My bad I thought you had passive intake room to room,ie Daisy chained 
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It is kinda, the lung room will feed the other 3 rooms independently, so air from the lung room will be sent by 3 separate blowers.
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If I rethink this and have the lung room feed the veg room, then the veg room feed the bloom room and the bloom room feed the trim room??? But my thoughts were doing it that way would there be a lower quality air in the later rooms? Thinking good air from the lung room to each room would be better but I’m no rocket scientist
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If the air passes from one room to the next in turn, the CO2 level in the last room will be less than the first. How much less depends on how many plants are in each room. It might not be measurable or, even if it is, enough to matter.
If you have a problem with insect pests, having each room feed the next would make it easier for them to migrate from one room to others.
Either way, the volume of air the fan must exchange equals the total volume of the three rooms. When estimating the fan’s required CFM, allow for the restriction caused by the carbon filter, if you use one.
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Only use carbon filters for exhaust to outside, not going into the rooms.
So 3 rooms, 6’x8’x10’H, 4’x8’x10’, 8’x8’x10’,
Combine all 3 rooms and that would be what I need into my lung room?
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6’ x 8’ x 10’ = 480 ft³
4’ x 8’ x 10’ = 320 ft³
8’ x 8’ x 10’ = 640 ft³
Sum = 1440 ft³ plus the lung room’s volume.
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Huh, lol the 8” I have is 724 CFM, so sounds like I need 2 of them
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With a 2-3 week stretch, I’m looking at day 6-13 of bloom.
Purple Kush
Durbin Poison
Pineapple Donut
And my baby Purple Kush
Anything to be concerned about? Just a couple of brown spots? The baby a purple Kush has some brown tips.
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You’re overlooking the lung room’s volume and implicitly requiring 1 air exchange every minute.
Let’s say the total volume is 1600 ft³. 1600 ft³/724 CFM = 2.2 minutes.
So, your fan will exchange 1600 ft³ once every 2.2 minutes.
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Thank you for your time, its really appreciated, this forum is absolutely the best.
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This is correct, and should be of concern.
@Mntmannw you can certainly have more than the minimum air exchange. You may even need more than the minimum to manage heat. If you have individual exhaust fans that are reasonably sized you should be plenty good.
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My plan was, maybe still is, a 8” pulling into the lung room, and 3 6” pulling into the 3 rooms independently. The two grow rooms will have a carbon filter, with a 6” exhaust each (each room), and the trim room intake and outtake will only be on if being used. Although I think I should have some airflow just to control temps and mold in the trim room even if not being used.
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As far as passing from one room to the next, no, air will be pumped to each room from the lung room, then each room will exhaust outside.
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Good plan.
Your preceding post sounds as if you may be thinking you need 2 fans/room: One for intake and one for exhaust. Intake fans shouldn’t be necessary.
For that matter, you shouldn’t need an intake fan for the lung room. The exhaust fans in the other rooms should provide sufficient airflow.
You’ll want to give the lung room a 10" or 12" port, if you try first without an intake fan. The three 6-inch ports have a combined area = 85 inches². A 10" port’s area is 79 inches², which is close to ideal but errs on the small side. A 12" port’s area is 113 inches².
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I’m not sure I understand. My stick built grow room is inside a metal building which gets hot and cold depending on outside temps. The purpose of the lung room is to control temps and humidity before being piped into the actual grow rooms. Wouldn’t I need inline fans to pipe the good air into the grow rooms? And an in-line fan to take the exhaust out? I don’t want to set it up from room to room as when it got to the last room the temps would be higher and humidity would change, so I thought each room would pull directly off the lung room.
I’m about 1 week out from finishing the grow rooms, so now is the time for me to understand before cutting a bunch of holes in the walls.
Here is a rough diagram of my intentions.
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No. Make these passive intakes and just exhaust from each room. The exhaust in each of the grow rooms will put them under negative pressure which will naturally draw air from the lung room as long as passive intakes are in place.
If you do this right you can make them light tight and use louver to adjust if need be.
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No. Each “Air in” spot on your diagram need only be a 6" port.
Yes. The “Air out” spots are where the 6" inline fans and carbon filters go. The vacuum they’ll create will draw air through all three 6" ports and, ultimately, the lung room intake port.
I’d make that port’s area a bit smaller than the combined area of the 6" ports. That would produce a slight vacuum and thereby ensure the air moves through the rooms as intended. You could experiment with its size until the airspeed seems satisfactory.
In other words, everything @dbrn32 said while I was writing this, but longer. 
His idea of using a louver to adjust the intake port’s size is excellent. 
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I would go larger than 6" if intended to be passive.
When I built my previous room it was studded on 16" centers and covered in sheetrock on both sides. I used adjustable wall vents on both sides and glued in 1/4" plywood between studs so air would go in one up and over plywood and out the other. This allowed air to move and function as a light trap.
I bought from local big box store but something like this
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Ok, I get what your saying, I know I can be a little slow at things I don’t know, so with this method the veg and bloom room would draw from the lung room but the trim/dry room would draw from the bloom room, would the trim/dry room be getting less quality of oxygen depending on what the bloom room depleted?
I do like the concept of port holes instead on inline fans, less power consumption.
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Mine is 2x6’s on 16” centers and R-19 in the walls and R-30 in the ceiling.
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