Curtain Walling: Watertightness

Open full view...

Categories: Performance : Curtain Walling


The watertightness is assessed by either:

  • Testing as an Initial Type Test
  • Testing as a project test
  • The values obtained by testing and declared on the CE Mark may relate only to the fixed components of the wall or may also cover the performance of the windows and doors. The watertightness performance of windows and doors may be tested and CE Marked separately (using the Product Standard for windows and doors). Watertightness of the interface joints between the curtain wall and any window or door insert is assessed as part of any curtain wall test.

    Watertightness is assessed by using the static water test described in EN 12155. The current Standard allows CE marking of walls of different geometry without further consideration. The revised Product Standard requires framing members in the project wall to deflect no more than those in the test wall. It is recommended that this be interpreted as curvature and end rotation as currently required in CWCT SSBE. It is advisable to use this criterion when CE Marking to the current Standard.

    The Product Standard EN 13830 includes an optional dynamic water tightness test which may be requested by the Specifier. The result of this test does not appear on the CE Mark.

    Dynamic watertightness testing

    It has been common practice in the UK to require walls with a declared static watertightness of 600 Pa or greater to also be tested using the Dynamic aero engine test described in CWCT SSBE. This has not been adopted as an EN method of test and is not included in EN 13830. The CPR prevents Specifiers from requesting the Dynamic aero engine test when a curtain wall kit is placed on the market on the basis of Initial Type Testing at the manufacturers expense (although they may specify the dynamic fan test EN 13050). It does not prevent the specification of the dynamic aero engine test as part of a sequence of project specific tests the cost of which is borne by the project.
    (note that the dynamic aero engine test is still allowed for ventilated rainscreen walls and similar forms of construction)


    Site watertightness testing

    It has been common practice in the UK to perform a water penetration - hose test on the test specimen. This is done to validate the test for later use at site. Neither this test nor the spray bar test described in EN 13051 are referenced from the Product Standard and do not appear on the CE Mark.
    Note: The CPR does not affect the specification of site testing and curtain wall manufacturers are still advised to conduct a hose test on any specimen in case a Client subsequently requires the test on a completed wall.



    EN12154Windows and doors - Watertightness - Performance requirements and classification
    EN12155Curtain walling - Watertightness - Laboratory test understatic pressure
    EN13050Curtain walling - Watertightness - Laboratory test under dynamic condition of air pressure and water spray


    Method of test

    A large specimen of curtain waling should be tested in accordance with EN 12155. 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.

    The revised test specimen confguration includes a window insert. However, the project wall will often have different windows and doors than those included in the Initial Type Test. Watertightness of the window/wall interface will be similar if the following features are similar:

  • Gaskets, beads and other sealing details
  • Drainage routes from the window frame
  • The stiffness of the window insert



    For guidance on appropriate classes of watertightness performance for use in the UK refer to CWCT SSBE. The following classes are recognised across Europe:

    ClassMaximum pressureWater spray rate
    R4150 Pa2 l/min/m2
    R5300 Pa2 l/min/m2
    R6450 Pa2 l/min/m2
    R7600 Pa2 l/min/m2
    RX>600 Pa2 l/min/m2


    CE Marking

    UK Regulations make general statements about preventing water ingress rather than placing a specific requirement on the curtain wall. However, it could be argued that the information is required for the building designer to assess the overall performance of the building. The allowable use of No Performance Determined (npd) is as follows:

    Locationnpd allowed
    England and WalesProbably
    Northern IrelandProbably

    Note that Specifiers may still expect a value to be declared on the CE Mark