Curtain Walling: Wind load resistance

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Categories: Performance : Curtain Walling


The curtain wall shall have sufficient strength to resist the difference between internal and external pressure and shall have sufficient stiffness to ensure the serviceability of the wall.

Resistance to wind load is determined by Initial Type Testing (ITT), and where the geometry of the wall is different, calculation of deflections and strength of the framing members. Calculation is based on the approriate Eurocode for the framing material.

The current Product Standard requires the out of plane deflections of a vertical framing member to be the smaller of:

  • δ ≤ 5mm
  • δ ≤ L/200
  • The revised Product Standard requires the out of plane deflections of a vertical framing member to be:

  • δ ≤ L/200 if L ≤ 3000 mm
  • δ ≤ 5mm + L/300 if 3000 mm < L ≤ 7500 mm
  • δ ≤ L/250 if L > 7500 mm
  • The values in the revised Product Standard are those from CWCT SSBE and have been used in the UK for some time. It is recommended that these values be adopted for CE Marking immediately.

    Wind loads should be considered in conjunction with other loads. Guidance on load combinations to be considered is given in CWCT SSBE and CWCT TU14 Load combinations.


    EN13116Curtain walling - resistance to wind load - Performance requirements
    EN12179Curtain walling - resistance to wind load - test method
    EN1991-1-4Eurocode 1 - Basis of design and actions on structures - Part 1-4: Actions on structures - wind loads
    EN1993-1-1Eurocode 3 - Design of steel structures
    EN1995-1-1Eurocode 5 - Design of timber structures
    EN1999-1-1Eurocode 9 - Design of aluminium alloy structures. Part 1-1: General structural rules
    CWCT TU14Load combinations


    Method of test

    A large specimen of curtain waling should be tested in accordance with EN 12179. The revised Product Standard EN 13830 will give a clearer definition of suitable specimen configurations and sizes in an Informative Annex. Full details of specimen requirements are included in the testing section. Testing a specimen to the requirements of CWCT SSBE will meet the current and future requirements of EN 13830.


    There is no classification for resistance to wind load. The safe wind load resistance, calculated in accordance with the relevant Eurocode, is declared on the CE Mark in units of kN/m2. It is inadvisable to declare values in excess of the wind load achieved in the Initial Type Test.

    CE Marking

    UK Regulations require a building to be structurally safe:

    Locationnpd allowed
    England and WalesNo
    Northern IrelandNo