We have a three-story, Type IIB, fully sprinklered, E occupancy building, 2015 IBC, which has non fire-resistance-rated floor assemblies and the first floor eating space is atmospherically connected to the second floor balcony above that is connected to the classroom wing. We also have science labs elsewhere in the building with fume hoods on the second floor of the classroom wing that are ducted, penetrating through the third floor, through the roof to the exterior. The duct on the third floor is furred out to conceal the duct at the third floor. We also have a custodial room on the second floor that has a ducted exhaust fan, penetrating through the third floor, and exhausting to a sidewall louver to the exterior. Would this fall under the intent that this building is connected at all three stories and would require a fire damper at the third floor duct penetration in order to maintain the connected first and second story and comply with all parts of section 712.1.9 for two-story openings? If we do not provide a fire damper at the third floor duct penetrations, would we be in violation of IBC section 712.1.9 (6)? Does the described condition above not meet the intent of section 717.6.3 (2) in that the actual duct connects not more than two stories and that just the annular space around the penetrating duct be protected, without a fire damper?
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Two story opening or three story opening, 712.1.9 (6)
- Thread starter C Calvano
- Start date
mtlogcabin
SAWHORSE
The duct has to connect 3 stories before the damper in the duct would be required. From my understanding this project does not
The following diagram may help in understanding the situation. The duct passing through the third floor is simply furred out with framing/GWB to conceal duct from classroom.
https://www.dropbox.com/s/qyz30cs0pigefze/IBC 717.6.3.JPG?dl=0
https://www.dropbox.com/s/qyz30cs0pigefze/IBC 717.6.3.JPG?dl=0
Builder Bob
SAWHORSE
IF the floor ratings are non-rated, i do not see where the ductwork is penetrating three floors - besides, you wouldn't want a damper in an exhaust duct being used to exhaust hazardous fumes anyway,,,,,The duct itself does not connect more than two stories