Smoke barriers required for passive smoke control and a smoke control system using the pressurization method shall comply with Section 709 of the California Building Code. The maximum allowable leakage area shall be the aggregate area calculated using the following leakage area ratios:
- Walls: A/Aw = 0.00100
- Interior exit stairways and ramps and exit passageways: A/Aw = 0.00035
- Enclosed exit access stairways and ramps and all other shafts: A/Aw = 0.00150
Floors and roofs: A/AF = 0.00050
where:
A = Total leakage area, square feet (m2) AF = Unit floor or roof area of barrier, square feet (m2). Aw = Unit wall area of barrier, square feet (m2).
The leakage area ratios shown do not include openings due to gaps around doors and operable windows. The total leakage area of the smoke barrier shall be determined in accordance with Section 909.5.1 and tested in accordance with Section 909.5.2.
Total leakage area of the barrier is the product of the smoke barrier gross area multiplied by the allowable leakage area ratio, plus the area of other openings such as gaps around doors and operable windows.
Compliance with the maximum total leakage area shall be determined by achieving the minimum air pressure difference across the barrier with the system in the smoke control mode for mechanical smoke control systems utilizing the pressurization method. Compliance with the maximum total leakage area of passive smoke control systems shall be verified through methods such as door fan testing or other methods, as approved by the fire code official.
Openings in smoke barriers shall be protected by self-closing devices or automatic-closing devices actuated by the required controls for the mechanical smoke control system. Door openings shall be protected by fire door assemblies complying with Section 716.5.3 of the California Building Code.
Exceptions:
- Passive smoke control systems with automatic-closing devices actuated by spot-type smoke detectors listed for releasing service installed in accordance with Section 907.3. When used in a Group I-2 or a I-2.1, such detectors shall activate the fire alarm system and shall close all the smoke barrier doors within the effected zone.
- Fixed openings between smoke zones that are protected utilizing the airflow method in other than Group I-2 or I-2.1.
- In Group I-2, I-2.1, R-2.1 and ambulatory care facilities, where a pair of opposite-swinging doors are installed across a corridor in accordance with Section 909.5.3.1, the doors shall not be required to be protected in accordance with Section 716 of the California Building Code. The doors shall be close-fitting within operational tolerances and shall not have a center mullion or undercuts in excess of 3/4-inch (19.1 mm) louvers or grilles. The doors shall have head and jamb stops and astragals or rabbets at meeting edges. Positive-latching devices are required. Doors installed across corridors shall comply with Section 1010.1.1.
- In Group I-2, I-2.1, and ambulatory care facilities, where such doors are special-purpose horizontal sliding, accordion or folding door assemblies installed in accordance with Section 1010.1.4.3 and are automatic closing by smoke detection in accordance with Section 716.5.9.3. The doors shall be close fitting within operational tolerances and shall not have undercuts in excess of 3/4 inch (19.1 mm), louvers or grilles. Where permitted by the manufacturer’s listing, positive-latching devices are not required. Doors installed across corridors shall comply with Section 1010.1.1.
- Group I-3.
- Openings between smoke zones with clear ceiling heights of 14 feet (4267 mm) or greater and bank-down capacity of greater than 20 minutes as determined by the design fire size.
- In Group I-2 or I-2.1, smoke damper activation may be accomplished by a fire alarm control unit provided that an open area smoke detection system is provided within all areas served by an HVAC system.
In Group I-2, I-2.1, R-2.1, and ambulatory care facilities, where doors are installed across a corridor, the doors shall be automatic closing by smoke detection in accordance with Section 716.5.9.3 of the California Building Code. Vision panels consisting of fire-rated glazing in approved frames shall be provided in each cross-corridor swinging door and at each cross-corridor horizontal-sliding door in a smoke barrier.
Ducts and air transfer openings are required to be protected with a minimum Class II, 250°F (121°C) smoke damper complying with Section 717 of the California Building Code.