Dear all,
For a LEED EAp2/EAc1 energy model, does the following above-grade wall
situation fall under a mass wall or a steel-framed wall in the baseline?
8" CMU wall (load bearing) with steel studs to the interior just to create
a cavity for the batt insulation etc.
Thanks,
Ramana Koti.
Ramana,
Per Table G3.1 section 5b, the baseline is always a steel-framed wall
for Appendix G modeling. So you get to take credit for additional
thermal mass.
Chris Baker
Assuming it's new construction, of course.
[Description: IES]
Nathan Kegel
Thank you guys, that was helpful.
Ramana.
To round out the topic: Outside the context of LEED/Appendix G modeling (if you're concerned with prescriptive compliance), the threshold of what constitutes a mass wall is based on heat capacity (thermal mass), defined further in the 90.1 definitions.
I once looked hard at the issue and came away with this easy rule of thumb: any wall construction including a course of standard 4" brick exceeds the threshold and can be considered a mass wall. I would expect pretty much any wall including CMU to follow suit, filled or not.
NICK CATON, P.E.