porches on attached rowhouses.

[Arcsol]

Maybe I took a stupid pill this morning. I'm looking at a design of some townhouses (2009 IRC) that have 2 story covered porches on the front. I can't find anything that specifically mandates fire separation because they are not enclosed. as per R302.2.1. Table R301.2 would require "projections" to be 2 ft away from the property line and one-hour rated on the bottom, but it doesn't seem to apply because these porches have roofs, floors, and columns, but no walls. But it seems to me that a row of flammable covered porches built adjacent to each other would allow fire to travel the length of the building and circumvent the firewalls. And yet, I see sundecks on townhouses built like that all over the place, with no more than inches between them. What am I missing? (everyone in the office is saying - its probably as big as an elephant in the room so thats why we are missing it)

Anybody have any insight?

 

[hlfireinspector]

I'm in 2006 my 09 is at the office. R317.2.1

 

[Francis Vineyard]

Arcsol welcome! The roofs and underside of horizontal projections are controlled depend on the orientation of the projection from the exterior wall to the lot line.

R302.1 Exterior walls.

Exceptions:

1. Walls, projections, openings or penetrations in walls perpendicular to the line used to determine the fire separation distance.

R902.1 Roofing covering materials.

Roofs shall be covered with materials as set forth in :Next('./icod_irc_2012_9_sec004.htm')'>Sections R904 and :Next('./icod_irc_2012_9_sec005.htm')'>R905. Class A, B or C roofing shall be installed in areas designated by law as requiring their use or when the edge of the roof is less than 3 feet (914 mm) from a lot line. Classes A, B and C roofing required by this section to be listed shall be tested in accordance with UL 790 or ASTM E 108 (note exceptions).

If you've ever seen heat damaged done to a building adjacent to a fire it's enlightening to see all the walls parallel to the exposure damage from heat but the ones perpendicular including the attached overhang or projections suffer very little if any heat damage. Any combustible projection will eventually catch fire and spread, but the life safety risk with IRC structures is less restrictive than the IBC.

Francis

 

[gbhammer]

Sprinkler the building and put a dry head on the porch.

 

[brudgers]

Sprinkler the building and put a dry head on the porch.

Is that in 13D?

 

[gbhammer]

I was thinking 13R it does not apply to 13D sorry.

 

[High Desert]

Oregon amended that section to address that very situation. I don't think the unamended language gives much protection for connected covered porches.

If you click the website in my signature, you can see what Oregon has done. click on the 2011 Oregon Residential Specialty code near the bottom and go to chapter 3.

 

[mtlogcabin]

R302.2 Townhouses. Each townhouse shall be considered a separate building and shall be separated by fire-resistance-rated wall assemblies meeting the requirements of Section R302.1 for exterior walls.

FIRE SEPARATION DISTANCE. The distance measured from the building face to one of the following:

1. To the closest interior lot line ; or

2. To the centerline of a street, an alley or public way; or

3. To an imaginary line between two buildings on the lot .

TABLE R302.1

EXTERIOR WALLS

Protections (Roof and deck) Nothing closer than 2 ft, Between 2 ft and 5 ft 1 hour protection

Any space between the deck and the roof is a wall opening

Less than 3 ft not permitted

3 ft to 5 ft 25% maximum opening

5 ft or more unlimited openings.

Since the IRC is silent about decks and balconies this is the interpretation the previous BO made and this is what we have kept with.

Keep the distances between the decks or construct a 1-hour wall if less than 5 ft. Similar to the old UBC & SBCCI requirements

 

[brudgers]

R302.2 Townhouses. Each townhouse shall be considered a separate building and shall be separated by fire-resistance-rated wall assemblies meeting the requirements of Section R302.1 for exterior walls. FIRE SEPARATION DISTANCE. The distance measured from the building face to one of the following: 1. To the closest interior lot line ; or 2. To the centerline of a street, an alley or public way; or 3. To an imaginary line between two buildings on the lot . TABLE R302.1 EXTERIOR WALLS Protections (Roof and deck) Nothing closer than 2 ft, Between 2 ft and 5 ft 1 hour protection Any space between the deck and the roof is a wall opening Less than 3 ft not permitted 3 ft to 5 ft 25% maximum opening 5 ft or more unlimited openings. Since the IRC is silent about decks and balconies this is the interpretation the previous BO made and this is what we have kept with. Keep the distances between the decks or construct a 1-hour wall if less than 5 ft. Similar to the old UBC & SBCCI requirements

I agree - five feet with 100% openings.

 

[Francis Vineyard]

mtlogcabin and brudgers seems to agree with Oregon's amendments; wonder if Arcsol is in Virginia or the neighboring AHJ has a similar interpretation.

R302.1 Exterior walls.

Exceptions:

6. Decks and open porches.

Francis