Rodent Room - Exhaust Question

[CapeFearConstrictors]

Hey guys! I'm in the planning and designing portion of my new snake and rodent rooms. I've searched and I've yet to find a good answer to the question of exhaust for a rodent room.

My rodent room is going to be 7.5' x 12' x 8' ceilings. The closest suggestion I've found for a rodent room exhaust was for a ~500 cfm exhaust fan. However, seeing as that will completely replace the total volume of air in my room in 1.5 minutes, it seems like overkill.

With 500 cfm, I don't imagine it would need to be run very often. However, I would like to use a smaller fan if I could. That would result in smaller pipes and smaller holes. Would 250 cfm work and how often would I need to run it?

Basically, I'm not looking for a fan that will run 24/7, but I'm also not looking for overkill. Having the fan run for a few hours a day to keep the smell tolerable when I walk into the room will be acceptable. I'm setting it up so that as air is exhausted out of the room, fresh air from outside will be pulled in. Therefore, the room itself will be sealed from the rest of the building.

Any thoughts or suggestions are appreciated.

[jasbus]

I've never done the math on my fans...
I always go for overkill. Mine are set on for 15 minutes every hour. But, I don't have a huge amount of vents for the fresh air to come in, just three medium sized vents, so I'm not pulling huge amounts of air when it comes on. Mine just vents right outside, no piping at all. If i'm in one of my rooms when the fan comes on, I can feel the rush of air, but it's not so overwhelming that it literally sucks all of the cool air out all at once. My temps rise up about 3 or 4 degrees before the fan kicks off. I think my fans are like 1350CFM, but I can't remember exactly. My buildings are, 10x20x8 and the other is 14x28x14, that one has two fans.
By the end of the cleaning cycle, by the time the fan kicks on, the smell is just starting to get strong. So, they do work for me...

[tonkatoyman]

Your rodent room has 720 cubic feet of space. A 500 cfm fan will totally change the air in about 45 seconds. However there are things to consider.
1. There needs to be air available i.e. open vents on the opposite wall from which to draw the air. If the fan has to draw the air through cracks etc. it will work harder and not draw the rated volume but considerably less.
2. You can get by will smaller fans if you rig one to blow air in and one to exhaust the air on the other side of the room. If you size the intake fan slightly larger than the exhaust it will create a positive pressure forcing the air to move out easier.

[reptilegirl07]

What about neighbors when you're exhausting the air?

Will it bother surrounding properties/neighbors (i'm not sure if you guys are in residential or commercial areas).

That is something I'm worried about with an exhaust system. How to make it so the smell doesn't bother neighbors?

[jasbus]

They won't even notice...
I have one of my buildings in the backyard of my store, probably 40 yards from the neighbors, and you can't smell it until you get right up to the building....

[reptilegirl07]

Thanks! I was wondering about that. I just moved and live on almost 1 acre now. We're building a large carriage house for the rats and I was worried about neighbors complaining