On 15th July 2013 the BFRC announced important changes to the way spacer bar thermal values are determined and handed responsibility for spacer bar thermal values to the European Warm Edge Working Group. The BFRC wrote to thermal simulators and sealed unit makers to advise them of these changes.
The European Warm Edge Working Group is made up of the leading warm edge spacer bar suppliers in Europe and is run under the guidance of the Bundesverband Flachglas (BF) – the German Flat Glass Group. Each warm edge spacer bar on the BF website has been tested by ift Rosenheim under identical agreed conditions.
The results are published on the Bundesverband Flachglas website and thermal simulators and sealed unit makers now need to refer to the datasheets on this website and take the equivalent 2-box model conductivity values for spacer bars. The datasheets can be accessed or downloaded at http://www.bundesverband-flachglas.de/shop/kostenfreie-downloads/bf-data-sheets-english.
The test results show that SWISSPACER ULTIMATE is the best warm edge spacer bar for thermal efficiency. Under the current rules of substitution, ULTIMATE is the only warm edge spacer that can be substituted for any other spacer bar.
Until January 2014, BFRC is also accepting equivalent conductivity reports for spacer bars tested to WA17/1 that do not yet have an official 2-box report. However, from 1st January 2014, only the spacer bars listed on the Bundesverband Flachglas website will be valid for use in Window Energy Ratings.