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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