Looking for advice on venting into drain\sewer (septic)

[SparkDogg]

Good morning all. I'm new here and in the planning phases of building my first grow room. The area that I'll be using is the far corner of a storage area in my basement. The entire room is 10' by a little over 40', and I'll be building what's essentialy a wall with a false door around 5 or 6feet deep. I think it's a perfect spot. It's in the far corner of my basement in a room which requires you to pass through two others to get to it, I have plenty of water lines to tap into, and I have my breaker box on the other side of it so that I can run whatever runs I need to provide adequate (and safe) electricity.

Here's a shot of the room I'll be using. I'm going to move those shelves out to the face of the wall of my room, and I'll have to crawl under the lowest shelf to get to the hidden door.

I'm trying to figure out how and where I'm going to vent this room, and one idea I gleaned from the FAQ here was to utilize the sewer system to vent into. On the opposite side of my wall around 3' out is a drain from the bathroom which resides on the other side. I believe it's 3" pipe from my pics.

We have a well and septic system, and I'm curious if it would be feasible to just tap into that cleanout on the drain, or if I need to look elsewhere? As there's a bathroom on the other side of this wall, there's also a vent installed and perhaps I could utilize that line.

Thanks in advance for any help.

Peace

 

[SparkDogg]

Hmm, I'm not seeing my pictures, I'm guessing that there's a minimum post requirement. If curious, they're in my gallery.

 

[FreakNature]

Boy I'd be uncomfortable blowing air into the waste line. Depending on the power of your fan (CFM) and the size of the drain you can calculate what the static pressure would be in inches of water. In other words...the air pressure from the fan can hold up so many inches of water. If the static pressure exceeds the capacity of the traps in your sewage system you could bubble air out of your fixtures. This would assume a big clump of whathaveyou is working its way downstream from where your exhaust duct connects, so the path of least resistance is upstream.

AND NOW after looking at your pictures that vertical pipe is probably a combination drain/vent so it should have a free path for air (fairly) straight up through the roof...maybe no worries. The problem is it only looks like a 3" and can only flow about 50 CFM at 1000 FPM, which is gonna make some noise. Maybe you could even go 1500 FPM which kicks you up to about 74 CFM.

 

[SparkDogg]

Boy I'd be uncomfortable blowing air into the waste line. Depending on the power of your fan (CFM) and the size of the drain you can calculate what the static pressure would be in inches of water. In other words...the air pressure from the fan can hold up so many inches of water. If the static pressure exceeds the capacity of the traps in your sewage system you could bubble air out of your fixtures. This would assume a big clump of whathaveyou is working its way downstream from where your exhaust duct connects, so the path of least resistance is upstream.

AND NOW after looking at your pictures that vertical pipe is probably a combination drain/vent so it should have a free path for air (fairly) straight up through the roof...maybe no worries. The problem is it only looks like a 3" and can only flow about 50 CFM at 1000 FPM, which is gonna make some noise. Maybe you could even go 1500 FPM which kicks you up to about 74 CFM.

This was my concern as well. I can get in the attic and verify that there's a vent, but I too am concerned that a 3" pipe won't be able to flow the volume of air that I'll need, especially if I ever ramp things up a bit (couple of 600s or 1000s).

Otherwise I'm probably looking at running a vent through the joists and out the bandboard of the front of my house. My concerns with doing that are that I'll have a vent blowing out the front of my house, which (especially in winter) might draw some suspicion.

Another way that I just thought of is that I could vent my room into the adjacent furnace room. That way my intakes at the floor would be pulling from one room and dumping into another completely seperate room. Is there any reason why it would be a bad thing to keep the vented air inside the house (assuming proper smell control is used)?

Here's the opening that I'd utilize to dump into the furnace room. With all the ductwork in there I can't imagine a vent would look at all out of place.

 

[FreakNature]

If your furnace takes its air from the room it's in, maybe the heat from your lights vented there would be recycled to heat your house. This might work in the colder months, not so sure about the times of year when you're not using the furnace...where would the heat go? Is the furnace room vented so outside air can get to the furnace?

Does the furnace have a vent / flue? You might be able to tie into that.

 

[SparkDogg]

Thanks for all of the insight FN. I really need to dig around the whole area and get some better pics this weekend I think. I'll map out all of the ductwork, intakes, vents, ect.

Another potential might be our attached garage. It might be in close enough proximity to this room that I could dump into that. We have our dryer venting into it, and I can't imagine that a bit of heat in a large open space like that would do much (3-car with really high ceilings).

It's interesting, I find this aspect to be the most challenging\vexing part of the whole process.

Again, my sincere thanks for all of the advice.

 

[simondetroit]

Thanks for all of the insight FN. I really need to dig around the whole area and get some better pics this weekend I think. I'll map out all of the ductwork, intakes, vents, ect.

Another potential might be our attached garage. It might be in close enough proximity to this room that I could dump into that. We have our dryer venting into it, and I can't imagine that a bit of heat in a large open space like that would do much (3-car with really high ceilings).

It's interesting, I find this aspect to be the most challenging\vexing part of the whole process.

Again, my sincere thanks for all of the advice.

I've spent the last 3 months trying to figure out all of the same scenarios SparkDogg. I came to the conclusion (due to allot of advice from this forum) that I really needed at least 6" ducting out of the room. I'm in a basement too. I actually have a sunroom addition 12x12 attatched to my house with a crawl space that vents passively. So I'm running my exhaust out the basement into the crawl. Do you have anything like that at your house?

 

[SparkDogg]

This weekend I believe I found my solution (2 actually). The adjacent room that I mentioned above not only has a 6" vent line that dumps outside for the furnace, there's also a 6" line for my stove vent that vents underneath my back deck (stealthier and the likely place I'll use.)

Thanks again everyone for the suggestions\advice.

 

[FreakNature]

I like your choice, as long as you can't back-pressure that stove vent with your grow fan. The same would go for the furnace vent.

 

[SparkDogg]

I like your choice, as long as you can't back-pressure that stove vent with your grow fan. The same would go for the furnace vent.

It's interesting, I was thinking of that too. I wonder if they make a simple 1-way valve (i.e. a rubber flapper oriented to allow air to pass out but not back in) in 6" duct size.

If not, hmmm, perhaps I've just identified a good idea for a future product.

 

[FreakNature]

Yep, it's a backdraft damper. Put it in the hood vent line upstream from your new connection and you'd be all set.

Here's an example:
Buy Aldes 6" Backdraft Damper - BDD6 | American Aldes 99 025