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Earlier editions: 20222019

Index

Index — V

California Mechanical Code (Title 24, Part 4) · 2025 edition · updated 2026-10-23 · California

CBSC: official editions, supplements and errata

Italicized text is a California amendment to the model code, as printed in the official publication.

Cite as: 2025 California Mechanical Code (Title 24, Part 4) · Effective January 1, 2026 · Official source: Building Standards Commission

– V –

VALIDITY OF PERMITS . . . . . . . . . . . . . . . . . . . . . .104.4.2

VALVE TYPES

Bleed lines for diaphragm-type . . . . . . . . . . . . . .902.15 Companion or block, definition . . . . . . . . . . . . . . .224.0

Pressure relief . . . . . . . . . . . . . . . . . . . . . .224.0, 904.7,

926.4, 1112.0,

1113.0, 1115.4, C 109.1

Safety or relief . . . . . . . . . . . . .1005.0, 1009.0, C 109.1

Shutoff . . . . . . . . . .904.7, 1006.0, 1308.12, 1310.10.1.1,

1310.11, 1312.3.1, 1312.3.2,

1312.5.3, 1312.6, 1406.2.1.5,

C 109.1, D 103.0, D 104.3,

D 110.4, D 112.3

Stop . . . . . . . . . . . . . . . . . . . . . . . . . . . . .224.0, 1112.6

VALVES

For fuel gas piping . . . . . . . . . . . .1308.4.1, 1308.4.7.5,

1308.10.1, 1308.12, 1309.1,

1310.3.3.1, 1310.10.1.1,

1310.11, 1310.14.6,

1312.3.1, 1312.3.2,

1312.5.3, 1312.6, 1312.9,

1313.1.4, 1313.1.5,

D 103.0, D 104.3, D 110.4,

D 112.3, D 113.3

For hydronics . . . . . . . . . . . . . . . . . . . . . . . . . . . .1212.0

For mobile home parks . . . .D 103.0, D 104.3, D 110.4,

D 112.3, D 113.3

For recreational vehicle park . . . . . . .D 103.0, D 104.3,

D 110.4, D 112.3, D 113.3

For refrigeration systems . . . . . . . . . . . .1105.3, 1109.0,

1110.0, 1112.6,

1112.9, 1113.6

VENT

Appliances not requiring vents . . . . . . . . . . . . . .802.2.1 Caps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .802.7.4(3)

Clearance . . . . . . . . . . . . . . .802.7.3.4, Table 303.10.1,

Table 802.7.3.3

Dampers . . . . . . . . . . . . . . . . .802.13, 802.14, 802.14.1

Direct vent . . . . . . . . . . . . . . . . . . . . . . . . . . . . .802.2.6

General requirements . . . . . . . . . . . . . . . . . . . . . .802.0

Insulation shield . . . . . . . . . . . . . . . . . . . . . . . .802.6.1.1

Integral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .802.2.7

Listing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .802.1

Mechanical draft . . . . . . . . . . . . . . . .802.3.3–802.3.3.4

Obstruction of flow . . . . . . . . . . . . . . . . . . . . . . .802.15

Plastic piping . . . . . . . . . . . . . . . . . . . . . . . . . . .802.4.1 Special . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .802.4.3

Termination . . . . . . . . . . . . . . . . . . . . .802.6.1, 802.7.2,

802.8

Wall penetration . . . . . . . . . . . . . . . . . . . . . . . . . .802.8

VENT, ATTIC . . . . . . . . . . . . . . . . . . .802.10.1.1, 802.10.1.2

VENT, GAS . . . . . . . . . . . . . . .224.0, 802.4, 802.6, 802.6.2,

802.6.2.1, 802.6.2.2

VENT, GAS CONNECTORS . . . . . . . . . . .(see Connectors,

gas vent) VENT DAMPERS . . . . . . . . . . . . . . . . . . . . .(see Dampers)

VENT SIZING

Category I appliances . . . . . . . . . . . . .802.6.2.1, 803.0

Multiple appliances . . . . . . . . . . . . . . . . . . . . . . .803.2,

Table 803.2(1)–Table 803.2(9)

Multistory . . . . . . . . . . . . . . . . . . . . .802.6.3, 802.6.3.2,

803.2.16

Single appliance . . . . .802.7.4(1)(b), 802.10.2.1, 803.1,

Table 803.1.2(1)–Table 803.1.2(6)

VENTED

Decorative appliances . . . . . . . . . . . . . . . .224.0, 911.0,

Table 802.4

Equipment not

required to be . . . . . . . . . . . . . . . . . . . . . . . . .802.2.1

Fireplaces . . . . . . . . . . . . . . . . . . . . . . .912.0, E 602.0,

Table 1308.3.1

Wall furnace . . . . . . . . . . . . . .224.0, 907.2, Table 802.4

VENTED APPLIANCE CATEGORIES

Category I . . . . . . . . . . . . . . . .224.0, 701.1.1, 802.6.2.1,

802.6.3, 802.10, 802.10.1.1,

802.10.3.2, 803.0,

Appendix F, Table 802.4,

Table 803.1.2(1)–Table 803.1.2(4),

Table 803.2(1)–Table 803.2(4)

Category II . . . . . . . . . . . . . . . . . . . . .224.0, 802.6.2.3,

802.9, 802.11, Table 802.4

Category III . . . . . . . . . . . . . . . . . . . . .224.0, 802.6.2.3,

802.9.1, Table 802.4

Category IV. . . . . . . . . . . . . . . . . . . . . 224.0, 802.6.2.3,

802.9, 802.11, Table 802.4

VENTILATED SPACES . . . . . . . . . . . . . . . . . . . . . . 802.2.5

VENTILATING

Ceiling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224.0, 607.0

Equipment . . . . . . . . . . . . . . . . . . . . . . 513.4.2, 514.1.2

Hoods . . . . . . . . . . . . . . . . . . . . . . . . . 802.2.4, 802.3.4,

919.5.2, 921.2

Kits for use in refrigerators. . . . . . . . . . . . . . . . . . . 927.3

Portable, equipment, definition . . . . . . . . . . . . . . . 218.0

VENTILATION

Air balance . . . . . . . . . . . . . . . . . . . . . . . . 403.10 , 407.3

Air class and recirculation . . . . . . . . . . . . . . 403.9 , 407.4

Mechanical. . . . . . . . . . . . . . . . . . . . . . . . . 402.3, 405.0

Multiple zone systems. . . . . . . . . . . . . . . . . . . . . . 404.0

Natural. . . . . . . . . . . . . . . . . . . . . . . . . 402.2, 402.2.1.2,

405.1.1, E 605.1.1

Obstructions of . . . . . . . . . . . . . . . . . . . . . . . . . . 802.15

Outdoor air intakes . . . . . . . . . . . . . . 402.4 , 403.9, 407.2

Parking garages . . . . . . . . . . . . . . . . . . 403.7.1, 403.7.2

Rates . . . . . . . . . . . . . . . . . . . . . . . . 403.0, Table 402.1

Requirements for Acute Care Hospitals,

Skilled Nursing Facilities, Intermediate Care Facilities, Outpatient Facilities,

Licensed Clinics,Correctional Treatment

Centers and Acute Psychiatric Hospitals . . . . Table 4-A System Details [OSHPD]. . . . . . . . . . . . . . . . . . . . 407.0

Variable Air Volume . . . . . . . . . . . . . . . . . . . . . . . . 407.5

VENTILATION SYSTEM DETAILS [OSHPD] . . . . . . . . . 407.0

VENTILATORS, HEAT

(ENERGY) RECOVERY . . . . . . . . . . . . . . . . 210.0, 504.5

VENTILATING SYSTEMS AND HOODS [OSHPD]

Airborne Infection Isolation Rooms. . . . . . . . . . . . 414.0

Boiler, Mechanical, and Electrical Rooms. . . . . . . 412.0

Kitchen and Dining Areas . . . . . . . . . . . . . . . . . . . 411.0

Laboratory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 410.0

Odorous Rooms . . . . . . . . . . . . . . . . . . . . . . . . . . 413.0

Protective Environment Rooms. . . . . . . . . . . . . . . 415.0

VENTING COLLAR

Definition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224.0

VENTING SELECTION TABLES

Exterior masonry chimney. . . . . . . . . . Table 803.1.2(6),

Table 803.2(6),

Table 803.2(7),

Table 803.2(8),

Table 803.2(9)

Masonry Chimneys . . . . . . . . . . . . . . . Table 803.1.2(3),

Table 803.1.2(4),

Table 803.2(3),

Table 803.2(4)

Single appliances . . . Table 803.1.2(1)–Table 803.1.2(6) Single-wall metal

pipe or type B

asbestos cement vent . . . . . . . . . . Table 803.1.2(5),

Table 803.2(5)

Two or more

appliances . . . . . . . . . Table 803.2(1)–Table 803.2(9)

Type B double-wall

gas vent . . . . . . . . . . . . . . . . . . . . . . Table 803.1.2(1),

Table 803.1.2(2),

Table 803.2(1),

Table 803.2(2)

VIBRATION ISOLATORS . . . . . . . . . . . . . . . . 602.6, 1001.5

VOLUME DAMPERS

Definition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206.0

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