Section 722 — California Building Code (Title 24, Part 2)

722.1 General.¶

The provisions of this section contain procedures by which the fire resistance of specific materials or combinations of materials is established by calculations. These procedures apply only to the information contained in this section and shall not be otherwise used. The calculated fire resistance of specific materials or combinations of materials shall be established by one of the following:

Concrete, concrete masonry and clay masonry assemblies shall be permitted in accordance with ACI 216.1/TMS 0216.
Precast and precast, prestressed concrete assemblies shall be permitted in accordance with PCI 124.
Steel assemblies shall be permitted in accordance with Chapter 5 of ASCE 29.
Exposed wood members and wood decking shall be permitted in accordance with Chapter 16 of ANSI/AWC NDS.

722.2 Concrete assemblies.¶

The provisions of this section contain procedures by which the fire-resistance ratings of concrete assemblies are established by calculations.

722.2.1 Concrete walls. Cast-in-place and precast concrete walls shall comply with Section 722.2.1.1. Multiwythe concrete walls shall comply with Section 722.2.1.2. Joints between precast panels shall comply with Section 722.2.1.3. Concrete walls with gypsum wallboard or plaster finish shall comply with Section 722.2.1.4.

722.2.1.1 Cast-in-place or precast walls. The minimum equivalent thicknesses of cast-in-place or precast concrete walls for fire-resistance ratings of 1 hour to 4 hours are shown in Table 722.2.1.1. For solid walls with flat vertical surfaces, the equivalent thickness is the same as the actual thickness. The values in Table 722.2.1.1 apply to plain, reinforced or prestressed concrete walls.

7-44 2022 CALIFORNIA BUILDING CODE

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FIRE AND SMOKE PROTECTION FEATURES

		TABLE 721.1(1) MINIMUM PROTECTION OF STRUCTURAL PARTS BASED ON TIME PERIODS FOR VARIOUS NONCOMBUSTIBLE INSULATING MATERIALSm	m
STRUCTURAL PARTS TO BE PROTECTED	ITEM NUMBER	INSULATING MATERIAL USED	MINIMUM THICKNESS OF INSULATING MATERIAL FOR THE FOLLOWING FIRE-RESISTANCE PERIODS (inches)	MINIMUM THICKNESS OF INSULATING MATERIAL FOR THE FOLLOWING FIRE-RESISTANCE PERIODS (inches)	MINIMUM THICKNESS OF INSULATING MATERIAL FOR THE FOLLOWING FIRE-RESISTANCE PERIODS (inches)	MINIMUM THICKNESS OF INSULATING MATERIAL FOR THE FOLLOWING FIRE-RESISTANCE PERIODS (inches)
STRUCTURAL PARTS TO BE PROTECTED	ITEM NUMBER	INSULATING MATERIAL USED	4 hours	3 hours	2 hours	1 hour
1. Steel col- umns and all of primary trusses (continued)	1-1.1	Carbonate, lightweight and sand-lightweight aggregate concrete, members 6" × 6" or greater (not including sandstone, granite and siliceous gravel).a	21/2	2	11/2	1
1. Steel col- umns and all of primary trusses (continued)	1-1.2	Carbonate, lightweight and sand-lightweight aggregate concrete, members 8" × 8" or greater (not including sandstone, granite and siliceous gravel).a	2	11/2	1	1
1. Steel col- umns and all of primary trusses (continued)	1-1.3	Carbonate, lightweight and sand-lightweight aggregate concrete, members 12" × 12" or greater (not including sandstone, granite and siliceous gravel).a	11/2	1	1	1
1. Steel col- umns and all of primary trusses (continued)	1-1.4	Siliceous aggregate concrete and concrete excluded in Item 1-1.1, members 6" × 6" or greater.a	3	2	11/2	1
1. Steel col- umns and all of primary trusses (continued)	1-1.5	Siliceous aggregate concrete and concrete excluded in Item 1-1.1, members 8" × 8" or greater.a	21/2	2	1	1
1. Steel col- umns and all of primary trusses (continued)	1-1.6	Siliceous aggregate concrete and concrete excluded in Item 1-1.1, members 12" × 12" or greater.a	2	1	1	1
1. Steel col- umns and all of primary trusses (continued)	1-2.1	Clay or shale brick with brick and mortar fill.a	33/4	—	—	21/4
1. Steel col- umns and all of primary trusses (continued)	1-3.1	4" hollow clay tile in two 2" layers;1/2" mortar between tile and column;3/8" metal mesh 0.046" wire diameter in horizontal joints; tile fill.a	4	—	—	—
1. Steel col- umns and all of primary trusses (continued)	1-3.2	2" hollow clay tile;3/4" mortar between tile and column;3/8" metal mesh 0.046" wire diameter in horizontal joints; limestone concrete filla; plastered with3/4" gypsum plaster.	3	—	—	—
1. Steel col- umns and all of primary trusses (continued)	1-3.3	2" hollow clay tile with outside wire ties 0.08" diameter at each course of tile or3/8" metal mesh 0.046" diameter wire in horizontal joints; limestone or trap-rock con- crete filla extending 1" outside column on all sides.	—	—	3	—
1. Steel col- umns and all of primary trusses (continued)	1-3.4	2" hollow clay tile with outside wire ties 0.08" diameter at each course of tile with or without concrete fill;3/4" mortar between tile and column.	—	—	—	2
1. Steel col- umns and all of primary trusses (continued)	1-4.1	Cement plaster over metal lath wire tied to3/4" cold-rolled vertical channels with 0.049" (No. 18 B.W. gage) wire ties spaced 3" to 6" on center. Plaster mixed 1:21/2 by volume, cement to sand.	—	—	21/2 b	7/8
1. Steel col- umns and all of primary trusses (continued)	1-5.1	Vermiculite concrete, 1:4 mix by volume over paper-backed wire fabric lath wrapped directly around column with additional 2" × 2" 0.065"/0.065" (No. 16/16 B.W. gage) wire fabric placed3/4" from outer concrete surface. Wire fabric tied with 0.049" (No. 18B.W. gage) wire spaced 6" on center for inner layer and 2" on center for outer layer.	2	—	—	—
1. Steel col- umns and all of primary trusses (continued)	1-6.1	Perlite or vermiculite gypsum plaster over metal lath wrapped around column and furred 11/4" from column flanges. Sheets lapped at ends and tied at 6" intervals with 0.049" (No. 18 B.W. gage) tie wire. Plaster pushed through to flanges.	11/2	1	—	—
1. Steel col- umns and all of primary trusses (continued)	1-6.2	Perlite or vermiculite gypsum plaster over self-furring metal lath wrapped directly around column, lapped 1" and tied at 6" intervals with 0.049" (No. 18 B.W. gage) wire.	13/4	13/8	1	—
1. Steel col- umns and all of primary trusses (continued)	1-6.3	Perlite or vermiculite gypsum plaster on metal lath applied to3/4" cold-rolled chan- nels spaced 24" apart vertically and wrapped flatwise around column.	11/2	—	—	—
1. Steel col- umns and all of primary trusses (continued)	1-6.4	Perlite or vermiculite gypsum plaster over two layers of1/2" plain full-length gyp- sum lath applied tight to column flanges. Lath wrapped with 1" hexagonal mesh of No. 20-gage wire and tied with doubled 0.035" diameter (No. 18 B.W. gage) wire ties spaced 23" on center. For three-coat work, the plaster mix for the second coat shall not exceed 100 pounds of gypsum to 21/2 cubic feet of aggregate for the 3-hour system.	21/2	2	—	—

(continued)

FIRE AND SMOKE PROTECTION FEATURES

		TABLE 721.1(1)—continued MINIMUM PROTECTION OF STRUCTURAL PARTS BASED ON TIME PERIODS FOR VARIOUS NONCOMBUSTIBLE INSULATING MATERIALSm	m
STRUCTURAL PARTS TO BE PROTECTED	ITEM NUMBER	INSULATING MATERIAL USED	MINIMUM THICKNESS OF INSULATING MATERIAL FOR THE FOLLOWING FIRE-RESISTANCE PERIODS (inches)	MINIMUM THICKNESS OF INSULATING MATERIAL FOR THE FOLLOWING FIRE-RESISTANCE PERIODS (inches)	MINIMUM THICKNESS OF INSULATING MATERIAL FOR THE FOLLOWING FIRE-RESISTANCE PERIODS (inches)	MINIMUM THICKNESS OF INSULATING MATERIAL FOR THE FOLLOWING FIRE-RESISTANCE PERIODS (inches)
STRUCTURAL PARTS TO BE PROTECTED	ITEM NUMBER	INSULATING MATERIAL USED	4 hours	3 hours	2 hours	1 hour
1. Steel col- umns and all of primary trusses (continued)	1-6.5	Perlite or vermiculite gypsum plaster over one layer of1/2" plain full-length gypsum lath applied tight to column flanges. Lath tied with doubled 0.049" (No. 18 B.W. gage) wire ties spaced 23" on center and scratch coat wrapped with 1" hexagonal mesh 0.035" (No. 20 B.W. gage) wire fabric. For three-coat work, the plaster mix for the second coat shall not exceed 100 pounds of gypsum to 21/2 cubic feet of aggregate.	—	2	—	—
1. Steel col- umns and all of primary trusses (continued)	1-7.1	Multiple layers of1/2" gypsum wallboardc adhesivelyd secured to column flanges and successive layers. Wallboard applied without horizontal joints. Corner edges of each layer staggered. Wallboard layer below outer layer secured to column with doubled 0.049" (No. 18 B.W. gage) steel wire ties spaced 15" on center. Exposed corners taped and treated.	—	—	2	1
1. Steel col- umns and all of primary trusses (continued)	1-7.2	Three layers of5/8" Type X gypsum wallboard.c First and second layer held in place by1/8" diameter by 13/8" long ring shank nails with5/16" diameter heads spaced 24" on center at corners. Middle layer also secured with metal straps at mid-height and 18" from each end, and by metal corner bead at each corner held by the metal straps. Third layer attached to corner bead with 1" long gypsum wallboard screws spaced 12" on center.	—	—	17/8	—
1. Steel col- umns and all of primary trusses (continued)	1-7.3	Three layers of5/8" Type X gypsum wallboard,c each layer screw attached to 15/8" steel studs 0.018" thick (No. 25 carbon sheet steel gage) at each corner of column. Middle layer also secured with 0.049" (No. 18 B.W. gage) double-strand steel wire ties, 24" on center. Screws are No. 6 by 1" spaced 24" on center for inner layer, No. 6 by 15/8" spaced 12" on center for middle layer and No. 8 by 21/4" spaced 12" on center for outer layer.	—	17/8	—	—
1. Steel col- umns and all of primary trusses (continued)	1-8.1	Wood-fibered gypsum plaster mixed 1:1 by weight gypsum-to-sand aggregate applied over metal lath. Lath lapped 1" and tied 6" on center at all end, edges and spacers with 0.049" (No. 18 B.W. gage) steel tie wires. Lath applied over1/2" spac- ers made of3/4" furring channel with 2" legs bent around each corner. Spacers located 1" from top and bottom of member and not greater than 40" on center and wire tied with a single strand of 0.049" (No. 18 B.W. gage) steel tie wires. Corner bead tied to the lath at 6" on center along each corner to provide plaster thickness.	—	—	15/8	—
1. Steel col- umns and all of primary trusses (continued)	1-9.1	Minimum W8x35 wide flange steel column (w/d ≥ 0.75) with each web cavity filled even with the flange tip with normal weight carbonate or siliceous aggregate con- crete (3,000 psi minimum compressive strength with 145 pcf ± 3 pcf unit weight). Reinforce the concrete in each web cavity with a minimum No. 4 deformed rein- forcing bar installed vertically and centered in the cavity, and secured to the column web with a minimum No. 2 horizontal deformed reinforcing bar welded to the web every 18" on center vertically. As an alternative to the No. 4 rebar,3/4" diameter by 3" long headed studs, spaced at 12" on center vertically, shall be welded on each side of the web mid-way between the column flanges.	—	—	—	See Note n
2. Webs or flanges of steel beams and girders (continued)	2-1.1	Carbonate, lightweight and sand-lightweight aggregate concrete (not including sandstone, granite and siliceous gravel) with 3" or finer metal mesh placed 1" from the finished surface anchored to the top flange and providing not less than 0.025 square inch of steel area per foot in each direction.	2	11/2	1	1
2. Webs or flanges of steel beams and girders (continued)	2-1.2	Siliceous aggregate concrete and concrete excluded in Item 2-1.1 with 3" or finer metal mesh placed 1" from the finished surface anchored to the top flange and pro- viding not less than 0.025 square inch of steel area per foot in each direction.	21/2	2	11/2	1
2. Webs or flanges of steel beams and girders (continued)	2-2.1	Cement plaster on metal lath attached to3/4" cold-rolled channels with 0.04" (No. 18 B.W. gage) wire ties spaced 3" to 6" on center. Plaster mixed 1:21/2 by volume, cement to sand.	—	—	21/2 b	7/8

(continued)

7-46 2022 CALIFORNIA BUILDING CODE

FIRE AND SMOKE PROTECTION FEATURES

		TABLE 721.1(1)—continued MINIMUM PROTECTION OF STRUCTURAL PARTS BASED ON TIME PERIODS FOR VARIOUS NONCOMBUSTIBLE INSULATING MATERIALSm	m
STRUCTURAL PARTS TO BE PROTECTED	ITEM NUMBER	INSULATING MATERIAL USED	MINIMUM THICKNESS OF INSULATING MATERIAL FOR THE FOLLOWING FIRE-RESISTANCE PERIODS (inches)	MINIMUM THICKNESS OF INSULATING MATERIAL FOR THE FOLLOWING FIRE-RESISTANCE PERIODS (inches)	MINIMUM THICKNESS OF INSULATING MATERIAL FOR THE FOLLOWING FIRE-RESISTANCE PERIODS (inches)	MINIMUM THICKNESS OF INSULATING MATERIAL FOR THE FOLLOWING FIRE-RESISTANCE PERIODS (inches)
STRUCTURAL PARTS TO BE PROTECTED	ITEM NUMBER	INSULATING MATERIAL USED	4 hours	3 hours	2 hours	1 hour
2. Webs or flanges of steel beams and girders (continued)	2-3.1	Vermiculite gypsum plaster on a metal lath cage, wire tied to 0.165" diameter (No. 8 B.W. gage) steel wire hangers wrapped around beam and spaced 16" on center. Metal lath ties spaced approximately 5" on center at cage sides and bottom.	—	7/8	—	—
2. Webs or flanges of steel beams and girders (continued)	2-4.1	Two layers of5/8" Type X gypsum wallboardc are attached to U-shaped brackets spaced 24" on center. 0.018" thick (No. 25 carbon sheet steel gage) 15/8" deep by 1" galvanized steel runner channels are first installed parallel to and on each side of the top beam flange to provide a1/2" clearance to the flange. The channel runners are attached to steel deck or concrete floor construction with approved fasteners spaced 12" on center. U-shaped brackets are formed from members identical to the channel runners. At the bent portion of the U-shaped bracket, the flanges of the channel are cut out so that 15/8"-deep corner channels can be inserted without attachment paral- lel to each side of the lower flange. As an alternative, 0.021" thick (No. 24 carbon sheet steel gage) 1" × 2" runner and corner angles shall be used in lieu of channels, and the web cutouts in the U-shaped brackets shall not be required. Each angle is attached to the bracket with1/2"-long No. 8 self-drilling screws. The vertical legs of the U-shaped bracket are attached to the runners with one1/2"-long No. 8 self-drilling screw. The completed steel framing provides a 21/8" and 11/2" space between the inner layer of wallboard and the sides and bottom of the steel beam, respectively. The inner layer of wallboard is attached to the top runners and bottom corner channels or corner angles with 11/4"-long No. 6 self-drilling screws spaced 16" on center. The outer layer of wallboard is applied with 13/4"-long No. 6 self-drilling screws spaced 8" on center. The bottom corners are reinforced with metal corner beads.	—	—	11/4	—
2. Webs or flanges of steel beams and girders (continued)	2-4.2	Three layers of5/8" Type X gypsum wallboardc attached to a steel suspension system as described immediately above utilizing the 0.018" thick (No. 25 carbon sheet steel gage) 1" × 2" lower corner angles. The framing is located so that a 21/8" and 2" space is provided between the inner layer of wallboard and the sides and bottom of the beam, respectively. The first two layers of wallboard are attached as described immediately above. A layer of 0.035" thick (No. 20 B.W. gage) 1" hexagonal galva- nized wire mesh is applied under the soffit of the middle layer and up the sides approximately 2". The mesh is held in position with the No. 6 15/8"-long screws installed in the vertical leg of the bottom corner angles. The outer layer of wallboard is attached with No. 6 21/4"-long screws spaced 8" on center. One screw is installed at the mid-depth of the bracket in each layer. Bottom corners are finished as described above.	—	17/8	—	—
3. Bonded pre- tensioned rein- forcement in prestressed concretee	3-1.1	Carbonate, lightweight, sand-lightweight and siliceousf aggregate concrete
3. Bonded pre- tensioned rein- forcement in prestressed concretee	3-1.1	Beams or girders	4g	3g	21/2	11/2
3. Bonded pre- tensioned rein- forcement in prestressed concretee	3-1.1	Solidh		2	11/2	1

(continued)

FIRE AND SMOKE PROTECTION FEATURES

		TABLE 721.1(1)—continued MINIMUM PROTECTION OF STRUCTURAL PARTS BASED ON TIME PERIODS FOR VARIOUS NONCOMBUSTIBLE INSULATING MATERIALSm	m
STRUCTURAL PARTS TO BE PROTECTED	ITEM NUMBER	INSULATING MATERIAL USED	MINIMUM THICKNESS OF INSULATING MATERIAL FOR THE FOLLOWING FIRE-RESISTANCE PERIODS (inches)	MINIMUM THICKNESS OF INSULATING MATERIAL FOR THE FOLLOWING FIRE-RESISTANCE PERIODS (inches)	MINIMUM THICKNESS OF INSULATING MATERIAL FOR THE FOLLOWING FIRE-RESISTANCE PERIODS (inches)	MINIMUM THICKNESS OF INSULATING MATERIAL FOR THE FOLLOWING FIRE-RESISTANCE PERIODS (inches)
STRUCTURAL PARTS TO BE PROTECTED	ITEM NUMBER	INSULATING MATERIAL USED	4 hours	3 hours	2 hours	1 hour
4. Bonded or unbonded post-ten- sioned ten- dons in prestressed concretee, i	4-1.1	Carbonate, lightweight, sand-lightweight and siliceousf aggregate concrete Unrestrained members:
4. Bonded or unbonded post-ten- sioned ten- dons in prestressed concretee, i	4-1.1	Solid slabsh	—	2	11/2	—
4. Bonded or unbonded post-ten- sioned ten- dons in prestressed concretee, i	4-1.1	Beams and girdersj	Beams and girdersj	Beams and girdersj	Beams and girdersj	Beams and girdersj
4. Bonded or unbonded post-ten- sioned ten- dons in prestressed concretee, i	4-1.1	8" wide		41/2	21/2	13/4
4. Bonded or unbonded post-ten- sioned ten- dons in prestressed concretee, i	4-1.1	greater than 12" wide	3	21/2	2	11/2
4. Bonded or unbonded post-ten- sioned ten- dons in prestressed concretee, i	4-1.2	Carbonate, lightweight, sand-lightweight and siliceous aggregate Restrained members:k
4. Bonded or unbonded post-ten- sioned ten- dons in prestressed concretee, i	4-1.2	Solid slabsh	11/4	1	3/4	—
4. Bonded or unbonded post-ten- sioned ten- dons in prestressed concretee, i	4-1.2	Beams and girdersj	Beams and girdersj	Beams and girdersj	Beams and girdersj	Beams and girdersj
4. Bonded or unbonded post-ten- sioned ten- dons in prestressed concretee, i	4-1.2	8" wide	21/2	2	13/4	—
4. Bonded or unbonded post-ten- sioned ten- dons in prestressed concretee, i	4-1.2	greater than 12" wide	2	13/4	11/2	—
5. Reinforcing steel in rein- forced con- crete columns, beams girders and trusses	5-1.1	Carbonate, lightweight and sand-lightweight aggregate concrete, members 12" or larger, square or round. (Size limit does not apply to beams and girders monolithic with floors.)	11/2	11/2	11/2	11/2
5. Reinforcing steel in rein- forced con- crete columns, beams girders and trusses	5-1.1	Siliceous aggregate concrete, members 12" or larger, square or round. (Size limit does not apply to beams and girders monolithic with floors.)	2	11/2	11/2	11/2
6. Reinforcing steel in rein- forced con- crete joists1	6-1.1	Carbonate, lightweight and sand-lightweight aggregate concrete	11/4	11/4	1	3/4
6. Reinforcing steel in rein- forced con- crete joists1	6-1.2	Siliceous aggregate concrete	13/4	11/2	1	3/4
7. Reinforcing and tie rods in floor and roof slabs1	7-1.1	Carbonate, lightweight and sand-lightweight aggregate concrete	1	1	3/4	3/4
7. Reinforcing and tie rods in floor and roof slabs1	7-1.2	Siliceous aggregate concrete	11/4	1	1	3/4

For SI: 1 inch = 25.4 mm, 1 square inch = 645.2 mm ², 1 cubic foot = 0.0283 m ³, 1 pound per cubic foot = 16.02 kg/m ³ . a. Reentrant parts of protected members to be filled solidly. b. Two layers of equal thickness with a ³ /4-inch airspace between. c. For all of the construction with gypsum wallboard described in Table 721.1(1), gypsum base for veneer plaster of the same size, thickness and core type shall be permitted to be substituted for gypsum wallboard, provided that attachment is identical to that specified for the wallboard and the joints on the face layer are reinforced, and the entire surface is covered with not less than ¹ /16-inch gypsum veneer plaster. d. An approved adhesive qualified under ASTM E119 or UL 263. e. Where lightweight or sand-lightweight concrete having an oven-dry weight of 110 pounds per cubic foot or less is used, the tabulated minimum cover shall be permitted to be reduced 25 percent, except that the reduced cover shall be not less than ³ /4 inch in slabs or 1 ¹ /2 inches in beams or girders. f. For solid slabs of siliceous aggregate concrete, increase tendon cover 20 percent. g. Adequate provisions against spalling shall be provided by U-shaped or hooped stirrups spaced not to exceed the depth of the member with a clear cover of 1 inch. h. Prestressed slabs shall have a thickness not less than that required in Table 721.1(3) for the respective fire-resistance time period. i. Fire coverage and end anchorages shall be as follows: Cover to the prestressing steel at the anchor shall be ¹ /2 inch greater than that required away from the anchor. Minimum cover to steel-bearing plate shall be 1 inch in beams and ³ /4 inch in slabs. j. For beam widths between 8 inches and 12 inches, cover thickness shall be permitted to be determined by interpolation. k. Interior spans of continuous slabs, beams and girders shall be permitted to be considered restrained. l. For use with concrete slabs having a comparable fire endurance where members are framed into the structure in such a manner as to provide equivalent performance to that of monolithic concrete construction. m. Generic fire-resistance ratings (those not designated as PROPRIETARY* in the listing) in GA 600 shall be accepted as if herein specified. n. Additional insulating material is not required on the exposed outside face of the column flange to achieve a 1-hour fire-resistance rating.

7-48 2022 CALIFORNIA BUILDING CODE

FIRE AND SMOKE PROTECTION FEATURES

		TABLE 721.1(2) RATED FIRE-RESISTANCE PERIODS FOR VARIOUS WALLS AND PARTITIONS	a, o, p
MATERIAL	ITEM NUMBER	CONSTRUCTION	MINIMUM FINISHED THICKNESS FACE-TO-FACEb (inches)	MINIMUM FINISHED THICKNESS FACE-TO-FACEb (inches)	MINIMUM FINISHED THICKNESS FACE-TO-FACEb (inches)	MINIMUM FINISHED THICKNESS FACE-TO-FACEb (inches)
MATERIAL	ITEM NUMBER	CONSTRUCTION	4 hours	3 hours	2 hours	1 hour
1. Brick of clay or shale	1-1.1	Solid brick of clay or shale.c	6	4.9	3.8	2.7
1. Brick of clay or shale	1-1.2	Hollow brick, not filled.	5.0	4.3	3.4	2.3
1. Brick of clay or shale	1-1.3	Hollow brick unit wall, grout or filled with perlite vermiculite or expanded shale aggregate.	6.6	5.5	4.4	3.0
1. Brick of clay or shale	1-2.1	4" nominal thick units not less than 75 percent solid backed with a hat-shaped metal furring channel3/4" thick formed from 0.021" sheet metal attached to the brick wall on 24" centers with approved fasteners, and1/2" Type X gypsum wallboard attached to the metal furring strips with 1"-long Type S screws spaced 8" on center.	—	—	5d	—
2. Combina- tion of clay brick and load-bearing hollow clay tile	2-1.1	4" solid brick and 4" tile (not less than 40 percent solid).	—	8	—	—
2. Combina- tion of clay brick and load-bearing hollow clay tile	2-1.2	4" solid brick and 8" tile (not less than 40 percent solid).	12	—	—	—
3. Concrete masonry units	3-1.1f, g	Expanded slag or pumice.	4.7	4.0	3.2	2.1
3. Concrete masonry units	3-1.2f, g	Expanded clay, shale or slate.	5.1	4.4	3.6	2.6
3. Concrete masonry units	3-1.3f	Limestone, cinders or air-cooled slag.	5.9	5.0	4.0	2.7
3. Concrete masonry units	3-1.4f, g	Calcareous or siliceous gravel.	6.2	5.3	4.2	2.8
4. Solid con- creteh, i	4-1.1	Siliceous aggregate concrete.	7.0	6.2	5.0	3.5
4. Solid con- creteh, i	4-1.1	Carbonate aggregate concrete.	6.6	5.7	4.6	3.2
4. Solid con- creteh, i	4-1.1	Sand-lightweight concrete.	5.4	4.6	3.8	2.7
4. Solid con- creteh, i	4-1.1	Lightweight concrete.	5.1	4.4	3.6	2.5
5. Glazed or unglazed fac- ing tile, non- load-bearing	5-1.1	One 2" unit cored 15 percent maximum and one 4" unit cored 25 percent maximum with3/4" mortar-filled collar joint. Unit positions reversed in alternate courses.	—	63/8	—	—
5. Glazed or unglazed fac- ing tile, non- load-bearing	5-1.2	One 2" unit cored 15 percent maximum and one 4" unit cored 40 percent maximum with3/4" mortar-filled collar joint. Unit positions side with3/4" gypsum plaster. Two wythes tied together every fourth course with No. 22 gage corrugated metal ties.	—	63/4	—	—
5. Glazed or unglazed fac- ing tile, non- load-bearing	5-1.3	One unit with three cells in wall thickness, cored 29 percent maximum.	—	—	6	—
5. Glazed or unglazed fac- ing tile, non- load-bearing	5-1.4	One 2" unit cored 22 percent maximum and one 4" unit cored 41 percent maximum with1/4" mortar-filled collar joint. Two wythes tied together every third course with 0.030"(No. 22 galvanized sheet steel gage) corrugated metal ties.	—	—	6	—
5. Glazed or unglazed fac- ing tile, non- load-bearing	5-1.5	One 4" unit cored 25 percent maximum with3/4" gypsum plaster on one side.	—	—	43/4	—
5. Glazed or unglazed fac- ing tile, non- load-bearing	5-1.6	One 4" unit with two cells in wall thickness, cored 22 percent maximum.	—	—	—	4
5. Glazed or unglazed fac- ing tile, non- load-bearing	5-1.7	One 4" unit cored 30 percent maximum with3/4" vermiculite gypsum plaster on one side.	—	—	41/2	—
5. Glazed or unglazed fac- ing tile, non- load-bearing	5-1.8	One 4" unit cored 39 percent maximum with3/4" gypsum plaster on one side.	—	—	—	41/2

(continued)

FIRE AND SMOKE PROTECTION FEATURES

		TABLE 721.1(2)—continued RATED FIRE-RESISTANCE PERIODS FOR VARIOUS WALLS AND PARTITIONS	a, o, p
MATERIAL	ITEM NUMBER	CONSTRUCTION	MINIMUM FINISHED THICKNESS FACE-TO-FACEb (inches)	MINIMUM FINISHED THICKNESS FACE-TO-FACEb (inches)	MINIMUM FINISHED THICKNESS FACE-TO-FACEb (inches)	MINIMUM FINISHED THICKNESS FACE-TO-FACEb (inches)
MATERIAL	ITEM NUMBER	CONSTRUCTION	4 hours	3 hours	2 hours	1 hour
6. Solid gyp- sum plaster	6-1.1	3/4" by 0.055" (No. 16 carbon sheet steel gage) vertical cold-rolled channels, 16" on center with 2.6-pound flat metal lath applied to one face and tied with 0.049" (No. 18 B.W. gage) wire at 6" spacing. Gypsum plaster each side mixed 1:2 by weight, gypsum to sand aggregate.	—	—	—	2d
6. Solid gyp- sum plaster	6-1.2	3/4" by 0.05" (No. 16 carbon sheet steel gage) cold-rolled channels 16" on center with metal lath applied to one face and tied with 0.049" (No. 18 B.W. gage) wire at 6" spacing. Perlite or vermiculite gypsum plaster each side. For three-coat work, the plaster mix for the second coat shall not exceed 100 pounds of gypsum to 21/2 cubic feet of aggregate for the 1-hour system.	—	—	21/2 d	2d
6. Solid gyp- sum plaster	6-1.3	3/4" by 0.055" (No. 16 carbon sheet steel gage) vertical cold-rolled channels, 16" on center with3/8" gypsum lath applied to one face and attached with sheet metal clips. Gypsum plaster each side mixed 1:2 by weight, gypsum to sand aggregate.	—	—	—	2d
6. Solid gyp- sum plaster	6-2.1	Studless with1/2" full-length plain gypsum lath and gypsum plaster each side. Plas- ter mixed 1:1 for scratch coat and 1:2 for brown coat, by weight, gypsum to sand aggregate.	—	—	—	2d
6. Solid gyp- sum plaster	6-2.2	Studless with1/2" full-length plain gypsum lath and perlite or vermiculite gypsum plaste_r_ each side.	—	—	21/2 d	2d
6. Solid gyp- sum plaster	6-2.3	Studless partition with3/8" rib metal lath installed vertically adjacent edges tied 6" on center with No. 18 gage wire ties, gypsum plaster each side mixed 1:2 by weight, gypsum to sand aggregate.	—	—	—	2d
7. Solid per- lite and Port- land cement	7-1.1	Perlite mixed in the ratio of 3 cubic feet to 100 pounds of Portland cement and machine applied to stud side of 11/2" mesh by 0.058-inch (No. 17 B.W. gage) paper- backed woven wire fabric lath wire-tied to 4"-deep steel trussed wirej studs 16" on center. Wire ties of 0.049" (No. 18 B.W. gage) galvanized steel wire 6" on center vertically.	—	—	31/8 d	—
8. Solid neat wood fibered gypsum plas- ter	8-1.1	3/4" by 0.055-inch (No. 16 carbon sheet steel gage) cold-rolled channels, 12" on cen- ter with 2.5-pound flat metal lath applied to one face and tied with 0.049" (No. 18 B.W.gage) wire at 6" spacing. Neat gypsum plaster applied each side.	—	—	2d	—
9. Solid wall- board parti- tion	9-1.1	One full-length layer1/2" Type X gypsum wallboarde laminated to each side of 1" full-length V-edge gypsum coreboard with approved laminating compound. Vertical joints of face layer and coreboard staggered not less than 3".	—	—	2d	—
10. Hollow (studless) gypsum wall- board parti- tion	10-1.1	One full-length layer of5/8" Type X gypsum wallboarde attached to both sides of wood or metal top and bottom runners laminated to each side of 1" × 6" full-length gypsum coreboard ribs spaced 2" on center with approved laminating compound. Ribs centered at vertical joints of face plies and joints staggered 24" in opposing faces. Ribs may be recessed 6" from the top and bottom.	—	—	—	21/4 d
10. Hollow (studless) gypsum wall- board parti- tion	10-1.2	1" regular gypsum V-edge full-length backing board attached to both sides of wood or metal top and bottom runners with nails or 15/8" drywall screws at 24" on center. Minimum width of runners 15/8". Face layer of1/2" regular full-length gypsum wall- board laminated to outer faces of backing board with approved laminating com- pound.	—	—	45/8 d	—

(continued)

7-50 2022 CALIFORNIA BUILDING CODE

FIRE AND SMOKE PROTECTION FEATURES

		TABLE 721.1(2)—continued RATED FIRE-RESISTANCE PERIODS FOR VARIOUS WALLS AND PARTITIONS	a, o, p
MATERIAL	ITEM NUMBER	CONSTRUCTION	MINIMUM FINISHED THICKNESS FACE-TO-FACEb (inches)	MINIMUM FINISHED THICKNESS FACE-TO-FACEb (inches)	MINIMUM FINISHED THICKNESS FACE-TO-FACEb (inches)	MINIMUM FINISHED THICKNESS FACE-TO-FACEb (inches)
MATERIAL	ITEM NUMBER	CONSTRUCTION	4 hours	3 hours	2 hours	1 hour
11. Noncom- bustible studs—inte- rior partition with plaster each side	11-1.1	31/4" × 0.044" (No. 18 carbon sheet steel gage) steel studs spaced 24" on center.5/8" gypsum plaster on metal lath each side mixed 1:2 by weight, gypsum to sand aggre- gate.	—	—	—	43/4 d
11. Noncom- bustible studs—inte- rior partition with plaster each side	11-1.2	33/8" × 0.055" (No. 16 carbon sheet steel gage) approved nailablek studs spaced 24" on center.5/8" neat gypsum wood-fibered plaster each side over3/8" rib metal lath nailed to studs with 6d common nails, 8" on center. Nails driven 11/4" and bent over.	—	—	55/8	—
11. Noncom- bustible studs—inte- rior partition with plaster each side	11-1.3	4" × 0.044" (No. 18 carbon sheet steel gage) channel-shaped steel studs at 16" on center. On each side approved resilient clips pressed onto stud flange at 16" vertical spacing,1/4" pencil rods snapped into or wire tied onto outer loop of clips, metal lath wire-tied to pencil rods at 6" intervals, 1" perlite gypsum plaster, each side.	—	75/8 d	—	—
11. Noncom- bustible studs—inte- rior partition with plaster each side	11-1.4	21/2" × 0.044" (No. 18 carbon sheet steel gage) steel studs spaced 16" on center. Wood fibered gypsum plaster mixed 1:1 by weight gypsum to sand aggregate applied on3/4-pound metal lath wire tied to studs, each side.3/4" plaster applied over each face, including finish coat.	—	—	41/4 d	—
12. Wood studs—inte- rior partition with plaster each side	12-1.1l, m	2" × 4" wood studs 16" on center with5/8" gypsum plaster on metal lath. Lath attached by 4d common nails bent over or No. 14 gage by 11/4" by3/4" crown width staples spaced 6" on center. Plaster mixed 1:11/2 for scratch coat and 1:3 for brown coat, by weight, gypsum to sand aggregate.	—	—	—	51/8
12. Wood studs—inte- rior partition with plaster each side	12-1.2l	2" × 4" wood studs 16" on center with metal lath and7/8" neat wood-fibered gypsum plaster each side. Lath attached by 6d common nails, 7" on center. Nails driven 11/4" and bent over.	—	—	51/2 d	—
12. Wood studs—inte- rior partition with plaster each side	12-1.3l	2" × 4" wood studs 16" on center with3/8" perforated or plain gypsum lath and1/2" gypsum plaster each side. Lath nailed with 11/8" by No. 13 gage by19/64" head plas- terboard blued nails, 4" on center. Plaster mixed 1:2 by weight, gypsum to sand aggregate.	—	—	—	51/4
12. Wood studs—inte- rior partition with plaster each side	12-1.4l	2" × 4" wood studs 16" on center with3/8" Type X gypsum lath and1/2" gypsum plaster each side. Lath nailed with 11/8" by No. 13 gage by19/64" head plasterboard blued nails, 5" on center. Plaster mixed 1:2 by weight, gypsum to sand aggregate.	—	—	—	51/4
13. Noncom- bustible studs—inte- rior partition with gypsum wallboard each side	13-1.1	0.018" (No. 25 carbon sheet steel gage) channel-shaped studs 24" on center with one full-length layer of5/8" Type X gypsum wallboarde applied vertically attached with 1"-long No. 6 dry wall screws to each stud. Screws are 8" on center around the perimeter and 12" on center on the intermediate stud. Where applied horizontally, the Type X gypsum wallboard shall be attached to 35/8" studs and the horizontal joints shall be staggered with those on the opposite side. Screws for the horizontal application shall be 8" on center at vertical edges and 12" on center at intermediate studs.	—	—	—	27/8 d
13. Noncom- bustible studs—inte- rior partition with gypsum wallboard each side	13-1.2	0.018" (No. 25 carbon sheet steel gage) channel-shaped studs 25" on center with two full-length layers of1/2" Type X gypsum wallboarde applied vertically each side. First layer attached with 1"-long, No. 6 drywall screws, 8" on center around the perimeter and 12" on center on the intermediate stud. Second layer applied with ver- tical joints offset one stud space from first layer using 15/8" long, No. 6 drywall screws spaced 9" on center along vertical joints, 12" on center at intermediate studs and 24" on center along top and bottom runners.	—	—	35/8 d	—
13. Noncom- bustible studs—inte- rior partition with gypsum wallboard each side	13-1.3	0.055" (No. 16 carbon sheet steel gage) approved nailable metal studse 24" on center with full-length5/8" Type X gypsum wallboarde applied vertically and nailed 7" on center with 6d cement-coated common nails. Approved metal fastener grips used with nails at vertical butt joints along studs.	—	—	—	47/8

(continued)

FIRE AND SMOKE PROTECTION FEATURES

TABLE 721.1(2)—continued¶

RATED FIRE-RESISTANCE PERIODS FOR VARIOUS WALLS AND PARTITIONS ^{a, o, p}

MATERIAL	ITEM NUMBER	CONSTRUCTION	MINIMUM FINISHED THICKNESS FACE-TO-FACEb (inches)
MATERIAL	ITEM NUMBER	CONSTRUCTION	4 hours	3 hours	2 hours	1 hour
14. Wood studs—inte- rior partition with gypsum wallboard each side	14-1.1h, m	2" × 4" wood studs 16" on center with two layers of3/8" regular gypsum wallboarde each side, 4d coolern or wallboardn nails at 8" on center first layer, 5d coolern or wallboardn nails at 8" on center second layer with laminating compound between layers, joints staggered. First layer applied full length vertically, second layer applied horizontally or vertically.	—	—	—	5
14. Wood studs—inte- rior partition with gypsum wallboard each side	14-1.2l, m	2" × 4" wood studs 16" on center with two layers1/2" regular gypsum wallboarde applied vertically or horizontally each sidek, joints staggered. Nail base layer with 5d coolern or wallboardn nails at 8" on center face layer with 8d coolern or wall- boardn nails at 8" on center.	—	—	—	51/2
14. Wood studs—inte- rior partition with gypsum wallboard each side	14-1.3l, m	2" × 4" wood studs 24" on center with5/8" Type X gypsum wallboarde applied ver- tically or horizontally nailed with 6d coolern or wallboardn nails at 7" on center with end joints on nailing members. Stagger joints each side.	—	—	—	43/4
14. Wood studs—inte- rior partition with gypsum wallboard each side	14-1.4l	2" × 4" fire-retardant-treated wood studs spaced 24" on center with one layer of5/8" Type X gypsum wallboarde applied with face paper grain (long dimension) parallel to studs. Wallboard attached with 6d coolern or wallboardn nails at 7" on center.	—	—	—	43/4 d
14. Wood studs—inte- rior partition with gypsum wallboard each side	14-1.5l, m	2" × 4" wood studs 16" on center with two layers5/8" Type X gypsum wallboarde each side. Base layers applied vertically and nailed with 6d coolern or wallboardn nails at 9" on center. Face layer applied vertically or horizontally and nailed with 8d coolern or wallboardn nails at 7" on center. For nail-adhesive application, base layers are nailed 6" on center. Face layers applied with coating of approved wall- board adhesive and nailed 12" on center.	—	—	6	—
14. Wood studs—inte- rior partition with gypsum wallboard each side	14-1.6l	2" × 3" fire-retardant-treated wood studs spaced 24" on center with one layer of5/8" Type X gypsum wallboarde applied with face paper grain (long dimension) at right angles to studs. Wallboard attached with 6d cement-coated box nails spaced 7" on center.	—	—	—	35/8 d
15. Exterior or interior walls (continued)	15-1.1l, m	Exterior surface with3/4" drop siding over1/2" gypsum sheathing on 2" × 4" wood studs at 16" on center, interior surface treatment as required for 1-hour-rated exte- rior or interior 2" × 4" wood stud partitions. Gypsum sheathing nailed with 13/4" by No.11 gage by7/16" head galvanized nails at 8" on center. Siding nailed with 7d gal- vanized smooth box nails.	—	—	—	Varies
15. Exterior or interior walls (continued)	15-1.2l, m	2" × 4" wood studs 16" on center with metal lath and3/4" cement plaster on each side. Lath attached with 6d common nails 7" on center driven to 1" minimum pene- tration and bent over. Plaster mix 1:4 for scratch coat and 1:5 for brown coat, by volume, cement to sand.	—	—	—	53/8
15. Exterior or interior walls (continued)	15-1.3l, m	2" × 4" wood studs 16" on center with7/8" cement plaster (measured from the face of studs) on the exterior surface with interior surface treatment as required for inte- rior wood stud partitions in this table. Plaster mix 1:4 for scratch coat and 1:5 for brown coat, by volume, cement to sand.	—	—	—	Varies
15. Exterior or interior walls (continued)	15-1.4	35/8" No. 16 gage noncombustible studs 16" on center with7/8" cement plaster (measured from the face of the studs) on the exterior surface with interior surface treatment as required for interior, nonbearing, noncombustible stud partitions in this table. Plaster mix 1:4 for scratch coat and 1:5 for brown coat, by volume, cement to sand.	—	—	—	Variesd

(continued)

7-52 2022 CALIFORNIA BUILDING CODE

FIRE AND SMOKE PROTECTION FEATURES

TABLE 721.1(2)—continued RATED FIRE-RESISTANCE PERIODS FOR VARIOUS WALLS AND PARTITIONS ^{a, o, p}

MATERIAL	ITEM NUMBER	CONSTRUCTION	MINIMUM FINISHED THICKNESS FACE-TO-FACEb (inches)
MATERIAL	ITEM NUMBER	CONSTRUCTION	4 hours	3 hours	2 hours	1 hour
15. Exterior or interior walls (continued)	15-1.5m	21/4" × 33/4" clay face brick with cored holes over1/2" gypsum sheathing on exterior surface of 2" × 4" wood studs at 16" on center and two layers5/8" Type X gypsum wallboarde on interior surface. Sheathing placed horizontally or vertically with verti- cal joints over studs nailed 6" on center with 13/4" × No. 11 gage by7/16" head galva- nized nails. Inner layer of wallboard placed horizontally or vertically and nailed 8" on center with 6d coolern or wallboardn nails. Outer layer of wallboard placed hori- zontally or vertically and nailed 8" on center with 8d coolern or wallboardn nails. Joints staggered with vertical joints over studs. Outer layer joints taped and finished with compound. Nail heads covered with joint compound. 0.035 inch (No. 20 galva- nized sheet gage) corrugated galvanized steel wall ties3/4" by 65/8" attached to each stud with two 8d coolern or wallboardn nails every sixth course of bricks.	—	—	10	—
15. Exterior or interior walls (continued)	15-1.6l, m	2" × 6" fire-retardant-treated wood studs 16" on center. Interior face has two layers of5/8" Type X gypsum with the base layer placed vertically and attached with 6d box nails 12"on center. The face layer is placed horizontally and attached with 8d box nails 8" on center at joints and 12" on center elsewhere. The exterior face has a base layer of5/8" Type X gypsum sheathing placed vertically with 6d box nails 8" on cen- ter at joints and 12" on center elsewhere. An approved building paper is next applied, followed by self-furred exterior lath attached with 21/2", No. 12 gage galva- nized roofing nails with a3/8" diameter head and spaced 6" on center along each stud. Cement plaster consisting of a1/2" brown coat is then applied. The scratch coat is mixed in the proportion of 1:3 by weight, cement to sand with 10 pounds of hydrated lime and 3 pounds of approved additives or admixtures per sack of cement. The brown coat is mixed in the proportion of 1:4 by weight, cement to sand with the same amounts of hydrated lime and approved additives or admixtures used in the scratch coat.	—	—	81/4	—
15. Exterior or interior walls (continued)	15-1.7l, m	2" × 6" wood studs 16" on center. The exterior face has a layer of5/8" Type X gyp- sum sheathing placed vertically with 6d box nails 8" on center at joints and 12" on center elsewhere. An approved building paper is next applied, followed by 1" by No. 18 gage self-furred exterior lath attached with 8d by 21/2"-long galvanized roofing nails spaced 6" on center along each stud. Cement plaster consisting of a1/2" scratch coat, a bonding agent and a1/2" brown coat and a finish coat is then applied. The scratch coat is mixed in the proportion of 1:3 by weight, cement to sand with 10 pounds of hydrated lime and 3 pounds of approved additives or admixtures per sack of cement. The brown coat is mixed in the proportion of 1:4 by weight, cement to sand with the same amounts of hydrated lime and approved additives or admixtures used in the scratch coat. The interior is covered with3/8" gypsum lath with 1" hexag- onal mesh of 0.035 inch (No. 20 B.W. gage) woven wire lath furred out5/16" and 1" perlite or vermiculite gypsum plaster. Lath nailed with 11/8" by No. 13 gage by19/64" head plasterboard glued nails spaced 5" on center. Mesh attached by 13/4" by No. 12 gage by3/8" head nails with3/8" furrings, spaced 8" on center. The plaster mix shall not exceed 100 pounds of gypsum to 21/2 cubic feet of aggregate.	—	—	83/8	—

(continued)

FIRE AND SMOKE PROTECTION FEATURES

		TABLE 721.1(2)—continued RATED FIRE-RESISTANCE PERIODS FOR VARIOUS WALLS AND PARTITIONS	a, o, p
MATERIAL	ITEM NUMBER	CONSTRUCTION	MINIMUM FINISHED THICKNESS FACE-TO-FACEb (inches)	MINIMUM FINISHED THICKNESS FACE-TO-FACEb (inches)	MINIMUM FINISHED THICKNESS FACE-TO-FACEb (inches)	MINIMUM FINISHED THICKNESS FACE-TO-FACEb (inches)
MATERIAL	ITEM NUMBER	CONSTRUCTION	4 hours	3 hours	2 hours	1 hour
15. Exterior or interior walls (continued)	15-1.8l, m	2" × 6" wood studs 16" on center. The exterior face has a layer of5/8" Type X gyp- sum sheathing placed vertically with 6d box nails 8" on center at joints and 12" on center elsewhere. An approved building paper is next applied, followed by 11/2" by No. 17 gage self-furred exterior lath attached with 8d by 21/2"-long galvanized roof- ing nails spaced 6" on center along each stud. Cement plaster consisting of a1/2" scratch coat and a1/2" brown coat is then applied. The plaster may be placed by machine. The scratch coat is mixed in the proportion of 1:4 by weight, plastic cement to sand. The brown coat is mixed in the proportion of 1:5 by weight, plastic cement to sand. The interior is covered with3/8" gypsum lath with 1" hexagonal mesh of No. 20-gage woven wire lath furred out5/16" and 1" perlite or vermiculite gypsum plaster. Lath nailed with 11/8" by No. 13 gage by19/64" head plasterboard glued nails spaced 5" on center. Mesh attached by 13/4" by No.12 gage by3/8" head nails with3/8" furrings, spaced 8" on center. The plaster mix shall not exceed 100 pounds of gypsum to 21/2 cubic feet of aggregate.	—	—	83/8	—
15. Exterior or interior walls (continued)	15-1.9	4" No. 18 gage, nonload-bearing metal studs, 16" on center, with 1" Portland cement lime plaster (measured from the back side of the3/4-pound expanded metal lath) on the exterior surface. Interior surface to be covered with 1" of gypsum plaster on3/4- pound expanded metal lath proportioned by weight—1:2 for scratch coat, 1:3 for brown, gypsum to sand. Lath on one side of the partition fastened to1/4" diameter pencil rods supported by No. 20 gage metal clips, located 16" on center vertically, on each stud. 3" thick mineral fiber insulating batts friction fitted between the studs.	—	—	61/2 d	—
15. Exterior or interior walls (continued)	15-1.10	Steel studs 0.060" thick, 4" deep or 6" at 16" or 24" centers, with1/2" glass fiber- reinforced concrete (GFRC) on the exterior surface. GFRC is attached with flex anchors at 24" on center, with 5" leg welded to studs with two1/2"-long flare-bevel welds, and 4" foot attached to the GFRC skin with5/8"-thick GFRC bonding pads that extend 21/2" beyond the flex anchor foot on both sides. Interior surface to have two layers of1/2" Type X gypsum wallboard.e The first layer of wallboard to be attached with 1"-long Type S buglehead screws spaced 24" on center and the second layer is attached with 15/8"-long Type S screws spaced at 12" on center. Cavity is to be filled with 5" of 4 pcf (nominal) mineral fiber batts. GFRC has 11/2" returns packed with mineral fiber and caulked on the exterior.	—	—	61/2	—
15. Exterior or interior walls (continued)	15-1.11	Steel studs 0.060" thick, 4" deep or 6" at 16" or 24" centers, respectively, with1/2" glass fiber-reinforced concrete (GFRC) on the exterior surface. GFRC is attached with flex anchors at 24" on center, with 5" leg welded to studs with two1/2"-long flare-bevel welds, and 4" foot attached to the GFRC skin with5/8"-thick GFRC bonding pads that extend 21/2" beyond the flex anchor foot on both sides. Interior surface to have one layer of5/8" Type X gypsum wallboarde, attached with 11/4"-long Type S buglehead screws spaced 12" on center. Cavity is to be filled with 5" of 4 pcf (nominal) mineral fiber batts. GFRC has 11/2" returns packed with mineral fiber and caulked on the exterior.	—	—	—	61/8
15. Exterior or interior walls (continued)	15-1.12q	2" × 6" wood studs at 16" with double top plates, single bottom plate; interior and exterior sides covered with5/8" Type X gypsum wallboard, 4′ wide, applied horizon- tally or vertically with vertical joints over studs, and fastened with 21/4" Type S dry- wall screws, spaced 12" on center. Cavity to be filled with 51/2" mineral wool insulation.	—	—	—	63/4

(continued)

7-54 2022 CALIFORNIA BUILDING CODE

FIRE AND SMOKE PROTECTION FEATURES

		TABLE 721.1(2)—continued RATED FIRE-RESISTANCE PERIODS FOR VARIOUS WALLS AND PARTITIONS	a, o, p
MATERIAL	ITEM NUMBER	CONSTRUCTION	MINIMUM FINISHED THICKNESS FACE-TO-FACEb (inches)	MINIMUM FINISHED THICKNESS FACE-TO-FACEb (inches)	MINIMUM FINISHED THICKNESS FACE-TO-FACEb (inches)	MINIMUM FINISHED THICKNESS FACE-TO-FACEb (inches)
MATERIAL	ITEM NUMBER	CONSTRUCTION	4 hours	3 hours	2 hours	1 hour
15. Exterior or interior walls (continued)	15-1.13q	2" × 6" wood studs at 16" with double top plates, single bottom plate; interior and exterior sides covered with5/8" Type X gypsum wallboard, 4′ wide, applied verti- cally with all joints over framing or blocking and fastened with 21/4" Type S drywall screws, spaced 12" on center. R-19 mineral fiber insulation installed in stud cavity.	—	—	—	63/4
15. Exterior or interior walls (continued)	15-1.14q	2" × 6" wood studs at 16" with double top plates, single bottom plate; interior and exterior sides covered with5/8" Type X gypsum wallboard, 4′ wide, applied horizon- tally or vertically with vertical joints over studs, and fastened with 21/4" Type S dry- wall screws, spaced 7" on center.	—	—	—	63/4
15. Exterior or interior walls (continued)	15-1.15q	2" × 4" wood studs at 16" with double top plates, single bottom plate; interior and exterior sides covered with5/8" Type X gypsum wallboard and sheathing, respec- tively, 4′ wide, applied horizontally or vertically with vertical joints over studs, and fastened with 21/4" Type S drywall screws, spaced 12" on center. Cavity to be filled with 31/2" mineral wool insulation.	—	—	—	43/4
15. Exterior or interior walls (continued)	15-1.16q	2" × 6" wood studs at 24" centers with double top plates, single bottom plate; inte- rior and exterior side covered with two layers of5/8" Type X gypsum wallboard, 4′ wide, applied horizontally with vertical joints over studs. Base layer fastened with 21/4" Type S drywall screws, spaced 24" on center and face layer fastened with Type S drywall screws, spaced 8" on center, wallboard joints covered with paper tape and joint compound, fastener heads covered with joint compound. Cavity to be filled with 51/2" mineral wool insulation.	—	—	8	—
15. Exterior or interior walls (continued)	15-2.1d	35/8" No. 16 gage steel studs at 24" on center or 2" × 4" wood studs at 24" on center. Metal lath attached to the exterior side of studs with minimum 1" long No. 6 drywall screws at 6" on center and covered with minimum3/4" thick Portland cement plaster. Thin veneer brick units of clay or shale complying with ASTM C1088, Grade TBS or better, installed in running bond in accordance with Section 1404.10. Combined total thickness of the Portland cement plaster, mortar and thin veneer brick units shall be not less than 13/4". Interior side covered with one layer of5/8"-thick Type X gypsum wallboard attached to studs with 1" long No. 6 drywall screws at 12" on center.	—	—	—	6
15. Exterior or interior walls (continued)	15-2.2d	35/8" No. 16 gage steel studs at 24" on center or 2" × 4" wood studs at 24" on center. Metal lath attached to the exterior side of studs with minimum 1" long No. 6 drywall screws at 6" on center and covered with minimum3/4" thick Portland cement plaster. Thin veneer brick units of clay or shale complying with ASTM C1088, Grade TBS or better, installed in running bond in accordance with Section 1404.10. Combined total thickness of the Portland cement plaster, mortar and thin veneer brick units shall be not less than 2". Interior side covered with two layers of5/8"-thick Type X gypsum wallboard. Bottom layer attached to studs with 1"-long No. 6 drywall screws at 24" on center. Top layer attached to studs with 15/8"-long No. 6 drywall screws at 12" on center.	—	—	67/8	—
15. Exterior or interior walls (continued)	15-2.3d	35/8" No. 16 gage steel studs at 16" on center or 2" × 4" wood studs at 16" on center. Where metal lath is used, attach to the exterior side of studs with minimum 1"-long No. 6 drywall screws at 6" on center. Brick units of clay or shale not less than 25/8" thick complying with ASTM C216 installed in accordance with Section 1404.6 with a minimum 1" airspace. Interior side covered with one layer of5/8"-thick Type X gypsum wallboard attached to studs with 1"-long No. 6 drywall screws at 12" on center.	—	—	—	77/8

(continued)

FIRE AND SMOKE PROTECTION FEATURES

		TABLE 721.1(2)—continued RATED FIRE-RESISTANCE PERIODS FOR VARIOUS WALLS AND PARTITIONS	a, o, p
MATERIAL	ITEM NUMBER	CONSTRUCTION	MINIMUM FINISHED THICKNESS FACE-TO-FACEb (inches)	MINIMUM FINISHED THICKNESS FACE-TO-FACEb (inches)	MINIMUM FINISHED THICKNESS FACE-TO-FACEb (inches)	MINIMUM FINISHED THICKNESS FACE-TO-FACEb (inches)
MATERIAL	ITEM NUMBER	CONSTRUCTION	4 hours	3 hours	2 hours	1 hour
15. Exterior or interior walls	15-2.4d	35/8" No. 16 gage steel studs at 16" on center or 2" × 4" wood studs at 16" on center. Where metal lath is used, attach to the exterior side of studs with minimum 1"-long No. 6 drywall screws at 6" on center. Brick units of clay or shale not less than 25/8" thick complying with ASTM C216 installed in accordance with Section 1404.6 with a minimum 1" airspace. Interior side covered with two layers of5/8"-thick Type X gypsum wallboard. Bottom layer attached to studs with 1"-long No. 6 drywall screws at 24" on center. Top layer attached to studs with 15/8"-long No. 6 drywall screws at 12" on center.	—	—	81/2	—
16. Exterior walls rated for fire resis- tance from the inside only in accordance with Section 705.5.	16-1.1q	2" × 4" wood studs at 16" centers with double top plates, single bottom plate; inte- rior side covered with5/8" Type X gypsum wallboard, 4’ wide, applied horizontally unblocked, and fastened with 21/4" Type S drywall screws, spaced 12" on center, wallboard joints covered with paper tape and joint compound, fastener heads cov- ered with joint compound. Exterior covered with3/8" wood structural panels, applied vertically, horizontal joints blocked and fastened with 6d common nails (bright)— 12" on center in the field, and 6" on center panel edges. Cavity to be filled with 31/2" mineral wool insulation. Rating established for exposure from interior side only.	—	—	—	41/2
16. Exterior walls rated for fire resis- tance from the inside only in accordance with Section 705.5.	16-1.2q	2" × 6" wood studs at 16" centers with double top plates, single bottom plate; inte- rior side covered with5/8" Type X gypsum wallboard, 4’ wide, applied horizontally or vertically with vertical joints over studs and fastened with 21/4" Type S drywall screws, spaced 12" on center, wallboard joints covered with paper tape and joint compound, fastener heads covered with joint compound, exterior side covered with 7/16" wood structural panels fastened with 6d common nails (bright) spaced 12" on center in the field and 6" on center along the panel edges. Cavity to be filled with 51/2" mineral wool insulation. Rating established from the gypsum-covered side only.	—	—	—	69/16
16. Exterior walls rated for fire resis- tance from the inside only in accordance with Section 705.5.	16-1.3q	2" × 6" wood studs at 16" centers with double top plates, single bottom plates; inte- rior side covered with5/8" Type X gypsum wallboard, 4’wide, applied vertically with all joints over framing or blocking and fastened with 21/4" Type S drywall screws spaced 7" on center. Joints to be covered with tape and joint compound. Exterior covered with3/8" wood structural panels, applied vertically with edges over framing or blocking and fastened with 6d common nails (bright) at 12" on center in the field and 6" on center on panel edges. R-19 mineral fiber insulation installed in stud cavity. Rating established from the gypsum-covered side only.	—	—	—	61/2

For SI: 1 inch = 25.4 mm, 1 square inch = 645.2 mm ², 1 cubic foot = 0.0283 m ³ . a. Staples with equivalent holding power and penetration shall be permitted to be used as alternate fasteners to nails for attachment to wood framing. b. Thickness shown for brick and clay tile is nominal thicknesses unless plastered, in which case thicknesses are net. Thickness shown for concrete masonry and

clay masonry is equivalent thickness defined in Section 722.3.1 for concrete masonry and Section 722.4.1.1 for clay masonry. Where all cells are solid grouted or filled with silicone-treated perlite loose-fill insulation; vermiculite loose-fill insulation; or expanded clay, shale or slate lightweight aggregate, the equivalent thickness shall be the thickness of the block or brick using specified dimensions as defined in Chapter 21. Equivalent thickness shall include the thickness of applied plaster and lath or gypsum wallboard, where specified. c. For units in which the net cross-sectional area of cored brick in any plane parallel to the surface containing the cores is not less than 75 percent of the gross

cross-sectional area measured in the same plane. d. Shall be used for nonbearing purposes only. e. For all of the construction with gypsum wallboard described in this table, gypsum base for veneer plaster of the same size, thickness and core type shall be

a thickness of not less than 7 ⁵ /8 inches is 4 hours where cores that are not grouted are filled with silicone-treated perlite loose-fill insulation; vermiculite loosefill insulation; or expanded clay, shale or slate lightweight aggregate, sand or slag having a maximum particle size of ³ /8 inch. g. The fire-resistance rating of concrete masonry units composed of a combination of aggregate types or where plaster is applied directly to the concrete

masonry shall be determined in accordance with ACI 216.1/TMS 0216. Lightweight aggregates shall have a maximum combined density of 65 pounds per cubic foot. h. See Note b. The equivalent thickness shall be permitted to include the thickness of cement plaster or 1.5 times the thickness of gypsum plaster applied in

accordance with the requirements of Chapter 25.

(continued)

7-56 2022 CALIFORNIA BUILDING CODE

FIRE AND SMOKE PROTECTION FEATURES

TABLE 721.1(2)—continued RATED FIRE-RESISTANCE PERIODS FOR VARIOUS WALLS AND PARTITIONS ^{a, o, p}

i. Concrete walls shall be reinforced with horizontal and vertical temperature reinforcement as required by Chapter 19. j. Studs are welded truss wire studs with 0.18 inch (No. 7 B.W. gage) flange wire and 0.18 inch (No. 7 B.W. gage) truss wires. k. Nailable metal studs consist of two channel studs spot welded back to back with a crimped web forming a nailing groove. l. Wood structural panels shall be permitted to be installed between the fire protection and the wood studs on either the interior or exterior side of the wood

frame assemblies in this table, provided that the length of the fasteners used to attach the fire protection is increased by an amount not less than the thickness of the wood structural panel. m.For studs with a slenderness ratio, le/d, greater than 33, the design stress shall be reduced to 78 percent of allowable F′c. For studs with a slenderness ratio, le/d,

not exceeding 33, the design stress shall be reduced to 78 percent of the adjusted stress F′c calculated for studs having a slenderness ratio le/d of 33. n. For properties of cooler or wallboard nails, see ASTM C514, ASTM C547 or ASTM F1667. o. Generic fire-resistance ratings (those not designated as PROPRIETARY* in the listing) in the GA 600 shall be accepted as if herein specified. p. NCMA TEK 5-8A shall be permitted for the design of fire walls. q. The design stress of studs shall be equal to not more than 100 percent of the allowable F′c calculated in accordance with Section 2306.

TABLE 721.1(3)¶

MINIMUM PROTECTION FOR FLOOR AND ROOF SYSTEMS ^{a, q}

FLOOR OR ROOF CONSTRUCTION	ITEM NUMBER	CEILING CONSTRUCTION	THICKNESS OF FLOOR OR ROOF SLAB (inches)				MINIMUM THICKNESS OF CEILING (inches)
FLOOR OR ROOF CONSTRUCTION	ITEM NUMBER	CEILING CONSTRUCTION	4 hours	3 hours	2 hours	1 hour	4 hours	3 hours	2 hours	1 hour
1. Siliceous aggregate con- crete	1-1.1	Slab (ceiling not required). Minimum cover over nonpre- stressed reinforcement shall be not less than3/4".b	7.0	6.2	5.0	3.5	—	—	—	—
2. Carbonate aggregate con- crete	2-1.1	2-1.1	6.6	5.7	4.6	3.2	—	—	—	—
3. Sand-light- weight concrete	3-1.1	3-1.1	5.4	4.6	3.8	2.7	—	—	—	—
4. Lightweight concrete	4-1.1	4-1.1	5.1	4.4	3.6	2.5	—	—	—	—
5. Reinforced concrete	5-1.1	Slab with suspended ceiling of vermiculite gypsum plas- ter over metal lath attached to3/4" cold-rolled channels spaced 12" on center. Ceiling located 6" minimum below joists.	3	2	—	—	1	3/4	—	—
5. Reinforced concrete	5-2.1	5/8" Type X gypsum wallboardc attached to 0.018 inch (No.25 carbon sheet steel gage) by7/8" deep by 25/8" hat- shaped galvanized steel channels with 1"-long No. 6 screws. The channels are spaced 24" on center, span 35" and are supported along their length at 35" intervals by 0.033" (No. 21 galvanized sheet gage) galvanized steel flat strap hangers having formed edges that engage the lips of the channel. The strap hangers are attached to the side of the concrete joists with5/32" by 11/4"-long power- driven fasteners. The wallboard is installed with the long dimension perpendicular to the channels. End joints occur on channels and supplementary channels are installed parallel to the main channels, 12" each side, at end joint occurrences. The finished ceiling is located approximately 12" below the soffit of the floor slab.	—	—	21/2	—	—	—	5/8	—

(continued)

FIRE AND SMOKE PROTECTION FEATURES

TABLE 721.1(3)—continued MINIMUM PROTECTION FOR FLOOR AND ROOF SYSTEMS ^{a, q}

FLOOR OR ROOF CONSTRUCTION	ITEM NUMBER	CEILING CONSTRUCTION	THICKNESS OF FLOOR OR ROOF SLAB (inches)				MINIMUM THICKNESS OF CEILING (inches)
FLOOR OR ROOF CONSTRUCTION	ITEM NUMBER	CEILING CONSTRUCTION	4 hours	3 hours	2 hours	1 hour	4 hours	3 hours	2 hours	1 hour
6. Steel joists constructed with a poured rein- forced concrete slab on metal lath forms or steel form units.d, e	6-1.1	Gypsum plaster on metal lath attached to the bottom cord with single No. 16 gage or doubled No. 18 gage wire ties spaced 6" on center. Plaster mixed 1:2 for scratch coat, 1:3 for brown coat, by weight, gypsum-to-sand aggregate for 2-hour system. For 3-hour system plaster is neat.	—	—	21/2	21/4	—	—	3/4	5/8
6. Steel joists constructed with a poured rein- forced concrete slab on metal lath forms or steel form units.d, e	6-2.1	Vermiculite gypsum plaster on metal lath attached to the bottom chord with single No. 16 gage or doubled 0.049- inch (No. 18 B.W. gage) wire ties 6" on center.	—	2	—	—	—	5/8	—	—
6. Steel joists constructed with a poured rein- forced concrete slab on metal lath forms or steel form units.d, e	6-3.1	Cement plaster over metal lath attached to the bottom chord of joists with single No. 16 gage or doubled 0.049" (No. 18 B.W. gage) wire ties spaced 6" on center. Plaster mixed 1:2 for scratch coat, 1:3 for brown coat for 1-hour system and 1:1 for scratch coat, 1:11/2 for brown coat for 2-hour system, by weight, cement to sand.	—	—	—	2	—	—	—	5/8 f
6. Steel joists constructed with a poured rein- forced concrete slab on metal lath forms or steel form units.d, e	6-4.1	Ceiling of5/8" Type X wallboardc attached to7/8" deep by 25/8" by 0.021 inch (No. 25 carbon sheet steel gage) hat- shaped furring channels 12" on center with 1"-long No. 6 wallboard screws at 8" on center. Channels wire tied to bottom chord of joists with doubled 0.049 inch (No. 18 B.W. gage) wire or suspended below joists on wire hang- ers.g	—	—	21/2	—	—	—	5/8	—
6. Steel joists constructed with a poured rein- forced concrete slab on metal lath forms or steel form units.d, e	6-5.1	Wood-fibered gypsum plaster mixed 1:1 by weight gyp- sum to sand aggregate applied over metal lath. Lath tied 6" on center to3/4" channels spaced 131/2" on center. Channels secured to joists at each intersection with two strands of 0.049 inch (No. 18 B.W. gage) galvanized wire.	—	—	21/2	—	—	—	3/4	—
7. Reinforced concrete slabs and joists with hollow clay tile fillers laid end to end in rows 21/2" or more apart; reinforcement placed between rows and con- crete cast around and over tile.	7-1.1	5/8" gypsum plaster on bottom of floor or roof construc- tion.	—	—	8h	—	—	—	5/8	—
7. Reinforced concrete slabs and joists with hollow clay tile fillers laid end to end in rows 21/2" or more apart; reinforcement placed between rows and con- crete cast around and over tile.	7-1.2	None	—	—	—	51/2 i	—	—	—	—
8. Steel joists constructed with a reinforced con- crete slab on top poured on a1/2"- deep steel deck.e	8-1.1	Vermiculite gypsum plaster on metal lath attached to3/4" cold-rolled channels with 0.049" (No. 18 B.W. gage) wire ties spaced 6" on center.	21/2 j	—	—	—	3/4	—	—	—

(continued)

7-58 2022 CALIFORNIA BUILDING CODE

FIRE AND SMOKE PROTECTION FEATURES

TABLE 721.1(3)—continued MINIMUM PROTECTION FOR FLOOR AND ROOF SYSTEMS ^{a, q}

FLOOR OR ROOF CONSTRUCTION	ITEM NUMBER	CEILING CONSTRUCTION	THICKNESS OF FLOOR OR ROOF SLAB (inches)				MINIMUM THICKNESS OF CEILING (inches)
FLOOR OR ROOF CONSTRUCTION	ITEM NUMBER	CEILING CONSTRUCTION	4 hours	3 hours	2 hours	1 hour	4 hours	3 hours	2 hours	1 hour
9. 3"-deep cellu- lar steel deck with concrete slab on top. Slab thickness mea- sured to top.	9-1.1	Suspended ceiling of vermiculite gypsum plaster base coat and vermiculite acoustical plaster on metal lath attached at 6" intervals to3/4" cold-rolled channels spaced 12" on center and secured to 11/2" cold-rolled channels spaced 36" on center with 0.065" (No. 16 B.W. gage) wire. 11/2" channels supported by No. 8 gage wire hangers at 36" on center. Beams within envelope and with a 21/2" airspace between beam soffit and lath have a 4-hour rating.	21/2	—	—	—	11/8 k	—	—	—
10. 11/2"-deep steel roof deck on steel framing. Insulation board, 30 pcf density, composed of wood fibers with cement binders of thickness shown bonded to deck with uni- fied asphalt adhesive. Cov- ered with a Class A or B roof cov- ering.	10-1.1	Ceiling of gypsum plaster on metal lath. Lath attached to 3/4" furring channels with 0.049" (No. 18 B.W. gage) wire ties spaced 6" on center.3/4" channel saddle tied to 2" channels with doubled 0.065" (No. 16 B.W. gage) wire ties. 2"channels spaced 36" on center suspended 2" below steel framing and saddle tied with 0.165" (No. 8 B.W. gage) wire. Plaster mixed 1:2 by weight, gypsum- to-sand aggregate.	—	—	17/8	1	—	—	3/4 1	3/4 1
11. 11/2"-deep steel roof deck on steel-framing wood fiber insu- lation board, 17.5 pcf density on top applied over a 15-lb asphalt- saturated felt. Class A or B roof covering.	11-1.1	Ceiling of gypsum plaster on metal lath. Lath attached to 3/4" furring channels with 0.049" (No. 18 B.W. gage) wire ties spaced 6" on center.3/4" channels saddle tied to 2" channels with doubled 0.065" (No. 16 B.W. gage) wire ties. 2" channels spaced 36" on center suspended 2" below steel framing and saddle tied with 0.165" (No. 8 B.W. gage) wire. Plaster mixed 1:2 for scratch coat and 1:3 for brown coat, by weight, gypsum-to-sand aggregate for 1-hour system. For 2-hour system, plaster mix is 1:2 by weight, gypsum-to-sand aggregate.	—	—	11/2	1	—	—	7/8 g	3/4 1

(continued)

FIRE AND SMOKE PROTECTION FEATURES

TABLE 721.1(3)—continued MINIMUM PROTECTION FOR FLOOR AND ROOF SYSTEMS ^{a, q}

FLOOR OR ROOF CONSTRUCTION	ITEM NUMBER	CEILING CONSTRUCTION	THICKNESS OF FLOOR OR ROOF SLAB (inches)				MINIMUM THICKNESS OF CEILING (inches)
FLOOR OR ROOF CONSTRUCTION	ITEM NUMBER	CEILING CONSTRUCTION	4 hours	3 hours	2 hours	1 hour	4 hours	3 hours	2 hours	1 hour
12. 11/2" deep steel roof deck on steel-framing insulation of rigid board con- sisting of expanded perlite and fibers impregnated with integral asphalt waterproofing; density 9 to 12 pcf secured to metal roof deck by1/2"-wide rib- bons of water- proof, cold- process liquid adhesive spaced 6" apart. Steel joist or light steel construction with metal roof deck, insulation, and Class A or B built-up roof covering.e	12-1.1	Gypsum-vermiculite plaster on metal lath wire tied at 6" intervals to3/4" furring channels spaced 12" on center and wire tied to 2" runner channels spaced 32" on center. Runners wire tied to bottom chord of steel joists.	—	—	1	—	—	—	7/8	—
13. Double wood floor over wood joists spaced 16" on center.m, n	13-1.1	Gypsum plaster over3/8" Type X gypsum lath. Lath ini- tially applied with not less than four 11/8" by No. 13 gage by19/64" head plasterboard blued nails per bearing. Con- tinuous stripping over lath along all joist lines. Stripping consists of 3"-wide strips of metal lath attached by 11/2" by No. 11 gage by1/2" head roofing nails spaced 6" on center. Alternate stripping consists of 3"-wide 0.049" diameter wire stripping weighing 1 pound per square yard and attached by No. 16 gage by 11/2" by3/4" crown width staples, spaced 4" on center. Where alternate strip- ping is used, the lath nailing shall consist of two nails at each end and one nail at each intermediate bearing. Plas- ter mixed 1:2 by weight, gypsum-to-sand aggregate.	—	—	—	—	—	—	—	7/8
13. Double wood floor over wood joists spaced 16" on center.m, n	13-1.2	Cement or gypsum plaster on metal lath. Lath fastened with 11/2" by No. 11 gage by7/16" head barbed shank roofing nails spaced 5" on center. Plaster mixed 1:2 for scratch coat and 1:3 for brown coat, by weight, cement to sand aggregate.	—	—	—	—	—	—	—	5/8
13. Double wood floor over wood joists spaced 16" on center.m, n	13-1.3	Perlite or vermiculite gypsum plaster on metal lath secured to joists with 11/2" by No. 11 gage by7/16" head barbed shank roofing nails spaced 5" on center.	—	—	—	—	—	—	—	5/8
13. Double wood floor over wood joists spaced 16" on center.m, n	13-1.4	1/2" Type X gypsum wallboardc nailed to joists with 5d coolero or wallboardo nails at 6" on center. End joints of wallboard centered on joists.	—	—	—	—	—	—	—	1/2

(continued)

7-60 2022 CALIFORNIA BUILDING CODE

FIRE AND SMOKE PROTECTION FEATURES

TABLE 721.1(3)—continued MINIMUM PROTECTION FOR FLOOR AND ROOF SYSTEMS ^{a, q}

FLOOR OR ROOF CONSTRUCTION	ITEM NUMBER	CEILING CONSTRUCTION	THICKNESS OF FLOOR OR ROOF SLAB (inches)				MINIMUM THICKNESS OF CEILING (inches)
FLOOR OR ROOF CONSTRUCTION	ITEM NUMBER	CEILING CONSTRUCTION	4 hours	3 hours	2 hours	1 hour	4 hours	3 hours	2 hours	1 hour
14. Plywood stressed skin panels consist- ing of5/8"-thick interior C-D (exterior glue) top stressed skin on 2" × 6" nomi- nal (minimum) stringers. Adja- cent panel edges joined with 8d common wire nails spaced 6" on center. String- ers spaced 12" maximum on center.	14-1.1	1/2"-thick wood fiberboard weighing 15 to 18 pounds per cubic foot installed with long dimension parallel to stringers or3/8" C-D (exterior glue) plywood glued and/or nailed to stringers. Nailing to be with 5d coolero or wallboardo nails at 12" on center. Second layer of1/2" Type X gypsum wallboardc applied with long dimension perpendicular to joists and attached with 8d coolero or wallboardo nails at 6" on center at end joints and 8" on center elsewhere. Wallboard joints staggered with respect to_fiberboard_ joints.	—	—	—	—	—	—	—	1
15. Vermiculite concrete slab proportioned 1:4 (Portland cement to vermiculite aggregate) on a 11/2"-deep steel deck supported on individually protected steel framing. Maxi- mum span of deck 6′-10" where deck is less than 0.019 inch (No. 26 car- bon steel sheet gage) or greater. Slab reinforced with 4" × 8" 0.109/0.083" (No.12/14 B.W. gage) welded wire mesh.	15-1.1	None	—	—	—	3j	—	—	—	—

(continued)

FIRE AND SMOKE PROTECTION FEATURES

TABLE 721.1(3)—continued MINIMUM PROTECTION FOR FLOOR AND ROOF SYSTEMS ^{a, q}

FLOOR OR ROOF CONSTRUCTION	ITEM NUMBER	CEILING CONSTRUCTION	THICKNESS OF FLOOR OR ROOF SLAB (inches)				MINIMUM THICKNESS OF CEILING (inches)
FLOOR OR ROOF CONSTRUCTION	ITEM NUMBER	CEILING CONSTRUCTION	4 hours	3 hours	2 hours	1 hour	4 hours	3 hours	2 hours	1 hour
16. Perlite con- crete slab propor- tioned 1:6 (Portland cement to perlite aggre- gate) on a 11/4"- deep steel deck supported on individually pro- tected steel fram- ing. Slab reinforced with 4" × 8" 0.109/0.083" (No.12/14 B.W. gage) welded wire mesh.	16-1.1	None	—	—	—	31/2 j	—	—	—	—
17. Perlite con- crete slab propor- tioned 1:6 (Portland cement to perlite aggre- gate) on a9/16"- deep steel deck supported by steel joists 4′ on center. Class A or B roof cover- ing on top.	17-1.1	Perlite gypsum plaster on metal lath wire tied to3/4" fur- ring channels attached with 0.065" (No. 16 B.W. gage) wire ties to lower chord of joists.	—	2p	2p	—	—	7/8	3/4	—

(continued)

7-62 2022 CALIFORNIA BUILDING CODE

FIRE AND SMOKE PROTECTION FEATURES

TABLE 721.1(3)—continued MINIMUM PROTECTION FOR FLOOR AND ROOF SYSTEMS ^{a, q}

FLOOR OR ROOF CONSTRUCTION	ITEM NUMBER	CEILING CONSTRUCTION	THICKNESS OF FLOOR OR ROOF SLAB (inches)				MINIMUM THICKNESS OF CEILING (inches)
FLOOR OR ROOF CONSTRUCTION	ITEM NUMBER	CEILING CONSTRUCTION	4 hours	3 hours	2 hours	1 hour	4 hours	3 hours	2 hours	1 hour
18. Perlite concrete slab proportioned 1:6 (Port- land cement to perlite aggregate) on 11/4"- deep steel deck sup- ported on individually protected steel framing. Maximum span of deck 6′-10" where deck is less than 0.019" (No. 26 carbon sheet steel gage) and 8′-0" where deck is 0.019" (No. 26 carbon sheet steel gage) or greater. Slab reinforced with 0.042" (No. 19 B.W. gage) hexagonal wire mesh. Class A or B roof covering on top.	18-1.1	None	—	21/4 p	21/4 p	—	—	—	—	—
19. Floor and beam construction consisting of 3"-deep cellular steel floor unit mounted on steel members with 1:4 (proportion of Portland cement to perlite aggre- gate) perlite-concrete floor slab on top.	19-1.1	Suspended envelope ceiling of perlite gypsum plaster on metal lath attached to3/4" cold-rolled channels, secured to 11/2" cold-rolled channels spaced 42" on center supported by 0.203 inch (No. 6 B.W. gage) wire 36" on center. Beams in envelope with 3" minimum airspace between beam soffit and lath have a 4-hour rating.	2p	—	—	—	1l	—	—	—

(continued)

FIRE AND SMOKE PROTECTION FEATURES

TABLE 721.1(3)—continued MINIMUM PROTECTION FOR FLOOR AND ROOF SYSTEMS ^{a, q}

FLOOR OR ROOF CONSTRUCTION	ITEM NUMBER	CEILING CONSTRUCTION	THICKNESS OF FLOOR OR ROOF SLAB (inches)				MINIMUM THICKNESS OF CEILING (inches)
FLOOR OR ROOF CONSTRUCTION	ITEM NUMBER	CEILING CONSTRUCTION	4 hours	3 hours	2 hours	1 hour	4 hours	3 hours	2 hours	1 hour
20. Perlite concrete pro- portioned 1:6 (Portland cement to perlite aggre- gate) poured to1/8" thickness above top of corrugations of 15/16"- deep galvanized steel deck maximum span 8′- 0" for 0.024" (No. 24 galvanized sheet gage) or 6′-0" for 0.019" (No. 26 galvanized sheet gage) with deck sup- ported by individually protected steel framing. Approved polystyrene foam plastic insulation board having a flame spread not exceeding 75 (1" to 4" thickness) with vent holes that approxi- mate 3 percent of the board surface area placed on top of perlite slurry. A 2′ by 4′ insula- tion board contains six 23/4" diameter holes. Board covered with 21/4" minimum perlite con- crete slab. Slab rein- forced with mesh consisting of 0.042" (No.19 B.W. gage) gal- vanized steel wire twisted together to form 2" hexagons with straight 0.065" (No. 16 B.W. gage) galvanized steel wire woven into mesh and spaced 3". Alternate slab reinforce- ment shall be permitted to consist of 4" × 8", 0.109/0.238" (No. 12/4 B.W. gage), or 2" × 2", 0.083/0.083" (No. 14/14 B.W. gage) welded wire fabric. Class A or B roof covering on top.	20-1.1	None	—	—	Varies	—	—	—	—	—

(continued)

7-64 2022 CALIFORNIA BUILDING CODE

FIRE AND SMOKE PROTECTION FEATURES

TABLE 721.1(3)—continued

		MINIMUM PROTECTION FOR FLOOR AND	ROOF SYSTEMSa, q
FLOOR OR ROOF CONSTRUCTION	ITEM NUMBER	CEILING CONSTRUCTION	THICKNESS OF FLOOR OR ROOF SLAB (inches)	THICKNESS OF FLOOR OR ROOF SLAB (inches)	THICKNESS OF FLOOR OR ROOF SLAB (inches)	THICKNESS OF FLOOR OR ROOF SLAB (inches)	MINIMUM THICKNESS OF CEILING (inches)	MINIMUM THICKNESS OF CEILING (inches)	MINIMUM THICKNESS OF CEILING (inches)	MINIMUM THICKNESS OF CEILING (inches)
FLOOR OR ROOF CONSTRUCTION	ITEM NUMBER	CEILING CONSTRUCTION	4 hours	3 hours	2 hours	1 hour	4 hours	3 hours	2 hours	1 hour
21. Wood joists, wood I-joists, floor trusses and flat or pitched roof trusses spaced a maxi- mum 24" o.c. with1/2" wood structural panels with exterior glue applied at right angles to top of joist or top chord of trusses with 8 dnails. The wood struc- tural panel thickness shall be not less than nominal1/2" nor less than required by Chap- ter 23.	21-1.1	Base layer5/8" Type X gypsum wallboard applied at right angles to joist or truss 24" o.c. with 11/4" Type S or Type W drywall screws 24" o.c. Face layer5/8" Type X gypsum wall- board or veneer base applied at right angles to joist or truss through base layer with 17/8" Type S or Type W drywall screws 12" o.c. at joints and intermediate joist or truss. Face layer Type G drywall screws placed 2" back on either side of face layer end joints, 12" o.c.	—	—	—	Varies	—	—	—	11/4
22. Steel joists, floor trusses and flat or pitched roof trusses spaced a maximum 24" o.c. with1/2" wood structural panels with exterior glue applied at right angles to top of joist or top chord of trusses with No. 8 screws. The wood structural panel thick- ness shall be not less than nominal1/2" nor less than required by Chapter 23.	22-1.1	Base layer5/8" Type X gypsum board applied at right angles to steel framing 24" on center with 1" Type S dry wall screws spaced 24" on center. Face layer5/8" Type X gypsum board applied at right angles to steel framing attached through base layer with 15/8" Type S dry wall screws 12" on center at end joints and interme- diate joints and 11/2" Type G dry wall screws 12 inches on center placed 2" back on either side of face layer end joints. Joints of the face layer are offset 24" from the joints of the base layer.	—	—	—	Varies	—	—	—	11/4
23. Wood I-joist (mini- mum joist depth 91/4" with a minimum flange depth of 15/16" and a minimum flange cross- sectional area of 2.25 square inches) at 24" o.c. spacing with a min- imum 1 × 4 (3/4" × 3.5"actual) ledger strip applied parallel to and covering the bottom of the bottom flange of each member, tacked in place. 2" mineral wool insulation, 3.5 pcf (nominal) installed adjacent to the bottom flange of the I-joist and supported by the 1 × 4 ledger strip.	23-1.1	1/2"-deep single-leg resilient channel 16" on center (channels doubled at wallboard end joints), placed perpendicular to the furring strip and joist and attached to each joist by 17/8" Type S drywall screws.5/8" Type C gypsum wallboard applied perpendicular to the channel with end joints staggered not less than 4′ and fastened with 11/8" Type S drywall screws spaced 7" on center. Wallboard joints to be taped and covered with joint compound.	—	—	—	Varies	—	—	—	5/8

(continued)

FIRE AND SMOKE PROTECTION FEATURES

TABLE 721.1(3)—continued MINIMUM PROTECTION FOR FLOOR AND ROOF SYSTEMS ^{a, q}

FLOOR OR ROOF CONSTRUCTION	ITEM NUMBER	CEILING CONSTRUCTION	THICKNESS OF FLOOR OR ROOF SLAB (inches)				MINIMUM THICKNESS OF CEILING (inches)
FLOOR OR ROOF CONSTRUCTION	ITEM NUMBER	CEILING CONSTRUCTION	4 hours	3 hours	2 hours	1 hour	4 hours	3 hours	2 hours	1 hour
24. Wood I-joist (mini- mum I-joist depth 91/4" with a minimum flange depth of 11/2" and a minimum flange cross- sectional area of 5.25 square inches; mini- mum web thickness of 3/8") @ 24" o.c., 11/2" mineral wool insula- tion (2.5 pcf-nominal) resting on hat-shaped furring channels.	24-1.1	Minimum 0.026" thick hat-shaped channel 16" o.c. (channels doubled at wallboard end joints), placed perpendicular to the joist and attached to each joist by 11/4" Type S drywall screws.5/8" Type C gypsum wallboard applied perpendicu- lar to the channel with end joints staggered and fastened with 11/8" Type S drywall screws spaced 12" o.c. in the field and 8" o.c. at the wallboard ends. Wallboard joints to be taped and covered with joint compound.	—	—	—	Varies	—	—	—	5/8
25. Wood I-joist (mini- mum I-joist depth 91/4" with a minimum flange depth of 11/2" and a minimum flange cross- sectional area of 5.25 square inches; mini- mum web thickness of 7/16") @ 24" o.c., 11/2" mineral wool insula- tion (2.5 pcf-nominal) resting on resilient channels.	25-1.1	Minimum 0.019"-thick resilient channel 16" o.c. (channels doubled at wallboard end joints), placed perpendicular to the joist and attached to each joist by 15/8" Type S drywall screws.5/8" Type C gypsum wallboard applied perpendicu- lar to the channel with end joints staggered and fastened with 1" Type S drywall screws spaced 12" o.c. in the field and 8" o.c. at the wallboard ends. Wallboard joints to be taped and covered with joint compound.	—	—	—	Varies	—	—	—	5/8
26. Wood I-joist (mini- mum I-joist depth 91/4" with a minimum flange thickness of 11/2" and a minimum flange cross- sectional area of 2.25 square inches; mini- mum web thick-ness of 3/8") @ 24" o.c.	26-1.1	Two layers of1/2" Type X gypsum wallboard applied with the long dimension perpendicular to the I-joists with end joints staggered. The base layer is fastened with 15/8" Type S dry wall screws spaced 12" o.c. and the face layer is fastened with 2" Type S drywall screws spaced 12" o.c. in the field and 8" o.c. on the edges. Face layer end joints shall not occur on the same I-joist as base layer end joints and edge joints shall be offset 24"from base layer joints. Face layer to also be attached to base layer with 11/2" Type G drywall screws spaced 8" o.c. placed 6" from face layer end joints. Face layer wallboard joints to be taped and covered with joint compound.	—	—	—	Varies	—	—	—	1

(continued)

7-66 2022 CALIFORNIA BUILDING CODE

FIRE AND SMOKE PROTECTION FEATURES

TABLE 721.1(3)—continued

		MINIMUM PROTECTION FOR FLOOR AND	ROOF SYSTEMSa, q
FLOOR OR ROOF CONSTRUCTION	ITEM NUMBER	CEILING CONSTRUCTION	THICKNESS OF FLOOR OR ROOF SLAB (inches)	THICKNESS OF FLOOR OR ROOF SLAB (inches)	THICKNESS OF FLOOR OR ROOF SLAB (inches)	THICKNESS OF FLOOR OR ROOF SLAB (inches)	MINIMUM THICKNESS OF CEILING (inches)	MINIMUM THICKNESS OF CEILING (inches)	MINIMUM THICKNESS OF CEILING (inches)	MINIMUM THICKNESS OF CEILING (inches)
FLOOR OR ROOF CONSTRUCTION	ITEM NUMBER	CEILING CONSTRUCTION	4 hours	3 hours	2 hours	1 hour	4 hours	3 hours	2 hours	1 hour
27. Wood I-joist (min- imum I-joist depth 91/2" with a minimum flange depth of 15/16" and a minimum flange cross-sectional area of 1.95 square inches; minimum web thick- ness of3/8") @ 24" o.c.	27-1.1	Minimum 0.019" thick resilient channel 16" o.c. (channels doubled at wallboard end joints), placed perpendicular to the joist and attached to each joist by 11/4" Type S drywall screws. Two layers of1/2" Type X gypsum wallboard applied with the long dimension perpendicular to the resilient channels with end joints staggered. The base layer is fastened with 11/4" Type S drywall screws spaced 12" o.c. and the face layer is fas- tened with 15/8" Type S drywall screws spaced 12" o.c. Face layer end joints shall not occur on the same I-joist as base layer end joints and edge joints shall be offset 24" from base layer joints. Face layer to also be attached to base layer with 11/2" Type G drywall screws spaced 8" o.c. placed 6" from face layer end joints. Face layer wallboard joints to be taped and cov- ered with joint compound.	—	—	—	Varies	—	—	—	1
28. Wood I-joist (min- imum I-joist depth 91/4" with a minimum flange depth of 11/2" and a minimum flange cross-sectional area of 2.25 square inches; minimum web thick- ness of3/8") @ 24" o.c. Unfaced fiberglass insulation or mineral wool insulation is installed between the I-joists supported on the upper surface of the flange by stay wires spaced 12" o.c.	28-1.1	Base layer of5/8" Type C gypsum wallboard attached directly to I-joists with 15/8" Type S drywall screws spaced 12" o.c. with ends stag- gered. Minimum 0.0179"-thick hat-shaped7/8- inch furring channel 16" o.c. (channels doubled at wallboard end joints), placed perpendicular to the joist and attached to each joist by 15/8" Type S drywall screws after the base layer of gypsum wallboard has been applied. The middle and face layers of5/8" Type C gypsum wallboard applied perpendicular to the channel with end joints staggered. The middle layer is fastened with 1" Type S drywall screws spaced 12" o.c. The face layer is applied parallel to the middle layer but with the edge joints offset 24" from those of the middle layer and fastened with 15/8" Type S drywall screws 8" o.c. The joints shall be taped and covered with joint compound.	—	—	—	Varies	—	—	23/4	—
29. Channel-shaped 18 gage steel joists (minimum depth 8") spaced a maximum 24" o.c. supporting tongue-and-groove wood structural pan- els (nominal minimum 3/4"-thick) applied per- pendicular to framing members. Structural panels attached with 15/8" Type S-12 screws spaced 12" o.c.	29-1.1	Base layer5/8" Type X gypsum board applied perpendicular to bottom of framing members with 11/8" Type S-12 screws spaced 12" o.c. Second layer5/8" Type X gypsum board attached perpendicular to framing members with 15/8" Type S-12 screws spaced 12" o.c. Second layer joints offset 24" from base layer. Third layer5/8" Type X gypsum board attached perpendicular to framing members with 23/8" Type S-12 screws spaced 12" o.c. Third layer joints offset 12" from second layer joints. Hat- shaped7/8-inch rigid furring channels applied at right angles to framing members over third layer with two 23/8" TypeS-12 screws at each framing member. Face layer5/8" Type X gyp- sum board applied at right angles to furring channels with 11/8" Type S screws spaced 12" o.c.	—	—	Varies	—	—	—	33/8	—

(continued)

FIRE AND SMOKE PROTECTION FEATURES

TABLE 721.1(3)—continued MINIMUM PROTECTION FOR FLOOR AND ROOF SYSTEMS ^{a, q}

FLOOR OR ROOF CONSTRUCTION	ITEM NUMBER	CEILING CONSTRUCTION	THICKNESS OF FLOOR OR ROOF SLAB (inches)				MINIMUM THICKNESS OF CEILING (inches)
FLOOR OR ROOF CONSTRUCTION	ITEM NUMBER	CEILING CONSTRUCTION	4 hours	3 hours	2 hours	1 hour	4 hours	3 hours	2 hours	1 hour
30. Wood I-joist (mini- mum I-joist depth 91/2" with a minimum flange depth of 11/2" and a minimum flange cross- sectional area of 2.25 square inches; mini- mum web thickness of 3/8") @ 24" o.c. Fiber- glass insulation placed between I-joists sup- ported by the resilient channels.	30-1.1	Minimum 0.019"-thick resilient channel 16" o.c. (channels doubled at wallboard end joints), placed perpendicular to the joists and attached to each joist by 11/4" Type S dry wall screws. Two layers of1/2" Type X gypsum wallboard applied with the long dimension perpendicular to the resilient channels with end joints stag- gered. The base layer is fastened with 11/4" Type S drywall screws spaced 12" o.c. and the face layer is fastened with 15/8" Type S drywall screws spaced 12" o.c. Face layer end joints shall not occur on the same I-joist as base layer end joints and edge joints shall be offset 24" from base layer joints. Face layer to be attached to base layer with 11/2" Type G drywall screws spaced 8" o.c. placed 6" from face layer end joints. Face layer wallboard joints to be taped and covered with joint compound.	—	—	—	Varies	—	—	—	1

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound = 0.454 kg, 1 cubic foot = 0.0283 m ³, 1 pound per square inch = 6.895 kPa, 1 pound per linear foot = 1.4882 kg/m. a. Staples with equivalent holding power and penetration shall be permitted to be used as alternate fasteners to nails for attachment to wood framing. b. Where the slab is in an unrestrained condition, minimum reinforcement cover shall be not less than 1 ⁵ /8 inches for 4 hours (siliceous aggregate only); 1 ¹ /4

inches for 4 and 3 hours; 1 inch for 2 hours (siliceous aggregate only); and ³ /4 inch for all other restrained and unrestrained conditions. c. For all of the construction with gypsum wallboard described in this table, gypsum base for veneer plaster of the same size, thickness and core type shall be

permitted to be substituted for gypsum wallboard, provided that attachment is identical to that specified for the wallboard, and the joints on the face layer are reinforced and the entire surface is covered with not less than ¹ /16-inch gypsum veneer plaster. d. Slab thickness over steel joists measured at the joists for metal lath form and at the top of the form for steel form units. e. (a) The maximum allowable stress level for H-Series joists shall not exceed 22,000 psi. (b) The allowable stress for K-Series joists shall not exceed 26,000 psi, the nominal depth of such joist shall be not less than 10 inches and the nominal

joist weight shall be not less than 5 pounds per linear foot. f. Cement plaster with 15 pounds of hydrated lime and 3 pounds of approved additives or admixtures per bag of cement. g. Gypsum wallboard ceilings attached to steel framing shall be permitted to be suspended with 1 ¹ /2-inch cold-formed carrying channels spaced 48 inches on

center, that are suspended with No. 8 SWG galvanized wire hangers spaced 48 inches on center. Cross-furring channels are tied to the carrying channels with No. 18 SWG galvanized wire hangers spaced 48 inches on center. Cross-furring channels are tied to the carrying channels with No. 18 SWG galvanized wire (double strand) and spaced as required for direct attachment to the framing. This alternative is applicable to those steel framing assemblies recognized under Note q. h. Six-inch hollow clay tile with 2-inch concrete slab above. i. Four-inch hollow clay tile with 1 ¹ /2-inch concrete slab above. j. Thickness measured to bottom of steel form units. k. Five-eighths inch of vermiculite gypsum plaster plus ¹ /2 inch of approved vermiculite acoustical plastic. l. Furring channels spaced 12 inches on center. m.Double wood floor shall be permitted to be either of the following:

(a)Subfloor of 1-inch nominal boarding, a layer of asbestos paper weighing not less than 14 pounds per 100 square feet and a layer of 1-inch nominal

tongue-and-groove finished flooring. (b)Subfloor of 1-inch nominal tongue-and-groove boarding or ¹⁵ /32-inch wood structural panels with exterior glue and a layer of 1-inch nominal tongue and-groove finished flooring or ¹⁹ /32-inch wood structural panel finish flooring or a layer of Type I Grade M-1 particleboard not less than ⁵ /8-inch thick. n. The ceiling shall be permitted to be omitted over unusable space, and flooring shall be permitted to be omitted where unusable space occurs above. o. For properties of cooler or wallboard nails, see ASTM C514, ASTM C547 or ASTM F1667. p. Thickness measured on top of steel deck unit. q. Generic fire-resistance ratings (those not designated as PROPRIETARY* in the listing) in the GA 600 shall be accepted as if herein specified.

7-68 2022 CALIFORNIA BUILDING CODE

TABLE 722.2.1.1¶

MINIMUM EQUIVALENT THICKNESS OF CAST-IN-PLACE OR PRECAST CONCRETE WALLS,

LOAD-BEARING OR NONLOAD-BEARING

CONCRETE TYPE	MINIMUM SLAB THICKNESS (inches) FOR FIRE-RESISTANCE RATING OF
CONCRETE TYPE	1 hour	11/2 hours	2 hours	3 hours	4 hours
Siliceous	3.5	4.3	5.0	6.2	7.0
Carbonate	3.2	4.0	4.6	5.7	6.6
Sand-lightweight	2.7	3.3	3.8	4.6	5.4
Lightweight	2.5	3.1	3.6	4.4	5.1

For SI: 1 inch = 25.4 mm.

722.2.1.1.1 Hollow-core precast wall panels.¶

For hollow-core precast concrete wall panels in which the cores are of constant cross section throughout the length, calculation of the equivalent thickness by dividing the net cross-sectional area (the gross cross section minus the area of the cores) of the panel by its width shall be permitted

722.2.1.1.2 Core spaces filled. Where all of the core spaces of hollow-core wall panels are filled with loosefill material, such as expanded shale, clay or slag, or vermiculite or perlite, the fire-resistance rating of the wall is the same as that of a solid wall of the same concrete type and of the same overall thickness.

722.2.1.1.3 Tapered cross sections.¶

The thickness of panels with tapered cross sections shall be that determined at a distance 2 t or 6 inches (152 mm), whichever is less, from the point of minimum thickness, where t is the minimum thickness.

722.2.1.1.4 Ribbed or undulating surfaces. The equivalent thickness of panels with ribbed or undu

INSIDE WYTHE

CARBONATE

FIRE AND SMOKE PROTECTION FEATURES

lating surfaces shall be determined by one of the following expressions:

For s ≥ 4 t, the thickness to be used shall be t

For s ≤ 2 t, the thickness to be used shall be te For 4 t - s - 2 t, the thickness to be used shall be

4 t t + - 1 ( te - t ) ^--- s ^-

where:

(Equation 7-3)

s = Spacing of ribs or undulations. t = Minimum thickness. te = Equivalent thickness of the panel calculated as

the net cross-sectional area of the panel divided by the width, in which the maximum thickness used in the calculation shall not exceed 2 t .

722.2.1.2 Multiwythe walls.¶

For walls that consist of two wythes of different types of concrete, the fire-resistance ratings shall be permitted to be determined from Figure 722.2.1.2.

722.2.1.2.1 Two or more wythes. The fire-resistance rating for wall panels consisting of two or more wythes shall be permitted to be determined by the formula:

R = ( R 10.59 + R 20.59 +...+ Rn 0.59)1.7 (Equation 7-4)

where:

R = The fire endurance of the assembly, minutes. R1, R2, and Rn = The fire endurances of the individual wythes, minutes. Values of Rn0.59

0.59

for use in Equation 7-4 are given in Table 722.2.1.2(1). Calculated fire-resistance ratings are shown in Table 722.2.1.2(2).

INSIDE WYTHE

SILICEOUS

1 2 3 4 5

THICKNESS OF INSIDE WYTHE, INCHES

OUTSIDE WYTHE

CARBONATE

OUTSIDE WYTHE

SILICEOUS

1 2 3 4 5

For SI: 1 inch = 25.4 mm.

THICKNESS OF INSIDE WYTHE OF SAND-LIGHTWEIGHT CONCRETE, INCHES

FIGURE 722.2.1.2 FIRE-RESISTANCE RATINGS OF TWO-WYTHE CONCRETE WALLS

FIRE AND SMOKE PROTECTION FEATURES

	TABLE 722.2.1.2(1) VALUES OF Rn 0.59 FOR USE IN EQUATION 7-4
TYPE OF MATERIAL	THICKNESS OF MATERIAL (inches)	THICKNESS OF MATERIAL (inches)	THICKNESS OF MATERIAL (inches)	THICKNESS OF MATERIAL (inches)	THICKNESS OF MATERIAL (inches)	THICKNESS OF MATERIAL (inches)	THICKNESS OF MATERIAL (inches)	THICKNESS OF MATERIAL (inches)	THICKNESS OF MATERIAL (inches)	THICKNESS OF MATERIAL (inches)	THICKNESS OF MATERIAL (inches)	THICKNESS OF MATERIAL (inches)
TYPE OF MATERIAL	11/2	2	21/2	3	31/2	4	41/2	5	51/2	6	61/2	7
Siliceous aggregate concrete	5.3	6.5	8.1	9.5	11.3	13.0	14.9	16.9	18.8	20.7	22.8	25.1
Carbonate aggregate concrete	5.5	7.1	8.9	10.4	12.0	14.0	16.2	18.1	20.3	21.9	24.7	27.2c
Sand-lightweight concrete	6.5	8.2	10.5	12.8	15.5	18.1	20.7	23.3	26.0c	Note c	Note c	Note c
Lightweight concrete	6.6	8.8	11.2	13.7	16.5	19.1	21.9	24.7	27.8c	Note c	Note c	Note c
Insulating concretea	9.3	13.3	16.6	18.3	23.1	26.5c	Note c	Note c	Note c	Note c	Note c	Note c
Airspaceb	—	—	—	—	—	—	—	—	—	—	—	—

For SI: 1 inch = 25.4 mm, 1 pound per cubic foot = 16.02 kg/m ³ . a. Dry unit weight of 35 pcf or less and consisting of cellular, perlite or vermiculite concrete. b. The Rn 0.59 value for one 1/2″ to 31/2″ airspace is 3.3. The Rn 0.59 value for two 1/2″ to 31/2″ airspaces is 6.7.

c. The fire-resistance rating for this thickness exceeds 4 hours.

TABLE 722.2.1.2(2)¶

FIRE-RESISTANCE RATINGS BASED ON R ^0.59

a. Based on Equation 7-4.

Ra, MINUTES 60 120 180	R0.59 11.20 16.85 21.41
240	25.37

722.2.1.2.2 Foam plastic insulation. The fire-resistance ratings of precast concrete wall panels consisting of a layer of foam plastic insulation sandwiched between two wythes of concrete shall be permitted to be determined by use of Equation 7-4. Foam plastic insulation with a total thickness of less than 1 inch (25 mm) shall be disregarded. The Rn value for thickness of foam plastic insulation of 1 inch (25 mm) or greater, for use in the calculation, is 5 minutes; therefore Rn0.59 = 2.5.

722.2.1.3 Joints between precast wall panels.¶

Joints between precast concrete wall panels that are not insulated as required by this section shall be considered as openings in walls. Uninsulated joints shall be included in determining the percentage of openings permitted by Table 705.8. Where openings are not permitted or are required by this code to be protected, the provisions of this section shall be used to determine the amount of joint insulation required. Insulated joints shall not be considered openings for purposes of determining compliance with the allowable percentage of openings in Table 705.8.

722.2.1.3.1 Ceramic fiber joint protection.¶

Figure 722.2.1.3.1 shows thicknesses of ceramic fiber blankets to be used to insulate joints between precast concrete wall panels for various panel thicknesses and for joint widths of ³ /8 inch (9.5 mm) and 1 inch (25 mm) for fire-resistance ratings of 1 hour to 4 hours. For joint widths between ³ /8 inch (9.5 mm) and 1 inch (25 mm), the thickness of ceramic fiber blanket is allowed to be determined by direct

PANEL THICKNESS, INCHES

For SI: 1 inch = 25.4 mm.

FIGURE 722.2.1.3.1 CERAMIC FIBER JOINT PROTECTION

722.2.1.4 Walls with gypsum wallboard or plaster finishes.¶

finishes. The fire-resistance rating of cast-in-place or precast concrete walls with finishes of gypsum wallboard or plaster applied to one or both sides shall be permitted to be calculated in accordance with the provisions of this section.

722.2.1.4.1 Nonfire-exposed side. Where the finish of gypsum wallboard or plaster is applied to the side of the wall not exposed to fire, the contribution of the finish to the total fire-resistance rating shall be determined as follows: The thickness of the finish shall first be corrected by multiplying the actual thickness of the finish by the applicable factor determined from

interpolation. Other tested and labeled materials are acceptable in place of ceramic fiber blankets.

1 INCH MAXIMUM REGARDLESS OF OPENING RATING

JOINT WIDTH

CARBONATE OR SILICEOUS AGGREGATE

CONCRETE

SAND-LIGHTWEIGHT

OR LIGHTWEIGHT

CONCRETE

0 3 4 5 6 7 8

7-70 2022 CALIFORNIA BUILDING CODE

Table 722.2.1.4(1) based on the type of aggregate in the concrete. The corrected thickness of finish shall then be added to the actual or equivalent thickness of concrete and fire-resistance rating of the concrete and finish determined from Tables 722.2.1.1 and 722.2.1.2(1) and Figure 722.2.1.2.

722.2.1.4.2 Fire-exposed side.¶

Where gypsum wallboard or plaster is applied to the fire-exposed side of the wall, the contribution of the finish to the total fire-resistance rating shall be determined as follows: The time assigned to the finish as established by Table 722.2.1.4(2) shall be added to the fire-resistance rating determined from Tables 722.2.1.1 and 722.2.1.2(1) and Figure 722.2.1.2 for the concrete alone, or to the rating determined in Section 722.2.1.4.1 for the concrete and finish on the nonfireexposed side.

722.2.1.4.3 Nonsymmetrical assemblies.¶

For a wall without finish on one side or having different types or thicknesses of finish on each side, the calculation procedures of Sections 722.2.1.4.1 and 722.2.1.4.2 shall be performed twice, assuming either side of the wall to be the fire-exposed side. The fire-resistance rating of the wall shall not exceed the lower of the two values.

Exception: For an exterior wall with a fire separation distance greater than 5 feet (1524 mm) the fire shall be assumed to occur on the interior side only.

722.2.1.4.4 Minimum concrete fire-resistance rating.¶

rating. Where finishes applied to one or both sides of a concrete wall contribute to the fire-resistance rating, the concrete alone shall provide not less than one-half of the total required fire-resistance rating. Additionally, the contribution to the fire resistance of the finish on the nonfire-exposed side of a load-bearing wall shall not exceed one-half the contribution of the concrete alone.

722.2.1.4.5 Concrete finishes. Finishes on concrete walls that are assumed to contribute to the total fireresistance rating of the wall shall comply with the installation requirements of Section 722.3.2.5.

FIRE AND SMOKE PROTECTION FEATURES

TABLE 722.2.1.4(2)¶

TIME ASSIGNED TO FINISH MATERIALS

ON FIRE-EXPOSED SIDE OF WALL

FINISH DESCRIPTION	TIME (minutes)
Gypsum wallboard
3/8 inch	10
1/2 inch	15
5/8 inch	20
2 layers of3/8 inch	25
1 layer of3/8 inch, 1 layer of1/2 inch	35
2 layers of1/2 inch	40
Type X gypsum wallboard
1/2 inch	25
5/8 inch	40
Portland cement-sand plaster applied directly to concrete masonry	See Note a
Portland cement-sand plaster on metal lath
3/4 inch	20
7/8 inch	25
1 inch	30
Gypsum sand plaster on3/8-inch gypsum lath
1/2 inch	35
5/8 inch	40
3/4 inch	50
Gypsum sand plaster on metal lath
3/4 inch	50
7/8 inch	60
1 inch	80

For SI: 1 inch = 25.4 mm. a. The actual thickness of Portland cement-sand plaster, provided that it is ⁵ /8

inch or less in thickness, shall be permitted to be included in determining the equivalent thickness of the masonry for use in Table 722.3.2.

TABLE 722.2.1.4(1)¶

MULTIPLYING FACTOR FOR FINISHES ON NONFIRE-EXPOSED SIDE OF WALL

TYPE OF FINISH APPLIED TO CONCRETE OR CONCRETE MASONRY WALL	TYPE OF AGGREGATE USED IN CONCRETE OR CONCRETE MASONRY
TYPE OF FINISH APPLIED TO CONCRETE OR CONCRETE MASONRY WALL	Concrete: siliceous or carbonate concrete masonry: siliceous or carbonate; solid clay brick	Concrete: sand-lightweight concrete masonry: clay tile; hollow clay brick; concrete masonry units of expanded shale and < 20% sand	Concrete: lightweight concrete masonry: concrete masonry units of expanded shale, expanded clay, expanded slag, or pumice < 20% sand	Concrete masonry: concrete masonry units of expanded slag, expanded clay, or pumice
Portland cement-sand plaster	1.00	0.75a	0.75a	0.50a
Gypsum-sand plaster	1.25	1.00	1.00	1.00
Gypsum-vermiculite or perlite plaster	1.75	1.50	1.25	1.25
Gypsum wallboard	3.00	2.25	2.25	2.25

For SI: 1 inch = 25.4 mm. a. For Portland cement-sand plaster ⁵ /8 inch or less in thickness and applied directly to the concrete or concrete masonry on the nonfire-exposed side of the wall,

the multiplying factor shall be 1.00.

FIRE AND SMOKE PROTECTION FEATURES

722.2.2 Concrete floor and roof slabs.¶

Reinforced and prestressed floors and roofs shall comply with Section 722.2.2.1. Multicourse floors and roofs shall comply with Sections 722.2.2.2 and 722.2.2.3, respectively.

722.2.2.1 Reinforced and prestressed floors and roofs. The minimum thicknesses of reinforced and prestressed concrete floor or roof slabs for fire-resistance ratings of 1 hour to 4 hours are shown in Table 722.2.2.1.

Exception: Minimum thickness shall not be required for floors and ramps within parking garages constructed in accordance with Sections 406.5 and 406.6.

TABLE 722.2.2.1¶

MINIMUM SLAB THICKNESS (inches)

s = Spacing of ribs or undulations. t = Minimum thickness. te = Equivalent thickness of the slab calculated as

the net area of the slab divided by the width, in which the maximum thickness used in the calculation shall not exceed 2 t .

CONCRETE TYPE	FIRE-RESISTANCE RATING (hours)
CONCRETE TYPE	1	11/2	2	3	4
Siliceous	3.5	4.3	5	6.2	7
Carbonate	3.2	4	4.6	5.7	6.6
Sand-lightweight	2.7	3.3	3.8	4.6	5.4
Lightweight	2.5	3.1	3.6	4.4	5.1

For SI: 1 inch = 25.4 mm.

722.2.2.1.1 Hollow-core prestressed slabs.¶

For hollow-core prestressed concrete slabs in which the cores are of constant cross section throughout the length, the equivalent thickness shall be permitted to be obtained by dividing the net cross-sectional area of the slab including grout in the joints, by its width.

722.2.2.1.2 Slabs with sloping soffits. The thickness of slabs with sloping soffits (see Figure 722.2.2.1.2) shall be determined at a distance 2 t or 6 inches (152 mm), whichever is less, from the point of minimum thickness, where t is the minimum thickness.

722.2.2.1.3 Slabs with ribbed soffits.¶

The thickness of slabs with ribbed or undulating soffits (see Figure 722.2.2.1.3) shall be determined by one of the following expressions, whichever is applicable:

For s - 4 t, the thickness to be used shall be t

For s ≤ 2 t, the thickness to be used shall be te For 4 t - s - 2 t, the thickness to be used shall be

4 t t + - 1 ( te - t ) ^--- s ^-

where:

For SI: 1 inch = 25.4 mm.

(Equation 7-5)

WHICHEVER IS LESS

NEGLECT SHADED AREA IN CALCULATION OF EQUIVALENT THICKNESS

For SI: 1 inch = 25.4 mm.

FIGURE 722.2.2.1.3 SLABS WITH RIBBED OR UNDULATING SOFFITS

722.2.2.1.4 Flat plate concrete slabs with uniformly spaced hollow voids.¶

uniformly spaced hollow voids. Table 722.2.2.1 shall be used to determine the 1- and 2-hour fireresistance ratings for flat plate concrete slabs with uniformly spaced hollow voids. The equivalent thickness of the slab shall be determined by dividing the net concrete volume of the slab by the floor area. The net concrete volume of the slab shall be equal to the volume of concrete of a solid slab minus the average concrete volume displaced by the hollow voids.

722.2.2.2 Multicourse floors.¶

The fire-resistance ratings of floors that consist of a base slab of concrete with a topping (overlay) of a different type of concrete shall comply with Figure 722.2.2.2.

722.2.2.3 Multicourse roofs. The fire-resistance ratings of roofs that consist of a base slab of concrete with a topping (overlay) of an insulating concrete or with an insulating board and built-up roofing shall comply with Figures 722.2.2.3(1) and 722.2.2.3(2).

722.2.2.3.1 Heat transfer. For the transfer of heat, three-ply built-up roofing contributes 10 minutes to the fire-resistance rating. The fire-resistance rating for concrete assemblies such as those shown in Figure 722.2.2.3(1) shall be increased by 10 minutes. This increase is not applicable to those shown in Figure 722.2.2.3(2).

722.2.2.4 Joints in precast slabs.¶

Joints between adjacent precast concrete slabs need not be considered in calculating the slab thickness provided that a concrete topping not less than 1 inch (25 mm) thick is used. Where concrete topping is not used, joints must be grouted to a depth of not less than one-third the slab thickness at the joint, but not less than 1 inch (25 mm), or the joints must be made fire resistant by other approved methods.

FIGURE 722.2.2.1.2 DETERMINATION OF SLAB THICKNESS FOR SLOPING SOFFITS

7-72 2022 CALIFORNIA BUILDING CODE

FIRE AND SMOKE PROTECTION FEATURES

CELLULAR CONCRETE

CONCRETE

CARBONATE BASE SILICEOUS BASE

1 2 3 4 5

CARBONATE BASE

SILICEOUS BASE

SAND-LIGHTWEIGHT BASE

1 2 3 4 5

0 2 4

THICKNESS OF NORMAL-WEIGHT CONCRETE BASE SLAB, INCHES

THICKNESS OF CONCRETE BASE SLAB, INCHES

PERLITE CONCRETE

CONCRETE

SAND-LIGHTWEIGHT BASE

CARBONATE BASE

SILICEOUS BASE

CARBONATE BASE

SILICEOUS BASE

1 2 3 4 5

THICKNESS OF CONCRETE BASE SLAB, INCHES

VERMICULITE CONCRETE

CONCRETE

0 2 4

SAND-LIGHTWEIGHT BASE

CARBONATE BASE

SILICEOUS BASE

THICKNESS OF SAND-LIGHTWEIGHT CONCRETE BASE SLAB, INCHES

For SI: 1 inch = 25.4 mm.

FIGURE 722.2.2.2 FIRE-RESISTANCE RATINGS FOR TWO-COURSE CONCRETE FLOORS

722.2.3 Concrete cover over reinforcement.¶

The minimum thickness of concrete cover over reinforcement in concrete slabs, reinforced beams and prestressed beams shall comply with this section.

722.2.3.1 Slab cover. The minimum thickness of concrete cover to the positive moment reinforcement shall comply with Table 722.2.3(1) for reinforced concrete and Table 722.2.3(2) for prestressed concrete. These tables are applicable for solid or hollow-core one-way or two-way slabs with flat undersurfaces. These tables are applicable to slabs that are either cast in place or precast. For precast prestressed concrete not covered elsewhere, the procedures contained in PCI 124 shall be acceptable.

722.2.3.2 Reinforced beam cover.¶

The minimum thickness of concrete cover to the positive moment reinforcement (bottom steel) for reinforced concrete beams is shown in Table 722.2.3(3) for fire-resistance ratings of 1 hour to 4 hours.

722.2.3.3 Prestressed beam cover. The minimum thickness of concrete cover to the positive moment prestressing tendons (bottom steel) for restrained and unrestrained prestressed concrete beams and stemmed units shall comply with the values shown in Tables 722.2.3(4) and 722.2.3(5) for fire-resistance ratings of 1 hour to 4 hours. Values in Table 722.2.3(4) apply to beams 8 inches (203 mm) or greater in width. Values

(a)

(b)

(c)

THICKNESS OF CONCRETE BASE SLAB, INCHES

For SI: 1 inch = 25.4 mm.

FIGURE 722.2.2.3(1) FIRE-RESISTANCE RATINGS FOR CONCRETE ROOF ASSEMBLIES

in Table 722.2.3(5) apply to beams or stems of any width, provided that the cross-section area is not less than 40 square inches (25 806 mm ² ). In case of differences between the values determined from Table 722.2.3(4) or 722.2.3(5), it is permitted to use the smaller value. The concrete cover shall be calculated in accordance with Section 722.2.3.3.1. The minimum concrete cover for nonprestressed reinforcement in prestressed concrete beams shall comply with Section 722.2.3.2.

722.2.3.3.1 Calculating concrete cover.¶

The concrete cover for an individual tendon is the minimum thickness of concrete between the surface of the tendon and the fire-exposed surface of the beam, except that for ungrouted ducts, the assumed cover thickness is the minimum thickness of concrete between the surface of the duct and the fire-exposed surface of the beam. For beams in which two or more tendons are used, the cover is assumed to be the average of the minimum cover of the individual tendons. For corner tendons (tendons equal distance from the bottom and side), the minimum cover used in the calculation shall be one-half the actual value. For stemmed members with two or more prestressing

0 2 4

FIRE AND SMOKE PROTECTION FEATURES

tendons located along the vertical centerline of the stem, the average cover shall be the distance from the bottom of the member to the centroid of the tendons. The actual cover for any individual tendon shall be not less than one-half the smaller value shown in Tables 722.2.3(4) and 722.2.3(5), or 1 inch (25 mm), whichever is greater.

722.2.4 Concrete columns.¶

Concrete columns shall comply with this section.

TABLE 722.2.4 MINIMUM DIMENSION OF CONCRETE COLUMNS (inches)

CARBONATE BASE

SILICEOUS BASE SAND-LIGHTWEIGHT BASE

TYPES OF CONCRETE	FIRE-RESISTANCE RATING (hours)
TYPES OF CONCRETE	1	11/2	2a	3a	4b
Siliceous	8	9	10	12	14
Carbonate	8	9	10	11	12
Sand-lightweight	8	81/2	9	101/2	12

(d)

(e)

2 3 4

1 2 3 4

THICKNESS OF CONCRETE BASE SLAB, INCHES

For SI: 1 inch = 25 mm. a. The minimum dimension is permitted to be reduced to 8 inches for

rectangular columns with two parallel sides not less than 36 inches in length. b. The minimum dimension is permitted to be reduced to 10 inches for

rectangular columns with two parallel sides not less than 36 inches in length.

722.2.4.1 Minimum size.¶

The minimum overall dimensions of reinforced concrete columns for fireresistance ratings of 1 hour to 4 hours for exposure to fire on all sides shall comply with this section.

CARBONATE BASE

SILICEOUS BASE SAND-LIGHTWEIGHT BASE

0 1 3

0 5 1 3

0 1 3

THICKNESS OF CONCRETE BASE SLAB, INCHES

For SI: 1 inch = 25.4 mm.

FIGURE 722.2.2.3(2) FIRE-RESISTANCE RATINGS FOR CONCRETE ROOF ASSEMBLIES

TABLE 722.2.3(1) COVER THICKNESS FOR REINFORCED CONCRETE FLOOR OR ROOF SLABS (inches)

CONCRETE AGGREGATE TYPE	FIRE-RESISTANCE RATING (hours)
CONCRETE AGGREGATE TYPE	Restrained	Restrained	Restrained	Restrained	Restrained	Unrestrained	Unrestrained	Unrestrained	Unrestrained	Unrestrained
CONCRETE AGGREGATE TYPE	1	11/2	2	3	4	1	11/2	2	3	4
Siliceous	3/4	3/4	3/4	3/4	3/4	3/4	3/4	1	11/4	15/8
Carbonate	3/4	3/4	3/4	3/4	3/4	3/4	3/4	3/4	11/4	11/4
Sand-lightweight or lightweight	3/4	3/4	3/4	3/4	3/4	3/4	3/4	3/4	11/4	11/4

For SI: 1 inch = 25.4 mm.

TABLE 722.2.3(2)¶

COVER THICKNESS FOR PRESTRESSED CONCRETE FLOOR OR ROOF SLABS (inches)

CONCRETE AGGREGATE TYPE	FIRE-RESISTANCE RATING (hours)
CONCRETE AGGREGATE TYPE	Restrained	Restrained	Restrained	Restrained	Restrained	Unrestrained	Unrestrained	Unrestrained	Unrestrained	Unrestrained
CONCRETE AGGREGATE TYPE	1	11/2	2	3	4	1	11/2	2	3	4
Siliceous	3/4	3/4	3/4	3/4	3/4	11/8	11/2	13/4	23/8	23/4
Carbonate	3/4	3/4	3/4	3/4	3/4	1	13/8	15/8	21/8	21/4
Sand-lightweight or lightweight	3/4	3/4	3/4	3/4	3/4	1	13/8	11/2	2	21/4

For SI: 1 inch = 25.4 mm.

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FIRE AND SMOKE PROTECTION FEATURES

TABLE 722.2.3(3)¶

MINIMUM COVER FOR MAIN REINFORCING BARS OF REINFORCED CONCRETE BEAMS ^c

(APPLICABLE TO ALL TYPES OF STRUCTURAL CONCRETE)

RESTRAINED OR UNRESTRAINEDa	BEAM WIDTHb (inches)	FIRE-RESISTANCE RATING (hours)
RESTRAINED OR UNRESTRAINEDa	BEAM WIDTHb (inches)	1	11/2	2	3	4
Restrained	5	3/4	3/4	3/4	1a	11/4 a
Restrained	7	3/4	3/4	3/4	3/4	3/4
Restrained	≥10	3/4	3/4	3/4	3/4	3/4
Unrestrained	5	3/4	1	11/4	—	—
Unrestrained	7	3/4	3/4	3/4	13/4	3
Unrestrained	≥ 10	3/4	3/4	3/4	1	13/4

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm. a. Tabulated values for restrained assemblies apply to beams spaced more than 4 feet on center. For restrained beams spaced 4 feet or less on center, minimum

cover of ³ /4 inch is adequate for ratings of 4 hours or less. b. For beam widths between the tabulated values, the minimum cover thickness can be determined by direct interpolation. c. The cover for an individual reinforcing bar is the minimum thickness of concrete between the surface of the bar and the fire-exposed surface of the beam. For

beams in which several bars are used, the cover for corner bars used in the calculation shall be reduced to one-half of the actual value. The cover for an individual bar must be not less than one-half of the value given in Table 722.2.3(3) nor less than ³ /4 inch.

TABLE 722.2.3(4)¶

MINIMUM COVER FOR PRESTRESSED CONCRETE BEAMS 8 INCHES OR GREATER IN WIDTH ^b

RESTRAINED OR UNRESTRAINEDa	CONCRETE AGGREGATE TYPE	BEAM WIDTH (inches)	FIRE-RESISTANCE RATING (hours)
RESTRAINED OR UNRESTRAINEDa	CONCRETE AGGREGATE TYPE	BEAM WIDTH (inches)	1	11/2	2	3	4
Restrained	Carbonate or siliceous	8	11/2	11/2	11/2	13/4 a	21/2 a
Restrained	Carbonate or siliceous	≥ 12	11/2	11/2	11/2	11/2	17/8 a
Restrained	Sand lightweight	8	11/2	11/2	11/2	11/2	2a
Restrained	Sand lightweight	≥ 12	11/2	11/2	11/2	11/2	15/8 a
Unrestrained	Carbonate or siliceous	8	11/2	13/4	21/2	5c	—
Unrestrained	Carbonate or siliceous	≥ 12	11/2	11/2	17/8 a	21/2	3
Unrestrained	Sand lightweight	8	11/2	11/2	2	31/4	—
Unrestrained	Sand lightweight	≥ 12	11/2	11/2	15/8	2	21/2

cover of ³ /4 inch is adequate for 4-hour ratings or less. b. For beam widths between 8 inches and 12 inches, minimum cover thickness can be determined by direct interpolation. c. Not practical for 8-inch-wide beam but shown for purposes of interpolation.

TABLE 722.2.3(5)¶

MINIMUM COVER FOR PRESTRESSED CONCRETE BEAMS OF ALL WIDTHS

RESTRAINED OR UNRESTRAINEDa	CONCRETE AGGREGATE TYPE	BEAM AREAb A (square inches)	FIRE-RESISTANCE RATING (hours)
RESTRAINED OR UNRESTRAINEDa	CONCRETE AGGREGATE TYPE	BEAM AREAb A (square inches)	1	11/2	2	3	4
Restrained	All	40 ≤ A ≤ 150	11/2	11/2	2	21/2	—
Restrained	Carbonate or siliceous	150 < A ≤ 300	11/2	11/2	11/2	13/4	21/2
Restrained	Carbonate or siliceous	300 < A	11/2	11/2	11/2	11/2	2
Restrained	Sand lightweight	150 < A	11/2	11/2	11/2	11/2	2
Unrestrained	All	40 ≤ A ≤ 150	2	21/2	—	—	—
Unrestrained	Carbonate or siliceous	150 < A ≤ 300	11/2	13/4	21/2	—	—
Unrestrained	Carbonate or siliceous	300 < A	11/2	11/2	2	3c	4c
Unrestrained	Sand lightweight	150 < A	11/2	11/2	2	3c	4c

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 square inch = 645.2 mm ² . a. Tabulated values for restrained assemblies apply to beams spaced more than 4 feet on center. For restrained beams spaced 4 feet or less on center, minimum

cover of ³ /4 inch is adequate for 4-hour ratings or less. b. The cross-sectional area of a stem is permitted to include a portion of the area in the flange, provided that the width of the flange used in the calculation does

not exceed three times the average width of the stem. c. U-shaped or hooped stirrups spaced not to exceed the depth of the member and having a minimum cover of 1 inch shall be provided.

FIRE AND SMOKE PROTECTION FEATURES

722.2.4.1.1 Concrete strength less than or equal to 12,000 psi.¶

12,000 psi. For columns made with concrete having a specified compressive strength, f′c, of less than or equal to 12,000 psi (82.7 MPa), the minimum dimension shall comply with Table 722.2.4.

722.2.4.1.2 Concrete strength greater than 12,000 psi. For columns made with concrete having a specified compressive strength, f’c, greater than 12,000 psi (82.7 MPa), for fire-resistance ratings of 1 hour to 4 hours the minimum dimension shall be 24 inches (610 mm).

722.2.4.2 Minimum cover for R/C columns.¶

The minimum thickness of concrete cover to the main longitudinal reinforcement in columns, regardless of the type of aggregate used in the concrete and the specified compressive strength of concrete, f’c, shall be not less than 1 inch (25 mm) times the number of hours of required fire resistance or 2 inches (51 mm), whichever is less.

722.2.4.3 Tie and spiral reinforcement. For concrete columns made with concrete having a specified compressive strength, f’c, greater than 12,000 psi (82.7 MPa), tie and spiral reinforcement shall comply with the following:

The free ends of rectangular ties shall terminate with a 135-degree (2.4 rad) standard tie hook.
The free ends of circular ties shall terminate with a 90-degree (1.6 rad) standard tie hook.
The free ends of spirals, including at lap splices, shall terminate with a 90-degree (1.6 rad) standard tie hook.

The hook extension at the free end of ties and spirals shall be the larger of six bar diameters and the extension required by Section 25.3.2 of ACI 318. Hooks shall project into the core of the column.

722.2.4.4 Columns built into walls.¶

The minimum dimensions of Table 722.2.4 do not apply to a reinforced concrete column that is built into a concrete or masonry wall provided that all of the following are met:

The fire-resistance rating for the wall is equal to or greater than the required rating of the column.
The main longitudinal reinforcing in the column has cover not less than that required by Section 722.2.4.2.
Openings in the wall are protected in accordance with Section 716.

Where openings in the wall are not protected as required by Section 716, the minimum dimension of columns required to have a fire-resistance rating of 3 hours or less shall be 8 inches (203 mm), and 10 inches (254 mm) for columns required to have a fire-resistance rating of 4 hours, regardless of the type of aggregate used in the concrete.

722.2.4.5 Precast cover units for steel columns.¶

See Section 722.5.1.4.

722.3 Concrete masonry.¶

The provisions of this section contain procedures by which the fire-resistance ratings of concrete masonry are established by calculations.

722.3.1 Equivalent thickness. The equivalent thickness of concrete masonry construction shall be determined in accordance with the provisions of this section.

722.3.1.1 Concrete masonry unit plus finishes. The equivalent thickness of concrete masonry assemblies, Tea, shall be computed as the sum of the equivalent thickness of the concrete masonry unit, Te, as determined by Section 722.3.1.2, 722.3.1.3 or 722.3.1.4, plus the equivalent thickness of finishes, Tef, determined in accordance with Section 722.3.2:

Tea = Te + Tef (Equation 7-6)

722.3.1.2 Ungrouted or partially grouted construc- tion. Te shall be the value obtained for the concrete masonry unit determined in accordance with ASTM C140.

722.3.1.3 Solid grouted construction. The equivalent thickness, Te, of solid grouted concrete masonry units is the actual thickness of the unit.

722.3.1.4 Airspaces and cells filled with loose-fill material. The equivalent thickness of completely filled hollow concrete masonry is the actual thickness of the unit where loose-fill materials are: sand, pea gravel, crushed stone, or slag that meet ASTM C33 requirements; pumice, scoria, expanded shale, expanded clay, expanded slate, expanded slag, expanded fly ash, or cinders that comply with ASTM C331; or perlite or vermiculite meeting the requirements of ASTM C549 and ASTM C516, respectively.

722.3.2 Concrete masonry walls. The fire-resistance rating of walls and partitions constructed of concrete masonry units shall be determined from Table 722.3.2. The rating shall be based on the equivalent thickness of the masonry and type of aggregate used.

722.3.2.1 Finish on nonfire-exposed side. Where plaster or gypsum wallboard is applied to the side of the wall not exposed to fire, the contribution of the finish to the total fire-resistance rating shall be determined as follows: The thickness of gypsum wallboard or plaster shall be corrected by multiplying the actual thickness of the finish by applicable factor determined from Table 722.2.1.4(1). This corrected thickness of finish shall be added to the equivalent thickness of masonry and the fire-resistance rating of the masonry and finish determined from Table 722.3.2.

722.3.2.2 Finish on fire-exposed side. Where plaster or gypsum wallboard is applied to the fire-exposed side of the wall, the contribution of the finish to the total fire-resistance rating shall be determined as follows: The time assigned to the finish as established by Table 722.2.1.4(2) shall be added to the fire-resistance rating determined in Section 722.3.2 for the masonry alone, or in Section 722.3.2.1 for the masonry and finish on the nonfire-exposed side.

7-76 2022 CALIFORNIA BUILDING CODE

FIRE AND SMOKE PROTECTION FEATURES

TABLE 722.3.2 MINIMUM EQUIVALENT THICKNESS (inches) OF BEARING OR NONBEARING CONCRETE MASONRY WALLS ^{a, b, c, d}

TYPE OF AGGREGATE	FIRE-RESISTANCE RATING (hours)
TYPE OF AGGREGATE	1/2	3/4	1	11/4	11/2	13/4	2	21/4	21/2	23/4	3	31/4	31/2	33/4	4
Pumice or expanded slag	1.5	1.9	2.1	2.5	2.7	3.0	3.2	3.4	3.6	3.8	4.0	4.2	4.4	4.5	4.7
Expanded shale, clay or slate	1.8	2.2	2.6	2.9	3.3	3.4	3.6	3.8	4.0	4.2	4.4	4.6	4.8	4.9	5.1
Limestone, cinders or unexpanded slag	1.9	2.3	2.7	3.1	3.4	3.7	4.0	4.3	4.5	4.8	5.0	5.2	5.5	5.7	5.9
Calcareous or siliceous gravel	2.0	2.4	2.8	3.2	3.6	3.9	4.2	4.5	4.8	5.0	5.3	5.5	5.8	6.0	6.2

For SI: 1 inch = 25.4 mm. a. Values between those shown in the table can be determined by direct interpolation. b. Where combustible members are framed into the wall, the thickness of solid material between the end of each member and the opposite face of the wall, or

between members set in from opposite sides, shall be not less than 93 percent of the thickness shown in the table. c. Requirements of ASTM C55, ASTM C73, ASTM C90 or ASTM C744 shall apply. d. Minimum required equivalent thickness corresponding to the hourly fire-resistance rating for units with a combination of aggregate shall be determined by

linear interpolation based on the percent by volume of each aggregate used in manufacture.

722.3.2.3 Nonsymmetrical assemblies. For a wall without finish on one side or having different types or thicknesses of finish on each side, the calculation procedures of this section shall be performed twice, assuming either side of the wall to be the fire-exposed side. The fire-resistance rating of the wall shall not exceed the lower of the two values calculated.

Exception: For exterior walls with a fire separation distance greater than 5 feet (1524 mm), the fire shall be assumed to occur on the interior side only.

722.3.2.4 Minimum concrete masonry fire-resis- tance rating. Where the finish applied to a concrete masonry wall contributes to its fire-resistance rating, the masonry alone shall provide not less than one-half the total required fire-resistance rating.

722.3.2.5 Attachment of finishes. Installation of finishes shall be as follows:

Gypsum wallboard and gypsum lath applied to concrete masonry or concrete walls shall be secured to wood or steel furring members spaced not more than 16 inches (406 mm) on center (o.c.).
Gypsum wallboard shall be installed with the long dimension parallel to the furring members and shall have all joints finished.
Other aspects of the installation of finishes shall comply with the applicable provisions of Chapters 7 and 25.

722.3.3 Multiwythe masonry walls. The fire-resistance rating of wall assemblies constructed of multiple wythes of masonry materials shall be permitted to be based on the fire-resistance rating period of each wythe and the continuous airspace between each wythe in accordance with the following formula:

RA = ( R 10.59 + R 20.59 + ... + Rn 0.59 + A 1 + A 2 + ... + An )1.7

(Equation 7-7)

where:

RA = Fire-resistance rating of the assembly (hours).

R 1, R 2, ..., R n = Fire-resistance rating of wythes for 1, 2,

n (hours), respectively.

A 1, A 2, ..., A n = 0.30, factor for each continuous airspace

for 1, 2, ... n, respectively, having a depth of ¹ /2 inch (12.7 mm) or more between wythes.

722.3.4 Concrete masonry lintels. Fire-resistance ratings for concrete masonry lintels shall be determined based on the nominal thickness of the lintel and the minimum thickness of concrete masonry or concrete, or any combination thereof, covering the main reinforcing bars, as determined in accordance with Table 722.3.4, or by approved alternate methods.

TABLE 722.3.4 MINIMUM COVER OF LONGITUDINAL REINFORCEMENT IN FIRE-RESISTANCE-RATED REINFORCED CONCRETE MASONRY LINTELS (inches)

NOMINAL WIDTH OF LINTEL (inches)	FIRE-RESISTANCE RATING (hours)
NOMINAL WIDTH OF LINTEL (inches)	1	2	3	4
6	11/2	2	—	—
8	11/2	11/2	13/4	3
10 or greater	11/2	11/2	11/2	13/4

For SI: 1 inch = 25.4 mm.

722.3.5 Concrete masonry columns. The fire-resistance rating of concrete masonry columns shall be determined based on the least plan dimension of the column in accordance with Table 722.3.5 or by approved alternate methods.

FIRE AND SMOKE PROTECTION FEATURES

	TABLE 722.3.5 MINIMUM DIMENSION OF CONCRETE MASONRY COLUMNS (inches)
	FIRE-RESISTANCE RATING (hours)
1	2 3	4
8 inches	10 inches 12 inches	14 inches

For SI: 1 inch = 25.4 mm.

722.4 Clay brick and tile masonry.¶

The provisions of this section contain procedures by which the fire-resistance ratings of clay brick and tile masonry are established by calculations.

722.4.1 Masonry walls. The fire-resistance rating of masonry walls shall be based on the equivalent thickness as calculated in accordance with this section. The calculation shall take into account finishes applied to the wall and airspaces between wythes in multiwythe construction.

722.4.1.1 Equivalent thickness. The fire-resistance ratings of walls or partitions constructed of solid or hollow clay masonry units shall be determined from Table 722.4.1(1) or Table 722.4.1(2). The equivalent thickness of the clay masonry unit shall be determined by Equation 7-8 where using Table 722.4.1(1). The fire-resistance rating determined from Table 722.4.1(1) shall be permitted to be used in the calculated fire-resistance rating procedure in Section 722.4.2.

Te = Vn / LH (Equation 7-8)

where:

Te = The equivalent thickness of the clay masonry unit

(inches). Vn = The net volume of the clay masonry unit (inches). L = The specified length of the clay masonry unit

(inches). H = The specified height of the clay masonry unit

(inches).

722.4.1.1.1 Hollow clay units. The equivalent thickness, Te, shall be the value obtained for hollow clay units as determined in accordance with Equation 7-8. The net volume, Vn, of the units shall be determined using the gross volume and percentage of void area determined in accordance with ASTM C67.

722.4.1.1.2 Solid grouted clay units. The equivalent thickness of solid grouted clay masonry units shall be taken as the actual thickness of the units.

722.4.1.1.3 Units with filled cores. The equivalent thickness of the hollow clay masonry units is the actual thickness of the unit where completely filled with loose-fill materials of: sand, pea gravel, crushed stone, or slag that meet ASTM C33 requirements; pumice, scoria, expanded shale, expanded clay, expanded slate, expanded slag, expanded fly ash, or cinders in compliance with ASTM C331; or perlite or vermiculite meeting the requirements of ASTM C549 and ASTM C516, respectively.

R 0.59 n	TABLE 7 VALUES	22.4.1 OF R n	R (hours)
1			1.0
2			1.50
3			1.91
4			2.27
TABLE 722.4.1(4) COEFFICIENTS FOR PLASTER,****pla
THICKNESS OF PLASTER (inch)	ONE	SIDE	TWO SIDES
1/2	0.3	0.3	0.6
5/8	0.37	0.37	0.75
3/4	0.45	0.45	0.90

For SI: 1 inch = 25.4 mm. a. Values specified in the table are for 1:3 sanded gypsum plaster.

TABLE 722.4.1(1) FIRE-RESISTANCE PERIODS OF CLAY MASONRY WALLS

MATERIAL TYPE	MINIMUM REQUIRED EQUIVALENT THICKNESS FOR FIRE RESISTANCEa, b, c (inches)
MATERIAL TYPE	1 hour	2 hours	3 hours	4 hours
Solid brick of clay or shaled	2.7	3.8	4.9	6.0
Hollow brick or tile of clay or shale, unfilled	2.3	3.4	4.3	5.0
Hollow brick or tile of clay or shale, grouted or filled with mate- rials specified in Section 722.4.1.1.3	3.0	4.4	5.5	6.6

For SI: 1 inch = 25.4 mm. a. Equivalent thickness as determined from Section 722.4.1.1. b. Calculated fire resistance between the hourly increments specified shall be determined by linear interpolation. c. Where combustible members are framed in the wall, the thickness of solid material between the end of each member and the opposite face of the wall, or

between members set in from opposite sides, shall be not less than 93 percent of the thickness shown. d. For units in which the net cross-sectional area of cored brick in any plane parallel to the surface containing the cores is not less than 75 percent of the gross

cross-sectional area measured in the same plane.

7-78 2022 CALIFORNIA BUILDING CODE

FIRE AND SMOKE PROTECTION FEATURES

TABLE 722.4.1(2) FIRE-RESISTANCE RATINGS FOR BEARING STEEL FRAME BRICK VENEER WALLS OR	PARTITIONS
WALL OR PARTITION ASSEMBLY	PLASTER SIDE EXPOSED (hours)	BRICK FACED SIDE EXPOSED (hours)
Outside facing of steel studs:1/2″ wood fiberboard sheathing next to studs,3/4″ airspace formed with3/4″ × 15/8″ wood strips placed over the fiberboard and secured to the studs; metal or wire lath nailed to such strips, 33/4″ brick veneer held in place by filling3/4″ airspace between the brick and lath with mortar. Inside facing of studs:3/4″ unsanded gypsum plaster on metal or wire lath attached to5/16″ wood strips secured to edges of the studs.	1.5	4
Outside facing of steel studs: 1″ insulation board sheathing attached to studs, 1″ airspace, and 33/4″ brick veneer attached to steel frame with metal ties every 5th course. Inside facing of studs:7/8″ sanded gypsum plaster (1:2 mix) applied on metal or wire lath attached directly to the studs.	1.5	4
Same as previous assembly except use7/8″ vermiculite-gypsum plaster or 1″ sanded gypsum plaster (1:2 mix) applied to metal or wire.	2	4
Outside facing of steel studs:1/2″ gypsum sheathing board, attached to studs, and 33/4″ brick veneer attached to steel frame with metal ties every 5th course. Inside facing of studs:1/2″ sanded gypsum plaster (1:2 mix) applied to1/2″ perforated gypsum lath securely attached to studs and having strips of metal lath 3 inches wide applied to all horizontal joints of gypsum lath.	2	4

For SI: 1 inch = 25.4 mm.

TABLE 722.4.1(5) REINFORCED MASONRY LINTELS

tion and whether one or two sides of the wall are plastered.

722.4.1.3 Multiwythe walls with airspace. Where a continuous airspace separates multiple wythes of the wall or partition, the total fire-resistance rating shall be determined by the formula:

R = ( R 10.59 + R 20.59 + ...+ Rn 0.59 + as ) 1.7 (Equation 7-10)

where:

R = The fire-resistance rating of the assembly

(hours). R1, R2 and Rn = The fire-resistance rating of the

individual wythes (hours). as = Coefficient for continuous airspace.

NOMINAL LINTEL WIDTH (inches)	MINIMUM LONGITUDINAL REINFORCEMENT COVER FOR FIRE RESISTANCE (inches)
NOMINAL LINTEL WIDTH (inches)	1 hour	2 hours	3 hours	4 hours
6	11/2	2	NP	NP
8	11/2	11/2	13/4	3
10 or more	11/2	11/2	11/2	13/4

For SI: 1 inch = 25.4 mm. NP = Not Permitted.

TABLE 722.4.1(6) REINFORCED CLAY MASONRY COLUMNS

COLUMN SIZE	FIRE-RESISTANCE RATING (hours)
COLUMN SIZE	1	2	3	4
Minimum column dimension (inches)	8	10	12	14

For SI: 1 inch = 25.4 mm.

722.4.1.2 Plaster finishes. Where plaster is applied to the wall, the total fire-resistance rating shall be determined by the formula:

R = ( Rn 0.59 + pl ) 1.7 (Equation 7-9)

where:

R = The fire-resistance rating of the assembly

(hours). R n = The fire-resistance rating of the individual wall

(hours). pl = Coefficient for thickness of plaster.

Values for Rn 0.59 for use in Equation 7-9 are given in

Table 722.4.1(3). Coefficients for thickness of plaster shall be selected from Table 722.4.1(4) based on the actual thickness of plaster applied to the wall or parti

Values for Rn 0.59 for use in Equation 7-10 are given

in Table 722.4.1(3). The coefficient for each continuous airspace of ¹ /2 inch to 3 ¹ /2 inches (12.7 to 89 mm) separating two individual wythes shall be 0.3.

722.4.1.4 Nonsymmetrical assemblies. For a wall without finish on one side or having different types or thicknesses of finish on each side, the calculation procedures of this section shall be performed twice, assuming either side to be the fire-exposed side of the wall. The fire resistance of the wall shall not exceed the lower of the two values determined.

Exception: For exterior walls with a fire separation distance greater than 5 feet (1524 mm), the fire shall be assumed to occur on the interior side only.

722.4.2 Multiwythe walls. The fire-resistance rating for walls or partitions consisting of two or more dissimilar wythes shall be permitted to be determined by the formula:

R = ( R 10.59 + R 20.59 + ...+ Rn 0.59) 1.7 (Equation 7-11)

FIRE AND SMOKE PROTECTION FEATURES

where:

R = The fire-resistance rating of the assembly (hours). R 1 , R 2 and Rn = The fire-resistance rating of the individual wythes (hours). Values for Rn0.59 for use in Equation 7-11 are given in

Table 722.4.1(3).

722.4.2.1 Multiwythe walls of different material. For walls that consist of two or more wythes of different materials (concrete or concrete masonry units) in combination with clay masonry units, the fire-resistance rating of the different materials shall be permitted to be determined from Table 722.2.1.1 for concrete; Table 722.3.2 for concrete masonry units or Table 722.4.1(1) or Table 722.4.1(2) for clay and tile masonry units.

722.4.3 Reinforced clay masonry lintels. Fire-resistance ratings for clay masonry lintels shall be determined based on the nominal width of the lintel and the minimum covering for the longitudinal reinforcement in accordance with Table 722.4.1(5).

722.4.4 Reinforced clay masonry columns. The fireresistance ratings shall be determined based on the last plan dimension of the column in accordance with Table 722.4.1(6). The minimum cover for longitudinal reinforcement shall be 2 inches (51 mm).

722.5 Steel assemblies.¶

The provisions of this section contain procedures by which the fire-resistance ratings of steel assemblies are established by calculations.

722.5.1 Structural steel columns. The fire-resistance ratings of structural steel columns shall be based on the size of the element and the type of protection provided in accordance with this section.

722.5.1.1 General. These procedures establish a basis for determining the fire resistance of column assemblies as a function of the thickness of fire-resistant material, and the weight, W, and heated perimeter, D, of structural steel columns. As used in these sections, W is the average weight of a structural steel column in pounds per linear foot. The heated perimeter, D, is the inside perimeter of the fire-resistant material in inches as illustrated in Figure 722.5.1(1).

R = Fire resistance (minutes). h = Total thickness of gypsum wallboard (inches). D = Heated perimeter of the structural steel column

(inches). W’ = Total weight of the structural steel column and

gypsum wallboard protection (pounds per linear foot). W’ = W + 50 hD /144.

722.5.1.2.1 Attachment.¶

The gypsum board or gypsum panel products shall be supported as illustrated in either Figure 722.5.1(2) for fire-resistance ratings of 4 hours or less, or Figure 722.5.1(3) for fire-resistance ratings of 3 hours or less.

722.5.1.1.1 Nonload-bearing protection. The application of these procedures shall be limited to column assemblies in which the fire-resistant material is not designed to carry any of the load acting on the column.

722.5.1.1.2 Embedments. In the absence of substantiating fire-endurance test results, ducts, conduit, piping, and similar mechanical, electrical, and plumbing installations shall not be embedded in any required fire-resistant materials.

722.5.1.1.3 Weight-to-perimeter ratio.¶

Table 722.5.1(1) contains weight-to-heated-perimeter ratios ( W/D ) for both contour and box fire-resistant profiles, for the wide flange shapes most often used as columns. For different fire-resistant protection profiles or column cross sections, the weight-toheated-perimeter ratios ( W/D ) shall be determined in accordance with the definitions given in this section.

722.5.1.2 Gypsum wallboard protection. The fire resistance of structural steel columns with weight-toheated-perimeter ratios ( W/D ) less than or equal to 3.65 and that are protected with Type X gypsum wallboard shall be permitted to be determined from the following expression:

where:

(Equation 7-12)

722.5.1.2.2 Gypsum wallboard equivalent to¶

structural steel columns from Figure 722.5.1(4) is permitted for various thicknesses of gypsum wallboard as a function of the weight-to-heated-perimeter ratio ( W/D ) of the column. For structural steel columns with weight-to-heated-perimeter ratios ( W/D ) greater than 3.65, the thickness of gypsum

D=4bf + 2d - 2tw D=2(a+d) D=2(bf + d) wallboard required for specified fire-resistance

ratings shall be the same as the thickness determined for a W14 × 233 wide flange shape. FIGURE 722.5.1(1) DETERMINATION OF THE HEATED PERIMETER OF STRUCTURAL STEEL COLUMNS

D=4bf + 2d - 2tw D=2(a+d)

D=2(bf + d)

7-80 2022 CALIFORNIA BUILDING CODE

TABLE 722.5.1(1)¶

W/D RATIOS FOR STEEL COLUMNS

STRUCTURAL SHAPE	CONTOUR PROFILE	BOX PROFILE
W14 × 233	2.55	3.65
× 211	2.32	3.35
× 193	2.14	3.09
× 176	1.96	2.85
× 159	1.78	2.60
× 145	1.64	2.39
× 132	1.56	2.25
× 120	1.42	2.06
× 109	1.29	1.88
× 99	1.18	1.72
× 90	1.08	1.58
× 82	1.23	1.68
× 74	1.12	1.53
× 68	1.04	1.41
× 61	0.928	1.28
× 53	0.915	1.21
× 48	0.835	1.10
× 43	0.752	0.99
W12 × 190	2.50	3.51
× 170	2.26	3.20
× 152	2.04	2.90
× 136	1.86	2.63
× 120	1.65	2.36
× 106	1.47	2.11
× 96	1.34	1.93
× 87	1.22	1.76
× 79	1.11	1.61
× 72	1.02	1.48
× 65	0.925	1.35
× 58	0.925	1.31
× 53	0.855	1.20
× 50	0.909	1.23
× 45	0.829	1.12
× 40	0.734	1.00
W10 × 112	1.81	2.57
× 100	1.64	2.33
× 88	1.45	2.08
× 77	1.28	1.85
× 68	1.15	1.66
× 60	1.01	1.48
× 54	0.922	1.34
× 49	0.84	1.23
× 45	0.888	1.24
× 39	0.78	1.09
× 33	0.661	0.93

(continued)

FIRE AND SMOKE PROTECTION FEATURES

TABLE 722.5.1(1)—continued W/D RATIOS FOR STEEL COLUMNS

STRUCTURAL SHAPE	CONTOUR PROFILE	BOX PROFILE
W8 × 67	1.37	1.94
× 58	1.20	1.71
× 48	1.00	1.44
× 40	0.849	1.23
× 35	0.749	1.08
× 31	0.665	0.97
× 28	0.688	0.96
× 24	0.591	0.83
× 21	0.577	0.77
× 18	0.499	0.67
W6 ×25	0.696	1.00
× 20	0.563	0.82
× 16	0.584	0.78
× 15	0.431	0.63
× 12	0.448	0.60
× 9	0.338	0.46
W5 ×19	0.644	0.93
× 16	0.55	0.80
W4 ×13	0.556	0.79

For SI: 1 pound per linear foot per inch = 0.059 kg/m/mm.

FIRE AND SMOKE PROTECTION FEATURES

TABLE 722.5.1(2)¶

PROPERTIES OF CONCRETE

PROPERTY	NORMAL-WEIGHT CONCRETE	STRUCTURAL LIGHTWEIGHT CONCRETE
Thermal conductivity (_k_c)	0.95 Btu/hr × ft × °F	0.35 Btu/hr × ft × °F
Specific heat (_c_c)	0.20 Btu/lb °F	0.20 Btu/lb °F
Density (_P_c)	145 lb/ft3	110 lb/ft3
Equilibrium (free) moisture content (m) by volume	4%	5%

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 lb/ft ³ = 16.0185 kg/m ³, Btu/hr × ft × °F = 1.731 W/(m × K).

TABLE 722.5.1(3) THERMAL CONDUCTIVITY OF CONCRETE OR CLAY MASONRY UNITS

DENSITY (d ) OF UNITS (lb/ft3) m	THERMAL CONDUCTIVITY (K) OF UNITS (Btu/hr · ft · °F)
Concrete Masonry Units	Concrete Masonry Units
80	0.207
85	0.228
90	0.252
95	0.278
100	0.308
105	0.340
110	0.376
115	0.416
120	0.459
125	0.508
130	0.561
135	0.620
140	0.685
145	0.758
150	0.837
Clay Masonry Units	Clay Masonry Units
120	1.25
130	2.25

For SI: 1 pound per cubic foot = 16.0185 kg/m ³, Btu/hr × ft × °F = 1.731 W/(m × K)

7-82 2022 CALIFORNIA BUILDING CODE

TABLE 722.5.1(4)¶

WEIGHT-TO-HEATED-PERIMETER RATIOS (W/D) FOR TYPICAL WIDE FLANGE BEAM AND GIRDER SHAPES

FIRE AND SMOKE PROTECTION FEATURES

TABLE 722.5.1(4)—continued WEIGHT-TO-HEATED-PERIMETER RATIOS (W/D) FOR TYPICAL WIDE FLANGE BEAM AND GIRDER SHAPES

STRUCTURAL SHAPE	CONTOUR PROFILE	BOX PROFILE	STRUCTURAL SHAPE	CONTOUR PROFILE	BOX PROFILE
W36 × 300	2.50	3.33	W24 × 68	0.942	1.21
× 280	2.35	3.12	× 62	0.934	1.14
× 260	2.18	2.92	× 55	0.828	1.02
× 245	2.08	2.76	W21 × 147	1.87	2.60
× 230	1.95	2.61	× 132	1.68	2.35
× 210	1.96	2.45	× 122	1.57	2.19
× 194	1.81	2.28	× 111	1.43	2.01
× 182	1.72	2.15	× 101	1.30	1.84
× 170	1.60	2.01	× 93	1.40	1.80
× 160	1.51	1.90	× 83	1.26	1.62
× 150	1.43	1.79	× 73	1.11	1.44
× 135	1.29	1.63	× 68	1.04	1.35
W33 × 241	2.13	2.86	W21 × 62	0.952	1.23
× 221	1.97	2.64	× 57	0.952	1.17
× 201	1.79	2.42	× 50	0.838	1.04
× 152	1.53	1.94	× 44	0.746	0.92
× 141	1.43	1.80	W18 × 119	1.72	2.42
× 130	1.32	1.67	× 106	1.55	2.18
× 118	1.21	1.53	× 97	1.42	2.01
W30 × 211	2.01	2.74	× 86	1.27	1.80
× 191	1.85	2.50	× 76	1.13	1.60
× 173	1.66	2.28	× 71	1.22	1.59
× 132	1.47	1.85	× 65	1.13	1.47
× 124	1.39	1.75	× 60	1.04	1.36
× 116	1.30	1.65	× 55	0.963	1.26
× 108	1.21	1.54	× 50	0.88	1.15
× 99	1.12	1.42	× 46	0.878	1.09
W27 × 178	1.87	2.55	× 40	0.768	0.96
× 161	1.70	2.33	× 35	0.672	0.85
× 146	1.55	2.12	W16 × 100	1.59	2.25
× 114	1.39	1.76	× 89	1.43	2.03
× 102	1.24	1.59	× 77	1.25	1.78
× 94	1.15	1.47	× 67	1.09	1.56
× 84	1.03	1.33	× 57	1.09	1.43
W24 × 162	1.88	2.57	× 50	0.962	1.26
× 146	1.70	2.34	× 45	0.870	1.15
× 131	1.54	2.12	× 40	0.780	1.03
× 117	1.38	1.91	× 36	0.702	0.93
× 104	1.24	1.71	× 31	0.661	0.83
× 94	1.28	1.63	× 26	0.558	0.70
× 84	1.15	1.47	W14 × 132	1.89	3.00
× 76	1.05	1.34	× 120	1.71	2.75
			× 109	1.57	2.52

(continued)

FIRE AND SMOKE PROTECTION FEATURES

TABLE 722.5.1(4)—continued WEIGHT-TO-HEATED-PERIMETER RATIOS (W/D) FOR TYPICAL WIDE FLANGE BEAM AND GIRDER SHAPES

STRUCTURAL SHAPE	CONTOUR PROFILE	BOX PROFILE
W14 × 99	1.43	2.31
× 90	1.31	2.11
× 82	1.45	2.12
× 74	1.32	1.93
× 68	1.22	1.78
× 61	1.10	1.61
× 53	1.06	1.48
× 48	0.970	1.35
W14 × 43	0.874	1.22
× 38	0.809	1.09
× 34	0.725	0.98
× 30	0.644	0.87
× 26	0.628	0.79
× 22	0.534	0.68
W12 × 87	1.47	2.34
× 79	1.34	2.14
× 72	1.23	1.97
× 65	1.11	1.79
× 58	1.10	1.69
× 53	1.02	1.55
× 50	1.06	1.54
× 45	0.974	1.40
× 40	0.860	1.25
× 35	0.810	1.11
× 30	0.699	0.96
× 26	0.612	0.84
× 22	0.623	0.77
× 19	0.540	0.67
× 16	0.457	0.57
× 14	0.405	0.50
W10 × 112	2.17	3.38
× 100	1.97	3.07
× 88	1.74	2.75
× 77	1.54	2.45
× 68	1.38	2.20
× 60	1.22	1.97
× 54	1.11	1.79
× 49	1.01	1.64
× 45	1.06	1.59
× 39	0.94	1.40
× 33	0.77	1.20

(continued)

TABLE 722.5.1(4)—continued WEIGHT-TO-HEATED-PERIMETER RATIOS (W/D) FOR TYPICAL WIDE FLANGE BEAM AND GIRDER SHAPES

STRUCTURAL SHAPE	CONTOUR PROFILE	BOX PROFILE
W10 × 30	0.806	1.12
× 26	0.708	0.98
× 22	0.606	0.84
× 19	0.607	0.78
× 17	0.543	0.70
× 15	0.484	0.63
× 12	0.392	0.51
W8 × 67	1.65	2.55
× 58	1.44	2.26
× 48	1.21	1.91
× 40	1.03	1.63
× 35	0.907	1.44
× 31	0.803	1.29
× 28	0.819	1.24
× 24	0.704	1.07
× 21	0.675	0.96
× 18	0.583	0.84
× 15	0.551	0.74
× 13	0.483	0.65
× 10	0.375	0.51
W6 × 25	0.839	1.33
× 20	0.678	1.09
× 16	0.684	0.96
× 15	0.521	0.83
× 12	0.526	0.75
× 9	0.398	0.57
W5 × 19	0.776	1.24
× 16	0.664	1.07
W4 × 13	0.670	1.05

For SI: 1 pound per linear foot per inch = 0.059 kg/m/mm.

7-84 2022 CALIFORNIA BUILDING CODE

FIRE AND SMOKE PROTECTION FEATURES


COLUMN SIZE	CONCRETE MASONRY DENSITY POUNDS PER CUBIC FOOT	MINIMUM REQUIRED EQUIVALENT THICKNESS FOR FIRE-RESISTANCE RATING OF CONCRETE MASONRY PROTECTION ASSEMBLY,Te(inches) 1 hour 2 hours 3 hours 4 hours	MINIMUM REQUIRED EQUIVALENT THICKNESS FOR FIRE-RESISTANCE RATING OF CONCRETE MASONRY PROTECTION ASSEMBLY,Te(inches) 1 hour 2 hours 3 hours 4 hours	MINIMUM REQUIRED EQUIVALENT THICKNESS FOR FIRE-RESISTANCE RATING OF CONCRETE MASONRY PROTECTION ASSEMBLY,Te(inches) 1 hour 2 hours 3 hours 4 hours	MINIMUM REQUIRED EQUIVALENT THICKNESS FOR FIRE-RESISTANCE RATING OF CONCRETE MASONRY PROTECTION ASSEMBLY,Te(inches) 1 hour 2 hours 3 hours 4 hours	COLUMN SIZE	CONCRETE MASONRY DENSITY POUNDS PER CUBIC FOOT	MINIMUM REQUIRED EQUIVALENT THICKNESS FOR FIRE-RESISTANCE RATING OF CONCRETE MASONRY PROTECTION ASSEMBLY,Te(inches) 1 hour 2 hours 3 hours 4 hours	MINIMUM REQUIRED EQUIVALENT THICKNESS FOR FIRE-RESISTANCE RATING OF CONCRETE MASONRY PROTECTION ASSEMBLY,Te(inches) 1 hour 2 hours 3 hours 4 hours	MINIMUM REQUIRED EQUIVALENT THICKNESS FOR FIRE-RESISTANCE RATING OF CONCRETE MASONRY PROTECTION ASSEMBLY,Te(inches) 1 hour 2 hours 3 hours 4 hours	MINIMUM REQUIRED EQUIVALENT THICKNESS FOR FIRE-RESISTANCE RATING OF CONCRETE MASONRY PROTECTION ASSEMBLY,Te(inches) 1 hour 2 hours 3 hours 4 hours
	80	0.74	1.61	2.36	3.04		80	0.92	1.83	2.60	3.30
W14 × 82	100 110	0.89 0.96	1.85 1.97	2.67 2.81	3.40 3.57	W10 × 45	100 110	1.08 1.16	2.07 2.18	2.90 3.04	3.64 3.80
	120	1.03	2.08	2.95	3.73		120	1.23	2.29	3.18	3.96
	80	0.83	1.70	2.45	3.13		80	1.06	2.00	2.79	3.49
W14 × 68	100 110	0.99 1.06	1.95 2.06	2.76 2.91	3.49 3.66	W10 × 33	100 110	1.22 1.30	2.23 2.34	3.07 3.20	3.80 3.96
	120	1.14	2.18	3.05	3.82		120	1.37	2.44	3.33	4.12
	80	0.91	1.81	2.58	3.27		80	0.94	1.85	2.63	3.33
W14 × 53	100 110	1.07 1.15	2.05 2.17	2.88 3.02	3.62 3.78	W8 × 40	100 110	1.10 1.18	2.10 2.21	2.93 3.07	3.67 3.83
	120	1.22	2.28	3.16	3.94		120	1.25	2.32	3.20	3.99
	80	1.01	1.93	2.71	3.41		80	1.06	2.00	2.78	3.49
W14 × 43	100 110	1.17 1.25	2.17 2.28	3.00 3.14	3.74 3.90	W8 × 31	100 110	1.22 1.29	2.23 2.33	3.07 3.20	3.81 3.97
	120	1.32	2.38	3.27	4.05		120	1.36	2.44	3.33	4.12
	80	0.81	1.66	2.41	3.09		80	1.14	2.09	2.89	3.59
W12 × 72	100 110	0.91 0.99	1.88 1.99	2.70 2.84	3.43 3.60	W8 × 24	100 110	1.29 1.36	2.31 2.42	3.16 3.28	3.90 4.05
	120	1.06	2.10	2.98	3.76		120	1.43	2.52	3.41	4.20
	80	0.88	1.76	2.52	3.21		80	1.22	2.20	3.01	3.72
W12 × 58	100 110	1.04 1.11	2.01 2.12	2.83 2.97	3.56 3.73	W8 × 18	100 110	1.36 1.42	2.40 2.50	3.25 3.37	4.01 4.14
	120	1.19	2.23	3.11	3.89		120	1.48	2.59	3.49	4.28
W12 × 50	80 100 110	0.91 1.07 1.15	1.81 2.05 2.17	2.58 2.88 3.02	3.27 3.62 3.78	8 × 8 ×1/2 wall thick- ness	80 100 110	0.77 0.92 1.00	1.66 1.91 2.02	2.44 2.75 2.89	3.13 3.49 3.66
	120	1.22	2.28	3.16	3.94		120	1.07	2.14	3.03	3.82
W12 × 40	80 100 110	1.01 1.17 1.25	1.94 2.17 2.28	2.72 3.01 3.14	3.41 3.75 3.90	8 × 8 ×3/8 wall thick- ness	80 100 110	0.91 1.07 1.14	1.84 2.08 2.19	2.63 2.92 3.06	3.33 3.67 3.83
	120	1.32	2.39	3.27	4.06		120	1.21	2.29	3.19	3.98
W10 × 68	80 100 110	0.72 0.87 0.94	1.58 1.83 1.95	2.33 2.65 2.79	3.01 3.38 3.55	8 × 8 ×1/4 wall thick- ness	80 100 110	1.10 1.25 1.32	2.06 2.28 2.38	2.86 3.13 3.25	3.57 3.87 4.02
	120	1.01	2.06	2.94	3.72		120	1.39	2.48	3.38	4.17
W10 × 54	80 100 110	0.88 1.04 1.11	1.76 2.01 2.12	2.53 2.83 2.98	3.21 3.57 3.73	6 × 6 ×1/2 wall thick- ness	80 100 110	0.82 0.98 1.05	1.75 1.99 2.10	2.54 2.84 2.98	3.25 3.59 3.75
	120	1.19	2.24	3.12	3.90		120	1.12	2.21	3.11	3.91

(continued)

FIRE AND SMOKE PROTECTION FEATURES

TABLE 722.5.1(5)—continued¶

FIRE RESISTANCE OF CONCRETE MASONRY PROTECTED STEEL COLUMNS

TABLE 722.5.1(5)—continued FIRE RESISTANCE OF CONCRETE MASONRY PROTECTED STEEL COLUMNS

COLUMN SIZE	CONCRETE MASONRY DENSITY POUNDS PER CUBIC FOOT	MINIMUM REQUIRED EQUIVALENT THICKNESS FOR FIRE-RESISTANCE RATING OF CONCRETE MASONRY PROTECTION ASSEMBLY, T(inches) e
COLUMN SIZE	CONCRETE MASONRY DENSITY POUNDS PER CUBIC FOOT	1 hour	2 hours	3 hours	4 hours
6 × 6 ×3/8 wall thick- ness	80	0.96	1.91	2.71	3.42
6 × 6 ×3/8 wall thick- ness	100	1.12	2.14	3.00	3.75
6 × 6 ×3/8 wall thick- ness	110	1.19	2.25	3.13	3.90
6 × 6 ×3/8 wall thick- ness	120	1.26	2.35	3.26	4.05
6 × 6 ×1/4 wall thick- ness	80	1.14	2.11	2.92	3.63
6 × 6 ×1/4 wall thick- ness	100	1.29	2.32	3.18	3.93
6 × 6 ×1/4 wall thick- ness	110	1.36	2.43	3.30	4.08
6 × 6 ×1/4 wall thick- ness	120	1.42	2.52	3.43	4.22
4 × 4 ×1/2 wall thick- ness	80	0.93	1.90	2.71	3.43
4 × 4 ×1/2 wall thick- ness	100	1.08	2.13	2.99	3.76
4 × 4 ×1/2 wall thick- ness	110	1.16	2.24	3.13	3.91
4 × 4 ×1/2 wall thick- ness	120	1.22	2.34	3.26	4.06
4 × 4 ×3/8 wall thick- ness	80	1.05	2.03	2.84	3.57
4 × 4 ×3/8 wall thick- ness	100	1.20	2.25	3.11	3.88
4 × 4 ×3/8 wall thick- ness	110	1.27	2.35	3.24	4.02
4 × 4 ×3/8 wall thick- ness	120	1.34	2.45	3.37	4.17
4 × 4 ×1/4 wall thick- ness	80	1.21	2.20	3.01	3.73
4 × 4 ×1/4 wall thick- ness	100	1.35	2.40	3.26	4.02
4 × 4 ×1/4 wall thick- ness	110	1.41	2.50	3.38	4.16
4 × 4 ×1/4 wall thick- ness	120	1.48	2.59	3.50	4.30
6 double extra strong 0.864 wall thickness	80	0.59	1.46	2.23	2.92
6 double extra strong 0.864 wall thickness	100	0.73	1.71	2.54	3.29
6 double extra strong 0.864 wall thickness	110	0.80	1.82	2.69	3.47
6 double extra strong 0.864 wall thickness	120	0.86	1.93	2.83	3.63
6 extra strong 0.432 wall thickness	80	0.94	1.90	2.70	3.42
6 extra strong 0.432 wall thickness	100	1.10	2.13	2.98	3.74
6 extra strong 0.432 wall thickness	110	1.17	2.22	3.11	3.89
6 extra strong 0.432 wall thickness	120	1.24	2.34	3.24	4.04
6 standard 0.280 wall thickness	80	1.14	2.12	2.93	3.64
6 standard 0.280 wall thickness	100	1.29	2.33	3.19	3.94
6 standard 0.280 wall thickness	110	1.36	2.43	3.31	4.08
6 standard 0.280 wall thickness	120	1.42	2.53	3.43	4.22
5 double extra strong 0.750 wall thickness	80	0.70	1.61	2.40	3.12
5 double extra strong 0.750 wall thickness	100	0.85	1.86	2.71	3.47
5 double extra strong 0.750 wall thickness	110	0.91	1.97	2.85	3.63
5 double extra strong 0.750 wall thickness	120	0.98	2.02	2.99	3.79
5 extra strong 0.375 wall thickness	80	1.04	2.01	2.83	3.54
5 extra strong 0.375 wall thickness	100	1.19	2.23	3.09	3.85
5 extra strong 0.375 wall thickness	110	1.26	2.34	3.22	4.00
5 extra strong 0.375 wall thickness	20	1.32	2.44	3.34	4.14

(continued)

COLUMN SIZE	CONCRETE MASONRY DENSITY POUNDS PER CUBIC FOOT	MINIMUM REQUIRED EQUIVALENT THICKNESS FOR FIRE-RESISTANCE RATING OF CONCRETE MASONRY PROTECTION ASSEMBLY, T(inches) e
COLUMN SIZE	CONCRETE MASONRY DENSITY POUNDS PER CUBIC FOOT	1 hour	2 hours	3 hours	4 hours
5 standard 0.258 wall thickness	80	1.20	2.19	3.00	3.72
5 standard 0.258 wall thickness	100	1.34	2.39	3.25	4.00
5 standard 0.258 wall thickness	110	1.41	2.49	3.37	4.14
5 standard 0.258 wall thickness	120	1.47	2.58	3.49	4.28
4 double extra strong 0.674 wall thickness	80	0.80	1.75	2.56	3.28
4 double extra strong 0.674 wall thickness	100	0.95	1.99	2.85	3.62
4 double extra strong 0.674 wall thickness	110	1.02	2.10	2.99	3.78
4 double extra strong 0.674 wall thickness	120	1.09	2.20	3.12	3.93
4 extra strong 0.337 wall thickness	80	1.12	2.11	2.93	3.65
4 extra strong 0.337 wall thickness	100	1.26	2.32	3.19	3.95
4 extra strong 0.337 wall thickness	110	1.33	2.42	3.31	4.09
4 extra strong 0.337 wall thickness	120	1.40	2.52	3.43	4.23
4 standard 0.237 wall thickness	80	1.26	2.25	3.07	3.79
4 standard 0.237 wall thickness	100	1.40	2.45	3.31	4.07
4 standard 0.237 wall thickness	110	1.46	2.55	3.43	4.21
4 standard 0.237 wall thickness	120	1.53	2.64	3.54	4.34

For SI: 1 inch = 25.4 mm, 1 pound per cubic feet = 16.02 kg/m ³ . Note: Tabulated values assume 1-inch air gap between masonry and steel section.

7-86 2022 CALIFORNIA BUILDING CODE

FIRE AND SMOKE PROTECTION FEATURES

TABLE 722.5.1(6)¶

FIRE RESISTANCE OF CLAY MASONRY PROTECTED STEEL COLUMNS

COLUMN SIZE	CLAY MASONRY DENSITY, POUNDS PER CUBIC FOOT	MINIMUM REQUIRED EQUIVALENT THICKNESS FOR FIRE-RESISTANCE RATING OF CLAY MASONRY PROTECTION ASSEMBLY, T (inches) e				COLUMN SIZE	CLAY MASONRY DENSITY, POUNDS PER CUBIC FOOT	MINIMUM REQUIRED EQUIVALENT THICKNESS FOR FIRE-RESISTANCE RATING OF CLAY MASONRY PROTECTION ASSEMBLY,T (inches) e
COLUMN SIZE	CLAY MASONRY DENSITY, POUNDS PER CUBIC FOOT	1 hour	2 hours	3 hours	4 hours	4 hours	4 hours	1 hour	2 hours	3 hours	4 hours
W14 × 82	120	1.23	2.42	3.41	4.29	W10 × 68	120	1.27	2.46	3.26	4.35
W14 × 82	130	1.40	2.70	3.78	4.74	4.74	130	1.44	2.75	3.83	4.80
W14 × 68	120	1.34	2.54	3.54	4.43	W10 × 54	120	1.40	2.61	3.62	4.51
W14 × 68	130	1.51	2.82	3.91	4.87	4.87	130	1.58	2.89	3.98	4.95
W14 × 53	120	1.43	2.65	3.65	4.54	W10 × 45	120	1.44	2.66	3.67	4.57
W14 × 53	130	1.61	2.93	4.02	4.98	4.98	130	1.62	2.95	4.04	5.01
W14 × 43	120	1.54	2.76	3.77	4.66	W10 × 33	120	1.59	2.82	3.84	4.73
W14 × 43	130	1.72	3.04	4.13	5.09	5.09	130	1.77	3.10	4.20	5.13
W12 × 72	120	1.32	2.52	3.51	4.40	W8 × 40	120	1.47	2.70	3.71	4.61
W12 × 72	130	1.50	2.80	3.88	4.84	4.84	130	1.65	2.98	4.08	5.04
W12 × 58	120	1.40	2.61	3.61	4.50	W8 × 31	120	1.59	2.82	3.84	4.73
W12 × 58	130	1.57	2.89	3.98	4.94	4.94	130	1.77	3.10	4.20	5.17
W12 × 50	120	1.43	2.65	3.66	4.55	W8 × 24	120	1.66	2.90	3.92	4.82
W12 × 50	130	1.61	2.93	4.02	4.99	4.99	130	1.84	3.18	4.28	5.25
W12 × 40	120	1.54	2.77	3.78	4.67	W8 × 18	120	1.75	3.00	4.01	4.91
W12 × 40	130	1.72	3.05	4.14	5.10	5.10	130	1.93	3.27	4.37	5.34
STEEL TUBING	STEEL TUBING	STEEL TUBING	STEEL TUBING	STEEL TUBING	STEEL TUBING	STEEL PIPE	STEEL PIPE	STEEL PIPE	STEEL PIPE	STEEL PIPE	STEEL PIPE
NOMINAL TUBE SIZE (inches)	CLAY MASONRY DENSITY, POUNDS PER CUBIC FOOT	MINIMUM REQUIRED EQUIVALENT THICKNESS FOR FIRE-RESISTANCE RATING OF CLAY MASONRY PROTECTION ASSEMBLY,_T_e (inches)	MINIMUM REQUIRED EQUIVALENT THICKNESS FOR FIRE-RESISTANCE RATING OF CLAY MASONRY PROTECTION ASSEMBLY,_T_e (inches)	MINIMUM REQUIRED EQUIVALENT THICKNESS FOR FIRE-RESISTANCE RATING OF CLAY MASONRY PROTECTION ASSEMBLY,_T_e (inches)	MINIMUM REQUIRED EQUIVALENT THICKNESS FOR FIRE-RESISTANCE RATING OF CLAY MASONRY PROTECTION ASSEMBLY,_T_e (inches)	NOMINAL PIPE SIZE (inches)	CLAY MASONRY DENSITY, POUNDS PER CUBIC FOOT	MINIMUM REQUIRED EQUIVALENT THICKNESS FOR FIRE-RESISTANCE RATING OF CLAY MASONRY PROTECTION ASSEMBLY,_T_e (inches)	MINIMUM REQUIRED EQUIVALENT THICKNESS FOR FIRE-RESISTANCE RATING OF CLAY MASONRY PROTECTION ASSEMBLY,_T_e (inches)	MINIMUM REQUIRED EQUIVALENT THICKNESS FOR FIRE-RESISTANCE RATING OF CLAY MASONRY PROTECTION ASSEMBLY,_T_e (inches)	MINIMUM REQUIRED EQUIVALENT THICKNESS FOR FIRE-RESISTANCE RATING OF CLAY MASONRY PROTECTION ASSEMBLY,_T_e (inches)
NOMINAL TUBE SIZE (inches)	CLAY MASONRY DENSITY, POUNDS PER CUBIC FOOT	1 hour	2 hours	3 hours	4 hours	4 hours	4 hours	1 hour	2 hours	3 hours	4 hours
4 × 4 ×1/2 wall thickness	120	1.44	2.72	3.76	4.68	4 double extra strong 0.674 wall thickness	120	1.26	2.55	3.60	4.52
4 × 4 ×1/2 wall thickness	130	1.62	3.00	4.12	5.11	5.11	130	1.42	2.82	3.96	4.95
4 × 4 ×3/8 wall thickness	120	1.56	2.84	3.88	4.78	4 extra strong 0.337 wall thickness	120	1.60	2.89	3.92	4.83
4 × 4 ×3/8 wall thickness	130	1.74	3.12	4.23	5.21	5.21	130	1.77	3.16	4.28	5.25
4 × 4 ×1/4 wall thickness	120	1.72	2.99	4.02	4.92	4 standard 0.237 wall thickness	120	1.74	3.02	4.05	4.95
4 × 4 ×1/4 wall thickness	130	1.89	3.26	4.37	5.34	5.34	130	1.92	3.29	4.40	5.37
6 × 6 ×1/2 wall thickness	120	1.33	2.58	3.62	4.52	5 double extra strong 0.750 wall thickness	120	1.17	2.44	3.48	4.40
6 × 6 ×1/2 wall thickness	130	1.50	2.86	3.98	4.96	4.96	130	1.33	2.72	3.84	4.83
6 × 6 ×3/8 wall thickness	120	1.48	2.74	3.76	4.67	5 extra strong 0.375 wall thickness	120	1.55	2.82	3.85	4.76
6 × 6 ×3/8 wall thickness	130	1.65	3.01	4.13	5.10	5.10	130	1.72	3.09	4.21	5.18
6 × 6 ×1/4 wall thickness	120	1.66	2.91	3.94	4.84	5 standard 0.258 wall thickness	120	1.71	2.97	4.00	4.90
6 × 6 ×1/4 wall thickness	130	1.83	3.19	4.30	5.27	5.27	130	1.88	3.24	4.35	5.32
8 × 8 ×1/2 wall thickness	120	1.27	2.50	3.52	4.42	6 double extra strong 0.864 wall thickness	120	1.04	2.28	3.32	4.23
8 × 8 ×1/2 wall thickness	130	1.44	2.78	3.89	4.86	4.86	130	1.19	2.60	3.68	4.67
8 × 8 ×3/8 wall thickness	120	1.43	2.67	3.69	4.59	6 extra strong 0.432 wall thickness	120	1.45	2.71	3.75	4.65
8 × 8 ×3/8 wall thickness	130	1.60	2.95	4.05	5.02	5.02	130	1.62	2.99	4.10	5.08
8 × 8 ×1/4 wall thickness	120	1.62	2.87	3.89	4.78	6 standard 0.280 wall thickness	120	1.65	2.91	3.94	4.84
8 × 8 ×1/4 wall thickness	130	1.79	3.14	4.24	5.21	5.21	130	1.82	3.19	4.30	5.27

For SI: 1 inch = 25.4 mm, 1 pound per cubic foot = 16.02 kg/m ³ .

FIRE AND SMOKE PROTECTION FEATURES

TABLE 722.5.1(7)¶

MINIMUM COVER (inch) FOR STEEL COLUMNS

ENCASED IN NORMAL-WEIGHT CONCRETE ^a

TABLE 722.5.1(8) MINIMUM COVER (inch) FOR STEEL COLUMNS ENCASED IN STRUCTURAL LIGHTWEIGHT CONCRETE ^a

	[FIGURE 722.5.1(6)(c)]
STRUCTURAL SHAPE	FIRE-RESISTANCE RATING (HOURS)	FIRE-RESISTANCE RATING (HOURS)	FIRE-RESISTANCE RATING (HOURS)	FIRE-RESISTANCE RATING (HOURS)	FIRE-RESISTANCE RATING (HOURS)
STRUCTURAL SHAPE	1	11/2	2	3	4
W14 × 233	1	1	1	1	11/2
× 193	× 193	× 193	× 193	11/2	11/2
× 74	× 74	× 74	× 74	× 74	2
× 61	× 61	× 61	× 61	× 61	21/2
× 43	× 43	× 43	11/2	2	2
W12 × 65	1	1	1	11/2	2
× 53	× 53	× 53	× 53	2	21/2
× 40	× 40	× 40	11/2	11/2	11/2
W10 × 112	1	1	1	11/2	2
× 88	× 88	× 88	× 88	× 88	× 88
× 60	× 60	× 60	× 60	2	21/2
× 33	× 33	× 33	11/2	11/2	11/2
W8 × 35	1	1	11/2	2	21/2
× 28	× 28	× 28	× 28	× 28	3
× 24	× 24	× 24	× 24	21/2	21/2
× 18	× 18	11/2	11/2	11/2	11/2

For SI: 1 inch = 25.4 mm. a. The tabulated thicknesses are based on the assumed properties of

structural lightweight concrete given in Table 722.5.1(2).

	[FIGURE 722.5.1(6)(c)]
STRUCTURAL SHAPE	FIRE-RESISTANCE RATING (hours)	FIRE-RESISTANCE RATING (hours)	FIRE-RESISTANCE RATING (hours)	FIRE-RESISTANCE RATING (hours)	FIRE-RESISTANCE RATING (hours)
STRUCTURAL SHAPE	1	11/2	2	3	4
W14 × 233	1	1	1	11/2	2
× 176	× 176	× 176	× 176	× 176	21/2
× 132	× 132	× 132	× 132	2	2
× 90	× 90	× 90	11/2	11/2	11/2
× 61	× 61	× 61	× 61	× 61	3
× 48	× 48	11/2	11/2	21/2	21/2
× 43	× 43	× 43	× 43	× 43	× 43
W12 × 152	1	1	1	2	21/2
× 96	× 96	× 96	× 96	× 96	× 96
× 65	× 65	11/2	11/2	11/2	3
× 50	× 50	× 50	× 50	21/2	21/2
× 40	× 40	× 40	× 40	× 40	× 40
W10 × 88	1	11/2	11/2	2	3
× 49	1	1	1	21/2	21/2
× 45	× 45	× 45	× 45	× 45	× 45
× 39	× 39	× 39	× 39	× 39	31/2
× 33	× 33	× 33	2	2	2
W8 × 67	1	1	11/2	21/2	3
× 58	× 58	× 58	× 58	× 58	× 58
× 48	× 48	11/2	11/2	11/2	31/2
× 31	× 31	× 31	2	3	3
× 21	× 21	× 21	× 21	× 21	× 21
× l8	× l8	× l8	× l8	× l8	4
W6 × 25	1	11/2	2	3	31/2
× 20	× 20	2	21/2	21/2	4
× 16	× 16	× 16	× 16	31/2	31/2
× 15	11/2	11/2	11/2	11/2	11/2
× 9	× 9	× 9	× 9	× 9	× 9

For SI: 1 inch = 25.4 mm. a. The tabulated thicknesses are based on the assumed properties of normal weight concrete given in Table 722.5.1(2).

7-88 2022 CALIFORNIA BUILDING CODE

TABLE 722.5.1(9)¶

MINIMUM COVER (inch) FOR STEEL COLUMNS

IN NORMAL-WEIGHT PRECAST COVERS ^a

FIRE AND SMOKE PROTECTION FEATURES

TABLE 722.5.1(10) MINIMUM COVER (inch) FOR STEEL COLUMNS IN STRUCTURAL LIGHTWEIGHT PRECAST COVERS ^a

[FIGURE 722.5.1 (6)(a)]

STRUCTURAL SHAPE	1	RE-RESIS 11/ 2	TANCE RA 2	TING (hour 3	4	STRUCTURAL SHAPE	1	RE-RESIS 11/ 2	TANCE RA 2	TING (hour 3	4
W14 × 233 × 211 × 176 × 145 × 109	11/2	11/2	11/2 2	21/2 3	3 31/2	W14 × 233 × 176 × 145 × 132 × 109	11/2	11/2	11/2	2 21/2	21/2 3
× 99 × 61 × 43		2	21/2	31/2	4 41/2	× 99 × 68 × 43			2	3	31/2
W12 × 190 × 152 × 120 × 96 × 87 × 58 × 40 W10 × 112 × 88	11/2	11/2 2 11/2	11/2 2 21/2 2	21/2 3 31/2 3	31/2 4 41/2 31/2	W12 × 190 × 152 × 136 × 106 × 96 × 87 × 65 × 40 W10 × 112	11/2	11/2	11/2 2	2 21/2 3 2	21/2 3 31/2
× 77	11/2				4	× 100			11/2		3
× 54 × 33		2	21/2	31/2	41/2	× 88 × 77	11/2	11/2		21/2
W8 × 67 × 58 × 48 × 28	11/2	11/2 2	2 21/2	3 31/2	4	× 60 × 39 × 33 W8 × 67		2	2 11/2	3 21/2	31/2 3
× 21 × 18 W6 × 25 × 20 × 16 × 12 × 9	11/2 2	21/2 2 21/2	3 21/2 3	4 31/2 4	41/2 41/2 5	× 48 × 35 × 28 × 18 W6 × 25 × 15 × 9	11/2 11/2	11/2 2 2	2 21/2 2 21/2	3 3 31/2	31/2 4 31/2 4

For SI: 1 inch = 25.4 mm. a. The tabulated thicknesses are based on the assumed properties of normal weight concrete given in Table 722.5.1(2).

For SI: 1 inch = 25.4 mm. a. The tabulated thicknesses are based on the assumed properties of structural

lightweight concrete given in Table 722.5.1(2).

FIRE AND SMOKE PROTECTION FEATURES

SNAP-LOCK PITTSBURGH SEAM LAP

CORNER JOINT DETAILS (A)

For SI:1 inch = 25.4 mm, 1 foot = 305 mm. 1.Structural steel column, either wide flange or tubular shapes. 2. Type X gypsum board or gypsum panel products in accordance with ASTM C1177, C1178, C1278, C1396 or C1658. The total thickness of gypsum board or gypsum panel products calculated as h in Section 722.5.1.2 shall be applied vertically to an individual column using one of the following methods:

SI:1 inch = 25.4 mm, 1 foot = 305 mm. 1.Structural steel column, either wide flange or tubular shapes. 2. Type X gypsum board or gypsum panel products in accordance with ASTM C1177, C1178, C1278, C1396 or C1658. The total thickness of gypsum board or gypsum panel products calculated as h in Section 722.5.1.2 shall be applied vertically to an individual column using one of the following methods:

As a single layer without horizontal joints.
As multiple layers with horizontal joints not permitted in any layer.
As multiple layers with horizontal joints staggered not less than 12 inches vertically between layers and not less than 8 feet vertically in any single layer. The total required thickness of gypsum board or gypsum panel products shall be determined on the basis of the specified fireresistance rating and the weight-to-heated-perimeter ratio (W/D) of the column. For fire-resistance ratings of 2 hours or less, one of the required layers of gypsum board or gypsum panel product may be applied to the exterior of the sheet steel column covers with 1-inch long Type S screws spaced 1 inch from the wallboard edge and 8 inches on center. For such installations, 0.0149-inch minimum thickness galvanized steel corner beads with 1 ¹ /2-inch legs shall be attached to the wallboard with Type S screws spaced 12 inches on center. 3.For fire-resistance ratings of 3 hours or less, the column covers shall be fabricated from 0.0239-inch minimum thickness galvanized or stainless steel. For 4-hour fire-resistance ratings, the column covers shall be fabricated from 0.0239-inch minimum thickness stainless steel. The column covers shall be erected with the Snap Lock or Pittsburgh joint details. For fire-resistance ratings of 2 hours or less, column covers fabricated from 0.0269-inch minimum thickness galvanized or stainless steel shall be permitted to be erected with lap joints. The lap joints shall be permitted to be located anywhere around the perimeter of the column cover. The lap joints shall be secured with ¹ /2-inch-long No. 8 sheet metal screws spaced 12 inches on center. The column covers shall be provided with a minimum expansion clearance of ¹ /8 inch per linear foot between the ends of the cover and any restraining construction.

FIGURE 722.5.1(2) GYPSUM-PROTECTED STRUCTURAL STEEL COLUMNS WITH SHEET STEEL COLUMN COVERS

For SI:1 inch = 25.4 mm, 1 foot = -305 mm. 1.Structural steel column, either wide flange or tubular shapes. 2.1 ⁵ /8-inch deep studs fabricated from 0.0179-inch minimum thickness galvanized steel with 1 ⁵ /16 or 1 ⁷ /16-inch legs. The length of the steel studs shall be ¹ /2 inch less than the height of the assembly. 3. Type X gypsum board or gypsum panel products in accordance with ASTM C1177, C1178, C1278, C1396 or C1658. The total thickness of gypsum board or gypsum panel products calculated as h in Section 722.5.1.2 shall be applied vertically to an individual column using one of the following methods:

legs. The length of the steel studs shall be ¹ /2 inch less than the height of the assembly. 3. Type X gypsum board or gypsum panel products in accordance with ASTM C1177, C1178, C1278, C1396 or C1658. The total thickness of gypsum board or gypsum panel products calculated as h in Section 722.5.1.2 shall be applied vertically to an individual column using one of the following methods:

As a single layer without horizontal joints.
As multiple layers with horizontal joints not permitted in any layer.
As multiple layers with horizontal joints staggered not less than 12 inches vertically between layers and not less than 8 feet vertically in any single layer. The total required thickness of gypsum board or gypsum panel products shall be determined on the basis of the specified fire-resistance rating and the weight-to-heated-perimeter ratio (W/D) of the column. 4.Galvanized 0.0149-inch minimum thickness steel corner beads with 1 ¹ /2inch legs attached to the gypsum board or gypsum panel products with 1inch-long Type S screws spaced 12 inches on center. 5.No. 18 SWG steel tie wires spaced 24 inches on center. 6.Sheet metal angles with 2-inch legs fabricated from 0.0221-inch minimum thickness galvanized steel. 7.Type S screws, 1 inch long, shall be used for attaching the first layer of gypsum board or gypsum panel product to the steel studs and the third layer to the sheet metal angles at 24 inches on center. Type S screws 1 ³ /4 inches long shall be used for attaching the second layer of gypsum board or gypsum panel product to the steel studs and the fourth layer to the sheet metal angles at 12 inches on center. Type S screws 2 ¹ /4 inches long shall be used for attaching the third layer of gypsum board or gypsum panel product to the steel studs at 12 inches on center.

FIGURE 722.5.1(3) GYPSUM-PROTECTED STRUCTURAL STEEL COLUMNS

WITH STEEL STUD/SCREW ATTACHMENT SYSTEM

3 LAYERS = 1 ⁷ /8 ″ OR 1½ ″

4 LAYERS = 2½ ″ OR 2 ″

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2½ ″ 4

1½

2 ″ 1 ⁷ /8 ″ 1½ ″ 1¼ ″

1 ″

5/8 ″

½ ″

FIRE AND SMOKE PROTECTION FEATURES

FIGURE 722.5.1(5) WIDE FLANGE STRUCTURAL STEEL COLUMNS WITH

SPRAYED FIRE-RESISTANT MATERIALS

0.5 1.0 1.5 2.0 2.5 3.0 3.5

WEIGHT-TO-HEATED-PERIMETER RATIO (W/D) ^a

For SI:1 inch = 25.4 mm, 1 pound per linear foot/inch = 0.059 kg/m/mm. a.The W/D ratios for typical wide flange columns are listed in Table

722.5.1(1). For other column shapes, the W/D ratios shall be determined in accordance with Section 722.5.1.1.

FIGURE 722.5.1(4) FIRE RESISTANCE OF STRUCTURAL STEEL COLUMNS PROTECTED WITH VARIOUS THICKNESSES OF TYPE X GYPSUM WALLBOARD

(a) PRECAST CONCRETE

COLUMN

COVERS

(b) CONCRETE

ENCASED STRUCTURAL

TUBE

ENCASED WIDE-FLANGE

SHAPE

a.Where the inside perimeter of the concrete protection is not square, L shall be taken as the average of L 1 and L 2. Where the thickness of concrete cover is not

constant, h shall be taken of the average of h 1 and h 2. b. Joints shall be protected with not less than a 1-inch thickness of ceramic fiber blanket but in no case less than one-half the thickness of the column cover (see

Section 722.2.1.3).

FIGURE 722.5.1(6) CONCRETE PROTECTED STRUCTURAL STEEL COLUMNS ^{a, b}

FIRE AND SMOKE PROTECTION FEATURES

D=2(w+d)+2(w-tweb) D = ϖ d D = 2w + 2d

W SHAPE COLUMN STEEL PIPE COLUMN STRUCTURAL TUBE COLUMN

For SI:1 inch = 25.4 mm. d = Depth of a wide flange column, outside diameter of pipe column, or outside dimension of structural tubing column (inches). tweb = Thickness of web of wide flange column (inches). w = Width of flange of wide-flange column (inches).

FIGURE 722.5.1(7)

determined from the following expression:

where:

R = Fire resistance (minutes). h = Thickness of sprayed fire-resistant material

(inches). D = Heated perimeter of the structural steel column

(inches). C1 and C2 = Material-dependent constants. W = Weight of structural steel columns (pounds per

linear foot).

The fire resistance of structural steel columns protected with intumescent or mastic fire-resistant coatings shall be determined on the basis of fire-resistance tests in accordance with Section 703.2.

722.5.1.3.1 Material-dependent constants.¶

The material-dependent constants, C1 and C2, shall be determined for specific fire-resistant materials on the basis of standard fire endurance tests in accordance with Section 703.2. Unless evidence is submitted to the building official substantiating a broader application, this expression shall be limited to determining the fire resistance of structural steel columns with weight-to-heated-perimeter ratios ( W/D ) between the largest and smallest columns for which standard fireresistance test results are available.

722.5.1.3.2 Identification.¶

Sprayed fire-resistant materials shall be identified by density and thickness required for a given fire-resistance rating.

Ro = 10 ( W/D ) ^0.7 + 17 ( h ^1.6 / kc 0.2) ×

[1 + 26 { H/pccch ( L + h) } ^0.8 ]

As used in these expressions: R = Fire endurance at equilibrium moisture conditions (minutes). Ro = Fire endurance at zero moisture content

(minutes). m = Equilibrium moisture content of the concrete by

volume (percent). W = Average weight of the structural steel column

(pounds per linear foot). D = Heated perimeter of the structural steel column

(inches). h = Thickness of the concrete cover (inches). kc = Ambient temperature thermal conductivity of the

concrete (Btu/hr ft °F). H = Ambient temperature thermal capacity of the

steel column = 0.11W (Btu/ ft °F). pc = Concrete density (pounds per cubic foot). cc = Ambient temperature specific heat of concrete

(Btu/lb °F). L = Interior dimension of one side of a square

concrete box protection (inches).

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722.5.1.4.1 Reentrant space filled.¶

For wide-flange structural steel columns completely encased in concrete with all reentrant spaces filled Figure 722.5.1(6), illustration (c), the thermal capacity of the concrete within the reentrant spaces shall be permitted to be added to the thermal capacity of the steel column, as follows:

H = 0.11 W + ( pccc /144) ( bfd - As )

where:

(Equation 7-15)

FIRE AND SMOKE PROTECTION FEATURES

Te = Equivalent thickness of concrete or clay

masonry unit (inches) (see Table 722.3.2, Note a or Section 722.4.1). K = Thermal conductivity of concrete or clay

masonry unit (Btu/hr × ft × °F) [see Table 722.5.1(3)]. As = Cross-sectional area of structural steel column

(square inches). dm = Density of the concrete or clay masonry unit

(pounds per cubic foot). p = Inner perimeter of concrete or clay masonry

protection (inches) [see Figure 722.5.1(7)].

bf = Flange width of the structural steel column

(inches).

722.5.1.4.6 Equivalent concrete masonry thick-ness.¶

ness. For structural steel columns protected with concrete masonry, Table 722.5.1(5) gives the equivalent thickness of concrete masonry required for various fire-resistance ratings for typical column shapes. For structural steel columns protected with clay masonry, Table 722.5.1(6) gives the equivalent thickness of concrete masonry required for various fire-resistance ratings for typical column shapes.

722.5.2 Structural steel beams and girders. The fireresistance ratings of structural steel beams and girders shall be based on the size of the element and the type of protection provided in accordance with this section.

722.5.2.1 Determination of fire resistance.¶

These procedures establish a basis for determining resistance of structural steel beams and girders that differ in size from that specified in approved fire-resistance-rated assemblies as a function of the thickness of fire-resistant material and the weight ( W) and heated perimeter (D) of the beam or girder. As used in these sections, W is the average weight of a structural steel element in pounds per linear foot (plf). The heated perimeter, D, is the inside perimeter of the fire-resistant material in inches as illustrated in Figure 722.5.2.

722.5.2.1.1 Weight-to-heated perimeter.¶

The weight-to-heated-perimeter ratios (W/D), for both contour and box fire-resistant protection profiles, for the wide flange shapes most often used as beams or girders are given in Table 722.5.1(4). For different shapes, the weight-to-heated-perimeter ratios (W/D) shall be determined in accordance with the definitions given in this section.

722.5.2.1.2 Beam and girder substitutions. Except as provided for in Section 722.5.2.2, structural steel beams in approved fire-resistance-rated assemblies shall be considered to be the minimum permissible size. Other beam or girder shapes shall be permitted to be substituted provided that the weight-to-heatedperimeter ratio (W/D) of the substitute beam is equal to or greater than that of the beam specified in the approved assembly.

722.5.2.2 Sprayed fire-resistant materials.¶

The provisions in this section apply to structural steel beams and girders protected with sprayed fire-resistant materials. Larger or smaller beam and girder shapes shall be

d = Depth of the structural steel column (inches).

As = Cross-sectional area of the steel column

(square inches).

722.5.1.4.2 Concrete properties unknown. If specific data on the properties of concrete are not available, the values given in Table 722.5.1(2) are permitted.

722.5.1.4.3 Minimum concrete cover.¶

For structural steel column encased in concrete with all reentrant spaces filled, Figure 722.5.1(6), illustration (c) and Tables 722.5.1(7) and 722.5.1(8) indicate the thickness of concrete cover required for various fireresistance ratings for typical wide-flange sections. The thicknesses of concrete indicated in these tables apply to structural steel columns larger than those specified.

722.5.1.4.4 Minimum precast concrete cover. For structural steel columns protected with precast concrete column covers as shown in Figure 722.5.1(6), illustration (a), Tables 722.5.1(9) and 722.5.1(10) indicate the thickness of the column covers required for various fire-resistance ratings for typical wide-flange shapes. The thicknesses of concrete given in these tables apply to structural steel columns larger than those specified.

722.5.1.4.5 Masonry protection.¶

The fire resistance of structural steel columns protected with concrete masonry units or clay masonry units as illustrated in Figure 722.5.1(7) shall be permitted to be determined from the following expression:

R = 0.17 ( W/D ) ^0.7 + [0.285 ( Te 1.6/ K 0.2)]

[1.0 + 42.7 {( As/dm Te )/(0.25 p + Te )} ^0.8 ]

(Equation 7-16)

where:

R = Fire-resistance rating of column assembly

(hours).

W = Average weight of structural steel column

(pounds per foot).

D = Heated perimeter of structural steel column

(inches) [see Figure 722.5.1(7)].

FIRE AND SMOKE PROTECTION FEATURES

D = 3bf + 2d - 2tw D = 2d + bf

FIGURE 722.5.2 DETERMINATION OF THE HEATED PERIMETER OF

STRUCTURAL STEEL BEAMS AND GIRDERS

permitted to be substituted for beams specified in approved unrestrained or restrained fire-resistancerated assemblies, provided that the thickness of the fireresistant material is adjusted in accordance with the following expression:

h 2 = h 1 [( W 1 / D 1) + 0.60] / [( W 2 / D 2) + 0.60]

(Equation 7-17)

where:

h = Thickness of sprayed fire-resistant material in

inches. W = Weight of the structural steel beam or girder in

pounds per linear foot. D = Heated perimeter of the structural steel beam in

inches.

Subscript 1 refers to the beam and fire-resistant material thickness in the approved assembly.

Subscript 2 refers to the substitute beam or girder and the required thickness of fire-resistant material.

The fire resistance of structural steel beams and girders protected with intumescent or mastic fire-resistant coatings shall be determined on the basis of fireresistance tests in accordance with Section 703.2.

722.5.2.2.1 Minimum thickness.¶

The use of Equation 7-17 is subject to the following conditions:

The weight-to-heated-perimeter ratio for the substitute beam or girder (W 2 /D 2 ) shall be not less than 0.37.
The thickness of fire protection materials calculated for the substitute beam or girder (T 1 ) shall be not less than ³ /8 inch (9.5 mm).
The unrestrained or restrained beam rating shall be not less than 1 hour.
Where used to adjust the material thickness for a restrained beam, the use of this procedure is limited to structural steel sections classified as compact in accordance with AISC 360.

722.5.2.3 Structural steel trusses.¶

The fire resistance of structural steel trusses protected with fire-resistant materials sprayed to each of the individual truss

elements shall be permitted to be determined in accordance with this section. The thickness of the fireresistant material shall be determined in accordance with Section 722.5.1.3. The weight-to-heated-perimeter ratio ( W/D ) of truss elements that can be simultaneously exposed to fire on all sides shall be determined on the same basis as columns, as specified in Section 722.5.1.1. The weight-to-heated-perimeter ratio ( W/D ) of truss elements that directly support floor or roof assembly shall be determined on the same basis as beams and girders, as specified in Section 722.5.2.1.

The fire resistance of structural steel trusses protected with intumescent or mastic fire-resistant coatings shall be determined on the basis of fire resistance tests in accordance with Section 703.2.

722.6 Wood assemblies.¶

The provisions of this section contain procedures by which the fire-resistance ratings of wood assemblies are established by calculations.

722.6.1 General. This section contains procedures for calculating the fire-resistance ratings of walls, floor/ceiling and roof/ceiling assemblies based in part on the standard method of testing referenced in Section 703.2.

722.6.1.1 Maximum fire-resistance rating. Fire-resistance ratings calculated for assemblies using the methods in Section 722.6 shall be limited to not more than 1 hour.

722.6.1.2 Dissimilar membranes. Where dissimilar membranes are used on a wall assembly that requires consideration of fire exposure from both sides, the calculation shall be made from the least fire-resistant (weaker) side.

722.6.2 Walls, floors and roofs. These procedures apply to both load-bearing and nonload-bearing assemblies.

722.6.2.1 Fire-resistance rating of wood frame assemblies. The fire-resistance rating of a wood frame assembly is equal to the sum of the time assigned to the membrane on the fire-exposed side, the time assigned to the framing members and the time assigned for additional contribution by other protective measures such as insulation. The membrane on the unexposed side shall not be included in determining the fire resistance of the assembly.

722.6.2.2 Time assigned to membranes. Table 722.6.2(1) indicates the time assigned to membranes on the fire-exposed side.

722.6.2.3 Exterior walls. For an exterior wall with a fire separation distance greater than 10 feet (3048 mm), the wall is assigned a rating dependent on the interior membrane and the framing as described in Table 722.6.2(1) and Table 722.6.2(2). The membrane on the outside of the nonfire-exposed side of exterior walls with a fire separation distance greater than 10 feet (3048 mm) shall consist of sheathing, sheathing paper and siding as described in Table 722.6.2(3).

722.6.2.4 Floors and roofs. In the case of a floor or roof, the standard test provides only for testing for fire exposure from below. Except as noted in Section 703.2.3, floor or roof assemblies of wood framing shall

7-94 2022 CALIFORNIA BUILDING CODE

have an upper membrane consisting of a subfloor and finished floor conforming to Table 722.6.2(4) or any other membrane that has a contribution to fire resistance of not less than 15 minutes in Table 722.6.2(1).

722.6.2.5 Additional protection. Table 722.6.2(5) indicates the time increments to be added to the fire resistance where glass fiber, rockwool, slag mineral wool or cellulose insulation is incorporated in the assembly.

722.6.2.6 Fastening. Fastening of wood frame assemblies and the fastening of membranes to the wood framing members shall be done in accordance with Chapter 23.

722.7 Fire-resistance rating for mass timber.¶

The required fire resistance of mass timber elements in Section 602.4 shall be determined in accordance with Section 703.2 or Section 703.3. The fire-resistance rating of building elements shall be as required in Tables 601 and 705.5 and as specified elsewhere in this code. The fire-resistance rating of the mass

FIRE AND SMOKE PROTECTION FEATURES

timber elements shall consist of the fire resistance of the unprotected element added to the protection time of the noncombustible protection.

722.7.1 Minimum required protection. Where required by Sections 602.4.1 through 602.4.3, noncombustible protection shall be provided for mass timber building elements in accordance with Table 722.7.1(1). The rating, in minutes, contributed by the noncombustible protection of mass timber building elements, components or assemblies, shall be established in accordance with Section 703.6. The protection contributions indicated in Table 722.7.1(2) shall be deemed to comply with this requirement where installed and fastened in accordance with Section 722.7.2.

722.7.2 Installation of gypsum board noncombustible protection. Gypsum board complying with Table 722.7.1(2) shall be installed in accordance with this section.

TABLE 722.6.2(1) TIME ASSIGNED TO WALLBOARD MEMBRANES ^{a, b, c, d}

DESCRIPTION OF FINISH	TIMEe (minutes)
3/8-inch wood structural panel bonded with exterior glue	5
15/32-inch wood structural panel bonded with exterior glue	10
19/32-inch wood structural panel bonded with exterior glue	15
3/8-inch gypsum wallboard	10
1/2-inch gypsum wallboard	15
5/8-inch gypsum wallboard	30
1/2-inch Type X gypsum wallboard	25
5/8-inch Type X gypsum wallboard	40
Double3/8-inch gypsum wallboard	25
1/2-inch +3/8-inch gypsum wallboard	35
Double1/2-inch gypsum wallboard	40

For SI: 1 inch = 25.4 mm. a. These values apply only where membranes are installed on framing members that are spaced 16 inches o.c. or less. b. Gypsum wallboard installed over framing or furring shall be installed so that all edges are supported, except ⁵ /8-inch Type X gypsum wallboard shall be

permitted to be installed horizontally with the horizontal joints staggered 24 inches each side and unsupported but finished. c. On wood frame floor/ceiling or roof/ceiling assemblies, gypsum board shall be installed with the long dimension perpendicular to framing members and shall

have all joints finished. d. The membrane on the unexposed side shall not be included in determining the fire resistance of the assembly. Where dissimilar membranes are used on a wall

assembly, the calculation shall be made from the least fire-resistant (weaker) side. e. The time assigned is not a finished rating.

TABLE 722.6.2(2) TIME ASSIGNED FOR CONTRIBUTION OF WOOD FRAME ^{a, b, c}

DESCRIPTION	TIME ASSIGNED TO FRAME (minutes)
Wood studs 16 inches o.c.	20
Wood floor and roof joists 16 inches o.c.	10

For SI: 1 inch = 25.4 mm. a. This table does not apply to studs or joists spaced more than 16 inches o.c. b. All studs shall be nominal 2 × 4 and all joists shall have a nominal thickness of not less than 2 inches. c. Allowable spans for joists shall be determined in accordance with Sections 2308.4.2.1, 2308.7.1 and 2308.7.2.

FIRE AND SMOKE PROTECTION FEATURES

TABLE 722.6.2(3) MEMBRANE ^a ON EXTERIOR FACE OF WOOD STUD WALLS

SHEATHING	PAPER	EXTERIOR FINISH
5/8-inch T & G lumber 5/16-inch exterior glue wood structural panel 1/2-inch gypsum wallboard 5/8-inch gypsum wallboard 1/2-inch fiberboard	Sheathing paper	Lumber siding Wood shingles and shakes 1/4-inch fiber-cement lap, panel or shingle siding 1/4-inch wood structural panels-exterior type 1/4-inch hardboard Metal siding Stucco on metal lath Masonry veneer Vinyl siding
None	—	3/8-inch exterior-grade wood structural panels

For SI: 1 inch = 25.4 mm. a. Any combination of sheathing, paper and exterior finish is permitted.

TABLE 722.6.2(4) FLOORING OR ROOFING OVER WOOD FRAMING ^a

ASSEMBLY	STRUCTURAL MEMBERS	SUBFLOOR OR ROOF DECK	FINISHED FLOORING OR ROOFING
Floor	Wood	15/32-inch wood structural panels or11/16-inch T & G softwood	Hardwood or softwood flooring on building paper; resilient flooring; par- quet floor; felted-synthetic fiber floor coverings, carpeting, or ceramic tile on1/4-inch-thick fiber-cement underlayment or3/8-inch-thick panel-type underlayment; ceramic tile on 11/4-inch mortar bed.
Roof	Wood	15/32-inch wood structural panels or11/16-inch T & G softwood	Finished roofing material with or without insulation

For SI: 1 inch = 25.4 mm. a. This table applies only to wood joist construction. It is not applicable to wood truss construction.

TABLE 722.6.2(5) TIME ASSIGNED FOR ADDITIONAL PROTECTION

For SI: 1 pound/cubic foot = 16.0185 kg/m ³ .

722.7.2.1 Interior surfaces. Layers of Type X gypsum board serving as noncombustible protection for interior surfaces of wall and ceiling assemblies determined in accordance with Table 722.7.1(1) shall be installed in accordance with the following:

Each layer shall be attached with Type S drywall screws of sufficient length to penetrate the mass timber at least 1 inch (25 mm) when driven flush with the paper surface of the gypsum board.

Exception: The third layer, where determined necessary by Section 722.7, shall be permitted to be attached with 1-inch (25 mm) No. 6 Type S drywall screws to furring channels in accordance with AISI S220.

Screws for attaching the base layer shall be 12 inches (305 mm) on center in both directions.
Screws for each layer after the base layer shall be 12 inches (305 mm) on center in both directions and offset from the screws of the previous layers by 4 inches (102 mm) in both directions.
All panel edges of any layer shall be offset 18 inches (457 mm) from those of the previous layer.
All panel edges shall be attached with screws sized and offset as in Items 1 through 4 and placed at least 1 inch (25 mm) but not more than 2 inches (51 mm) from the panel edge.
All panels installed at wall-to-ceiling intersections shall be installed such that ceiling panels are

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installed first and the wall panels are installed after the ceiling panel has been installed and is fitted tight to the ceiling panel. Where multiple layers are required, each layer shall repeat this process.

All panels installed at a wall-to-wall intersection shall be installed such that the panels covering an exterior wall or a wall with a greater fire-resistance rating shall be installed first and the panels covering the other wall shall be fitted tight to the panel covering the first wall. Where multiple layers are required, each layer shall repeat this process.
Panel edges of the face layer shall be taped and finished with joint compound. Fastener heads shall be covered with joint compound.
Panel edges protecting mass timber elements adjacent to unprotected mass timber elements in accordance with Section 602.4.2.2 shall be cov

FIRE AND SMOKE PROTECTION FEATURES

ered with 1 ¹ /4-inch (32 mm) metal corner bead and finished with joint compound.

722.7.2.2 Exterior surfaces. Layers of Type X gypsum board serving as noncombustible protection for the outside of the exterior mass timber walls determined in accordance with Table 722.7.1(1) shall be fastened 12 inches (305 mm) on center each way and 6 inches (152 mm) on center at all joints or ends. All panel edges shall be attached with fasteners located at least 1 inch (25 mm) but not more than 2 inches (51 mm) from the panel edge. Fasteners shall comply with one of the following:

Galvanized nails of minimum 12 gage with a ⁷ /16inch (11 mm) head of sufficient length to penetrate the mass timber a minimum of 1 inch (25 mm).
Screws that comply with ASTM C1002 (Type S, W or G) of sufficient length to penetrate the mass timber a minimum of 1 inch (25 mm).

TABLE 722.7.1(1) PROTECTION REQUIRED FROM NONCOMBUSTIBLE COVERING MATERIAL

REQUIRED FIRE-RESISTANCE RATING OF BUILDING ELEMENT PER TABLE 601 AND TABLE 705.5 (hours)	MINIMUM PROTECTION REQUIRED FROM NONCOMBUSTIBLE PROTECTION (minutes)
1	40
2	80
3 or more	120

TABLE 722.7.1(2) PROTECTION PROVIDED BY NONCOMBUSTIBLE COVERING MATERIAL

NONCOMBUSTIBLE PROTECTION	PROTECTION CONTRIBUTION (minutes)
1/2-inch Type X gypsum board	25
5/8-inch Type X gypsum board	40

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CALIFORNIA BUILDING CODE – MATRIX ADOPTION TABLE