Sec. 709A. of the California Building Code is revised in its entirety to read:
SECTION 709A
DECKING, CARPORTS, PATIO COVERS AND OTHER BUILDING APPENDAGES
Sec. 709A.1 Decking, floors and underfloor protection.
Sec. 709A.1.1 Decking and other building appendages. Exterior balconies, carports, decks, patio covers, unenclosed roofs and floors and similar architectural appendages and projections shall be constructed as described in sections 709A.1.2 and 709A.1.3. When these appendages or projections are attached to an exterior fire-resistant wall, they shall be constructed to maintain the fire-resistant integrity of the wall.
Exceptions:
1. A free-standing deck or trellis less than 250 square feet in area and greater than 30 feet from the nearest structure and property line is not required to meet the fire-resistance requirements of this chapter.
2. A detached deck that is separated from a building by at least 5 feet of noncombustible surface may be constructed of non-rated wood provided all of the following conditions are met:
a. The decking surface material shall be at least 1-1/2 inches thick.
b. The deck is located at or below the elevation of the building ground floor level and not exposed to any underfloor area or basement opening.
c. The deck is skirted from the deck walking surface to ground level with non-combustible material.
d. If the deck is skirted, the underdeck area shall be vented in conformance with section 707A.5 and section 1203.3 of the County Building Code.
Sec. 709A.1.2 Structural supports and framing members. Structural supports and framing members shall be constructed of one of the following:
1. Noncombustible material
2. Exterior fire-retardant treated wood
3. One-hour fire-resistant material
4. Heavy timber construction
Exceptions:
1. Structural supports and framing may be constructed of non-fire-rated lumber when decks, balconies and similar projections are skirted from floor level to ground level with non- combustible material or an approved alternate. The skirted underdeck area shall be vented in conformance with section 707A.5 and section 1203.3 of the County Building Code.
2. The building official may reduce minimum dimensions for the lumber required for heavy timber construction when the construction conforms to guidance documents.
Sec. 709A.1.3 Decking surfaces. Decking surfaces, stair treads, risers and landings of decks, porches and balconies shall be constructed of one of the following:
1. Noncombustible material
2. Exterior fire-retardant treated wood
3. One-hour fire-resistant material
4. Alternative decking material passing performance testing requirements of section 709A.1.4
Sec. 709A.1.4 Testing of alternative decking materials. Alternative decking materials may be approved when tested to demonstrate the materials have passed the performance requirements of this section. The decking surface shall pass both the under-deck flame test described in Part A of State Fire Marshal standard 12-7A-4 and the burning brand exposure test described in section 709A.1.4.1.
Sec. 709A.1.4.1 Burning brand exposure test. The burning brand exposure test is intended to determine the degradation modes of deck or other horizontal boards when exposed to a burning brand on the upper surface. The test assembly and materials shall be as specified in State Fire Marshal standard 12-7A-4.
Sec. 709A.1.4.1.1 Equipment.
1. Wind tunnel. The wind tunnel shall have the capability of providing 12 mph airflow over the deck assembly.
2. Anemometer. Device for measuring airflow across the deck.
3. Burner. Gas-fueled burner for brand ignition.
Sec. 709A.1.4.1.2 Test system preparation. The ASTM E 108 "B" brand roof test apparatus is to be used, with the following modifications:
1. Deck support. The deck shall be supported horizontally with the center 60 inches from the front opening of the wind tunnel and the joists parallel to the airflow and resting on two transverse metal supports. The top surfaces of these supports, no more than 3 inches wide, are at the same height as the floor of the wind tunnel.
2. Fragments. Burning fragments shall be free to fall to the floor of the room.
Sec. 709A.1.4.1.3 Conduct of tests.
1. Number of tests. Conduct the test on three replicate assemblies.
2. Procedure. Adhere to ASTM E 108 "Standard Test Methods for Fire Tests of Roof Coverings" (burning brand test, "B" brand), with apparatus modified as described above in "Test system preparation" and the following procedure:
a) The air velocity shall be calibrated using the 60-inch framework spacing, with the deck positioned 60 inches from the front opening of the wind tunnel. All other measurement details shall be followed as specified in Sections 4.4.2, 4.4.3 and 4.4.4 of ASTM E 108. Although ASTM E 108 specifies calibration to be conducted with the 33-inch framework spacing used for the intermittent flame test set up, tests have shown that at the nominal 12 mph setting, there was no difference in measured velocity between the 33- and 60-inch framework spacing.
b) Ignite the "B" brands as specified in Section 9.4 of ASTM E 108, with the exception of the ignition sequence:
(i) Each 6 x 6-inch face for 30 seconds
(ii) Each 2.25 x 6-inch edge for 30 seconds
c) Center the burning brand laterally on the deck with the front edge 2.5 inches from the entering air edge of the deck.
d) Continue the exposure for a 40-minute period or until all combustion of the deck boards ceases or a board collapses.
f) Heat Release Rate is not monitored because of the impracticability with the specified airflow.
3. Observations. Note physical changes of the deck boards during the test, including deformation from the horizontal plane, location of flaming and glowing combustion, and loss of material (i.e., flaming drops of particles falling from the deck). It is desirable to capture the entire test with a video recorder to allow review of the details of performance.
Sec. 709A.1.4.1.4 Report.
The report shall include description of the deck board material, and the time of any degradation (accelerated combustion, board collapse, flaming drops or particles falling from the deck).
Sec. 709A.1.4.1.5 Conditions of Acceptance.
Should one of the three replicates fail to meet the Conditions of Acceptance, three additional tests may be run. All of the additional tests must meet the Conditions of Acceptance.
1. Absence of sustained flaming at the conclusion of the 40-minute observation period.
2. Absence of structural failure of any deck board.
3. Absence of falling particles that are still burning when reaching the floor.
Sec. 709A.1.4.1.6 Identification. In addition to labeling required by other sections of this chapter, decking materials passing the performance requirements of this section shall be identified with a grade stamp or label not more than every 6 feet along the length of the decking board.
Sec. 709A.1.5 Deck remodel or repair. When a person remodels or repairs a deck in a wildland- urban interface fire area and the remodeling or repair project involves 50% or more of the deck or 1,000 square feet of the deck area, whichever is less, the entire deck shall be remodeled or repaired to comply with section 709A. For the purpose of this section, multiple deck remodel or repair projects that involve less than 50% of the deck or less than 1,000 square feet, shall be separated by more than 12 months in order to be considered separate projects.
Sec. 709A.2 Underfloor and appendages protection.
Sec.709A.2.1 Underside of appendages and floor projections. The underside of cantilevered and overhanging appendages and floor projections shall maintain the ignition-resistant integrity of exterior walls, or the projection shall be enclosed to the grade.
Sec. 709A.2.2 Unenclosed underfloor protection. Buildings shall have all underfloor areas enclosed to the grade with exterior walls in accordance with section 707A.1.
Exception: The complete enclosure of underfloor areas may be omitted where the underside of all exposed floors, structural columns, beams and supporting walls are protected as required with exterior ignition-resistant material construction or be heavy timber construction.
(Added by Ord. No. 10146 (N.S.), effective 5-13-11; repealed and reenacted by Ord. No. 10464 (N.S.), effective 4-14-17; repealed and adopted by Ord. No. 10651 (N.S.), effective 2-28-20; repealed and adopted by Ord. No. 10829 (N.S.), effective 3-10-23)