Thermal conductivity group

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The thermal conductivity group (WLG) is part of the product description of a building (insulating) material. It indicates the thermal conductivity of a material for a heat flow.

In the course of the harmonization of EU standards, the designation WLG is replaced by WLS ( thermal conductivity level ).

Labelling

The thermal conductivity group or level is derived from the calculated design value of the thermal conductivity λ B according to DIN 4108-4: 2013-02. This value is determined from the nominal value of the thermal conductivity λ D according to DIN EN 13162 to 13171 and an increase factor. Depending on the building material, this can have a value of 1.03 to 1.23.

The rated value λ B of the thermal conductivity level is rounded up in steps of 0.001 W / (m ∙ K), that of the thermal conductivity group in 0.005 W / (m ∙ K) steps to three decimal places, as is e.g. B. can be seen in the information on insulation product labels. A value of 0.032 W / (m · K) thus corresponds to a WLS of 032 and a WLG of 035. It is assumed that the rated value is less than one, as only insulation materials are generally assigned to a WLG. The smaller the WLG value, the greater the thermal insulation effect.

Thermal conductivities, for example, play a major role in compliance with the requirements of the Energy Saving Ordinance (EnEV).

Application in the marking of a thermal insulation material

Example for the labeling of a thermal insulation material:

EPS 035 DAA ie

With:

  • EPS: rigid polystyrene foam
  • WLG / WLS: λ = 0.035 W / (m ∙ K)
  • DAA: External insulation of the roof or ceiling, protected from weathering, insulation under coverings
  • ie: high pressure resistance

See also

literature

  • DIN 4108-10: 2015. Thermal insulation and energy saving in buildings - Part 10: Application-related requirements for thermal insulation materials - Factory-made thermal insulation materials. Beuth Verlag, Berlin 2015.
  • DIN EN 13162: 2015. Thermal insulation products for buildings - Factory made mineral wool (MW) products - Specification; German version EN 13162: 2012 + A1: 2015. Beuth Verlag, Berlin 2015.
  • DIN 4108-4: 2017. Thermal insulation and energy saving in buildings - Part 4: Thermal and moisture-proof rated values. Beuth Verlag, Berlin 2017.
  • Walter Bläsi: Building Physics. 7th edition. Verlag Europa-Lehrmittel, Haan-Gruiten 2008, ISBN 978-3-8085-4267-5 .

Individual evidence

  1. DIN 4108-4: 2017. Thermal insulation and energy saving in buildings - Part 4: Thermal and moisture-proof rated values. Beuth Verlag, Berlin 2017.
  2. DIN 4108-10: 2015. Thermal insulation and energy saving in buildings - Part 10: Application-related requirements for thermal insulation materials - Factory-made thermal insulation materials. Beuth Verlag, Berlin 2015.