FIRE-RESISTANCE RATING REQUIREMENTS FOR BUILDING ELEMENTS (HOURS)
|BUILDING ELEMENT||TYPE I||TYPE II||TYPE III||TYPE IV||TYPE V|
|Primary structural framef (see Section 202)||3a||2a||1||0||1||0||HT||1||0|
|Nonbearing walls and partitions |
|See Table 602|
|Nonbearing walls and partitions |
|0||0||0||0||0||0||See Section 602.4.6||0||0|
|Floor construction and associated secondary members (see Section 202)||2||2||1||0||1||0||HT||1||0|
|Roof construction and associated secondary members (see Section 202)||11/2b||1b,c||1b,c||0c||1b,c||0||HT||1b,c||0|
For SI: 1 foot = 304.8 mm.
- Roof supports: Fire-resistance ratings of primary structural frame and bearing walls are permitted to be reduced by 1 hour where supporting a roof only.
- 1. Except in Group A, E, F-1, H, I, L, M, R-1, R-2, R-2.1 and S-1 occupancies, high-rise buildings, and other applications listed in Section 1.11 regulated by the Office of the State Fire Marshal, fire protection of structural members shall not be required, including protection of roof framing and decking where every part of the roof construction is 20 feet or more above any floor immediately below. Fire-retardant-treated wood members shall be allowed to be used for such unprotected members.
- 2 For Group A, E, I, L, R-1, R-2, and R-2.1 occupancies, high-rise buildings, and other applications listed in Section 1.11 regulated by the Office of the State Fire Marshal, fire protection of members other than the structural frame shall not be required, including protection of roof framing and decking where every part of the roof construction is 20 feet or more above any floor immediately below. Fire-retardant-treated wood members shall be allowed to be used for such unprotected members.
- 3. One-story portions of Group A and E assembly occupancies the roof-framing system of Type II A or Type III A construction may be of unprotected construction when such roof-framing system is open to the assembly area and does not contain concealed spaces.
- In all occupancies, heavy timber shall be allowed where a 1-hour or less fire-resistance rating is required.
- Not less than the fire-resistance rating required by other sections of this code.
- Not less than the fire-resistance rating based on fire separation distance (see Table 602).
- Not less than the fire-resistance rating as referenced in Section 704.10.
FIRE-RESISTANCE RATING REQUIREMENTS FOR EXTERIOR WALLS BASED ON FIRE SEPARATION DISTANCEa, d, g
|FIRE SEPARATION DISTANCE = X (feet)||TYPE OF CONSTRUCTION||OCCUPANCY GROUP He, L||OCCUPANCY GROUP F-1, M, S-1f||OCCUPANCY GROUP A, B, E, F-2, I, Rh, S-2, Uh|
|X < 5b||All||3||2||1|
|5 ≤ X < 10||IA||3||2||1|
|10 ≤ X < 30||IA, IB||2||1||1c|
|X ≥ 30||All||0||0||0|
For SI: 1 foot = 304.8 mm.
- Load-bearing exterior walls shall also comply with the fire-resistance rating requirements of Table 601.
- See Section 706.1.1 for party walls.
- Open parking garages complying with Section 406 shall not be required to have a fire-resistance rating.
- The fire-resistance rating of an exterior wall is determined based upon the fire separation distance of the exterior wall and the story in which the wall is located.
- For special requirements for Group H occupancies, see Section 415.6.
- For special requirements for Group S aircraft hangars, see Section 412.4.1.
- Where Table 705.8 permits nonbearing exterior walls with unlimited area of unprotected openings, the required fire-resistance rating for the exterior walls is 0 hours.
- Group R-3 and Group U occupancies when used as accessory to Group R-3 occupancies, shall not be required to have a fire-resistance rating where the fire separation distance is 5 feet or more; or when equipped throughout with an automatic residential fire sprinkler system installed in accordance with Section 903.3 the fire-resistance rating shall not be required where the fire separation distance is 3 feet or more.
Buildings and structures erected or to be erected, altered or extended in height or area shall be classified in one of the five construction types defined in Sections 602.2 through 602.5. The building elements shall have a fire-resistance rating not less than that specified in Table 601 and exterior walls shall have a fire-resistance rating not less than that specified in Table 602. Where required to have a fire-resistance rating by Table 601, building elements shall comply with the applicable provisions of Section 703.2. The protection of openings, ducts and air transfer openings in building elements shall not be required unless required by other provisions of this code.
Exception: Noncombustible structural members supporting solar photovoltaic panels are not required to meet the fire resistance rating for the following:
- Photovoltaic panel supported by a structure and having no use underneath. Signs may be provided, as determined by the enforcing agency prohibiting any use underneath including storage.
- Solar photovoltaic (PV) panels supported by noncombustible framing that have sufficient uniformly distributed and unobstructed openings throughout the top of the array (horizontal plane) to allow heat and gases to escape, as determined by the enforcing agency.
- 3.1. The area within the perimeter of the solar photovoltaic array has maximum rectangular dimension of 40 feet by 150 feet.
- 3.2. The distance between solar photovoltaic array structures is a minimum of 10 feet clear.
- 3.3. The driveway aisle separating solar photovoltaic array structures has a minimum width of 25 feet clear.
- 3.4. Solar photovoltaic array structure is used only for parking purposes with no storage.
- 3.5. Completely open on all sides (other than necessary structural supports) with no interior partitions.
Type IV construction (Heavy Timber, HT) is that type of construction in which the exterior walls are of noncombustible materials and the interior building elements are of solid or laminated wood without concealed spaces. The details of Type IV construction shall comply with the provisions of this section and Section 2304.11. Exterior walls complying with Section 602.4.1 or 602.4.2 shall be permitted. Minimum solid sawn nominal dimensions are required for structures built using Type IV construction (HT). For glued-laminated members and structural composite lumber (SCL) members, the equivalent net finished width and depths corresponding to the minimum nominal width and depths of solid sawn lumber are required as specified in Table 602.4. Cross-laminated timber (CLT) dimensions used in this section are actual dimensions.
WOOD MEMBER SIZE EQUIVALENCIES
|MINIMUM NOMINAL SOLID SAWN SIZE||MINIMUM GLUED-LAMINATED NET SIZE||MINIMUM STRUCTURAL COMPOSITE LUMBER NET SIZE|
|Width, inch||Depth, inch||Width, inch||Depth, inch||Width, inch||Depth, inch|
For SI: 1 inch = 25.4 mm.
Cross-laminated timber complying with Section 2303.1.4 shall be permitted within exterior wall assemblies with a 2-hour rating or less, provided the exterior surface of the cross-laminated timber is protected by one the following:
- Fire-retardant-treated wood sheathing complying with Section 2303.2 and not less than 15/32 inch (12 mm) thick;
- Gypsum board not less than 1/2 inch (12.7 mm) thick; or
- A noncombustible material.
Sawn or glued-laminated plank floors shall be one of the following:
- Sawn or glued-laminated planks, splined or tongue-and-groove, of not less than 3 inches (76 mm) nominal in thickness covered with 1-inch (25 mm) nominal dimension tongue-and-groove flooring, laid crosswise or diagonally, 15/32-inch (12 mm) wood structural panel or 1/2-inch (12.7 mm) particleboard.
- Planks not less than 4 inches (102 mm) nominal in width set on edge close together and well spiked and covered with 1-inch (25 mm) nominal dimension flooring or 15/32-inch (12 mm) wood structural panel or 1/2-inch (12.7 mm) particle-board.
The lumber shall be laid so that no continuous line of joints will occur except at points of support. Floors shall not extend closer than 1/2 inch (12.7 mm) to walls. Such 1/2-inch (12.7 mm) space shall be covered by a molding fastened to the wall and so arranged that it will not obstruct the swelling or shrinkage movements of the floor. Corbelling of masonry walls under the floor shall be permitted to be used in place of molding.
Roofs shall be without concealed spaces and wood roof decks shall be sawn or glued laminated, splined or tongue-and-groove plank, not less than 2 inches (51 mm) nominal in thickness; 11/8-inch-thick (32 mm) wood structural panel (exterior glue); planks not less than 3 inches (76 mm) nominal in width, set on edge close together and laid as required for floors; or of cross-laminated timber. Other types of decking shall be permitted to be used if providing equivalent fire resistance and structural properties.
Cross-laminated timber roofs shall be not less than 3 inches (76 mm) nominal in thickness and shall be continuous from support to support and mechanically fastened to one another.
Exterior walls shall be of one of the following:
- Noncombustible materials.
- 2.1. Fire-retardant-treated wood in accordance with Section 2303.2 and complying with Section 602.4.1.
- 2.2. Cross-laminated timber complying with Section 602.4.2.
Combustible materials shall be permitted in buildings of Type I or II construction in the following applications and in accordance with Sections 603.1.1 through 603.1.3:
- 1.1. Nonbearing partitions where the required fire-resistance rating is 2 hours or less.
- 1.2. Nonbearing exterior walls where fire-resistance rated construction is not required.
- 1.3. Roof construction, including girders, trusses, framing and decking.
- Insulation placed between two layers of noncombustible materials without an intervening airspace shall be allowed to have a flame spread index of not more than 100.
- Insulation installed between a finished floor and solid decking without intervening airspace shall be allowed to have a flame spread index of not more than 200.
- Foam plastics in accordance with Chapter 26.
- Roof coverings that have an A, B or C classification.
- Interior floor finish and floor covering materials installed in accordance with Section 804.
- Millwork such as doors, door frames, window sashes and frames.
- Interior wall and ceiling finishes installed in accordance with Sections 801 and 803.
- Trim installed in accordance with Section 806.
- Where not installed greater than 15 feet (4572 mm) above grade, show windows, nailing or furring strips and wooden bulkheads below show windows, including their frames, aprons and show cases.
- Finish flooring installed in accordance with Section 805.
- Partitions dividing portions of stores, offices or similar places occupied by one tenant only and that do not establish a corridor serving an occupant load of 30 or more shall be permitted to be constructed of fire-retardant-treated wood, 1-hour fire-resistance-rated construction or of wood panels or similar light construction up to 6 feet (1829 mm) in height.
- Stages and platforms constructed in accordance with Sections 410.3 and 410.4, respectively.
- Combustible exterior wall coverings, balconies and similar projections and bay or oriel windows in accordance with Chapter 14.
- Blocking such as for handrails, millwork, cabinets and window and door frames.
- Light-transmitting plastics as permitted by Chapter 26.
- Mastics and caulking materials applied to provide flexible seals between components of exterior wall construction.
- Exterior plastic veneer installed in accordance with Section 2605.2.
- Nailing or furring strips as permitted by Section 803.4.
- Heavy timber as permitted by Note c to Table 601 and Sections 602.4.7 and 1406.3.
- Aggregates, component materials and admixtures as permitted by Section 703.2.2.
- Sprayed fire-resistant materials and intumescent and mastic fire-resistant coatings, determined on the basis of fire resistance tests in accordance with Section 703.2 and installed in accordance with Sections 1705.14 and 1705.15, respectively.
- Materials used to protect penetrations in fire-resistance-rated assemblies in accordance with Section 714.
- Materials used to protect joints in fire-resistance-rated assemblies in accordance with Section 715.
- Materials allowed in the concealed spaces of buildings of Types I and II construction in accordance with Section 718.5.
- Materials exposed within plenums complying with Section 602 of the California Mechanical Code.
- Wall construction of freezers and coolers of less than 1,000 square feet (92.9 m2), in size, lined on both sides with noncombustible materials and the building is protected throughout with an automatic sprinkler system in accordance with Section 903.3.1.1.