Jeff\Jeremy,

I looked at this question again last week and I have come to this conclusion
with our engineer.

When separating a building the difference between your thermal zones is what
is important. Like it says in the exception I think that the model is
separating 2 spaces that are totally independent of one another in thermal
function. IE as it says in the exceptions like an aquatic room with swimming
pool, where humidity and temperature would be completely different to say
offices right next door. The other exception talks about laboratories which
again would have to run on a totally different system.

These exceptions as Jeremy pointed out earlier would be very difficult to do
and fairly rare unless you are doing aquatic centers, factories,
laboratories, or other uses that require total system separation.

This is an interpretation and could be disproven especially by the person
that wrote ASHRAE with those exceptions, but for now that's how I read it.

Thanks,

PETER HILLERMANN