fire wall problem

[Mr. Inspector]

2009 IBC. A 5B building is going to get a 2 hour fire wall between R-3 and S-2 occupancys so they only need sprinklers on the R side of the building. The building is 1 story and is not big enough to need sprinklers but needs it because of the R.

There is a porch roof that continues from the R side of the fire wall to the S side. The designer is asking me if they can extend the fire wall inside the porch roof to comply. I told him that it will need to be suported by a 2 hour rated column.

Would this comply with IBC 706.5.2 Horizontal projecting elements?

 

[JBI]

Would exception #1 apply? Hinges on no concealed spaces, so an open-to-the-rafters design would lave no concealed spaces.

706.5.2 Horizontal projecting elements. Fire walls shall extend to the outer edge of horizontal projecting elements such as balconies, roof overhangs, canopies, marquees and similar projections that are within 4 feet (1220 mm) of the fire wall.

Exceptions:

1. Horizontal projecting elements without concealed spaces, provided the exterior wall behind and below the projecting element has not less than 1-hour fire-resistance-rated construction for a distance not less than the depth of the projecting element on both sides of the fire wall. Openings within such exterior walls shall be protected by opening protectives having a fire protection rating of not less than 3/4 hour.

 

[Mr. Inspector]

They will have a cieling on the porch roof.

 

[JBI]

OK, exception 3?

3. For combustible horizontal projecting elements with concealed spaces, the fire wall need only extend through the concealed space to the outer edges of the projecting elements. The exterior wall behind and below the projecting element shall be of not less than 1-hour fire-resistance-rated construction for a distance not less than the depth of the projecting elements on both sides of the fire wall. Openings within such exterior walls shall be protected by opening protectives having a fire-protection rating of not less than 3/4 hour.

 

[Mr. Inspector]

They don't have the one hour exterior wall or the 3/4 hr opening protection. The designer asked if they put dryheads in the conceled space on the R side they could skip this. But still have the 2 hour wall continuing through the porch roof. I think that would be above code.

 

[spector51]

is this not a fire barrier as opposed to a fire wall?

 

[mtlogcabin]

is this not a fire barrier as opposed to a fire wall?

[F] 903.2.8 Group R.

An automatic sprinkler system installed in accordance with Section 903.3 shall be provided throughout all buildings with a Group R fire area

[F] FIRE AREA. The aggregate floor area enclosed and bounded by fire walls, fire barriers , exterior walls or horizontal assemblies of a building. Areas of the building not provided with surrounding walls shall be included in the fire area if such areas are included within the horizontal projection of the roof or floor next above.

Correct

A fire barrier is all that is required

 

[Builder Bob]

[F] 903.2.8 Group R.

An automatic sprinkler system installed in accordance with Section 903.3 shall be provided throughout all buildings with a Group R fire area

Wrong, unless the barrier is a fire wall to create a seperate building, a fire sprinkler system would have to be provided through out the building containing a group R fire area......

A group R fire exists within the building.

 

[steveray]

With BB on that....Gotta be very careful when they start mixing "throughout building" and "throughout fire area"......

 

[mtlogcabin]

Oops

Thanks for the correction

I was thinking IEBC and failed to "read" the IBC portion that applies to the project