We provide psi-value (Ψ-value) calculations free of charge, for use in work related to the design, energy assessments and build phases of construction projects using H+H aircrete blocks.
This set of calculations has now been extended to include an additional 2,000 junctions, bringing the total to over 5,300.
The calculations confirm to both BR497 (2016) and IP 1/06 and so may be used by energy assessors in their SAP calculations.
The updated version (Revision B) now contains the following additional wall insulation options for all existing junctions:
- Full fill rigid insulation options with thermal conductivities of 0.019, 0.022 and 0.030W/mK for 100, 125 and 150mm cavities. All insulation thicknesses assumed 10mm less than the cavity they are built in to provide a residual 10mm air gap.
- New 0.019W/mK conductivity partial fill insulation options added for 100, 125 and 150mm cavities. 0.018W/mK options have been retained in the tables for reference.
Having carried out extensive comparison calculations, we can also confirm that it is now permissible to interpolate between insulation thermal conductivities within the same Summary table for a given junction. This will allow for thermal conductivities other than those listed. Interpolation across different tables is not permitted due to changes in material thickness affecting the geometry of the modelled junction.
Other than the addition of the new values (and layout changes to the Junction Summary tables to accommodate them), there are no other changes to the Ψ-values given in the previous 2nd Issue (Revision A).
Further details of complete changes may be found under Revision Notes on page 2 of the document.