Flipping through the '04 plumbing code I see a few slopes called out
(1/4" per 1' for fixture vents, 1" per 1' for circuit vents, 1/2" per 1'
for combination drain/vent...). Fixture vents have a maximum distance of
a few feet from fixture trap to vent, but I don't think this prevents
you from then running that vent horizontally. 916.2 states that for
vents other than stack vents or vent stacks if your vent is >40' you
need to upsize the whole vent pipe (tough to do for an existing
building, of course). Stack vents have a "maximum developed length" of
100' for a 1.5" vent which should be enough space to get away from under
the PV. I don't see any slope requirements specifically for stack vents
but my non-plumber's eye may be missing something.
The stack vent sizing Table 916.1 appears (in part) here too and it
looks like the tables match up to a 2.5":
http://www.engineeringtoolbox.com/drainage-vents-d_1110.html
DKC
On 2014/9/24 10:19, Jason Szumlanski wrote:
I am unable to find anything in the Florida code that precludes
covering a plumbing vent. The code does require the vent to be 6"
above the roof surface I believe.
I was unable to determine if these vents need to be vertical with no
bends in the attic. Obviously you wouldn't want to create a trap in
the attic, but a couple of 45's to relocate a plumbing vent to
accommodate more PV seems like a desirable thing to do sometimes. Does
anyone know if these can be relocated, i.e. to an adjacent roof surface?
On my own home I had a vent to deal with. I broke out my saws-all,
split the lead like a banana and peeled it back, cut the pipe at an
angle, and folded the lead back into the pipe after applying sealant
between the lead and pipe. There is a 1" gap between the rim of the
pipe and the back of the module. My theory on this working safely is
that, a) there will be far less rainwater falling in and around this
pipe with a module over it, and b) it is about 24" from the roof ridge
and there is a module over it so there will be very little water
sheeting down from above the vent. Code notwithstanding, I felt this
was a solid method on my own home, and I have inspected it after 6
months of Florida downpours and found no issues.
Jason Szumlanski
Fafco Solar
On Wed, Sep 24, 2014 at 6:38 AM, Bill Loesch <[email protected]
<mailto:[email protected]>> wrote:
Bruce, August, et al,
This is but one more example of confusing terminology. A plumbing
vent is not an exhaust vent!
A plumbing vent (what August calls a cold vent) is provided to
allow the sanitary drain traps (and perhaps more) to operate
properly. Without the properly functioning traps you would have
sewer gas smell and sewer gas from the plumbing fixtures. This was
commonplace when indoor plumbing was introduced to early adopters.
An exhaust vent is another animal entirely. An exhaust vent
carries the combustion products to a suitable exterior location
for dilution with ambient air. With the advent of power vented
combustion appliances, a direct vent (one that takes in combustion
air from the outside and naturally exhausts combustion products to
the outside) is IMHO the only responsible way to install any power
vented appliance in a freezing climate. (Power vented appliances
come in both condensing and non-condensing flavors-they can
penetrate the side wall or the roof). Originally, two separate
pipes (with two independent properly separated penetrations) was
used. That technique is still often used today. More recently
concentric vents have been introduced both for condensing and
non-condensing applications. A concentric vent can simplify some
installations by putting the exhaust pipe inside a larger air
intake pipe allowing for one, albeit larger, penetration. As you
might imagine if the exhaust flow is hindered/diverted/redirected
by an inappropriately located solar module combustion gasses will
be re-ingested into the intake air. Not good for equipment
performance. My understanding is the power vented _appliance
manufacturer_ dictates what kind of separation/clearances are
needed with their product. My guess is you find they want at least
a foot of separation between the top of the " inverted cone" and
the module. Probably not what you had in mind for an aesthetically
pleasing installation.
I hope this helps,
Bill Loesch
Solar 1 - Saint Louis Solar
314 631 1094 <tel:314%20631%201094>
On 23-Sep-14 6:54 PM, August Goers wrote:
Bruce and All, Sorry, I hit send before I had a chance to
complete my thoughts. What I meant to say was that I've found
AHJs often allow us to cover cold plumbing vents but I've never
tried or had any luck with covering hot vents including
condensing boiler PVC vents. Once again, if in doubt you could
see what the plan checker or inspector thinks. Best, August
-----Original Message----- From: August Goers
[mailto:[email protected]] Sent: Tuesday, September 23, 2014
4:15 PM To: 'RE-wrenches' Subject: RE: [RE-wrenches] Modules over
vents Bruce, I'll send you the CA plumbing code vent section
offlist (attachment too large for this list). The way I read the
code is that you technically can't cover any type of plumbing or
hot vent. However, and I've run into little resistance from AHJs
in the Bay Area by covering these. You might want to check in
with your plan checker. Best, August Luminalt -----Original
Message----- From: RE-wrenches
[mailto:[email protected]] On Behalf Of
Bruce Leininger Sent: Tuesday, September 23, 2014 3:49 PM To:
RE-wrenches Subject: [RE-wrenches] Modules over vents Hi all.
We're designing a system on a roof that is literally infested
with plumbing, exhaust and combustion vents. The combustion vents
are PVC and none of the vents are more than 1.5' above the roof.
A racking company says that we can cover them with modules, since
the modules will be at least 4' above the roof. They have not yet
provided any building code references to say that this is ok. Do
any of you know if the building code allows this? Thanks. Bruce
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