New Requirements for Testing Curtain Walls

In December 2023, two updated standards for testing and classifying the air permeability of curtain walls, DIN EN 12153 (test) and DIN EN 12152 (classification), will be published as German versions. This means that the new standards must be observed for testing, classification and CE marking. This is because in the product standard for curtain walls DIN EN 13830:2003, EN 12153 and EN 12152 are listed as "undated" in accordance with paragraph 4.4. This means that the latest version must always be used for CE marking in order to meet the normative and therefore building law requirements.

Inquiries from manufacturers and licensers at ift Rosenheim show that both the German and European market supervisory authorities are paying increasing attention to such details. Manufacturers of facades and facade systems (licenser) should therefore be aware of and observe the relevant changes:

1. The test method of EN 12153 for determining air permeability under negative pressure (negative wind pressure), which was previously only specified as optional, has now been made mandatory. This is understandable, as negative wind pressure generally results in a higher load.
2. When describing the classification of class "AE" according to EN 12152, the maximum test pressure must be specified; For example, a classification such as AE+1200 is now possible if the airtightness of a curtain wall was determined at a maximum test pressure of 1,200 Pa.
3. Introduction of a new classification of air permeability under negative pressure (negative wind pressure), so that the classification reports no longer have to specify only one class, but now four.

Manufacturers of facades and facade systems (licenser) should therefore carefully check their test certificates to ensure that they meet the new requirements and fulfill the higher requirements. However, owners and users of ift-Test certificates do not generally need to carry out new tests, as ift Rosenheim has been using this method to determine airtightness in the event of negative wind pressure since the first test standard was published in 2000. The ift-Experts have recommended the previously optional test of negative wind pressure, as this realistically depicts the load. This means that owners and users of ift-Test certificates do not need to worry and can carry out the CE marking correctly in terms of building law. 

However, a few formal steps are required for this: In order to be able to continue to use existing test results, quasi according to the "old standard", for the CE marking, the manufacturer or licenser must consult the notified body that carried out the tests and performance assessments that are also indicated on the CE mark. The testing body verifies the change to the standard and decides whether a new product test is required or, ideally, whether a simplified procedure can be used. Existing (historical) test data is evaluated. If this is possible, a corresponding assessment document including a new classification report is created. For this verification, ift Rosenheim has access to an extensive standards database and a digital archive with the corresponding test results and documents ("historical data") for the performance assessment. Experience has shown that in most cases this performance evaluation can be carried out without new product tests.

Attention should also be paid to the following aspects, which are not new but are often misinterpreted:

• The application of the new testing and classification standards also affects facade projects that are to be tested in accordance with international regulations (e.g. CWCT - Centre for window and cladding technology), as the standard test methods for building envelopes also make undated reference to these standards.
• If curtain walls are to be tested in conjunction with prefabricated stone elements that are connected to the facade construction or into which the facade construction is installed, the surfaces and joints of the stone elements must not be added to the curtain wall for the test. This means that only the joint lengths and surface area of the actual facade construction may be used for the classification. This must be taken into account in the test, the specimen description and the test certificate. An "informative" test of the overall construction (facade + stone elements) "by analogy" is of course possible.
• Although it is possible to test openable elements according to EN 12153, it is not possible to classify them. If a classification is required for openable elements, a separate test on a suitable test stand according to EN 1026 and classification according to EN 12207 is required.