I have a current design for a fully sprinkled mixed use building of type 2 first floor and 4 floors of 3B, R2 above. Designer chose to use FRTW for his exterior bearing walls throughout the R2 use. However, he has placed combustible floor joists on top of his bearing walls with a typical one hour separation between dwelling units. Can he even have this combustible material in his exterior load bearing wall?? Not to mention he has a one hour floor assembly supporting the two hour exterior bearing wall at every floor. Thoughts please.
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FRTW an 3B Construction
- Thread starter agb4
- Start date
syarn
Silver Member
2009 IBC section 603 lists combustible materials allowed in type I and II construction.
25. Fire-retardant-treated wood shall be permitted in:
25.1. Nonbearing partitions where the required fire-resistance rating is 2 hours or less.
25.2. Nonbearing exterior walls where no fire rating is required.
25.3. Roof construction, including girders, trusses, framing and decking.
Exception: In buildings of Type IA construction exceeding two stories above grade plane, fire-retardant-treated wood is not permitted
in roof construction when the vertical distance from the upper floor to the roof is less than 20 feet (6096 mm).
25. Fire-retardant-treated wood shall be permitted in:
25.1. Nonbearing partitions where the required fire-resistance rating is 2 hours or less.
25.2. Nonbearing exterior walls where no fire rating is required.
25.3. Roof construction, including girders, trusses, framing and decking.
Exception: In buildings of Type IA construction exceeding two stories above grade plane, fire-retardant-treated wood is not permitted
in roof construction when the vertical distance from the upper floor to the roof is less than 20 feet (6096 mm).
Architect1281
REGISTERED
I may have gone to the wrong school but
methinks you only get one construction type per structure like as in pick ONE
602.1 General. Buildings and structures erected or to be
erected, altered or extended in height or area shall be classified
in one of the five construction types defined in Sections 602.2
through 602.5.
methinks you only get one construction type per structure like as in pick ONE
602.1 General. Buildings and structures erected or to be
erected, altered or extended in height or area shall be classified
in one of the five construction types defined in Sections 602.2
through 602.5.
mtlogcabin
SAWHORSE
Agree you can mix construction types BUT the least Type of construction (in this case IIIB) will determine height & number of stories and area based on occupancy type.
hlfireinspector
Silver Member
Alowable height and area for 3B for R-2 is 4 floors and 16,000 sq.ft . He can get the story increase with the sprinkler. Op did not say use of 1st floor but I assume this is a hotel with meeting and office on 1st ? or could be parking garage?
Paul Sweet
SAWHORSE
It varies. Some jurisdictions won't allow the joists to penetrate the rated gypsum board on the interior face of the wall. Others will allow it if the floor/ceiling assembly has the same rating as the wall. Others will allow it if the space between joists is fireblocked solid.
