blowing warm air into soil stack
RedfordHenry
| Posted in Construction Techniques on
This may be the dumbest idea I’ve had this month but I need to install an exhaust fan in a tiny attic room. No easy access to a gable wall for the exhaust, and the 12 pitch roof will make going through the roof a real project. There’s an existing PVC soil stack just a few feet away. How many reasons can you name to convince me to not even think about installing a “T” in the stack and running into it with some duct from the fan?
Replies
1. Backflow.
2. The check valve you put in to prevent backflow will eventually fail, leading to backflow.
3. In a case of power snake vs. fan, the power snake wins every time.
Sound! Everytime the plumbing is used below, the noise will "trumpet" into the room.
Any possibility of piping down and along a wall or between the floor / ceiling and then out?
Don't use a "T".. Instead use a "Y". This way there will be less opportunity for the fan to blow down into the stack and for the stack fumes to waft into the attic when the fan is off.
Don't know about the blowback though.
Why do you need the fan in the first place?
F
There he goes—one of God's own prototypes—a high powered mutant of some kind never even considered for mass production. Too weird to live and too rare to die.
—Hunter S. Thompson
from Fear And Loathing In Las Vegas
How many reasons can you name to convince me to not even think about installing a "T" in the stack and running into it with some duct from the fan?
How many reasons do you need? You've already gotten some good ones.
Do you know what sewer gas smells like? Do you want that smell in your attic?
Do you know how flamable sewer gas can be? Do you want that wafting through a fan that is likely (near certainty) not rated as explosion proof?
Is it really that tough to put a boot on a vent pipe up through the roof?
Do you really want any more reasons? (or any more of my stupid questions?) ;-)
"Let's get crack-a-lackin" --- Adam Carolla
if U can get to the stack ...
why can't U get to a convient location to cut thru the roof?
Jeff
Buck Construction
Artistry In Carpentry
Pittsburgh Pa
I've read the responses, and I've never done this, but frankly it's occurred to me more than once. With proper detailing (backflow of fumes and rainwater related, mainly), I bet it could be done- I like one less roof penetration.
Maybe a good-sealing dryer vent-type flapper for a "check" valve in the fan vent entry into the soil vent - it could also deflect the power auger, but be light enough for the fan to blow open.
Put some convolutions in the fan duct to block noise; use some 4" flex HVAC duct, too.
Hmmmmmmmm. . .
Forrest
Its against every code that I'm aware off. You could possibly create a health hazard. Unless you like checking gas cans with matches, don't do it!
Being out of sawzall blades is not an excuse to use the plumbing stack.
Thanks for the feedback. I just hate putting another hole in a perfectly good roof but you all have presented more reasons to do it than not.
Here's to add-ons!