Hi,

We've received a nice boost in some models in Canada lately as the Proposed
and Baseline designs only need to have the same amount of outdoor air in the
breathing zone under CaGBC Rules. Meaning that if your baseline design is
VAV Reheat and your proposed design is chilled beam and baseboard heating
then your proposed design will have to condition somewhere in the range of
40% less outdoor air due to higher zone effectiveness and system efficiency.
It makes a lot of sense to me and becomes a significant energy savings
measure.

Is this allowed by the USGBC or by ASHRAE? I just read in 90.1 in G.3.1.2.5
that "Minimum outdoor air ventilation rates shall be the same for the
proposed and baseline designs." That doesn't specify whether they mean in
the breathing zone or outdoor air intake but I think most assume it to be
the outdoor air intake.

Aaron Smith, P.Eng