Plumbing Code - Can I tie my bathroom exaust fan into the main plumbing vent to the outside.
johnnymo
Hello - I bought an older house and I am renovating and making my half
bath a full bath. I wanted to install an exhaust fan in the bathroom,
but it is not very convienent to send it to the side of the house and I
don't won't to bother cutting a hole in the roof. So, I was wondering,
since the main air vent to both bathrooms is directly above my new
bathroom, can I have piece of PVC installed so that my exhaust vent
blows into the air vent? Is this code worthy?
Thanks for the suggestions...
John
tra...@optonline.net
No. It won't pass code and for good reason. Do you want sewer gas
coming into your bathroom?
ba...@sme-online.com
No. Except there's a water-trap, you can only connect draing piping to
the
outside, via drain line or vent. Sewer gas can be explosive, and it's
happened
that contractor cracks a gas main near a sewer line, with natural gas
getting into house with dry trap. With house coming apart in a
fireball.
This was a block away.
So you see why sewer venting is not a "convenience" thing.
J
johnnymo
Ok...I am no plumber and makes good sense, but is there enough pressure
in the air vent to push the "sewer gases" sideways and down to my
exhaust fan. I was thinking as long as I don't create a direct route I
would be ok. I just wanted to tie on to the side, kind of like my sink
is right now.
Thanks for the suggestions. I guess I will do a little more research.
JoeSpareBedroom
news:1162327248....@b28g2000cwb.googlegroups.com...
The flex hose from mine is wired to the inside of one of the existing roof
vents. It works fine. When I re-roof soon, I'm having it routed to its own
vent, but you could get away with jury-rigging it, if necessary.
johnnymo
Cool...I am fixing this house to live in, but not very long (~5 years),
so I wanna stay close to code so that people won't make me fix it when
I go to sell the house.
JoeSpareBedroom
>
> Cool...I am fixing this house to live in, but not very long (~5 years),
> so I wanna stay close to code so that people won't make me fix it when
> I go to sell the house.
>
Be sure to wire the pipe as far up in the vent as possible, so moisture is
blown all the way out. Otherwise, it's possible to have condensation on the
inside of the metal vent, which may drip back down again. I wondered about
this with mine, so I've observed while the shower as on full blast. You
should do the same when you're done.
johnnymo
Yea, that is why I thought the idea was a good one, b/c it is a very
short distance, just up 1' and over 1' ft, but the air vent still has a
way to go, so I thought if there was condensation, it is going to drain
down the air stack and into the sewer.
I just want to make sure you guys don't think the sewer gas is going to
make its way past my exhaust fan?
Thanks
Grandpa
sewer vent, Joe. Sounds like Johnny wants to hook into the sewer vent
pipe stack which will cause all sorts of trouble when he wants to sell
the house. Not to mention that "wonderful" odor he'll be trying to track
down in his bathroom on those occasional days.
My advice Johnny, is don't tap into the sewer vent stack unless you
intend to use it to dump sewage into.
--
Grandpa
Chris Lewis
If you interconnected the bathroom vent to the DWV vent, and
if the exhaust fan isn't running, why wouldn't it get
past? It's a _gas_, remember?
Would just need a minor vacuum in the house (eg: woodstove or
stove vent) to make it a high volume blast of stink.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.
JoeSpareBedroom
You're not going to attach it to the sewer pipe or vent. I'm talking about
the attic vents. If you don't have one nearby, it would really be worth your
money to install a vent specifically made for the fan, or have a roofer do
it.
Repeat: You are not going anywhere near the sewer pipe. Crush the idea.
Grandpa
--
Grandpa
Chris Lewis
> I sure hope you are talking about one of the attic vents and not the
> sewer vent, Joe. Sounds like Johnny wants to hook into the sewer vent
> pipe stack which will cause all sorts of trouble when he wants to sell
> the house. Not to mention that "wonderful" odor he'll be trying to track
> down in his bathroom on those occasional days.
Whaddya mean "occasional"? I suspect it'd be pretty much all stench,
all the time ;-)
johnnymo
Thanks Grandpa.
So, what is the difference in hooking up a sink to the side of the
sewer vent than hooking up a piece of flex hosing that goes down.
Maybe the trap? Is it b/c there is always water/gunk in the trap not
allowing the gases to go up through the sink?
My exhaust fan hose is always going to be dry so that would be a
problem. Hmm....maybe not such a good idea?
JoeSpareBedroom
Give some thought to the fact that nobody does this. Not ever. There is a
reason.
johnnymo
Awesome...good ideas. Idea is dead. Makes sense. I thought I was onto
to something, but as usual, there is a reason why it is not done this
way.
I was just testing you guys....jk. have a whole house fan, and the
minute I turn that sucker on, I can see it sucking the air from my
bathroom including the air in my exchaut fan vent when the fan is not
running.
Back to the drawing board. I appreciated every ones ideas and
suggestions. Seems like a really dumb idea now that I look back.
Peace.
JoeSpareBedroom
Call a roofer or two or three and find out what it could cost to have a
proper vent installed. It might be cheaper than you think.
Chris Lewis
> Call a roofer or two or three and find out what it could cost to have a
> proper vent installed. It might be cheaper than you think.
Another approach is to run tubing/hose from the bathroom vent to the
eaves, and face the outlet _down_ thru the soffit.
Prevents warm air siphoning, no wall rework required.
Randy
That would be the exact reason, sink drains have traps to prevent sewer
gas from entering the room.
The fan connection to the DWV vent pipe not only violates code(s), its
a plain Bad Idea as stated by others. Aside from a low pressure
conditon in the building (think kitchen exahust fan, opening a well
sealed outside door with all the windows closed, the aforementioned
fireplace or wood stove) causing sewer gas to be drawn in when the fan
is not operating, it is possible (though less likely,) that with the
bathroom fan operating, it is conceivable that the positive pressure
introduced by the fan could have an adverse affect on one of the drain
trap's contents, should the vent outlet become (partially or fully)
obstructed, say be snow. I admit, this is a long shot, but you are
looking for reasons why this is a Bad Idea, that's another.
I'll echo what a previous poster said - make sure the fan exhaust makes
it outside. Don't let it loose inside the attic. You'll be asking for
moisture trouble.
Pat
Here's something to think about. Know why managers of large commercial
buildings have ALL the floors mopped routinely -- even in areas that
are never used? It's to keep the floor drains wet so they don't stink
(seriously). They also make floor drains with "drippers" built in that
connect to a water line. They drip to keep the trap wet.
I guess all I can add to this is to cut the pipe open, take a good
whiff, and see what you think.
BTW, what you are proposing is known to happen in larger applications,
but they use a mechanically ventilated pipe so there's no back draft.
Doug Miller
>
>Thanks Grandpa.
>
>So, what is the difference in hooking up a sink to the side of the
>sewer vent than hooking up a piece of flex hosing that goes down.
>
>Maybe the trap? Is it b/c there is always water/gunk in the trap not
>allowing the gases to go up through the sink?
Precisely. That's *exactly* what the trap is for. Many people believe,
mistakenly, that the trap is there to catch objects and stop them from going
down the drain. Nope. It's there for one reason: to keep sewer gas from coming
*up*. And that's why it's important for there to be water in the trap all the
time.
>
>My exhaust fan hose is always going to be dry so that would be a
>problem. Hmm....maybe not such a good idea?
How many times do you need to be told it's not a good idea, before that
finally sinks in?
--
Regards,
Doug Miller (alphageek at milmac dot com)
It's time to throw all their damned tea in the harbor again.
JoeSpareBedroom
news:klT1h.20771$GR.1...@newssvr29.news.prodigy.net...
He was waiting for YOU to stop by and tell him. He didn't believe anyone
else.
Doug Miller
You really should see a therapist, Joe. This fixation you have on me isn't
healthy.
--
Regards,
Doug Miller (alphageek at milmac dot com)
It's time to throw all their damned tea in the harbor again.
JoeSpareBedroom
My fixation? 4-5 hours ago, half a dozen people told him his idea was lame.
You needed to chime in and say the exact same thing?
Doug Miller
I see you're still having trouble with reading comprehension -- I responded to
his question about the trap.
--
Regards,
Doug Miller (alphageek at milmac dot com)
It's time to throw all their damned tea in the harbor again.
Bill Gill
see one of the simplest answers. The sewer stack isn't
big enough. The vent fan needs a 4 inch line. For a
sewer vent plus a fan vent you need a 6 to 8 inch
line. I doubt if you have a sewer stack that large.
The proper way is to run the vent fan in a 4 inch
metal vent pipe to its own outside vent.
Bill Gill
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mockplumb
http://www.thestuccocompany.com/maintenance/Re-Plumbing-Code-Can-I-tie-my-bathroom-exaust-fan-into-th-161606-.htm
:
I would not tie in to your bathroom air vent. You need to run a new vent
up through the room.
tra...@optonline.net wrote:
> johnnymo wrote:
>> Hello - I bought an older house and I am renovating and making my
>> half
>> bath a full bath. I wanted to install an exhaust fan in the
>> bathroom,
>> but it is not very convienent to send it to the side of the house
>> and I
>> don't won't to bother cutting a hole in the roof. So, I was
>> wondering,
>> since the main air vent to both bathrooms is directly above my new
>> bathroom, can I have piece of PVC installed so that my exhaust
>> vent
>> blows into the air vent? Is this code worthy?
>>
>> Thanks for the suggestions...
>>
>> John
> No. It won't pass code and for good reason. Do you want sewer gas
> coming into your bathroom?
-------------------------------------
Chris Mock
http://www.mockplumbing.com
bud--
the answer provided by trader (an probably numerous other people) in a 3
year old thread with the OP long gone.
The succo company response is spam from a plumber. With a response this
stupid it is a company for anyone in Louisiana to avoid.
--
bud--
Attila
Exhaust fans have a flap door, so air can move only one direction. Also keeps
bugs out!
So I don't understand how sewer gas can go down into the exhaust fan. It can
open the door against the reversed airflow?
If the air duct from the exhaust fan connected into the vertical main sewer
vent which is 3 or 4 inch pipe with a T fitting, then any condensation from
the moist air forced out by the fan is just dripping down into the sewer!
When your fan is working, it creates positive pressure in the vent system
which is even help the water flow down if somebody flash the toilet or drain
the bat tub. It would act like the turbo charger on vehicles! If the fan do
not work at the time, when water is draining, the draining water creates
negative pressure in the vent so it sucks air from outside as usual and may
some air from your bathroom too, through the exhaust fan.
I can't think of a scenario, when a sewer gas rising up inside the main vent
would make a major U turn down towards the exhaust fan, open the flap door,
and sneak into your bathroom!
In a windy day you can see the water in your toilet moving up and down, cause
the pressure change in the vent pipe moving the trap water in the P-trap.
Because the exhaust fan have a flap door allowing air flow only one direction,
the sewer gas can't flow back downwards, passing the one way door!
Its act like the air admittance valves!
--
for full context, visit https://www.homeownershub.com/maintenance/plumbing-code-can-i-tie-my-bathroom-exaust-fan-into-the-ma-161591-.htm
trader_4
> replying to johnnymo, Attila wrote:
> Exhaust fans have a flap door, so air can move only one direction. Also keeps
> bugs out!
> So I don't understand how sewer gas can go down into the exhaust fan. It can
> open the door against the reversed airflow?
> If the air duct from the exhaust fan connected into the vertical main sewer
> vent which is 3 or 4 inch pipe with a T fitting, then any condensation from
> the moist air forced out by the fan is just dripping down into the sewer!
> When your fan is working, it creates positive pressure in the vent system
> which is even help the water flow down if somebody flash the toilet or drain
> the bat tub. It would act like the turbo charger on vehicles! If the fan do
> not work at the time, when water is draining, the draining water creates
> negative pressure in the vent so it sucks air from outside as usual and may
> some air from your bathroom too, through the exhaust fan.
> I can't think of a scenario, when a sewer gas rising up inside the main vent
> would make a major U turn down towards the exhaust fan, open the flap door,
> and sneak into your bathroom!
I've heard them bounce around on a
windy day. Sewer gas is stinky. Do you want sewer stink leaking into your
bathroom? Aside from that, it's a code violation and it should not be
hard to properly vent a bathroom fan to the outside.
> In a windy day you can see the water in your toilet moving up and down, cause
> the pressure change in the vent pipe moving the trap water in the P-trap.
> Because the exhaust fan have a flap door allowing air flow only one direction,
> the sewer gas can't flow back downwards, passing the one way door!
> Its act like the air admittance valves!
actual plumbing standard and would be a better seal and reliable compared
to a flimsy piece of metal acting like a damper in a cheap bathroom fan.