Humidity Calculations at Peak Conditions

James, I think that since the previous field in the form is a narrative, GBCI is looking for something more along the lines of engineered numbers or calculations.

My engineer is asking for help with these calculations. He says that he has no idea what they want. Any guidance I can provide him would be helpful.

My load calculation/ energy simulation software provides a "Building Humidity Profile" output that lists the maximum relative humidity in every space, at both occupied and unoccupied times. I use Trace 700, but I'm sure other programs have a similar output.

James, I see this is an old question, but I don't think it has been resolved based on the answers I see. What did you decide to do and was it approved by LEED?
I'm a mechanical engineer and know how to do all the calculations provided that it is explained what the desired set of conditions/requirements are, but I am confused to what is really being asked when LEED asks "provide humidity calculations at peak conditions, both occupied and unoccupied" . I think the occupied condition is easy: peak weather day combined with peak occupancy. That condition is easy to document, our Trace 700 load software also creates a report for that. Of course this is assuming they want the calculation to include the effect of the mechanical cooling system, but the LEED credit wording doesn't even explicitly state that.
The confusion for me is the unoccupied condition. In practice, there is no outside air brought in and by definition there are no internal latent loads during unoccupied times (unless it is a pool or aquarium or the like) , and with new tight envelopes with proper vapor barriers there should be no humidity infiltration. Therefore any calculation would show there is no latent gain during unoccupied hours. That calculation wouldn’t tell you what the humidity %RH is though. Is this really what LEED wants to see: a hand calculation stating there is no humidity gain therefore the space humidity is the same as it is whenever the building was last occupied? The credit already requires the designer to explain the method used to control humidity at all load conditions, occupied and unoccupied. Assuming that method is a sequence of operations or design intent narrative and that it is acceptable to the reviewer then it should follow that if your control method works at low load conditions, you will always satisfy it during unoccupied times. So why ask for the unoccupied calculation?