Appeal 33486

OMSC 607.5.5 and OSSC 717.5.3

Code 607.5.5: Shaft enclosures that are permitted to be penetrated by ducts and air transfer openings shall be protected with listed fire and smoke dampers installed in accordance with their listing.
Code 717.5.3: Shaft enclosures that are permitted to be penetrated by ducts and air transfer openings shall be protected with approved fire and smoke dampers installed in accordance with their listing.

We would like to waive the code requirements for fire smoke dampers, allowing the fire dampers already installed in conjunction with the Building smoke detectors to comply with the code’s intent instead of combination fire/smoke dampers.

Installations of fire dampers at the entrance of the fire rated shaft between the 3 floors instead of fire smoke dampers

Reconsideration Text: Allow the use of the smoke detectors in each room in conjunction with fire dampers in the ductwork on each floor to comply with OMSC 607.5.5 and OSSC 717.5.3.

The HVAC systems return ductwork if allowed to remain open during the smoke phase of the fire can be used as a means to exhaust smoke from the fire area, using the barometric relive damper of the economizer. see attached side view of the ductwork.

and if the temperature increases over 105 deg. it will trigger the fire damper fusible link closing the fire damper.

the multiple smoke detectors through the building and on each of the rooms will serve as an early detection and activation of the fire alarm system.

This building is open concept, no fire walls or fire sealings other than the shaft for the ductwork. This building also has fully operational fire sprinkler system.
The HVAC is divided into 6 RTU units that are isolated--2 per floor. Within each floor each unit supplies air to one half of the building, front or back. The return ductwork of these units only has one opening which is no more than 5 ft from the shaft and the fire damper--and it’s connected to the RTU on the roof and made of 24-gauge galvanized metal.
The duct meets one of the exceptions in Section 717.5.3: Because all exhaust ducts run continuously and independently to the exterior, without serving multiple floors, fire dampers are not required. The exhaust ducts meet OSSC CHAPTER 7, SECTION 717.5.3, EXCEPTION 1.2 (PENETRATIONS ARE TESTED IN ACCORDANCE WITH ASTM E 119 OR UL 236).

Reconsideration Text: There is one smoke detector in each room and multiple smoke detectors in open areas, along with fire sprinkler system throughout building on each floor. It is our understanding that past exceptions have been made previously to allow smoke detectors in each room instead of fire/smoke dampers to provide early warning of danger from fire.