Forums >> Revit Systems >> Technical Support >> Load Calcs not using CFM/SF?

Gyvven

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Joined: Wed, Dec 19, 2007
69 Posts

It's been quite a while since I've used Revit to run any sort of load calc, but I've been asked to look into it again. So, I whipped up a quick little model consisting of 2 open office areas, 2 private offices and a restroom, each with a plenum. Each space was assigned it's own zone (including the plenum) and everything was defined for each zone and space. Outdoor Air was defined as .085 CFM/SF (.06 + .025 per person) to fudge 62.1 figures.

When I run the calculations it returns 0 Ventilation Load if I only have the CFM/SF checked. If I check Per Person and define it as 5 CFM I get a return of 4 CFM per person (.02 CFM/SF) in my Loads Report, which is at least returning a value even though it's wrong. Air Chnages per Hour also seems to work, though I haven't really dug into those numbers very closely.

Why won't CFM/SF return a value in my Load Reports? I'm sure it's something simple I'm missing, but I don't understand why the other two options work.

I started this in 2012 and migrated up to 2013 to see if that would fix anything. It didn't. I recall I had gotten decent results in 2010 using the CFM/SF but can't seem to replicate it in '12 or '13. I'll keep playing around with it, but if anyone has some insight I'd appreciate it.

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Gyvven

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Joined: Wed, Dec 19, 2007
69 Posts

I don't know what the issue was, but I re-started the project from scratch and the CFM/SF started working. I'd like to figure out what the issue was in case it happens on a larger project that can be quickly redrawn.

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