A new service to be launched by building physics consultancy Greengauge will bring calculated thermal bridge details within reach for many designers and assessors who currently rely on standard details.
Advanced Details, to be launched at Ecobuild, is a searchable web-based database offering high-performance details for a full range of standard junctions. Compared to the standard details, using the service can cut the DER by 10%, and by 25% compared to using default psi values – without the need to make significant changes to the design. This could be especially valuable if, as anticipated, changes to SAP bring in higher default values.
The database offers ultra-high-performance options for many junctions. Greengauge director Toby Cambray explained: “As experienced Certified Passivhaus Designers, we understand the importance of minimising thermal bridging and we wanted to make it as easy as possible for everyone to do this. Our solution is a comprehensive, user-friendly library of details.”
The pressure to achieve excellent SAP results is being driven by increases in the SAP scores demanded by Part L, and also by sustainability targets set by clients and local authorities. With the anticipated changes due in SAP 2016, this challenge may get tougher, as Toby Cambray warns.
“In the recent consultation for the next version of SAP there are several changes proposed that will increase the penalties for failing to consider thermal bridging,” he says. “Many of the default psi-values (non-linear thermal bridge heat loss) are increasing, and it is proposed to increase the default Y-value by 33%, penalising designs where thermal bridge calculations are not available.”
The large dataset is accessed via a carefully designed search tool, which enables users to find the exact result they’re looking for, very fast. Details can be gathered together in the project manager tool, which can also calculate Y-values to help steer the overall design. Passivhaus designers will be pleased to know it lists the external Ψ-values they need for PHPP, the passivhaus energy model alongside the internal figures used in SAP and DEAP.
Gary Evans at Generate Building Performance Solutions Ltd has been helping to test the service. “It saves me loads of time reducing the thermal bridging in my projects, and I’ve come to rely on it.”
The full service will be formally launching at Ecobuild 2017 (Stand B177), where the team will be offering some fantastic introductory deals.