We have several unisex restrooms with dual flush toilets at a library. We assume some percentage of visitors use these restrooms, and another percentage use the group restrooms (with urinals). This means that some men will be using the df toilets for liquid waste at a half flush.

It appears that the LEED RG usage chart assumes for male visitors there would be 4 trips to the urinal for every 1 trip to the WC.
So tell me, why can't I use this ratio to figure out the dual flush average?

The Additional Guidance Document states 2:1 for residential (not sure why there either). But for visitors - can we use a 4:1 average on the DF toilets?

It seems like I can break the calculation out differently to not use the DF average at all - and just count flushes.

Anyone?