007 BP 1016

BP 10 October 2016

CATNIC | COVER STORY OCTOBER 2016 | BUILDING PRODUCTS 7 thermal bridge) of 0.05W/mK to ensure minimal heat loss through the lintel’s capacity as a potential thermal bridge. Achieving the lowest psi values for lintels In order to negate the need for additional more costly measures, the specifier needs to consider how best to ensure lintels with the lowest psi values possible are selected. Lintel psi values can be found from a number of sources. Primarily it is possible to work from the default values taken from BRE IP 1/06 or ACDs, these are the ones found in SAP calculators and really present the worst case scenario. Alternatively the specifier can turn to the lintel psi values that the insulation and block manufacturers include with their typical thermal details. However, the best option is always to use the psi values provided by the lintel manufacturer themselves. Further to this, improved lintel psi values can be achieved by using lintels without a base plate (removing the potential for additional thermal bridging) and thermally broken, or separate, lintels within cavity wall constructions. Of course within all these calculations the specifier needs to also take the wider view that the psi values are not only effected by the lintel but also by the wall construction, the type of insulation used and the position of windows, doors and any other openings within the building fabric that require structural support from a steel lintel solution. Innovating the solution While this shifting legislative landscape presents a challenge for architects, engineers and other specifiers, it presents an opportunity relished by product innovators. Catnic is one such manufacturer to rise to the challenge. It is the first to bring to market a lintel design that incorporates a complete thermal break between the inner and outer leaf of a cavity wall and delivering the thermal performance of two separate lintels with the same easy installation as a traditional steel cavity wall lintel. The result is a BRE-certified energy transmittance Psi value of 0.02 to 0.05 W/mK with no compromise to structural performance, modelled by Catnic and independently tested in a range of different wall constructions. As a result, the Catnic Thermally Broken Lintel range is listed on the BRE Certified Thermal Details and Products scheme. For specifiers this means the criteria of Appendix R, SAP 2012 can be achieved in a sophisticated and practical way by using any product from the patent-pending Thermally Broken Lintel (TBL) range, thus complying easily with Part L. The range has been designed to cover all building types from small domestic dwellings to large apartment buildings, including concrete floor loads. The flat top of the lintel provides a consistent junction with the cavity wall insulation, removing the reliance on site workmanship and ensuring the actual performance of the junction meets the design expectations. So, by replacing traditional lintels with Thermally Broken Lintels, specifiers stand to reduce heat loss through window head details, a key area of linear thermal bridging, by up to 96%. This is possible by combining the thermal performance of separate lintels within a single lintel format that offers the same stable installation benefits of a traditional cavity wall lintel, delivering industry leading linear thermal transmittance psi values of 0.02 to 0.05W/mK and safe working loads. Catnic.marketing@tatasteel.com Catnic.com/TBL


BP 10 October 2016
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