BFRC Spacer Bar Values

Please find below the relevant excerpt from the letter in question from the BFRC to simulators, which simply states that all current values MUST be confirmed with a valid conductivity report (IFT -WA-17/1). Please see below the relevant excerpt from BFRC’s letter to simulators: “From the date of this letter, Certified Simulators are required to include in the simulation report a copy of the relevant source of the conductivity data for the spacer bars used in the simulations. Failure to do so will render the simulation report invalid. Please note that from 1st January 2014, it is proposed that only official 2-box values obtained from the European Warm Edge Working Group BF Datasheets will be deemed to be acceptable for use in BFRC Energy Rating reports. This decision will provide an additional level of confidence to suppliers and users of warm edge products alike that all conductivity values used in simulations have been validated by an external body that is completely independent of the BFRC, and who are technically qualified to carry out this validation.” As mentioned in the above excerpt, a date has been proposed to move over to the 2-box model calculation method. This will require only test data that has been approved by IFT Rosenheim and the BF. At this point I’d just like to clarify the 2-box model: Box one will include the value for spacer bar, desiccant (and PIB in dual seal systems); Box two includes the secondary sealant. The figures generated from this method should bring an end to the conflicts arising from warm edge suppliers publishing claims of the best spacer. This is due to the fact that the figures generated from this calculation method take into account the thermal performance across the edge of the unit which is heavily influenced by the secondary sealant. Thermoseal Group has supplied IFT Rosenheim data (the figures for Box 1 of the 2 Box method) which has been accepted by the BFRC. In terms of the proposed changes for January 2014, a confidential document detailing a sealed unit edge systems comparison method similar to the BF 2-box model method of calculation has been formulated by the GGF working group to allow for simple BFRC substitution and comparison of systems. As far as we are aware the exact criteria of substitution has not yet been confirmed. However, it is thought that the minimum sealant depth used by the BF will not be adopted by the BFRC in preference of average sealant depths more reflective of the products sold in the UK marketplace. If and when the GGF two-box model becomes official, a simple comparison chart with the correct sealant depths and spacer dimensions will be published and distributed to both sealed unit and window manufactures to prevent misinterpretation. Please take into account that from January 2014, whichever method is agreed, should a 2-box model be adopted it will be the sum of the 2 box values and the overall sight line that determines if BFRC substitution is allowed without the need for a new simulation report. To carry out EN14351/10077 calculations only valid evidence of performance to a European standard is required by the Simulator/Window supplier, not exclusively an IFT report. Thermoseal Group is now a member of the Warm Edge Working Group and has submitted reports to the BF for inclusion on the website. There is no comment required from the Warm Edge Working Group/BF/IFT as the only value that is likely to be used by the BFRC from the data sheets is the box 1 value data. Other data required is likely to be unique to the BFRC WER system.

For more information on BFRC Spacer Bar Values talk to Thermoseal Group Ltd