Antipyretics for children are prescribed by a pediatrician. But there are situations of emergency care for fever, when the child needs to give the medicine immediately. Then the parents take responsibility and apply antipyretic drugs. What is allowed to give to infants? How can you bring down the temperature in older children? Which medications are the safest?
The article details how to find the necessary standards for self-calculation. Examples are given of calculation of what thickness should be walls made of aerated concrete for different climatic zones. Information is given in a simple and understandable language.
When building private houses, such material as aerated concrete became popular. In this connection, the question of what thickness should be the walls of aerated concrete becomes urgent. Many developers argue that the wall of light blocks of 30 to 40 cm thick is completely self-contained, and it does not make sense to insulate it. To verify this statement, it is necessary to refer to two documents:
SNiP 23-02-2003, it describes the standards of thermal protection for residential premises;
SP 23-101-2004 is a set of rules that must be followed when designing thermal protection.
Wall thickness in a seasonal residence (cottage)
In houses where they live only in the warm season, the minimum thickness of aerated concrete walls (taking into account the density of the selected material) is allowed. For example, structural and thermal insulation grades with a density of D350-D450 and strength greater than B2.0 can have a minimum thickness in single-storey houses with self-supporting walls of at least 20 cm. If autoclaved aerated concrete is used, the thickness of the bearing walls should be from 60 cm, and the self-supporting walls - 30 cm (in accordance with CTO 501-52-01-2007, specified in paragraph 6.2.11.).
Attention! Norms SNiPa 23-02-2003 apply only to residential buildings designed for permanent residence. That is, in the country (seasonal) houses, in which the heating takes place periodically, this code of rules does not apply. The building of walls in this case will not be a rational expenditure of funds.
Wall thickness in private houses (permanent residence)
In this case, it is necessary to be guided by the requirements for thermal protection specified in SNIP 23-02-2003.
Note! The norms specified in SNiPe can be changed depending on the climatic features of the terrain.
This means that the thickness of the walls of aerated concrete in the middle zone of Russia and the far north will be different, since the climatic conditions differ. That is, for a mild climate, where the temperature rarely drops below 0 ° C in winter, the norms can be revised downwards.
How is the thickness of the wall made of aerated concrete
Tell in detail how to calculate the thickness of the wall of aerated concrete. To do this, it is necessary to know the dependence of the reduced resistance of heat transfer (Rreg) for aerated concrete walls on a parameter such as Dd (degree-day) typical for the area in which construction work is carried out. Such a table is given in SNiPe 23-02-2003 in clause 5.3.
The standardized resistance to heat transfer can be calculated as follows:
Rreg = coefficient a * Dd + coeff.b
In this case, the wall coefficient a will be 0.00035, and the coefficient b is 1.4.
The values of Dd for all regions of the Russian Federation are indicated in the table contained in the reference book "Construction Climatology". For more accurate data by region, you need to refer to Table 4-1, which is included in the reference book for SNiP 23-01-99.
Important! Requirements in relation to the average indoor temperature (during the heating season) affect the value of Dd (degree-day).
With these data, it is easy to make the calculation necessary for planning the level of thermal protection at home. We remind you that the optimum temperature inside the apartment building is in the range from 20 to 22 ° C. For a bathroom and a kitchen the temperature range is somewhat wider - from 18 to 26 ° C.
As an example, we calculate the value of the normalized heat transfer resistance for a private house in the Rostov region, taking into account the support for the average temperature inside the living quarters at 20 ° C, Dd in this case will be 3500. Using the previously mentioned formula, we obtain the following result:
Rreg = Coeff. A * Dd + Coeff = 0.00035 * 3500 + 1.4 = 2.625 m2 ° C / W.
To calculate the optimum wall thickness, in accordance with the requirements specified in SNiPe 23-02-2003, we still need to know the coefficient of thermal conductivity (?) Of gas-concrete blocks. It depends both on the brand of autoclaved aerated concrete, and on its density. These data are indicated in GOST 31359-2007 (see Table A1).
Important! The data in the table are given for the equilibrium moisture content, it is established for one to two years after the construction is completed.
Possessing information on the value of the coefficient of thermal conductivity for a particular aerated concrete, you can independently make calculations to determine the thickness of the walls. To do this, multiply the thermal conductivity factor (?) By the standardized resistance to heat transfer (corresponding to the region where construction takes place).
As an example, we will determine what the thickness of the walls in Siberia should be for a house being built in the Novosibirsk region. As the building material blocks of aerated concrete of average density of mark D700 are used. The average internal temperature in the house should be at least 20 ° C. To obtain the result, you must perform the following actions:
- find the value of the normalized resistance of heat transfer: Rreg = 0.00035 * 6700 + 1.4 = 3.745m2 ° C / W;
- using the table, find the corresponding thermal conductivity coefficient, D700, it will be equal to 0.208 W / m ° C (for humidity at the level of 5%);
- calculate the optimal thickness for the given region of the building walls: Wall thickness = Rreg *? = 3,745 * 0,208 = 0,77m = 77cm.
As a result, we received a decision that shows that for a house located in the Novosibirsk region, the thickness of walls of aerated concrete of medium density D700 should be 80cm.
Let's consider one more example: let's say it is necessary to determine what thickness of walls of aerated concrete in the Moscow Region is needed. For masonry we will use blocks of brand D400, for which the coefficient of thermal conductivity and density are somewhat lower.
We make the calculation:
we find the value of the normalized resistance of heat transfer: Rreg = 0.00035 * 5400 + 1.4 = 3.29m2 ° C / W;
using the table, we find for the brand D400 the corresponding coefficient of thermal conductivity, it will be equal to 0.147 W / m ° C (at a humidity of 5%);
calculate the optimal thickness for the given region of the building walls: Wall thickness = Rreg *? = 3,29 * 0,147 = 0,38 meters, which corresponds to 38 centimeters.
The thickness of the walls for aerated concrete in the south is calculated by the same principle.
Conclusion
In conclusion, we consider it necessary to recall the following:
It should be taken into account that the walls are made of blocks, so the coefficient of thermal conductivity of the built-up walls will have a greater value than for an individual block. In this case it is necessary to take into account that external enclosing structures, for example, reinforced concrete frame, reinforced belt or superstructure beam, can increase the thermal conductivity index;
To achieve the heat transfer resistance specified in the SNiPe, there is no need to increase the wall thickness. For this purpose, it is possible to build a two- or three-layer wall, filling the voids with a heater, for example, using basalt cotton wool. Moreover, its cost is much lower than aerated concrete blocks, not to mention the coefficient of thermal conductivity. In accordance with paragraph 8.11 of the code of rules governing the design of thermal protection (SP 23-101-2004), the recommended thickness of insulation - 50mm or more. In this case, it is necessary to adhere to the ratio of 1.25: 1, normalizing the thickness of the walls in relation to the thickness of the insulation.
Before the construction of the dacha everyone was thinking about what material to build a house for. It can cost to combine or apply one warm or light material, and the top is simply plastered. Variations are always born a lot, especially if there is a wide choice of building materials. But what to choose? This article will tell you about gas silicate blocks. Which is better to choose and for what wall they fit.
Block characteristics
Gas silicate blocks are ideal for warming and building the walls of country houses and not only them. They are the optimal solution in the context of "price-functionality". Let us consider in more detail the types, sizes and varieties of wall thickness from gas silicate blocks.
When designing the insulation of walls, one should note the factor of air permeability and protection against waterlogging of walls. What does it mean?
- The air permeability of the walls should not be large. Otherwise, the insulation will not have an effect. Increased air permeability can be the result of random errors in the calculation or construction.
- Thermal conductivity. One of the most important criteria of this building material. It is calculated during the construction of the building, depending on the thickness of the wall.
- Low cost. The cost price of gas-silicate products, in comparison with other materials, is negligible. And while all the blocks are easy to load and reliable for transportation and directly laying.
Most often, gas silicate blocks with a density of 300 kg / m3, with a length of 600 mm, a height of 250 mm and a thickness of 200 mm are used to construct the dacha. Blocks are divided into flat and pazogrebnevye.
On the diagram it is possible to look at brands of a variety of gas silicates and their physical and technical characteristics.
In the case of single-layer walls of gas silicate blocks, then it is worth using one wide block or a pair of different types. The best is D 500 (625 * 375 * 200).
Bearing walls in height above 20 meters do not build to build from gas silicate blocks, and for self-supporting walls this indicator can not be exceeded from the 90th floor (30 meters). As for the insuring blocks, they can be installed at any height. And depending on the number of floors, you need to use blocks of different strength classes. We'll talk about this below.
- Up to 5 floors class of strength "B 3.5", put on a solution M100.
- Houses of up to three floors are supposed to class "B 2.5" with a solution of M75.
- For a one-story and two-story country house is best to use a gas-silicate class "B 2", which is fixed with a solution of M50.
A multi-layer wall consists of many materials. Directly the gas silicate blocks are used for thermal insulation and the load-carrying capacities required for the calculation. But for the walls from the external cladding using a variety of materials, including clinker or silicate bricks, facade ceramic stone, siding, facing stone, etc.
Masonry thickness of blocks
Block masonry is carried out with the help of glue mortar, the brands of which were mentioned above. The horizontal grout joints should be in the redistribution of 2mm. There may also be deviations of +/- 1 mm.
The outer masonry of the walls must be made with a complete bandaging of at least 1/3 of the block in each row.
In multi-layered walls, it is necessary to fasten the main layers and lining. For this, anchor plates are used, which are laid in masonry seams of gas silicates, or plastic and steel bonds.
The photo shows an example of a multi-layer country house made of gas silicate blocks facing with brick and other building materials. 
From this article, we can draw a number of conclusions, which speak about the advantages of building houses from gas silicate materials. This material is easy to use, it is cheap and perfectly keeps the heat in the house. So buy and build!
The thickness of the walls of aerated concrete directly affects the heat in the house. The larger the width of the blocks, the more comfortable it will be in a frosty winter house. This advice is not always applicable in practice, because the quantity, and hence the cost of the material, is increasing. The main parameters of the house are laid at the design stage. Optimal thickness of the masonry is chosen taking into account climatic factors, SNiP standards and other criteria that affect the thermal conductivity of the walls.
Aerated concrete - thermal insulation characteristics
Related to the category of cellular concrete, differ one of the lowest values of thermal conductivity among other wall materials. This ensures the preservation of heat inside the premises in winter and the provision of optimal temperature conditions in the house in the summer.
Such characteristics are provided by the porous structure of the blocks. Gas bubbles in the production process are evenly distributed inside the material, significantly reducing its ability to transfer heat.
The porous structure gives the blocks not only positive qualities, it reduces their strength. Depending on the brand of aerated concrete its compressive strength is in the range of 15-50 kg / cm2. Stone blocks with low density (D200, D300) are characterized by minimal thermal conductivity, but also their load-bearing capacity is limited, mainly they act as heaters. Choosing the size of gas blocks for the construction of walls, take into account both factors.
Attention. Do not forget about the effect of moisture on thermal conductivity, when wetting the gas block reduces the ability to retain heat.
Classification of aerated concrete
To learn the standards of construction of cellular concrete can be in the STO 501-52-01-2007. According to its rules, when building buildings it is necessary to take into account the strength of the blocks for compression:
- В2,0 - it is allowed to use bearing walls, with a height of no more than 2 floors, with the use of M50 solution;
- В2,5 - it is authorized to use at construction of 3 floor buildings with use of a solution M75;
- В3,5 - it is recommended to use for the load-bearing walls of 5 storey constructions together with M100 solution.
According to the density index, autoclaved aerated concrete has a wide gradation - from 200 to 700 kg / m 3. Products with different indicators differ significantly in appearance.
Depending on the density value, the following block marks are distinguished:
- Up to D350 - heat-insulating or self-supporting insulation;
- D400-D600 - structural and thermal insulation;
- D700 and higher are structural.
Council. The optimal building material for a large number of regions is the D400-D500 block. They provide sufficient strength at low thermal conductivity (0.117-0.147 W / (m · K)).
Another indicator, significant for bearing walls, frost resistance. Aerated concrete of leading manufacturers can withstand up to 100 cycles of freezing.
What should be the thickness of the wall of aerated concrete?
The indicators of thermal protection of buildings are defined in SNiP 23-02-2003. The document provides standards that contribute to energy savings and the creation of a comfortable room temperature. He regulates the rules for buildings with permanent living and heating.
When designing a house, the following indicators should be considered:
- resistance of the material to frost, moisture, high temperature, corrosion;
- heating costs;
- protection against waterlogging, preventing the appearance of condensation on the inner surface of the walls.
The choice of the width of the wall from aerated concrete depends on many factors. The best option is heat engineering calculation by all rules, but it is only for specialists. For those who are not ready to shell out a solid amount, there are average indicators, which are quite enough for the house to be warm and cozy. It should be noted right away that the wall of the gas blocks is much inferior in thickness to the enclosing structures made of other materials: brick, wood, other types of cellular concrete.
- The minimum thickness of enclosing structures for cottages and houses of seasonal residence is 200 mm for self-supporting structures. In this case, the D300-D400 is used. But the specialist will not recommend this thickness, it is better to stop at 300 mm.
- During the construction of the basement and basement, high loads are applied to the material, therefore, D600, class B3.5, with a thickness of 400 mm is used.
- Partitions between the apartments are 300 mm thick with D500 products, interior partitions - 100-200 mm.
- The thickness of load-bearing walls from aerocrete of autoclave hardening is recommended from 375 mm, self-supporting - from 300 mm.
How is the thickness of walls made of aerated concrete calculated?
The coefficient of thermal conductivity of blocks λ, it differs for each density mark, the desired value is selected in the table of general values or in the test reports of a particular manufacturer.
For accurate calculation, the following values will be needed:
R reg - resistance to heat transfer of walls. This indicator can be found in the table or calculated independently.
Simplified formula for calculating the thickness of load-bearing walls of aerated concrete:
T = R reg *λ
If the values of R reg are not in the table, it is calculated by the formula:
R reg = coeff.a x Dd + coeff.b,
where the coefficient a is 0.00035;
the coefficient b is 1.4,
Dd - degree-day of the heating season.
Coefficients are taken from SNiP 23-02-2003, and the indicator Dd should be considered in more detail. Degree-day - the difference between the temperature in the room and the average street temperature for the heating season, multiplied by the duration of the heating period. The average temperature in living rooms should approach 22 °, but be at least 18 °. For regions with an outside temperature of -31 ° C, comfortable indices for premises are 21-23 °.
Council. The values of Dd are indicated in the manual "Construction climatology" and SNiP 23-01-99.
For example, let's calculate how much wall of aerated concrete should be in Moscow:
Dd - 4943 degrees-days, λ for D400 - 0.12, for D500 - 0.14
R reg = a * Dd + b = 0.00035 * 4943 + 1.4 = 3.13 - normalized resistance to heat transfer
T = 3.13 * 0.12 = 0.375 m - for brand D400 (at λ = 0.12)
T = 3.13 * 0.14 = 0.44 m- for the brand D500 (at λ = 0.14)
From this calculation, it turns out that the thickness of the supporting structure for Moscow's climatic conditions should be at least 44 cm when using D500 aerated concrete for masonry. For less dense material D400 the masonry size will be 37.5 cm. In a similar scheme it is easy to calculate the exact value of wall thickness from aerated concrete for your home.
Attention! The values of the coefficient of thermal conductivity of grades of gas blocks are calculated for a moisture level of 5%.
For northern regions, where the heating season lasts much longer than in the south and the middle lane, the calculated thicknesses of the walls will be 74-77 cm. A multilayer construction is recommended for the construction of houses in this climatic zone.
How does the thickness of walls of aerated concrete affect sound insulation?
The walls of the house protect us from the noise of the street, passing cars, neighbors. Blocks due to cellular structure well extinguish sound waves. But what is the thickness of the walls of aerated concrete should be to ensure comfort and silence?
The size of partitions between the rooms is 100-150 mm blocks D600, after plastering with gypsum plaster the noise insulation index will be 43 dB. This is the norm. Enclosing structures with a thickness of 300 mm will provide sound isolation of 52 dB. Interior plasterboard, which is often used for buildings made of cellular concrete, effectively reduces noise levels.
Factors reducing the energy efficiency of the building
The thickness of the walls of aerated concrete is calculated applicable to the whole block of cellular concrete. In practice, when building a building, a large number of elements are used, which are joined together by concrete or mortar joints. Each such junction is a potential "bridge of cold". In addition, in the thickness of the walls, reinforcement is laid, a reinforcing belt is created, due to which the thermal conductivity of the masonry increases.
The mortar connecting the masonry must be made of a special dry glue mixture intended for aerated concrete. In its composition, in addition to cement, there are mineral fillers and polymer modifiers. For winter works, a composition with antifreeze additives is recommended. Adhesive joint layer 2-3 mm - this thickness minimizes heat losses. If the professional mixture is replaced with a cement-sand mortar, the size of the seam and the effect of the "cold bridges" will increase.
The loss of heat through the walls is up to 25% of the total. The rest of the energy goes through the windows, the roof, the foundation. These areas need high-quality thermal insulation.
Creating multi-layered enclosing structures
Increasing the thickness of walls is not the only way out, which will create comfortable living conditions with minimal heating costs. It is possible to use two- and three-layer constructions with a heater and a finishing material.
Erection of external walls occurs in one of 4 ways:
- Single-layer construction - using fiberglass reinforcing mesh.
- Two-layer construction - a heater and a layer of plaster. As a heater is recommended semi-rigid, its vapor permeability is close to aerated concrete, and the thermal conductivity is lower. The thickness of the insulation must be selected according to SP 23-101-2004.
- Two-layer construction without insulation - ventilation gap and facing brick. Brick laying is carried out using standard technology using flexible connections.
- Three-layer construction - ventilated facade with a heater or brick lining with additional insulation between the outer and inner walls.
Execution of external insulation of the building from aerated concrete blocks should be carried out in a complex manner. It is impossible to ignore the isolation of the basement, the foundation, the device of the blind area. An important rule of mounting wall layers - their coefficient of vapor permeability should increase from the inside out. With such a multi-layer construction, the vapor will not be retained in the cellular blocks, but freely leave to the street.
Conclusion
The effective thickness of the walls of aerated concrete should provide low heat transfer and sufficient strength of the structure. To ensure both factors in the calculation, the strength class of aerated concrete blocks is taken into account (depending on the number of floors of the building and the height of the walls, B2.5 and above are recommended), their density and the coefficient of thermal conductivity. An important role is played by the climatic conditions of the region. The standards for the thickness of load-bearing enclosures and their thermal resistance directly depend on the region.
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The consumer is most interested in the combination of thermal insulation and strength characteristics of the density mark 400-600, because with increasing density, the thermal conductivity of the material naturally increases, which means that the advantages of aerated concrete and gas silicate are reduced before other building materials.
The porosity of aerated concrete in the context of its thermophysical properties is of two kinds. On the one hand, it increases the heat-protective properties of the material, on the other hand it reduces the strength characteristics. But finding a "golden mean" is a very difficult question. It is due to the high porosity of aerated concrete that the moisture content in the material has an extremely important effect on the formation of the complex of properties, because of which the wall thickness of the gas silicate blocks can not be calculated by a simple formula. And if the maximum permissible humidity values, increasing the risk of destruction, are within 40 and above percent depending on the density mark, with regard to the structural strength of the compression and bending, the thermal insulation capabilities of the structure should be determined taking into account a number of factors and depending on the recommended SNiP 23 -02-2003 (Thermal protection of buildings) of resistance to heat transfer R reg for a specific climatic zone of Russia.
According to the standard procedure given on the sites, the thickness of the walls from the gas silicate blocks is determined by the formula σ = R reg · δ, where δ is the thermal conductivity of concrete gas of a certain density. However, the claimed thermal conductivity values almost always refer to completely dry material, and therefore the actual values of the thermal conductivity of autoclaved aerated concrete and gas silicates should be taken from GOST 31359-2007, of course, if the materials are produced by the manufacturer in accordance with the requirements of this regulatory act.
For the capital area, according to SNIP II-3-79, SNiP 23-01-99 and SNIP 23-02-2003, resistance to heat transfer R reg = 3.15 is established. At a maximum moisture content of 6%, the thermal conductivity of grade 400 is (for example for Ytong) 0,117 W / (m · deg. C), and grades 500 - 0.132 W / (m · deg. C). Based on these values, the nominal thickness of the walls from the gas silicate blocks should be for the mark 400 - 0.368 m, grade 500 - 0.462 m. But this can not be considered complete. Without considering the masonry on the mortar (heat losses up to 25-30%), the seams of the recommended adhesive composition also reduce the thermal insulation properties of the construction by an average of 4-6% at a thickness of 3-4 mm. And the thickness of the walls of the gas silicate blocks should compensate for these losses. Calculations give a thickness for grade 400 about 0.385 m, grades 500 - 0.48 m.
The next "problem" place in the masonry can be a monolithic harness, arranged to preserve the structural strength of the house.
However, with sufficiently effective thermal protection of the strapping outside (a number of gas blocks of smaller width, etc.), these losses are rather small, especially since in the general heat losses of the house the masonry does not have a predominant value.
Information for reference: how good is the thermal conductivity of Ytong? When building a house from foam blocks , the best option for load-bearing walls is the D700 strength grade, whose thermal conductivity is 0.19 W / (m · deg. C).
Taking into account the masonry on the mortar (since the geometry of the foam blocks often leaves much to be desired) and even without the monolithic strapping, the thickness of the wall in the construction of foam concrete for the area of the capital according to SNIP should be 0.782 m.
- Cladding on glue from expanded clay blocks on expanded clay sand and claydite foam concrete 800 kg / m³, - thermal conductivity 0.31 W / (m · deg. C)
- Laying of clay ordinary (GOST 530) bricks on cement-sand mortar, - 0,76 W / (m · deg. C)
- of silicate (GOST 379) bricks on a cement-sand mortar, 0.87 W / (m · deg. C)
Of course, it becomes clear that in all these cases without additional insulation of the load-bearing wall is indispensable. In general, this determines a significant difference in real investment in the construction of walls made of gas silicate, aerated concrete and factory-made foam concrete (see articles and).
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