General information about thermal insulation materials
Thermal insulation materials are used for thermal protection of residential, industrial and other buildings, as well as materials and products used to isolate various thermal units.
The main indicator of the technical properties of insulating materials is their porosity. Material properties and thermal insulation properties are closely interrelated. The heat of the material depends on the low thermal conductivity of air in the pores. Using various production methods, it is possible to adjust its porosity and give them the desired properties. The density of thermal insulation materials should not exceed 700 kg / m3, and the coefficient of thermal conductivity should not exceed 0.21 W / (° C).
The following are requirements for all thermal insulation materials: a) must be durable, ensuring their safe installation and operation; b) they must be biologically resistant to their degradation and the destruction of rodents; c) must be chemically resistant to liquids and gases; d) the material must be dry and non-hygroscopic.
Some insulation materials have fairly good sound properties and are used as acoustic materials.
Properties of thermal insulation materials
Porosity is a key property that determines the quality of thermal insulation materials. The thermal conductivity of the material depends not only on the total porosity, but also on the nature, size and position of the pores.
The insulating properties of small porous materials indoors are higher in the air. The thermal conductivity of air in pumps is very low – 0.026 W / (m ° C). The presence of stable air in small closed pores reduces heat transfer. The thermal conductivity of porous materials can be converted to heat conversion. When the volume of air in the pores is smaller, its movement will be small, and thus, the thermal insulation properties will be good. The heat transfer of a material is proportional to its density, that is, the amount of solids it contains.
For example, due to the high content of solid particles in highly porous materials, the thermal conductivity of the multipurpose multipores is close to the heat of the air.
Density. The density of thermal insulation materials is the most important indicator of the quality of their thermal insulation. When the density of a material is low, its thermal conductivity is also low. The density of all insulation materials should not exceed 700 kg / m3 in order to improve the thermal conductivity of the materials used in the construction.
Durability. Most high temperature insulation materials are very durable. As a rule, the strength of growing porous materials is characterized by durability only under compression, the durability of fibrous structures — bending strength, elastic thermal insulation products (felt, mineral sheets, etc.).
The durability of building insulation materials is characterized by rigidity for tightness and bending, regardless of the structure of the repair. The thickness of the heat-insulating materials is usually 0.1-1.5 MPa, and the thickness of the cone-shaped heat-insulating material exceeds 5 MPa.
Moisture has a significant impact on the properties of insulating materials. Such materials are easily moistened because they are very rigid, which significantly impairs heat transfer, rigidity, biological stability and frost resistance.
Do not worry This property of thermal insulation materials is also very noticeable. Generally speaking, the pores of products associated with each other are more common, while closed pores are smaller.
Biological stability. The biological stability of organic thermal insulation materials is closely related to their ability to retain their moisture resistance. The ability to resist the ravages of microorganisms, bacteria, fungi, and some insect species is called biological resistance. Biological resistance may be required only from organic materials or insulating materials containing organic matter. It is possible to increase the biological stability by treating the antiseptic and toxic substances that are part of the organic raw materials.
Constructive insulation materials should be sufficiently roomy. It should be borne in mind that the insulating materials are usually very porous and have a low thermal conductivity, so their conditionality is higher than the thickness of the product from intensive materials.
Heat transfer. The main indicator of the quality of insulating materials is its heating. When the ambient temperature rises, most of the material is heated to a high temperature and rarely drops. Usually. The thermal conductivity of the material is shown for a temperature of 20-25 ° C. The reports should take into account the working temperature of the i