EN 13947:2006

1 Scope
2 Normative references
3 Terms and definitions, symbols and units
  3.1 Terms and definitions
  3.2 Symbols and units
  3.3 Subscripts
  3.4 Superscripts
4 Geometrical characteristics
  4.1 Main principles
  4.2 Developed areas and internal depth
  4.3 Boundaries of curtain wall structures
      4.3.1 General
      4.3.2 Boundaries of a representative reference element
      4.3.3 Curtain wall areas
5 Cut-off planes and partitioning of thermal zones
  5.1 Rules for thermal modelling
  5.2 Cut-off planes of the geometrical model
6 Calculation of curtain wall transmittance
  6.1 Methodologies
  6.2 Single assessment method
      6.2.1 Thermal transmittance of glazing units and
            panels (filling elements)
      6.2.2 Determination of the heat flow through filling
            element/mullion or transom/filling element
            connection
      6.2.3 Determination of the overall thermal transmittance
            of a curtain wall (U[cw])
  6.3 Component assessment method
      6.3.1 General
      6.3.2 Definition of areas
      6.3.3 Thermal transmittance of glazing units and panels
            (filling elements)
      6.3.4 Thermal transmittance of frames, mullions and transoms
      6.3.5 Linear thermal transmittance
  6.4 Thermal transmittance of a curtain wall built of different
      elements
7 Input data
8 Report
  8.1 Section drawings
  8.2 Overview drawing of the whole curtain wall element
  8.3 Values used for calculation
  8.4 Presentation of results
Annex A (informative) Guidance for calculating the thermal
        transmittance U[cw] of curtain walling using the two methods
Annex B (informative) Linear thermal transmittance of junctions
Annex C (normative) A method for calculating the thermal
        effect of screws using a 2D numerical method and the
        procedures specified in EN ISO 10077-2
    C.1 General
    C.2 Calculation of the equivalent thermal conductivity of
        the screw [lambda][s,eq]
    C.3 Consideration of screw heads and washers
Annex D (normative) Ventilated and unventilated air spaces
Annex E (informative) Component method: Calculation example
    E.1 Data for examples
    E.2 Frames
        E.2.1 Definition and evaluation of areas
        E.2.2 Evaluation of U[f] values
    E.3 Glazing units
        E.3.1 Definition and evaluation of areas
        E.3.2 Evaluation of U[g] values
        E.3.3 Definition of l[g] and evaluation of [psi][g],
              [psi][m,f] and [psi][t,f]
    E.4 Panels
        E.4.1 Definition and evaluation of areas
        E.4.2 Evaluation of U[p] values
        E.4.3 Definition of l[p] and evaluation of the
              [psi][p] values
        E.4.4 Calculation of a complete element
Annex F (informative) Single assessment method: Calculation
        example
    F.1 General description of examples
    F.2 Centre U-value of the glazing unit
    F.3 Centre U-value of the spandrel panel
    F.4 U-values of thermal joints
    F.5 Overall U-value of the curtain wall
Bibliography

This European Standard specifies a method for calculating the thermal transmittance of curtain walls consisting of glazed and/or opaque panels fitted in, or connected to, frames.The calculation includes:different types of glazing, e.g. glass or plastic; single or multiple glazing; with or without low emissivity coating; with cavities filled with air or other gases;frames (of any material) with or without thermal breaks;different types of opaque panels clad with metal, glass, ceramics or any other material.Thermal bridge effects at the rebate or connection between the glazed area, the frame area and the panel area are included in the calculation.The calculation does not include:effects of solar radiation;heat transfer caused by air leakage;calculation of condensation;effect of shutters;additional heat transfer at the corners and edges of the curtain walling;connections to the main building structure nor through fixing lugs;curtain wall systems with integrated heating.