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FIRE AND SMOKE PROTECTION FEATURES • ways,ramps and exit passageways except as permitted by 2. In Group B and R occupancies equipped through- Sections 1022.4 and 1023.6,respectively. out with an automatic sprinkler system in accor- Exception: Fire dampers are not required at penetra- dance with Section 903.3.1.1,smoke dampers are lions of fire barriers where any of the following apply: not required at penetrations of shafts where: I. Penetrations are tested in accordance with ASTM 2.1. Kitchen, clothes dryer,bathroom and[oi- 1 119 or UL 263 as part of the fire-resistance- let room exhaust openings are installed • rated assembly. with steel exhaust subducts, having a minimum wall thickness of 0.0187-inch 2. Ducts are used as part of an approved smoke con- trol system in accordance with Section 909 and (0.4712 mm)(No. 26 gage); - where the use of a fire damper would interfere 2.2. The subducts extend at least 22 inches with the operation of a smoke control system. (559 ram)vertically;and 3. Such walls are penetrated by ducted HVAC sys- 2.3. An exhaust fan is installed at the upper tems, have a required fire-resistance rating of I terminus of the shaft that is powered con- hour or less, are in areas of other than Group H tinuously in accordance with the provi- and are in buildings equipped throughout with an sions of Section 909.11,so as to maintain automatic sprinkler system in accordance with a continuous upward airflow to the out- Section 903.3.1.1 or 903.3.1.2. For the purposes side. of this exception,a ducted HVAC system shall be 3. Smoke dampers are not required at penetration of a duct system for conveying supply, return or exhaust or supply shafts in parking garages that exhaust air as part of the structure's HVAC sys- are separated from other building shafts by not tem. Such a duct system shall be constructed of less than 2-hour fire-resistance-rated construe- sheet steel not less than No. 26 gage thickness tion. and shall be continuous from the air-handling 4. Smoke dampers are not required at penetrations appliance or equipment to the air outlet and inlet of shafts where ducts are used as part of an terminals. approved mechanical smoke control system 717.5.2.1 Horizontal exits. A listed smoke damper designed in accordance with Section 909 and designed to resist the passage of smoke shall be pro- where the smoke damper will interfere with the vided at each point a duct or air transfer opening pene- operation of the smoke control system. traces afire barrier that serves as a horizontal exit. 5. Fire dampers and combination fire/smoke damp- 717.5.3 Shaft enclosures. Shaft enclosures that are per- ers are not required in kitchen and clothes dryer witted to be penetrated by ducts and air transfer openings exhaust systems when installed in accordance shall be protected with approved fire and smoke dampers with the Mechanical Code. installed in accordance with their listing. 717.5.4 Fire partitions. Ducts and air transfer openings Exceptions: that penetrate fire partitions shall be protected with listed 1. Fire dampers are not required at penetrations of fire dampers installed in accordance with their listing. shafts where: Exceptions: In occupancies other than Group H,fire 1.1. Steel exhaust subducts are extended at dampers are not required where any of the following least 22 inches (559 mm) vertically in apply: exhaust shafts,provided there is a contin- 1. Corridor walls in buildings equipped throughout uous airflow upward to the outside;or with an automatic sprinkler system in accordance 1.2. Penetrations are tested in accordance with with Section 903.3.1.1 or 903.3.1.2 and the duct ASTM E 119 or UL 263 as part of the is protected as a through penetration in accor- fire-resistance-rated assembly;or dance with Section 714. 1.3. Ducts are used as part of an approved 2. Tenant partitions in covered and open mall build- smoke control system designed and ings where the walls are not required by provi- installed in accordance with Section 909 sions elsewhere in the code to extend to the and where the fire damper will interfere underside of the floor or roof sheathing, slab or with the operation of the smoke control deck above. system;or 3. The duct system is constructed of approved mate- 1.4. The penetrations are in parking garage rials in accordance with the Mechanical Code exhaust or supply shafts that are separated and the duct penetrating the wall complies with i from other building shafts by not less than all of the following requirements: 2-hour fire-resistance-rated construction. 3.1.The duct shall not exceed 100 square inches(0.06 m'). 2014 OREGON STRUCTURAL SPECIALTY CODE 149