Richard Bate, Build Check’s Technical Director, warns companies looking to add triple glazed windows that they should ensure they are covered with a valid CE Mark. The CE Marking expert advises that changes to specifications must show in the Declaration of Performance (DoP), U-Values verified and any safety devices checked by a Notified Body for CE Marking.
Where companies already have valid CE Marking on products, it’s fairly straightforward to add more. It doesn’t always mean having more than one as companies must declare the worst case scenario for windows on the DoP. However, where performance characteristics of products are promoted in advertising, leaflets and brochures or on the internet, a separate DoP would be required to reflect this.
Legislation requires that all the components of the product are covered by the DoP as well as the essential characteristics. In the UK the mandatory characteristics for windows are thermal transmittance, load bearing capacity of safety devices and dangerous substances.
Adding a third pane of glass would require re-calculation for thermal transmittance. The Oracle, Build Check Publications’ online fenestration resource, already has triple glazing within its U-Value calculator. Verification of calculations by a UKAS Notified Body for CE Marking may also be needed.
However, the real issue for triple glazing is the significant impact extra weight would have on safety devices. Adding another pane of glass will increase the weight of the window. We estimate this increase would be 10 kg in a 1m x 1m window.
Build Check has been surprised by the number of failures it’s seen in the laboratory for double glazed units. It’s not just safety devices that are a cause for concern; it’s also the hinges on the other side that can fail in the safety device test. This means that the complete window does not pass. Because triple glazed units are much heavier, it’s important to have verification that safety devices used have passed the tests.
CE Marking is an ongoing mark of conformity. So it’s important that any changes or additions to products must be reflected in the DoP. Creating a new DoP, getting safety devices tested in the laboratory and U-Value calculations verified are all simple and straightforward procedures.
For a simple guide to CE Marking log on to www.buildcheck.co.uk/services/windows-doors-testing/ce-marking-guide/