This scenario may be a little hard to explain, but if you have a building with side walls that are 1-hr fire-rated party walls, and front and rear walls that are not fire-rated (because of setback distance from property lines), does the 1-hr fire rating from the side walls have to wrap around the corners of the non-rated front and rear walls some minimal distance? If so, can you direct me to the code section that applies? IBC 2012
-
Welcome to The Building Code Forum
Your premier resource for building code knowledge.
This forum remains free to the public thanks to the generous support of our Sawhorse Members and Corporate Sponsors. Their contributions help keep this community thriving and accessible.
Want enhanced access to expert discussions and exclusive features? Learn more about the benefits here.
Ready to upgrade? Log in and upgrade now.
Fire-rated Walls Turning Corners?
- Thread starter fj80
- Start date
JBI
REGISTERED
Fire separation distance only applies to walls that are parallel (or essentially parallel) to the property line, so I believe the rating may stop at the corner.
Builder Bob
SAWHORSE
706.5 Horizontal continuity.
Fire walls shall be continuous from exterior wall to exterior wall and shall extend at least 18 inches (457 mm) beyond the exterior surface of exterior walls.
Exceptions:
1. Fire walls shall be permitted to terminate at the interior surface of combustible exterior sheathing or siding provided the exterior wall has a fire-resistance rating of at least 1 hour for a horizontal distance of at least 4 feet (1220 mm) 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. 2. Fire walls shall be permitted to terminate at the interior surface of noncombustible exterior sheathing, exterior siding or other noncombustible exterior finishes provided the sheathing, siding, or other exterior noncombustible finish extends a horizontal distance of at least 4 feet (1220 mm) on both sides of the fire wall. 3. Fire walls shall be permitted to terminate at the interior surface of noncombustible exterior sheathing where the building on each side of the fire wall is protected by an automatic sprinkler system installed in accordance with Section 903.3.1.1 or 903.3.1.2. 706.5.1 Exterior walls.
Where the fire wall intersects exterior walls, the fire-resistance rating and opening protection of the exterior walls shall comply with one of the following: 1. The exterior walls on both sides of the fire wall shall have a 1-hour fire-resistance rating with 3/4-hour protection where opening protection is required by Section 705.8. The fire-resistance rating of the exterior wall shall extend a minimum of 4 feet (1220 mm) on each side of the intersection of the fire wall to exterior wall. Exterior wall intersections at fire walls that form an angle equal to or greater than 180 degrees (3.14 rad) do not need exterior wall protection. 2. Buildings or spaces on both sides of the intersecting fire wall shall assume to have an imaginary lot line at the fire wall and extending beyond the exterior of the fire wall. The location of the assumed line in relation to the exterior walls and the fire wall shall be such that the exterior wall and opening protection meet the requirements set forth in Sections 705.5 and 705.8. Such protection is not required for exterior walls terminating at fire walls that form an angle equal to or greater than 180 degrees (3.14 rad).
Fire walls shall be continuous from exterior wall to exterior wall and shall extend at least 18 inches (457 mm) beyond the exterior surface of exterior walls.
Exceptions:
1. Fire walls shall be permitted to terminate at the interior surface of combustible exterior sheathing or siding provided the exterior wall has a fire-resistance rating of at least 1 hour for a horizontal distance of at least 4 feet (1220 mm) 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. 2. Fire walls shall be permitted to terminate at the interior surface of noncombustible exterior sheathing, exterior siding or other noncombustible exterior finishes provided the sheathing, siding, or other exterior noncombustible finish extends a horizontal distance of at least 4 feet (1220 mm) on both sides of the fire wall. 3. Fire walls shall be permitted to terminate at the interior surface of noncombustible exterior sheathing where the building on each side of the fire wall is protected by an automatic sprinkler system installed in accordance with Section 903.3.1.1 or 903.3.1.2. 706.5.1 Exterior walls.
Where the fire wall intersects exterior walls, the fire-resistance rating and opening protection of the exterior walls shall comply with one of the following: 1. The exterior walls on both sides of the fire wall shall have a 1-hour fire-resistance rating with 3/4-hour protection where opening protection is required by Section 705.8. The fire-resistance rating of the exterior wall shall extend a minimum of 4 feet (1220 mm) on each side of the intersection of the fire wall to exterior wall. Exterior wall intersections at fire walls that form an angle equal to or greater than 180 degrees (3.14 rad) do not need exterior wall protection. 2. Buildings or spaces on both sides of the intersecting fire wall shall assume to have an imaginary lot line at the fire wall and extending beyond the exterior of the fire wall. The location of the assumed line in relation to the exterior walls and the fire wall shall be such that the exterior wall and opening protection meet the requirements set forth in Sections 705.5 and 705.8. Such protection is not required for exterior walls terminating at fire walls that form an angle equal to or greater than 180 degrees (3.14 rad).
BillS
Member
How can a party wall be only 1-HR rated? I thought that the minimum would be 2.
steveray
SAWHORSE
All very good information...And question from Bill.
I misspoke when I called it a party wall. It is not a party wall but rather an exterior wall of my building that is right on the property line, with the neighboring building's exterior right up to the property line as well. So I believe JBI is correct that the fire rating only applies to walls that are parallel, or generally parallel, to the property line, so there is no requirement to provide fire rating around the 90 degree corner to a non-rated wall. Thank you all for your help.
Builder Bob
SAWHORSE
706.1.1 Party walls.
Any wall located on a lot line between adjacent buildings, which is used or adapted for joint service between the two buildings, shall be constructed as a fire wall in accordance withSection 706. Party walls shall be constructed without openings and shall create separate buildings.
Exception: Openings in a party wall separating an anchor building and a mall shall be in accordance with Section 402.7.3.1.
Any wall located on a lot line between adjacent buildings, which is used or adapted for joint service between the two buildings, shall be constructed as a fire wall in accordance withSection 706. Party walls shall be constructed without openings and shall create separate buildings.
Exception: Openings in a party wall separating an anchor building and a mall shall be in accordance with Section 402.7.3.1.
JBI
REGISTERED
B Bob - In this case each building has a separate wall, so it is not a party wall 'used or adapted for joint service'. Though your earlier post has me thinking that an 18" extension beyond the intersecting walls may be needed...
Yeah, JBI, I am tending to agree with you. My boss said he used to do the 18" extension wall you're talking about when he did townhouses years ago. I don't see a requirement for it in the code anywhere, but it makes practical sense.
Builder Bob
SAWHORSE
JBI... Just wanted to ensure that the term party wall was technically identified to prohibit viewers from misconstruing the intent of the code. (non-code people). To clarify, the exterior wall for one structure is structurally independent of the other structure adjacent to it....In other words, you could knock the building down on one side and the remaining structure would remain standing without nay modifications.
Builder Bob
SAWHORSE
The extension would be required if a true wall condition existed, the condition that exists in your application is for fire separation distance from the lot lines.....
BayPointArchitect
Sawhorse
Just to clarify, we are talking about 2012 IBC Table 602, Fire-resistance rating requirements for exterior walls based on fire separation distance from a shared / neighboring property line.
Not so much Chapter 7 unless we take a peak at Section 705.5... where that exterior wall is rated for exposure from both sides if it is located less than 10 feet from the property line.
My predecessor required a 5' wrap around the corner but I fail to find that anywhere in the code. Maybe it was a '94 UBC thing. I expect that the rated exterior wall terminate at the corners. No wrap around the corner.
(graphic illustrations would have helped clarify the question)
Not so much Chapter 7 unless we take a peak at Section 705.5... where that exterior wall is rated for exposure from both sides if it is located less than 10 feet from the property line.
My predecessor required a 5' wrap around the corner but I fail to find that anywhere in the code. Maybe it was a '94 UBC thing. I expect that the rated exterior wall terminate at the corners. No wrap around the corner.
(graphic illustrations would have helped clarify the question)