The revised data sheets with Psi values for windows have been published just now. You can download them for free on the BF website (German Glass Association Bundesverband Flachglas) here.

The updated data sheets can be recognised  by the release index “April 2013”. Different from the first data sheet versions, where the representative Psi-values for windows have been calculated from individual thermal conductivity values of all the materials composing a spacer, now the Psi-values are determined on the basis of a measured equivalent thermal conductivity value of the complete spacer system including desiccant and butyle. An ift-Rosenheim guideline gives a detailed description of the measurement method – here.

Manufacturers of warm edge systems are allowed to still use old data sheet versions for their products, but they will expire latest 31.12.2013. Coexistence of old and new data sheet version for one and the same spacer system is not allowed. A research project of the BF working group “warm edge” served as a basis for the revision of the data sheets. First information about this research project can be found here (in German language). More will follow in the relevant specialist publications.

As usual, I will keep you informed here in this place.