BayPointArchitect
Sawhorse
Given:
Fully sprinkled, eleven story building
2009 IBC
2000 NFPA
Eleven story stair shaft with stair pressurization system that will keep smoke out while allowing doors to open. Supply fan is mounted on top of roof with a duct penetrating the top of the stairs.
12" x 12" barometric dampers are located near each and every door to ensure the that pressure is exactly 1/16" water column (12.5 pascals).
The problem is that if these openings within the 2 hour rated stair shaft were equipped with smoke dampers circuited to the alarm system, then the dampers would close and the stair pressure would exceed that which is allowed. Therefore it may become too difficult to open the doors (more than 30 pounds of pressure) thereby creating an impedance to safety.
Reference:
2009 IBC Section 716.5.3 Exception #4.
Air transfer opening within shaft enclosure does not require smoke damper where ducts are used as part of an approved mechanical smoke control system designed in accordance with Section 909 and where the smoke damper will interfere with the operation of the smoke control system.
Question:
May these vents remain without protection where located between the stairs and corridor?
Thanks
ICC Certified Plan Review
Fully sprinkled, eleven story building
2009 IBC
2000 NFPA
Eleven story stair shaft with stair pressurization system that will keep smoke out while allowing doors to open. Supply fan is mounted on top of roof with a duct penetrating the top of the stairs.
12" x 12" barometric dampers are located near each and every door to ensure the that pressure is exactly 1/16" water column (12.5 pascals).
The problem is that if these openings within the 2 hour rated stair shaft were equipped with smoke dampers circuited to the alarm system, then the dampers would close and the stair pressure would exceed that which is allowed. Therefore it may become too difficult to open the doors (more than 30 pounds of pressure) thereby creating an impedance to safety.
Reference:
2009 IBC Section 716.5.3 Exception #4.
Air transfer opening within shaft enclosure does not require smoke damper where ducts are used as part of an approved mechanical smoke control system designed in accordance with Section 909 and where the smoke damper will interfere with the operation of the smoke control system.
Question:
May these vents remain without protection where located between the stairs and corridor?
Thanks
ICC Certified Plan Review