Kingspan Insulation has released a new technical bulletin and RIBA approved CPD article, designed to support enhanced detailing. The documents explore the effects of linear thermal bridging around openings in the building envelope, and present new research on the subject, allowing specifiers to use Kingspan Kooltherm Cavity Closer as a premium performance, one-size-fits-most solution.
The CPD article and technical bulletin are based on a thermal modelling study of jamb details by BRE Scotland. The study covers a variety of cavity wall constructions closed using Kingspan Kooltherm Cavity Closer. The calculated ψ–values within the study are considerably better than those given in the SAP Table K1 “Approved” column (which reflect the values given in “Accredited Construction Details”) and, in the BRE’s opinion, are equally applicable to the equivalent sill details.
Importantly, the resulting ψ–values can also be used as a “safe approximation”, for frame depths and overlaps (between the frame and Kingspan Kooltherm Cavity Closer) for a broad range of constructions. This makes it simpler for designers to specify enhanced detailing around openings in the building envelope.
To quantify the level of improvement, Kingspan Insulation goes on to compare the transmission heat transfer coefficient (HTB) calculated using the “safe approximation” ψ–values from Table 1 with that calculated using jamb and sill ψ–values from the SAP Table K1 “Approved” column, for four different dwellings. The HTB calculated using the “safe approximation” ψ–values is significantly better (up to 13% better) than that calculated using ψ–values from the SAP Table K1 “Approved” column.