, it is important to correctly calculate the thickness of the insulation, since the principle “more is better” does not apply here. You will not only significantly raise the level and reduce the usable area of ​​the room, but also unjustifiably increase the cost of construction