Dear all,
I read numerous forum discussions and articles about the F-factor. My
question is much simpler!
For LEED purposes, ASHRAE 90.1 requires the F-factor for the unheated
slab-on grade floor in climate zone 3 to be F-1.264
I do not have insulation in my project.
I go to my floor construction makeup in eQUEST, and I have to enter the
U-value.
The question is: How can I transform the F-1.264 to a U-value that I can
enter into eQUEST?
Many thanks,
Omar Katanani
Omar,
Look in Appendix A in ASHRAE 90.1 to figure out what construction you need to meet the appropriate F-Value.
James M. Newman, EIT, LEED AP
Hi all,
This should be easy q, just looking for confirmation...
Looking at LEED v3, it seems that we have EA p2 requirement of 10%, but I don't see anymore the clause that was in v2.2 (print below) saying you need 2 EA c1 points mandatory?
Cheers,
Nikola
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Nikola,
As far as I know you are correct. They incorporated the minimum in the prerequisite (EA p2).
Regards,
Andrew Reilman, P.E.
James,
I did not understand the appendix exactly! Isn't there 1 value for
converting between F-value and U-value that anyone can help me with?
Thanks!
Omar Katanani
Omar,
U-factors describe heat transfer over an area (ft2). F-factors are very
similar except they describe heat transfer over a lineal foot (that may
be where the 'F' comes from... not sure) of perimeter.
There is not a straight conversion between U and F factors. F-factors
are accounting for heat transfer through multiple planes (the
wall/footing and the floor), and insulation present along one and/or the
other has slightly different effects.
While you could dig up the science/math behind it all, I find
representative F-factors are most easily found and used from 90.1
Appendix A - specifically read section A6 and the referenced table A6.3.
I believe ASHRAE Fundamentals may have a similar table if you want to
dig up other possibilities - I think theirs varies based on degree
days... but it's been awhile...
NICK CATON, E.I.T.