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705.5 Fire-resistance ratings

F

Fritz

Bronze Member
Joined
Feb 12, 2010
Messages
59
Location
Fargo, ND
Background: Section 705.5 essentially allows nonsymmetrical construction for exterior walls with a fire separation of greater than 10 feet. The hazard is considered to be predominately from inside the building.

Condition: A 2 story, 36 unit apartment of V-A construction with a 13 R sprinkler system.

So how does this section apply with combustible patio decks with potential of combustible sheathing and siding?

This seems to have some built-in problems.
 
Horizontal distance from where. The shell of the structure or the outermost edge of the deck.

If you say the shell, you overlook the basic premise, to protect a building from within. Deck fires.

If you say the deck, then that wall becomes an interior load bearing wall and must be protected.
 
OK, I do understand the fire separation distance. Old school would say, that this area be open, unused and void of a fire loading. Would you allow a deck to extend into a required FSD. I know some extensions into this area are allowed. But the question remains, the shell wall between the deck and main building. Symmetrical or nonsymmetrical assembly? I am leaning toward that where a deck is built, the 705.5 would not apply.

Exterior deck fires expand very fast and a 13R just can not handle those. They climb up the exterior into the attic and its all over.
 
Fritz, the load bearing wall between the balcony and building must be built just like every other load bearing wall in Type VA; 1 hr construction. There is no provision in this case to create a fire separation distance between one part of the building and another.

The balcony construction shall be just the same as any other floor/ceiling assembly in Type VA, with the exceptions that brudgers listed in 1406.3.

Don't get fire separation distance and construction type confused.
 
Slightly off topic, but if it's a new facility, you'd be doing them a favor to mention the applicable restrictions on open-flame cooking devices from the IFC (if adopted). We've had some managment companies work the language into leasing contracts, which helps them help us when we perform routine inspections.
 
Without knowing the writer, me, it is tough to know what I know or do not know, you know?

I do understand your replies and our community does allow cooking on decks. I believe 705.5 applies to all buildings, most notably buildings requiring FR rated assemblies. Otherwise, 705.5 would be meaningless as a lot of exterior walls are bearing. 1406.3 addresses deck construction but does not address what happens when you have a deck and the fire loading effects it has upon the building I do not question that a deck can be there, or what type of construction it is. For this question let's just say it is a complying deck.

I maintain 705.5, as well as any fire separation distance, is intended to be open and free of fire loadings. In fact there was a time the old UBC stated, a parking lot was not to be allowed in that space. Car fires.

With that view, am I on a trip allll by myself, when I say I think that if a deck is there, that 705.5 cannot be applied to that area of the structure?
 
A 13R system requires the decks to have sprinkler coverage see F] 903.3.1.2.1 Balconies and decks.

1406.3 requires rated construction FRTW or sprinkler coverage.

705.2 covers how far a deck may project into the distance where openings are not allowed or restricted.

I do not see your concern about fire loading from a construction stand point.
 
V-A is protected construction; the deck is (apparently) not... it's now a V-B building... probably.
 
Fritz, I'm still a little unclear as to what you're getting at. Are you saying that the exterior wall of a building is required to be rated because you are applying fire separation distance between one part of a building from another part of the building (exterior wall to deck)?

Read the definition of fire separation distance in 702. It is measured to closest lot line, centerline of a street, alley or public way, or an imaginary line between TWO buildings. It isn't applied between a wall and a balcony, if that was the case the opening would have to be protected as well.

A little off-topic, but since you mentioned it, I have UBC codes going back to 1979, and could find nothing about not being able to park cars next to a building.

If I'm understanding you correctly, and you're just trying to require symmetrical rating of the exterior wall because you think there is some hazard from the balcony, then I think you're trying to force something that just doesn't fit into the code.
 
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I differ with peach, as I believe 1406.3 allows a V-B balcony on a V-A building. This section does not designate type A or B, but it does call out where a FR rating is mandated, unless sprinklered. 2006 handbook

Architect seems to see it the way I do. But to be honest I only have seen it this way since we have had a number of deck fires lately.

Texabo, "Are you saying that the exterior wall of a building is required to be rated because you are applying fire separation distance between one part of a building from another part of the building (exterior wall to deck)?"

No, same building to the same property line or open yard, just 2 different points on the building. One point an exterior wall without a deck; the second point from the outermost point of the balcony or deck of the same building. So the FSD from the wall could be 30’ and the FSD from the deck could be 20’. However by using these 2 different points, can the wall between the building and the deck benefit from 705.5, as it loosely can now be called an interior wall?

The parking reference was from a call to UBC on an interpretation back in the day. The question was on FR corridors running along the front of a building, with parking within 3 feet of the windows. Wired glass or not, UBC hung its hat on the open yard issue.

Your last comment is spot on, with exception to your answer. Our experience has led me to believe that the hazards on decks are just now being more fully recognized. Our fires were started from left over smoking materials, not cooking. Once they got going, with combustible siding and sheathing the 13R was overrun and up the side of the building and into the attic.

Thank you all for your comments, I appreciate your input.
 
I believe 1406.3 allows a V-B balcony on a V-A building
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Agree and exception #3 will require the balcony to be sprinklered. If 13R systems on balconies are being over run maybe some one on here has a suggestion regarding different heads that we should be looking for (requiring) on the balcony/deck areas.
 
If it is getting into the attic then more than one hour should have elapsed since VA construction requires protection of roof construction and structural frame.
 
The deck or balcony is a projection, treated similar to openings. Fire separation distance is measured to the building face (see definition). Projections are limited by this:

2006 IBC:

704.2 Projections.

Cornices, eave overhangs, exterior balconies and similar projections extending beyond the floor area shall conform to the requirements of this section and Section 1406. Exterior egress balconies and exterior exit stairways shall also comply with Sections 1014.5 and 1023.1, respectively. Projections shall not extend beyond the distance determined by the following two methods, whichever results in the lesser projection:

1. A point one-third the distance to the lot line from an assumed vertical plane located where protected openings are required in accordance with Section 704.8.

2. More than 12 inches (305 mm) into areas where openings are prohibited.

704.2.1 Type I and II construction.

Projections from walls of Type I or II construction shall be of noncombustible materials or combustible materials as allowed by Sections 1406.3 and 1406.4.

704.2.2 Type III, IV or V construction.

Projections from walls of Type III, IV or V construction shall be of any approved material.

704.2.3 Combustible projections.

Combustible projections located where openings are not permitted or where protection of openings is required shall be of at least 1-hour fire-resistance-rated construction, Type IV construction, fire-retardant-treated wood or as required by Section 1406.3.

Exception: Type V construction shall be allowed for R-3 occupancies.

1406.3 Balconies and similar projections.

Balconies and similar projections of combustible construction other than fire-retardant-treated wood shall be fire-resistance rated in accordance with Table 601 for floor construction or shall be of Type IV construction in accordance with Section 602.4. The aggregate length shall not exceed 50 percent of the building’s perimeter on each floor.

Exceptions:

1. On buildings of Type I and II construction, three stories or less in height, fire-retardant-treated wood shall be permitted for balconies, porches, decks and exterior stairways not used as required exits.

2. Untreated wood is permitted for pickets and rails or similar guardrail devices that are limited to 42 inches (1067 mm) in height.

3. Balconies and similar projections on buildings of Type III, IV and V construction shall be permitted to be of Type V construction, and shall not be required to have a fire-resistance rating where sprinkler protection is extended to these areas.

4. Where sprinkler protection is extended to the balcony areas, the aggregate length of the balcony on each floor shall not be limited.
 
My "method":

Openings are prohibited when the FSD is 3' or less, so you get a maximum of a 12" projection/balcony/overhang when the FSD is 3' or less.

Protected openings are required when the FSD is >3'. So let's say you have a FSD of 15'. At a point 3'-01" from the exterior wall you would be 11'-11" from the lot line, and a third of the remaining distance is 3.97' (4'), so your projection could be 4' + 3'-01" or a hair over 7'.

Comments?
 
So the FSD from the wall could be 30’ and the FSD from the deck could be 20’. However by using these 2 different points, can the wall between the building and the deck benefit from 705.5, as it loosely can now be called an interior wall?
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No.

And the interpretation of ICBO was ludicrous, and not based in any way whatsoever on code language or intent.

Seriously, if you feel that decks pose a hazard to an apartment building, amend your ordinance; that will give you much stronger legal footing than trying to pervert the code to say something it doesn't.

And you are right about non fire rated projections being allowed on VA buildings under certain conditions.
 
Thanks to all.

Pervert, PERVERT!! We don't need no stinken perverting here?

Thats why the BO has the final say. Now would you change your opinion if it were an extended overhang under which the front half of a car could park. So passengers could get out without getting rained upon. Now its a different story. I know, we are all use to getting only enough information to give an answer the person is looking for:)

TJ, no comments I follow all the way, scary eh?

We are looking at a local modification, as one big fire is too many. No lives lost, but 105 dwelling units were. They were all able to find new places, but it took a little time.

Again Thanks
 
Fritz said:
Now would you change your opinion if it were an extended overhang under which the front half of a car could park.
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Actually, the code would change its mind. Vehicle parking under a building would constitute a mixed use occupancy, with the attendant separation requirements.

Although, even then it would be possible to construct the building such that it would not require separation.
 
Fritz said:
We are looking at a local modification, as one big fire is too many. No lives lost, but 105 dwelling units were. They were all able to find new places, but it took a little time.
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Fritz, did the fire in this example actually spread to location on property line? Or was it due to the BBQ / open flame on an existing deck?
 
Fritz said:
No lives lost, but 105 dwelling units were. They were all able to find new places, but it took a little time.
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That's exactly what a 13R system is designed to do - protect lives.

If you want to protect the building too, require a full 13 system in your ordinance.
 
yes, that is the one.

Yes I agree with you.

The building is already 99% gone, and plans to rebuild are on our examiners desk.

The issue I have, is that 13 or 13R are I believe designed for fires from with-in the structure.

I just think we need to look a little more closely to fire risks exterior of the building. With that I mean more than just the fire separation distance. In fact I believe the roof was involved long before any interior alarms went off.

Experience is a great teacher.
 
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