European market EN 10077: difference between CEN cavity and NFRC 100 cavity

[Riccardo Saccon]

Hello everyone,

I would like to ask you a question about the thermal calculation in European market and especially about the differences between the cavity frame "material" used to model the cavity according USA standards (NFRC 100 cavity) and according european standards (CEN cavity).

Is there anyone who can clarify the physical difference between the two cavities? how do they differ?

thank you

Riccardo Saccon

[vpe...@gmail.com]

Hi,

I am not an expert in this, but according to the paper published by RDH (rdh.com) on the International Window Standards (2014), where they compared the NFRC 100 & 200, PHI, ISO 10077-2 and 15099 standards, there are variations in results when using these different procedures to simulate window performance.

In that report, they state: "The frame cavity conductivity is higher for NFRC/CSA than for ISO (NFRC k = 0.5804 W/m-K compared to k = 0.4298 W/m-K for

ISO). The main material difference noted was that of fiberglass, which has a conductivity of 0.30 W/m-K for NFRC/CSA procedures,
compared to 0.40 W/m‐K for ISO procedures."

Hope this helps.

Thanks,

Vlad