[RE-wrenches] Modules over vents

Wed Sep 24 07:19:33 PDT 2014

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 <solar1online at charter.net>
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 Solar314 631 1094
>
> 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:august at luminalt.com <august at luminalt.com>]
> 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:re-wrenches-bounces at lists.re-wrenches.org <re-wrenches-bounces at lists.re-wrenches.org>] 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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