Occ vs Plumbing calcs

[princeofpen]

I work reviewing drawings for a design professional group doing mainly schools. Problem we run into is that plumbing calculations end up with a much higher fixture count than what real world needs. Example would be a classroom with calculated load of 44 persons that will never have more than 30 students. I wouldn't be comfortable reducing egress loads but would certainly like a way to provide a lower fixture count but don't know a way to do so.
Even with calculating auditorium and gym spaces separately from their daily vs. game/play uses we still end up with 35+ M/F water closets regularly.
Thoughts?

 

[steveray]

Our State generally mods them down.....West coast UPC folks have separate charts, but not sure how it works out...

 

[tmurray]

In the past, I have accepted as you suggest. Max occupancy for egress and functional occupancy for fixture counts.

 

[RLGA]

It depends on the jurisdiction. Before assuming anything, discuss it with the building official or the person assigned to conduct the plan review you do not want to be surprised later on. If they are willing to accept a reduced occupant load for plumbing fixture calculations, get it in writing, because if they do surprise you, you will have the documentation to back you up.

 

[brokenkeys]

In the dozen or so FL school districts I've worked in I've so far been unable to mod down the RR counts. FL public school classrooms are required to be certain sizes, but FL law also limits the number of students in each one, so the actual student body is usually less than half of the calculated-per-code count. The counter argument I always get is what happens when they go over capacity, or when the law changes, etc.

On the private and charter school side (also specific to FL) they use smaller classrooms, which usually tracks closer to code. Much cheaper for them to build, but their student capacity also has a hard limit based on the facility size. Public schools can't turn away kids, unlike private or charter, so it makes sense for them to overbuild; make a few operational tweaks (double-up teachers, use overlapping schedules, etc.) and you can go over capacity and still meet code.