just a one hour question

[cda]

apartment building

one hour walls between units

any problem where the bathrooms in adjoing units are back to back, and the plumbing is in the one hour wall, for both units???

may not be giving enough info

 

[north star]

* * * *

cda,

For clarity, there is a fully rated 1 hr. wall on each side of

the plumbing space cavity, with no penetrations?

Any kind of penetrations in to the rated assembly [ i.e -

electrical, mechanical, thermal insulation, lighting,

other ]?

* * * *

 

[mtlogcabin]

any problem where the bathrooms in adjoing units are back to back, and the plumbing is in the one hour wall, for both units???

Not as long as the membrane penetrations are properly protected.

Another note

If the plumbing sink drains are back to back then that may be considered a through penetration and would need to be protected accordingly

 

[Papio Bldg Dept]

Not as long as the membrane penetrations are properly protected.Another note

If the plumbing sink drains are back to back then that may be considered a through penetration and would need to be protected accordingly

Isn't there also a section in the NEC for back to back electrical too?

 

[mark handler]

cda

Bathrooms are back to back, More a sound issue, fire seals are easy.

 

[cda]

the wall between the units is one hour

the bathroom fixtures for both units will be back to back

there will be penetrations of the plumbing, to feed the sinks and toliets

* * * *cda,

For clarity, there is a fully rated 1 hr. wall on each side of

the plumbing space cavity, with no penetrations?

Any kind of penetrations in to the rated assembly [ i.e -

electrical, mechanical, thermal insulation, lighting,

other ]?

* * * *

 

[cda]

Another note

If the plumbing sink drains are back to back then that may be considered a through penetration and would need to be protected accordingly

""""a through penetration"""" because????????

or do you mean penetrating one side of the one hour wall??

 

[mtlogcabin]

713.3.1.2 Through-penetration firestop system.

Through penetrations shall be protected by an approved penetration firestop system installed as tested in accordance with ASTM E 814 or UL 1479, with a minimum positive pressure differential of 0.01 inch (2.49 Pa) of water and shall have an F rating of not less than the required fire-resistance rating of the wall penetrated.

PVC/ABS not a big deal, cast or steel the F rating needs to be accounted for

F RATING. The time period that the through-penetration firestop system limits the spread of fire through the penetration when tested in accordance with ASTM E 814 or UL 1479.

Back to back fixtures connected to a double fixture fitting, double sanitary tee or double Wye 1/8 bends of any material other than PVC or ABS could be a problem. The plastic with a intermesent collar will protect the through penetrations of that material but the others need to be delt with accordingly.

JMHO

 

[cda]

Thanks all

Since these will be apartment units, I may be using back to back wrong

Yes they will share the same wall , but more than likely independant piping

Any other code references will be appreciated

 

[iggentleman]

I assume that you can't take advantage of 709.3 exception 2 (IBC 2009) to drop the 1 hour rating to 1/2 hour?

 

[cda]

Iggen

I am on the fire side and trying to keep a Bo from painting the building red with fire stop caulk

So the building design is under review

 

[peach]

you can do back to back shared plumbing, too.. but it's ugly.

 

[Builder Bob]

I believe that the back to back configuration may cause the plumbing to be incorrectly installed === Back to Back weirs will cause a surge ( My crap is now your crap)when somebody flushes or if a party drains a tub.....

 

[cda]

I assume that you can't take advantage of 709.3 exception 2 (IBC 2009) to drop the 1 hour rating to 1/2 hour?

Yep not doing a 3.3.1.1 system

 

[cda]

I believe that the back to back configuration may cause the plumbing to be incorrectly installed === Back to Back weirs will cause a surge ( My crap is now your crap)when somebody flushes or if a party drains a tub.....

I think I used the wrong term

They will share the same rated wall to run each units plumbing

The Bo is worried about the penetration for the plumbing in one unit, almost lining up with the penetration of the other unit.

Designer is showing all kinds of fire stopping methods in the plans

I want to push for third party inspection of fire stopping

 

[north star]

& = & = &

"IF" the drains are pvc / abs, and "IF" said drains melted and

allowed a flame source to come in to contact with the sewer gases...

well, you know!

Papio asked:

"Isn't there also a section in the NEC for back to back electrical too?"

Yes, see Article 300.21 [ `08 NEC ] - Spread of Fire or Products

of Combustion.....Also, refer to Section 712 - Penetrations, in the IBC.

Section 712 gives the spacing dimensions of the electrical junction

boxes.

& = & = &

 

[north star]

* * * = * * *

From Section 706.3 [ `06 IPC ]:

706.3 Installation of fittings.

Fittings shall be installed to guide sewage and waste in the direction

of flow.........Change in direction shall be made by fittings installed in

accordance with Table 706.3..........Change in direction by combination

fittings, side inlets or increasers shall be installed in accordance with

Table 706.3 based on the pattern of flow created by the fitting.

Double sanitary tee patterns shall not receive the discharge of

back-to-back water closets and fixtures or appliances with pumping

action discharge.

Exception: Back-to-back water closet connections to double sanitary

tees shall be permitted where the horizontal developed length between

the outlet of the water closet and the connection to the double sanitary

tee pattern is 18 inches (457 mm) or greater.

* * * = * * *