Thermal Insulation Materials: Types and Properties

The basic requirement in thermal insulation materials is to prevent heat transfer. The lower the thermal conductivity calculation value, λh, the better the thermal insulation performance of the material. The length, width, deviation from square and surface flatness of the thermal insulation material should be produced within specified tolerances. In addition, the density and morphology of the material is also important. While a minimum density of 25 kg / m3 is required for the materials to be used on the walls, a density of 30 kg / m3 is required for the roofs.

Heat is an energy and tends to move from the region where the temperature is high to the region where it is low. Correctly made, suitable thickness and effective thermal insulation is done in order to save energy by reducing this transition. At the same time thermal insulation;

  • It contributes to the economy by reducing fuel consumption in the building. Studies show that 45% – 60% of the energy required to heat the building can be saved with a correct insulation.
  • Provides thermal comfort, the feeling of thermal comfort depends on the temperature of the air in the building and the surrounding surfaces. In buildings without thermal insulation, it feels cold even if the air temperature is high. This is due to the airflow effect.
  • It prevents condensation on wall and ceiling surfaces. Diffusion technique must be followed to avoid condensation on the material itself; Vapor barrier should not be placed on the cold part of the building element and insulation material should not be placed on the hot part.
  • It reduces the risk of cracks on the surface by protecting the structural elements against tensions caused by temperature differences.
  • It provides a uniform temperature in the environment with an effective heating system design.
  • The reduction of gases such as CO2 by up to 45% with the reduction of fuel consumption plays an important role in reducing air pollution.

Fire resistance is also important in technically and physically sufficient materials. Considering that the buildings may be exposed to fire, the reaction of the selected insulation material to fire and whether it spreads the fire is important.

Types of Thermal insulation materials

Here is the list of the types of thermal insulation materials:

  1. Glass wool
  2. Rock wool
  3. EPS (Expanded Polystyrene – Expanded Polystyrene)
  4. XPS (Extruded Polystyrene – Extruded Polystyrene)
  5. Glass Foam
  6. Calcium Silicate
  7. Melamine Foam
  8. PVC Foam
  9. Phenol Foam
  10. Polyethylene Foam
  11. Elastomeric Rubber Foam
  12. Polyurethane foam
  13. Mineralized Wood Fibers
  14. Hemp
  15. linen
  16. Airgel
  17. Vacuum Insulation Panel (VIP- Vacuum Insulation Panels)

The materials used in thermal insulation or types of thermal insulation materials and their properties are as follows:

1. Glass Wool

Glass wool is a heat and sound insulation material obtained by melting inorganic origin silica sand at 1200 ° C – 1250 ° C and turning it into fiber .

glass wool, Thermal Insulation Materials,

It is of different size and density according to the type of use; It can be produced in the form of cast, pipe, sheet and mattress with additives. Thermal conductivity calculation value is λh = 0.035-0.050 W / mK, water vapor diffusion resistance factor μ = 1 and usage temperature is between -50 ° C – + 250oC. Special glass wools with an operating temperature between -200 ° C – + 450 ° C can also be produced. It does not lose its properties over time and is a non-combustible material of class A1 (fireproof) or A2 (hardly flammable) according to TS EN 13501-1. It is produced in accordance with TS 901 EN 13162 10. In order to prevent the risk of condensation, aluminum foil with a very high water vapor diffusion resistance factor is placed between the glass wool plate and the plasterboard. This type of application is called “glass wool board covered with plasterboard on one side and with aluminum foil in between”. The boards are applied by screwing or gluing.

2. Rock Wool

It is a heat, sound and fire insulation material that is melted at 1400 ° C – 1600 ° C and transformed into fibers of inorganic stones such as dolomite, basalt and diabase. It is produced in the form of plates, pipes, mattresses and cast according to its use. Thermal conductivity calculation value is λh = 0.035-0.050 W / mK, water vapor diffusion resistance factor μ = 1 and usage temperature is between -50 ° C – + 750 ° C.

rock wool

Its behavior against chemical effects is weaker than glass wool. It does not lose its properties over time; It is an A1 or A2 class incombustible material. There is no change in size with temperature. It is produced in accordance with TS 901 EN 13162 10.

One of the applications of stone wool is “Exterior plate”. This application provides fire safety in heat, sound insulation and ventilated facades. Rock wool boards, one side of which is covered with aluminum foil or glass tulle, are placed on the reinforced concrete surface with facade cladding.

3. EPS (Expanded Polystyrene – Expanded Polystyrene)

Thermal conductivity calculation value is λh = 0.030-0.040 W / mK, water vapor diffusion resistance factor μ = 80 – 250 and the operating temperature is between -50 ° C – +75 ° C. It has no capillary absorbency. It does not get wet due to its closed porous structure.

It does not lose its performance over time and can be produced in the desired density. It is resistant to pressure and its compressive strength increases with density. It is not a fragile material. It loses its properties by burning at a temperature above 80oC, it is in D or E class against fire.

Apart from heat and sound insulation in buildings; It is used in joints, hollow blocks, composite board production and insulation plaster production.

4.XPS (Extruded Polystyrene – Extruded Polystyrene)

XPS produced from polystyrene raw material by extrusion method; It is a thermal insulation material with low thermal conductivity, closed pores, breathable, does not change shape over time, has high compressive strength and does not rot. XPS has similar properties with EPS thermal insulation material, but EPS absorbs 2-4% moisture while XPS absorbs 0.3% moisture. This situation adversely affects thermal conduction.

xps-heat-insulation-material-

Thermal conductivity calculation value is λh = 0.030-0.040 W / mK, water vapor diffusion resistance factor μ = 80 – 250 and the operating temperature is between -50 ° C – + 75 ° C. It has no capillary absorbency, does not absorb water and has fire reaction class D or E. It is produced in accordance with TS 11989 EN 13164.

5. Glass Foam

Glass foam obtained by melting powder glass together with carbon is a very hard, high compressive strength, easily broken, vapor-impermeable (μ = 10000) insulation material.

glass-foam

Its thermal conductivity calculation value is λh = 0.045-0.060 W / mK, it is a non-combustible material with A1-A2 fire class. Operating temperature is between -260 ° C – + 430 ° C. It does not absorb water and is not capillary due to its closed pores. It does not deteriorate over time and is resistant to chemical effects. It is produced in accordance with TS EN 13167.

6. Calcium Silicate

It is an insulation material consisting of a combination of pumice stone and lime with a high amount of silica. It has high pressure resistance and is suitable for fire insulation (types withstands 1100 ° C are available).

7. Melamine Foam

Melamine foam, which provides good sound insulation (α, sound absorption coefficient: 0.30-1.20) and thermal insulation (λh = 0.034 W / mK), is an insulation material preferred to be used in buildings with its decorative properties. Usage temperature varies between -60 ° C – + 150 ° C.

8. PVC Foam

It is a polyvinyl chloride based thermoplastic material. It can be produced as hard, semi-hard or soft as required. Hard ones are fragile, soft ones are elastic. It is resistant to corrosion and starts to soften at 50 – 60 ° C.

9. Phenol Foam

Phenolic foam, a thermoplastic material, can be produced at low (30-60 kg / m3) and high (80-120 kg / m3) density by adding inorganic blowing and hardening agents to phenol-formaldehyde bakelite. Temperature resistance is one of the best among foam materials (up to 150 ° C). It shrinks at high temperature, its compressive strength is low. When immersed in water, it takes up 9% of its volume in 14 days. It does not mold, it can corrode metals. Thermal conductivity calculation value is λh = 0.018-0.032 W / mK.

10. Polyethylene Foam

It is a plastic based material made of ethylene and propylene. It is elastic, waterproof due to its high water vapor diffusion resistance and has low thermal conductivity. Used for heat, impact sound and waterproofing

11. Elastomeric Rubber Foam

Rubber foam-based elastomeric rubber foam provides good thermal insulation and condensation control with its high vapor diffusion value. Thermal conductivity calculation value is between λh = 0.034-0.038 W / mK. Since the water-soluble parts in its structure are less than the specified levels, the risk of corrosion is low.

12. Polyurethane Foam

It is a plastic-based thermal insulation material that foams and hardens with the help of air and mixing polyol and isocyanurate. Since it is a thermoset plastic, it cannot be recycled or reused. Thermal conductivity calculation value is λh = 0.016-0.032 W / mK, and the usage temperature is between -180 ° C / + 110 ° C.

Since it emits hydrogen cyanide gas during fire, its use in the furniture industry has been prohibited since 1989. However, it is free to use in buildings.

13. Mineralized Wood Fibers

It is a sound and heat insulation material whose resistance to external effects is increased by mineralization of wood materials . Organic compounds are converted into inorganic forms by the mineralization process. Thermal conductivity calculation value is λh = 0.060-0.107 W / mK.

14. Hemp

Hemp thermal insulation material; It is used by mixing with polyester fiber and fire retardant additives to the fast growing, producing more than one crop per year, the cannabis plant that does not require fertilizers. Thermal conductivity calculation value is λh = 0.038-0.060 W / mK. It must be protected so that the thermal conductivity coefficient does not increase with the increase of humidity and is not damaged by insects.

15. Linen

Flax fibers are derived from an ancient plant, flax, which contains high amounts of cellulose.

linen

The good air preservation of flax fibers shows its thermal insulation feature, and the elasticity of the fibers shows its sound insulation feature. Thermal conductivity calculation value is between λh = 0.038-0.075 W / mK. Boron salts are used to increase fire resistance. It does not emit toxic gas during processing.

16. Airgel

The nanotechnological material developed in the laboratory by Samuel S. Kistler in the 1930s was defined as “the lightest solid substance on earth” with an air content of 95-99.9%. It provides high heat and sound insulation as the air molecules inside cannot move. Thermal conductivity calculation value is λh = 0.018 W / mK.

airgel

It is hydrophobic and protects the structure against moisture and mold; At the end of its useful life, only sand comes out. Therefore, it is a sustainable material. Studies have been able to withstand 1300 ° C temperature for up to 30 minutes.

17. Vacuum Insulation Panel (VIP- Vacuum Insulation Panels)

High performance Vacuum Insulation Panel is formed by vacuuming with degassing material or by putting it in the outer envelope alone, depending on the porous core. Its thermal conductivity calculation value is λh = 0.004 W / mK and it is up to 10 times more efficient than traditional thermal insulation materials . While it is another advantage of using it for many years; Some of the disadvantages are that the panels are suitable for perforation, that they cannot be easily cut and sized at the construction site, that they are waterproof and cause condensation.