[Bldg-rate] Under Floor Air & ASHRAE 62.1-2004

Duke Graham duke at gaiadevelopment.com
Wed Feb 4 16:29:37 PST 2009


I saw a thread related to this earlier, but I have another question.

I'm trying to show ASHRAE 62.1 - 2004 compliance for a LEED for Schools
project that uses UFAD.

Table 6.2 lists the distribution effectiveness as 1.2 (Ez) for floor supply
of cool air and ceiling return. This describes our system. The problem is
that the same configuration is used for all modes (i.e. heating also).

I assume, then, that Ez would have to be revised to 0.7, per table 6.2. This
would effectively penalize UFAD for minimum ventilation compliance, because
the heating mode would require the most outside air, and therefore be the
critical calculation.

This makes sense (sort of). However, in the LEED reference guide and other
sources, I've seen the calculations run with Ez of 1.2 for UFAD, presumably
just considering cooling. Our project is cooling dominated, but not totally
without heating.

Anyway, can anyone help me make sense of this? Does LEED (and ASHRAE)
actually penalize UFAD for EQ prerequisite 1? 

Incidentally, if you try the example in the LEED reference guide (p. 297),
substituting 0.7 for 1.2 for Ez to account for heating, the  provided
example would not comply.

Did I just get the wrong reviewer at the wrong time, or do I need to get (a
bunch) more OSA to my spaces to accommodate the rare heating modes?


Any insight would help. I'm pulling my hair out over this.





Gaia New 4-29-08


Duke Graham, PE, LEEDR AP

Gaia Development LLC

4040 Del Rey Ave., Suite 12

Marina del Rey, CA 90292

p. 310.591.8172

f.  310.827.1702



P Please consider the trees before printing this email


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