Polystyrene foam is a modern material that is used for thermal insulation of living space both outside and inside. This is due to its environmental friendliness, low hygroscopicity, and budget price. When choosing, the thermal conductivity of the foam is also taken into account. It is this parameter that we will talk about in today’s article.
Large sheets of foam plastic for insulating the facade of a house Source drive2.ru
What is polystyrene foam and its performance characteristics
Polystyrene foam, or, as it is called, expanded polystyrene, is a slab that can vary in thickness. The main material of this raw material is foamed polymer. There is air inside the material in the granules and between them, which ensures the thermal conductivity of the insulation. Polystyrene foam consists of 95-98% of a specific gas, which, in fact, retains heat.
Foamed polystyrene with low thermal conductivity Source avexpro.ru
Due to the fact that there is enough air in the middle layers of the raw material, polystyrene foam has a minimum density and has a low specific gravity. Also, the internal air layer provides good sound insulation.
The finished density and other characteristics of the insulating material depend on the polymer itself and the processes that were used during the manufacture of the material. As a result of applying different conditions at the production stage, foam plastic of unequal density and varying degrees of resistance to mechanical stress may be obtained.
Table of thermal conductivity values for different materials Source otoplenie-gid.ru
Other conditions
The method of construction is also important. Insulation for polystyrene foam walls must be selected professionally.
The walls in these objects are very thin, and cold air blows from all three sides. Batteries, as you know, are completely unacceptable there; they are absent.
Private construction does not involve calculating thickness at all. In this case, the special climatic conditions of the area in question are taken as a basis and rounded to the largest side. In the shopping center at the time of purchasing the goods, similar indicators are found and rounded up.
All additional insulation is subject to other requirements. Therefore, they should not be compared with standard rules and indicators.
See more on this topic on our website:
- Do-it-yourself insulation of the walls of a frame house from the inside Manufacturers of SIP panels and people who understand how the walls of a frame house are insulated say that well-installed walls can fully replace a half-meter wall.
Thickness of the walls of a frame house for winter living - diagrams What should be the thickness of the walls of a frame house for winter living in it? There is a clear answer to this question. at the same time, he is not there. Why? Because.
Correct installation of polystyrene foam on external walls Thanks to a number of excellent qualities, extruded polystyrene foam is readily used in construction or during renovation work. Installing polystyrene foam on walls is not the only purpose it serves.
External insulation for walls - insulating the walls of a house from the outside with your own hands When analyzing heat loss in housing conditions, about 40% falls on the walls, on the windows - 20%, on the roof - 25%, on the ventilation system - 15%. Thanks to.
Thickness of the wall of a frame house for permanent residence What should be the thickness of the wall of a frame house for permanent residence in a city or country village? The answer to this question, on the one hand.
The issue of insulation of houses and apartments, as well as other commercial premises, has recently been of great concern to Ukrainians. Rising energy prices, rising prices for home heating services, as well as the average wage level are powerful arguments to save money on heating. The most common insulation material is polystyrene foam (polystyrene foam, in common parlance), which is quite inexpensive and yet highly effective. However, on the building materials market there is foam insulation of different thicknesses
A logical question arises: if you choose polystyrene foam insulation, what should the thickness be? When it comes to foam insulation, thickness is important, since the overall effectiveness of insulation as a whole depends on this indicator
Photo. Work in Dnepr - foam insulation, thickness 100 mm, building facade
In this article, we decided to briefly consider the very essence of the issue, without specifics of the insulation object (house, apartment, facade of an industrial building, etc.). If you are interested in questions regarding how thick foam plastic is needed to insulate a house, or how thick foam plastic should be to insulate walls, or how thick foam plastic is needed to insulate a balcony, you can read these articles at any time.
Understanding that you value your time, looking ahead, we note the following:
Main characteristics of thermal conductivity of foam plastic
Before you find out what the thermal conductivity of polystyrene foam will be, you need to understand what this parameter is.
Thermal conductivity is a quantitative characteristic of foam plastic (or any other material), which evaluates the ability of a particular body to conduct heat. The unit of change for this parameter is W/mS. In this case, each designation is characterized as follows:
- Watt is the amount of thermal energy;
- Meter—distance of heat conduction through oneself;
- C is a certain temperature for a certain time.
We suggest looking at an example of what thermal conductivity is. Let's assume we have a sheet of polystyrene foam PSB-S 50. Its density is 50 kg/m3. The heat transfer parameter of this raw material is set by the factory. Based on this, it can be determined that the thermal conductivity of 50 mm foam is 0.041 W/mS. It should be noted that such an indicator will only be subject to exposure to temperatures not exceeding 20-30 degrees.
On a note! It is possible to clearly notice the heat penetration parameter of polystyrene foam only when comparing its values with the values of other thermal insulation materials.
Types of mineral plates for thermal protection
Today's building materials market is able to offer the buyer a large selection of heat-protective materials, all of which can successfully solve the problem of preserving thermal energy in the house.
When purchasing building materials, pay attention to a number of its important characteristics:
- The thermal conductivity coefficient should be as high as possible.
- Water absorption should be as low as possible.
- The density of the material affects the overall weight of the structure.
- Flammability is selected not lower than class G4.
- The service life should not be less than 25 years.
- Vapor permeability should be as high as possible.
Glass wool
This is a microfiber heat-insulating material that belongs to the class of mineral wool and is one of the popular heat insulators today. It is sold in the form of rolls and mats. In order to ensure reliable thermal insulation of brick walls, you will need a glass wool thickness of 150 mm.
The advantages of glass wool include:
- increased noise protection;
- low density and light weight of the protective structure;
- easy installation work;
- elasticity and bendability;
- low cost of work;
- compact packaging during transportation;
- resistance to biological contamination and damage by rodents.
The disadvantages include high safety requirements during work, the soft structure of the material with low load-bearing capacity and the instability of the slabs in a humid environment.
Basalt
Among the thermal insulators on the domestic building materials market, basalt wool is deservedly popular. The structure of the heat insulator consists of rock fibers from the basalt and gabbro group, which are obtained in molten form.
The advantages of this insulation include:
- High material density up to 150 kg/m3.
- Easy installation.
- Low thermal conductivity 0.032 W/m*K.
- Low moisture permeability no higher than 2%.
- Good vapor permeability 0.30 mg/(m*h*Pa).
- Highest fire resistance.
- High noise protection.
- Low indicators of biological and chemical activity.
The biggest disadvantage of basalt slabs is their high cost and high safety requirements during heat protection work; in addition, for external installation, enhanced protection is required in the form of a special waterproofing layer.
URSA insulation
This insulation from the very famous German brand Ursa Geo belongs to the mineral wool class. A universal material, perfect for insulating any surface of a residential building.
Advantage of Ursa isolator:
- non-flammable material;
- high heat-protective and noise-insulating properties;
- safe for the environment;
- moisture-resistant and bioresistant;
- reinforced fibrous structure;
- low thermal conductivity 0.033 W/m*K;
- wide permissible temperature from -60 to +220 C.
The only disadvantages include the rather significant cost of the product.
Stone
It is produced from volcanic rock by melting and dividing into fibers. The process is carried out using centrifugal/spun-drawing, blowing and windrowing. The resulting material is made loose, so it is fixed with adhesive phenol-formaldehyde resin.
Stone wool is available in different densities, but for brick walls you need to use hard mats with 176 kg/m3 and a thermal conductivity of 0.045 W/m*C.
Benefits of use
- A light weight.
- Highest insulating properties.
- Heat resistance, therefore not afraid of temperature changes.
- Under any climatic conditions, it maintains its original shape and retains its own characteristics.
- Non-flammable material.
- Good vapor permeability - 0.56 mg/m*h*Pa.
The disadvantages of this type of insulation include a strong susceptibility to damage by rodents, low environmental safety parameters due to impregnation with resins, and therefore installation work can only be carried out in a respirator and protective clothing.
Slag
To produce this insulation, slags formed during the blast furnace process are used. The thermal insulation fibers are approximately 15 mm long with a thickness of 12 microns. They are formed into slabs by pressing with a binder.
The main positive qualities of slag fiber:
- versatility, which allows its use for different types of surfaces;
- long period of operation over 50 years;
- high noise and heat insulation properties;
- low purchase cost of insulation;
- easy installation.
In addition, blast furnace slag, on the basis of which insulation is produced, often does not meet environmental and radiation safety requirements. Slag fiber does not tolerate temperature changes, which narrows its scope of application.
Comparison of thermal conductivity of polystyrene foam with other materials
Obviously, when changing the thickness of polystyrene foam brand PSB, the thermal conductivity index varies in the range - 0.037-0.043 W/mS. For example, if you compare it with raw materials such as mineral wool, then the differences in indicators will not be significant.
Also, to determine the optimal parameter, it is worth considering not only sheet heat insulators with various fillers, but also the building materials used to construct the walls of the structure.
It’s not for nothing that red brick is so often used in laying the walls of a house. This is due to the fact that it has a fairly high level of heat transfer of 0.7 W/mS. This is almost 19 times more than expanded polystyrene foam. That is, in order to do without a heat insulator, it is necessary to build a wall with a thickness of at least 80-85 cm. In the case of sand-lime brick, it will be necessary to build meter-long load-bearing structures.
Wood is also often used to build houses. It competes with foam a little better than red brick. The thermal conductivity of wood is 0.12 W/mS. It turns out that this is three times more than polystyrene foam. It turns out that if you build a wall from solid wood, then you will need a log house up to 23 cm thick so that the thermal conductivity indicator is equivalent to PSB with a thickness of 5 cm.
Classification of expanded polystyrene
Regular foam
Thermal insulation material obtained by foaming polystyrene. As mentioned above, its volume is 98% air , which is sealed into granules.
This speaks not only of its excellent thermal insulation qualities, but also of its sound insulation properties. The main advantage of the material is the lack of ability to absorb moisture. In addition, it does not rot or biodegrade. Durable material, light weight and easy to use. It can be glued to any building material.
Expanded polystyrene is easy to burn, but it contains a substance called a fire retardant. This is what gives the foam the ability to self-extinguish. In addition, expanded polystyrene cannot be used to insulate facades. This is due to its low vapor permeability . And in order to carry out work with foam plastic under the roof, you should carefully consider the ventilation system.
Use depending on the brand of material
- PSB-S 15. The marking of polystyrene foam indicates that it can be used to insulate structures that are not subject to mechanical stress. For example, insulation of the roof, the space between the slings and the ceiling.
- PSB-S 25 and 25F. Common markings for polystyrene foam. It says that any surface can be insulated. Walls, facades, ceilings or flooring, roofing.
- PSB-S 35 and 50. This material can be used to insulate objects that are under constant high load.
Extruded polystyrene foam
Thermal insulation material, which has high effect and quality. It is most often used to insulate building envelopes. And the thermal conductivity coefficient ranges from 0.027 to 0.033 W/m K.
The structure of the material is cellular. And the complete closure of each cell provides absolute protection against water penetration. Therefore, this material is recommended for use where humidity is high or where the material can come into contact with water. This is insulation of the basement or foundation of a cottage. Even in conditions of insufficient waterproofing, extruded polystyrene foam will retain its thermal insulation qualities.
In addition, this material is highly resistant to various deformations. This feature allows it to be used as insulation for surfaces bearing heavy loads. For example, facades can be insulated with extruded polystyrene foam. Especially if the cladding material is very heavy.
As for the temperature. Expanded polystyrene is able to withstand sudden changes, from -120 to +175 degrees. At the same time, its structure remains intact and unharmed.
The disadvantages of this material are flammability, but, like polystyrene foam, its constituent elements can cause it to extinguish. Contact of polystyrene foam with complex carbohydrates can lead to destruction.
Comparison of styrene with penoplex
Polystyrene foam and penoplex are relatively identical materials, made using the same granules. The only difference is the gluing technology, which gives unexpected results when comparing indicators.
The fact is that during the production of penoplex, styrene beads are processed under pressure at high temperatures. The result is a plastic mass that, when frozen, is homogeneous and durable. The air bubbles that remain inside are evenly distributed throughout the entire part of the stove.
When forming foam, the material pre-loaded into the mold is simply doused with steam. As a result, it gets a “popcorn” structure, and, as a result, the bonds between loose granules are much weaker.
Based on this, it can be noted that the thermal conductivity of extruded polystyrene foam is better and corresponds to 0.028-0.034 W/mS. Thus, only 30 mm of this material will be needed to replace 40 mm of conventional foam.
The structure of penoplex differs from polystyrene foam Source pgsstore.ru
Important! In cases where there is no need for high strength of the insulated wall, then you can safely give preference to budget polystyrene foam. True, you should first determine its optimal thickness, depending on climatic factors and operating conditions.
Lifetime
Most manufacturers indicate a service life of 20-30 years. This is the warranty time during which the useful properties of the material are within acceptable limits. Recent studies by European scientists have shown surprising and encouraging results. When demolishing houses built 40-50 years ago using polyurethane foam, scientists found that its properties remained virtually unchanged. The structure and texture remained the same as originally. Further laboratory studies only confirmed the durability of this material.
Environmental friendliness
An important parameter that modern builders are paying more and more attention to. During the production process, polyurethane foam goes from liquid to solid in 30 seconds
After this, harmful fumes from its surface stop. If it is heated to 450 Cº, carbon dioxide and carbon monoxide will begin to be released. However, the same thing can be observed when wood is heated. Polyurethane foam does not emit compounds harmful to the human body
Features of choosing foam sheets for insulation
First of all, when you buy polystyrene foam, focus on the quality certificate. Whether the thermal conductivity indicator will correspond to the real value that we discussed above completely depends on it.
It happens when a manufacturer manufactures a product using GOST and its own specifications. In such situations, technical characteristics, including the heat transfer rate, may vary.
Choosing the optimal foam thickness Source lazurit64.ru
Therefore, in order for the purchased material to be used with the expected effect, you need to ask the seller in the store to provide a document confirming the technical characteristics of the material of the particular brand you have chosen.
Note! The correspondence of the document to the type of polystyrene foam can be found by special symbols, which are usually printed on the side of each sheet of material.
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.
In the case of industrial buildings using a metal frame, insulation helps protect the metal surface from corrosion, which is the most detrimental defect for this type of structure. And the service life of a brick building is determined by the number of freeze/thaw cycles. The impact of these cycles is perceived by the insulation, because the dew point is located in the thermal insulation material, and not in the wall material.
Such insulation allows you to increase the service life of the building many times.
- Noise insulation.
Protection against increasing noise levels is achieved by using such noise-absorbing materials (thick mattresses, sound-reflecting wall panels).
- Increasing the usable area of buildings.
The use of a thermal insulation system makes it possible to reduce the thickness of external walls, while increasing the internal area of the building.
Why is it important to remember about vapor permeability?
When you decide to use polystyrene foam as insulation for the walls of your own home, it is advisable to remember the vapor permeability of this material. The lower this indicator, the better for the operation of the heat insulator.
The fact is that many insulation materials do not resist the penetration of steam. Over time, it turns into moisture and is deposited in layers of material. This causes the latter to deteriorate and lose its quality characteristics. Thermal conductivity also suffers: the foam plastic begins to transmit thermal energy through itself and release it to the street.
Fire resistance
Being a combustible material, polystyrene foam has good fire resistance, since the spontaneous combustion temperature is +4910 C. This indicator is 1.8 times higher than that of wood, for which +2600 C is enough. In the absence of fire within 4 seconds, the combustion dies out. During combustion, the material releases about 1000 MJ/m3 of energy, while wood - 7000-8000 MJ/m3 - which means that when burning polystyrene foam, the temperature increase will be much lower.
Manufacturers offer self-extinguishing polystyrene foam made with the addition of fire retardants. However, experiments show that the self-extinguishing effect is lost over time, and in the design the material, which was initially classified as belonging to the G2 flammability group, after some time already corresponds only to the G4 class (research carried out at the Research Institute of Industrial Safety and Emergency Situations of the Ministry of Emergency Situations of Belarus).
At the same time, it should be recognized that the products released during the combustion of different brands of polystyrene foam are still poorly studied.
Features of application and numbers in markings
Foam insulation can be used for indoor and outdoor conditions. This can be determined by the thermal conductivity coefficient. For example, if the product name contains the number “15”, then such sheets are suitable for gluing to vertical structures indoors. The thickness of this raw material is insignificant, and therefore will not use up useful space.
Low thermal conductivity foam for outdoor conditions Source 27del.ru
There is also a coefficient with the number “25”; this is a higher quality insulation, used only for thermal insulation of walls on the outside of the house. It is also often used in attics or basements where an enhanced level of thermal insulation is required. Expanded polystyrene with this coefficient can be used to insulate interfloor ceilings and roof slopes in multi-storey apartment buildings and the private sector.
Foam plastics, which are labeled with the number “35,” have the lowest thermal conductivity value. They try to insulate buried foundations, runways, highways and other capital industrial structures with such materials. It is irrational to use such insulation boards for a home.
Positive and negative properties of polyurethane foam
For a more convenient understanding of the essence, properties and scope of the material, you need to have an idea not only of the physical and chemical properties, but also know its positive and negative sides.
Positive
- Polyurethane foam has good adhesion. It adheres to wood, metal, and concrete surfaces without any problems. It does not require additional fasteners. Due to its elastic structure and method of application, polyurethane foam fits well on uneven substrates. Before applying it, the surface does not require additional treatment with primer or paint.
- PPU has a low cost. It is produced directly on the construction site by mixing two components. There are no costs for additional transportation and manufacturing.
- Polyurethane foam is a lightweight material that does not load building structures.
- In addition to heat and sound insulation, polyurethane foam strengthens load-bearing walls, making the structure stronger and more durable.
- It is practically unaffected by extremely low and high temperatures. PU foam is not destroyed by cyclic freezing and thawing.
- The polyurethane foam coating has a monolithic structure. There are no gaps for the appearance of cold bridges. The wind doesn't blow through it.
Negative
- Polyurethane foam quickly degrades under the influence of ultraviolet rays. Therefore, it does not remain open, but requires protection. It can be covered with a layer of paint or plastered. The use of various cladding panels is also suitable.
- Polyurethane foam is a non-flammable material. Still, it is not recommended to use it in places of possible contact with open fire. If this is technically impossible, then the polyurethane foam is covered with fire-resistant plasterboard.
Manufacturing technology
The equipment used is an extruder. Its name, arbitrary from the name of the head with dies located at the exit of the alloy from the unit, is extrusion.
The main component of the technological process is polystyrene granules. It is divided into several stages:
First
Second
Making the slab - staying in the holding chamber for 24 hours. All air is pumped out of the unit using a vacuum pump, and the material is left inside. It stabilizes, the pressure inside the granules filled with air is balanced.
Third
Blocks are formed in a closed type matrix. Steam is supplied inside the container under pressure. Residual moisture is lost. The aging stage ends for a day, with each new heating cycle increasing the density of the structure.
A moderately dried block is cut on a conveyor belt. Violation of technology leads to uneven edges. The cutting tool is a red-hot refractory steel string. The production uses equipment with an electronic program that controls the level of metal heating.
Source
Penofol
This insulation is produced in the form of rolls, the thickness of which is 2-10 mm. The material is based on foamed polyethylene. On sale you can find a heat insulator, on one side of which there is foil to form a reflective background. The thickness of the material is several times smaller than the previously presented materials, but this does not affect the thermal conductivity at all. It is capable of reflecting up to 97% of heat. Foamed polyethylene boasts a long service life and environmental friendliness.
Polyethylene foam insulation
The invention of polyethylene foam insulation (or polyethylene foam, PPE) raised the solution to the problem of thermal insulation to a completely new level. This lightweight and plastic material, which has a very high thermal protection coefficient and a host of other advantages, has pushed into the background a number of other insulating materials that require large physical and material investments. It can be easily used both at home and for industrial purposes.
