Birtley Lintels has reported a surge in interest for its new PSI Value Calculator as building designers look for cost effective ways of reducing cold bridging across the external envelope.
Highly accessible via PC, tablet or mobile, the new Birtley Lintels PSI Value Calculator offers an essential reference point for building designers and energy assessors.
The Value Calculator is capable of instantly presenting thermal transmittance data on the company’s Supatherm range of high performance lintels. Users simply input cavity width, block and insulation details, along with lintel length, for the tool to provide the required PSI value in W/mK.
PSI values, which are a measure of non-repeat thermal bridging, are an essential piece of data for anyone looking for cost effective ways of assessing or maximising the energy efficiency of the building by reducing thermal or ‘cold’ bridging.
Birtley’s PSI values can also be used by energy assessors in their SAP calculations, meaning they avoid modelling heat loss on the insulation being interrupted by a highly conductive, traditional steel lintel, which can have a PSI of around 0.3W/mK.
In reality, Birtley’s revolutionary Supatherm lintels, which are thermally broken and incorporate high levels of insulation, achieve a far superior PSI value, typically between 0.03 and 0.06 W/mK. Individual lintel PSI’s are available online via the new PSI Value Calculator.
In a typical small detached dwelling of around 105m² this is equivalent to upgrading from a double to a triple glazed window, yet at a fraction of the cost, whilst the ongoing savings on energy bills make an attractive proposition for homeowners.
The efficiencies are even greater on a larger detached dwelling of 304m², with Supatherm lintels enabling a reduction in cavity wall thickness from 150 to 125mm.
In these cases, Supatherm lintels are capable of improving the dwelling fabric energy efficiency (DFEE) by up to 3%, and the overall dwelling emission Rate (DER) by more than 1%.
“Our PSI tool is proving to be invaluable to specifiers and designers because it provides them with accurate heat transmittance data on non-repeating thermal bridges at design stage,” said Zoe Watson, Group Marketing Manager at Birtley Group. “Supplying this data to the energy assessor will also ensure that the SAP calculation accurately represents the lintel specified at design stage.”
As buildings have become better insulated, the heat loss though thermal bridging has come under greater scrutiny, which is why it now has greater prominence in latest building regulations.
The important of knowing an accurate PSI value can’t be underestimated because, in a well-insulated building, thermal bridging can be responsible for up to 30 percent of a total heat loss.
Birtley Lintels, including the revolutionary new Supatherm range, are available from stockists and distributors around the UK. The company has a fully comprehensive BIM library, available online for specifiers to download.
