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Vents at fire rated balcony construction

Y

Yikes

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Nov 2, 2009
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Southern California
Picture a type V-A apartment building with private balconies stacked over each other. You've used a membrane assembly (say, type X purple gyp board with stucco) on the underside of the balconies to achieve the 1-hour rated on the balcony wood-framed balcony floor.

Question: how to you both vent the balcony framing space as required by 2304.12.2.6 and maintain the continuity of a one hour floor-ceiling assembly?

This question was stirred by the reglet thread here, but we are dealing with floor-ceiling assemblies instead of walls.

CBC 2304.12.2.6 Ventilation beneath balcony or elevated walking surfaces. Enclosed framing in exterior balconies and elevated walking surfaces that are exposed to rain, snow or drainage from irrigation shall be provided with openings that provide a net free cross-ventilation area not less than 1/150 of the area of each separate space. ​

I thought the new 705.2.3.2 would clarify, but it talks about curtain walls?

705.2.3.2 Vents. [SFM] Vents required by Section 2304.12.2.6 in fire-rated exterior balconies or elevated walkway surfaces shall be designed where the voids created at the intersection of the exterior curtain wall and the balcony floor are sealed with an approved material or system to retard the interior spread of flame, hot gases and products of combustion. Rated assemblies shall comply with Section 715. Ventilation openings shall comply with the fire sprinkler protection as required by Section 903.3.1.1 or 903.3.1.2 and the reference standard.​
 
Balconies must carry loads as required for floors, but a balcony is not necessarily required to be a horizontal assembly that requires the same protection as the floor inside the building.

Refer to Section 705.2.3.1 (2018 IBC) for requirements applicable to balconies. If the framing is of fire-retardant-treated wood or heavy timber, then no other protection is required. If sprinklers provide protection at the balconies for Type III, IV, and V, then, per Exception 3, the construction can be of Type V construction with no fire-resistance rating required.
 
RLGA: In other words, on a type V-A building a balcony must have either FRT or a sprinkler head below it?

Mark: thanks, and I an aware of the continuous vent products, and have used them on projects. I just wondered if, in the process of venting, I was causing a problem with the fire rating.
 
Yikes said:
RLGA: In other words, on a type V-A building a balcony must have either FRT or a sprinkler head below it?
Click to expand...
No, you can use standard wood framing, but then you would need to comply with Table 601 for floor construction. FRTW, heavy timber, and sprinklers are just alternatives.
 
RLGA said:
Balconies must carry loads as required for floors, but a balcony is not necessarily required to be a horizontal assembly that requires the same protection as the floor inside the building.

Refer to Section 705.2.3.1 (2018 IBC) for requirements applicable to balconies. If the framing is of fire-retardant-treated wood or heavy timber, then no other protection is required. If sprinklers provide protection at the balconies for Type III, IV, and V, then, per Exception 3, the construction can be of Type V construction with no fire-resistance rating required.
Click to expand...
If it is located within a Wildland- Urban Interface Fire Area
you may want to look at:
709A.3 Decking Surfaces
 
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