# Townhome separation wall with plumbing vents



## lpiburn (Dec 9, 2014)

Hello all,

Is there any reason that plumbing piping is not allowed in the common wall between duplex residences? My plumbing engineer is saying that we can't and I cannot find a code reason why.

I am working on a renovation project with various apartments built in the early 80s. There are various plans including duplexes and townhomes. Some were not separated properly (1-hr instead of 2, no attic separation, etc.).  One townhouse was designed properly with a 2-HR wall and a parapet, but it has plumbing running through it, including washer boxes, dryer vents, water piping, and waste vents.

I've been searching the forums and the code and I found where the code prohibits this in the townhouses. Specifically, IRC2006 Section R317.2: _"A common 2-hour fire-resistance-rated wall is permitted for townhouses if such walls do not contain plumbing or mechanical equipment, ducts or vents in the cavity of the common wall."_

First, this section doesn't prohibit piping in general. Only those 4 specific things. Is water piping allowed?

Second, I cannot find where (or if) it prohibits plumbing in a duplex separation. That would be a 1-HR wall between two-family dwellings per R317.1. I then read R317.3.2 for membrane penetrations which leads to R317.3.1.1 _"Penetrations shall be installed as tested in the approved fireresistance-rated assembly."_

The way I read it, we should be able to run vent piping within the cavity of the 1-HR rated wall, then back out of the wall and up thru the roof. There are through penetration UL listings for this application where you essentially just fire seal it and call it a day. Am I missing something?

Thanks in advance.

-LP


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## mtlogcabin (Dec 9, 2014)

It is in the definitions that piping and ducts are included as equipment. So the answer is not allowed in a 2 hour common wall under today's code

IRC 2006

EQUIPMENT. All piping, ducts, vents, control devices and other components of systems other than appliances that are permanently installed and integrated to provide control of environmental conditions for buildings. This definition shall also include other systems specifically regulated in this code.



> I am working on a renovation project with various apartments built in the early 80s.


Check the code they where built under. May have been permitted at that time and therefore would be allowed to remain provided they are left undisturbed


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## lpiburn (Dec 9, 2014)

Thanks,  That clears up piping at the townhomes, but what about the duplexes?

These are definitely not going to be undisturbed. We are doing a major renovation down to wood studs and back. We are bringing everything above the slab up to 2006 IRC.


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## mtlogcabin (Dec 9, 2014)

I do not find a code prohibition for equipment in a duplex wall


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## north star (Dec 9, 2014)

*= & = & =*



lpiburn

Is your 1 hr. rated wall between the duplexes a true fire rated assembly ?

If so, ...do you have a U.L., or Factory Mutual, or other approved agency

that is certifying your 1 hr. rated assembly, ...that also includes the types

of piping & other components in them  [  i.e. - do you have an approved

drawing  ] ?



*= & = & =*


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## JBI (Dec 9, 2014)

'Townhouses' are supposed to be on separate lots, that's why you either build two one hour walls as exterior walls (zero lot line clearance) OR a single two hour 'party wall' which is what the IRC describes when it describes a single common wall - no openings, no plumbing or mechanicals, compare the description to that found in the IBC for 'party wall'. You are protecting one private home from another.

With a duplex you are on a single lot with adjoining tenants in most cases.


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## lpiburn (Dec 9, 2014)

north star said:
			
		

> Is your 1 hr. rated wall between the duplexes a true fire rated assembly ?


Yes. I don't have a UL number but I could find one if necessary. It's just typical 2x4 or 2x6 construction with 1 layer of type X each side.



			
				JBI said:
			
		

> 'Townhouses' are supposed to be on separate lots [...] You are protecting one private home from another.


Kind of... In both cases the actual lot line is irrelevant, and either way you are protecting one _tenant _ from another. You are correct that for townhomes you must build them AS IF they were separated by a lot line, hence the stricter measures. Regardless I think it's pretty clear that no plumbing is allowed there. I just need to confirm that piping in the duplex wall is ok.


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## mtlogcabin (Dec 9, 2014)

> 'Townhouses' are supposed to be on separate lots,


Requirement went away in the I-Codes

Was in CABO and I believe the other "legacy" codes


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## mark handler (Dec 10, 2014)

Your plumbing engineer maybe refering to roof penitrations of vent pipes within 5 feet of the wall?


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