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PAROC Technical Insulation - 16 Pages
■ PRODUCT PROPERTIES Thermal performance The main purpose of thermal and fire insulation materials is to prevent fire and heat flow. Thermal conductivity is one of the most important properties of any insulation material, and one factor to consider when choosing the right product for different applications. Low thermal conductivity means high resistance to heat transfer. Heat transfer Heat transfer is the transport of energy from an area with a higher temperature to an area with a lower temperature. In this way, it tends to equalize the temperatures. Heat transfer may happen in three ways: By conduction in the material between the two areas Օ By convection through flow of air or liquid By electromagnetic radiation. Thermal conductivity Thermal conductivity, the so-called lambda value (1), is the material property that determines the amount of heat (Watts) that will flow through a surface (1 m2) at a unit thickness of 1 metre of the material, when the temperature difference is 1 Kelvin between the surfaces. The unit of thermal conductivity in SI units is W/mK. For stone wool products, the thermal conductivity is the sum of four components: Օ Thermal conductivity of the static air in the cavities between the fibres Thermal conductivity through the fibres Օ Natural and/or forced convection by air movement in the wool Thermal radiation Graph 1 shows the relationship between these four components. The insulating capacity of stone wool is based on its ability to keep the air static in the fibres. Total thermal conductivity varies with the temperature, distribution and orientation of fibres in relation to the heat flow and density of the product. The contribution of radiation to the thermal conductivity of the product increases significantly with temperature. Radiation can be reduced by increasing the fibre density of the product, but in this way conduction in the fibres will also increase. The lowest total thermal conductivity in different mean temperatures Thermal conductivity ^10 W/mK 0.050- 0.040- Total thermal conductivity 0.030- 0.020- Radiation Conduction by air Conduction by fibres 0.010 0 0 20 40 60 80 100 Insulation density, kg/m3 Graph 1. Thermal conductivity in stone wool. Manufacturera test and measure the thermal conductivity values of the product only. In practice there are many other factors that affect the total thermal insulation capability of the whole insulation construction. supporting structures When using soft and flexible products as insulation material, it is necessary to provide a supporting structure to keep the cladding in the right place for the whole lifetime of the process. Normally mat products are supported with metal supporting rings on pipes. These structures conduct heat easily and this can lead to a 15-25 % reduction in the effectiveness of the whole insulation construction. inner surface temperature + outer surface temperature 2 is achieved by an optimal combination of the different components. At higher temperatures a higher density is needed. Measuring thermal conductivity Thermal conductivity is an insulation product's basic property. It is tested in a laboratory using different test methods. Slabs and mats can be measured with hot plate apparatus. It covers heat transfer without any joints. Pipe sections and mats can be measured with hot pipe apparatus. It covers heat transport in an insulation material with joints and is measured with a high temperature difference. 4
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♦»PAROC Insulate for life Product Properties PAROC Technical Insulation Technical Insulation Material properties February 2009 Replaces: June... -
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Properties to consider.............................3 Thermal performance............................4 Maximum service temprature................7 Fire... -
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PRODUCT PROPERTIES Properties to consider The demands placed on technical insulation are many and varied. Industrial, HVAC, marine and OEM applications... -
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PRODUCT PROPERTIES 1 Large range of easy-to-install solutions Օ High maximum service temprature Highly consistent dimensions and... -
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■ PRODUCT PROPERTIES Practical installation issues The circumstances on site are not always easy for installation work. In practice, getting the... -
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PRODUCT PROPERTIES Maximum service temprature Maximum service temprature is one of the most important properties of any insulation product, especially... -
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■ PRODUCT PROPERTIES Fire rsistance One of the strong basic properties of insulation material for technical applications is fire resistance. This... -
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PRODUCT PROPERTIES Temprature, °C 1200 -- Glass materials melt Wooden materials ignite Plastic materials melt PAROC stone wool continues to protect... -
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