I've heard the IPC interpreted both ways on this point. Many inspectors read
code as saying a house may get by with a 2" vent. Others quote the code article
that says the main vent stack shall continue undiminished from the building drain
through the roof. From this the say that in every dwelling there must be one
stack and if the building drain is 3", the stack must be 3" all the way.
I prefer a stack all the way through the roof. In my area, most of our
plumbers have switched over to the new code and only make on
penetration through the roof with a 2".
Then they catch every single remaining fixture in the house with a
Personally, I don't like it. But I can see where the savings on time
and material make the all-studor vented (with one penetration)
significantly more efficient (from a monetary point-of-view only).
Frankly, I've wondered why the code insists on one penetration through
the roof. I would think a vent stack studor vented in the attic area
more than sufficient. I've not looked into the matter as to why code
requires the one penetration. Seems to me no penetrations would be
necessary to let air OUT of the system, which is needed in order to prevent
traps from blowing from upstream pressure.
I've been out of the trade too long. Does the UPC allow these Studor
vents instead of a venting system? I haven't really been a full-time
plumber since 1985, though I do a lot on the side. Studor vents weren't
even around back then.
Here in NC we use IPC. Inspectors allow mechanical vents (Studor is the brand
of one of the better ones) but every building has to have at least one through
A couple more reasons why mechanical vents can never totally eliminate
1.The entire city sewer system depends on individual building vents to equalize
2. The rotting organic material in sewage creates methane gas which has to have a
place to go.
I would never live in a home without a House Trap.
There is not any proof a no house trap aids any individual
home in venting. You do use a FAV in a whole house trap,
Check Kenny's post on a local gas spill.
Log Home ? I only did one, VTR'ed it. They did not make
those kind of vents back then.
ya but on the flip side it keeps a lot of toxic and dangerous gases
from entering the structure. And in the big cities and populated areas
where everyone and thier grandmother are plumbers, it adds a second
defense against people who don't have a clue how a DWV system is
designed and use mechanical vents.
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