Hi @Yure
I was digging into this a little bit for another project I was working on, and came on these descriptions of the F-Factors in case they are helpful to you:
ASHRAE 90.1, Appendix A
Manual J:
And FWIW: I was able to add F-Factors to en E+ model using the process shown here: ASHRAE 90.1, F-Factors for Floors? - #5 by edpmay
best,
@edpmay