Townhouse Common Wall Penetration

[MAGB]

Can a fire sprinkler pipe penetrate through a townhouse common wall constructed in accordance with IRC R302.2.2? R302.2.2 describe penetrations of the membrane for electrical and refers to R302.4, but also states no plumbing shall be in the cavity of the common wall. We are working on a townhome project in Phoenix where our municipality is requiring a 13R sprinkler system and I am trying to determine if I can have a single FDC and riser for all the townhouses in a building/grouping or if each townhouse would have to have a separate system. We are using 2018 iCodes. It seems I could go to the double wall methodology, but I wonder about that from a cost constructability standpoint. Thank You!

 

[steveray]

13R system or P2904 IRC system? One is "plumbing" and one is not.....

 

[steveray]

Correction​

R302.2.2 Common Walls​

Common walls separating townhouse units shall be assigned a fire-resistance rating in accordance with Item 1 or 2 and shall be rated for fire exposure from both sides. Common walls shall extend to and be tight against the exterior sheathing of the exterior walls, or the inside face of exterior walls without stud cavities, and the underside of the roof sheathing. The common wall shared by two townhouse units shall be constructed without plumbing or mechanical equipment, ducts or vents, other than water-filled fire sprinkler piping in the cavity of the common wall. Electrical installations shall be in accordance with Chapters 34 through 43. Penetrations of the membrane of common walls for electrical outlet boxes shall be in accordance with Section R302.4.

 

[MAGB]

Correction​

R302.2.2 Common Walls​

Common walls separating townhouse units shall be assigned a fire-resistance rating in accordance with Item 1 or 2 and shall be rated for fire exposure from both sides. Common walls shall extend to and be tight against the exterior sheathing of the exterior walls, or the inside face of exterior walls without stud cavities, and the underside of the roof sheathing. The common wall shared by two townhouse units shall be constructed without plumbing or mechanical equipment, ducts or vents, other than water-filled fire sprinkler piping in the cavity of the common wall. Electrical installations shall be in accordance with Chapters 34 through 43. Penetrations of the membrane of common walls for electrical outlet boxes shall be in accordance with Section R302.4.

It looks like they added the “water-filled sprinkler piping” clarification to the 2021. We are still on 2018, but it merits a conversation with the AHJ. Thank you.

 

[MAGB]

13R system or P2904 IRC system? One is "plumbing" and one is not.....

Phoenix Fire is requiring 13R since it is a for rent product.

 

[steveray]

Phoenix Fire is requiring 13R since it is a for rent product.

Interesting....

 

[Yankee Chronicler]

R302.2.2 Common Walls. Common walls separating townhouse units shall be assigned a fire-resistance rating in accordance with Item 1 or 2 and shall be rated for fire exposure from both sides. Common walls shall extend to and be tight against the exterior sheathing of the exterior walls, or the inside face of exterior walls without stud cavities, and the underside of the roof sheathing. The common wall shared by two townhouse units shall be constructed without plumbing or mechanical equipment, ducts or vents, other than water-filled fire sprinkler piping in the cavity of the common wall. Electrical installations shall be in accordance with Chapters 34 through 43. Penetrations of the membrane of common walls for electrical outlet boxes shall be in accordance with Section R302.4.

This section isn't talking about penetrations -- this is talking about running things such as piping within the hollow space in a party wall. As I understand the question, it's not about running piping in the wall, it's asking about a sprinkler main penetrating through the party walls so the system can serve multiple dwelling units off a single riser.

 

[TheCommish]

Membrane pentrations are allowed, so if the sprinkler pipe was in the cavity could have a bullhead T with a membrane pentrations on both sides?

 

[Yankee Chronicler]

A "membrane penetration" is a penetration of one side of a wall assembly only (at least at that location). Anything passing straight through from one side to the other is a through penetration, not a membrane penetration.

 

[TheCommish]

A "membrane penetration" is a penetration of one side of a wall assembly only (at least at that location). Anything passing straight through from one side to the other is a through penetration, not a membrane penetration.

Agree, however I can see the argument coming that from each side it is a membrane pentation. The contractors in my area are very creative and believe the whole code is gray and I can make decision that favors their point of view.