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Chapter 4 — SPECIAL DETAILED REQUIREMENTS BASED ON OCCUPANCY AND USE

Section 427 — MEDICAL GAS SYSTEMS

2025 California Building Code (Title 24, Part 2) · 2025 edition · updated 2026-07-29 · California

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

[F] 427.1 General. Medical gases at health care-related facilities intended for patient or veterinary care shall comply with Sections 427.2 through 427.2.3 in addition to the requirements of Chapter 53 of the California Fire Code .

[F] 427.2 Interior supply location. Medical gases shall be located in areas dedicated to the storage of such gases without other storage or uses. Where containers of medical gases in quantities greater than the permitted amount are located inside the buildings, they shall be located in a 1-hour exterior room, 1-hour interior room or a gas cabinet in accordance with Section 427.2.1, 427.2.2 or 427.2.3, respectively. Rooms or areas where medical gases are stored or used in quantities exceeding the maximum allowable quantity per control area as set forth in Tables 307.1(1) and 307.1(2) shall be in accordance with Group H occupancies.

[F] 427.2.1 One-hour exterior room. A 1-hour exterior room shall be a room or enclosure separated from the remainder of the building by fire barriers constructed in accordance with Section 707 or horizontal assemblies constructed in accordance with Section 711, or both, with a fire-resistance rating of not less than 1 hour. Openings between the room or enclosure and interior spaces shall be provided with self-closing smoke- and draft-control assemblies having a fire protection rating of not less than 1 hour. Rooms shall have not less than one exterior wall that is provided with not less than two vents. Each vent shall have a minimum free air opening of not less than 36 square inches (232 cm [2] ) for each 1,000 cubic feet (28 m [3] ) at normal temperature and pressure (NTP) of gas stored in the room and shall be not less than 72 square inches (465 cm [2] ) in aggregate free opening area. One vent shall be within 6 inches (152 mm) of the floor and one shall be within 6 inches (152 mm) of the ceiling. Rooms shall be provided with not fewer than one automatic fire sprinkler to provide container cooling in case of fire.

[F] 427.2.2 One-hour interior room. Where an exterior wall cannot be provided for the room, a 1-hour interior room shall be provided and shall be a room or enclosure separated from the remainder of the building by fire barriers constructed in accordance with Section 707 or horizontal assemblies constructed in accordance with Section 711, or both, with a fire-resistance rating of not less than 1 hour. Openings between the room or enclosure and interior spaces shall be provided with self-closing smoke- and draft-control assemblies having a fire protection rating of not less than 1 hour. An automatic sprinkler system shall be installed within the room. The room shall be exhausted through a duct to the exterior. Supply and exhaust ducts shall be enclosed in a 1hour rated shaft enclosure from the room to the exterior. Approved mechanical ventilation shall comply with the California

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

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SPECIAL DETAILED REQUIREMENTS BASED ON OCCUPANCY AND USE

Mechanical Code and be provided with a minimum rate of 1 cubic foot per minute per square foot (0.00508 m [3] /s/m [2] ) of the area of the room.

[F] 427.2.3 Gas cabinets. Gas cabinets shall be constructed in accordance with Section 5003.8.6 of the California Fire Code and shall comply with the following:

  1. Cabinets shall be exhausted to the exterior through a dedicated exhaust duct system installed in accordance with Chapter 5 of the California Mechanical Code .

  2. Supply and exhaust ducts shall be enclosed in a 1-hour rated shaft enclosure from the cabinet to the exterior. The average velocity of ventilation at the face of access ports or windows shall be not less than 200 feet per minute (1.02 m/s) with a minimum of 150 feet per minute (0.76 m/s) at any point of the access port or window.

  3. Cabinets shall be provided with an automatic sprinkler system internal to the cabinet.

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▸ Contents — 2025 California Building Code (Title 24, Part 2)
2025 California Building Code (Title 24, Part 2)
  1. Chapter 1 — ADMINISTRATION
  2. Chapter 2 — DEFINITIONS
  3. Chapter 3 — OCCUPANCY CLASSIFICATION AND USE
  4. ▸ Chapter 4 — SPECIAL DETAILED REQUIREMENTS BASED ON OCCUPANCY A…
    Overview
    1. Section 401 — SCOPE
    2. Section 402 — COVERED MALL AND OPEN MALL BUILDINGS
    3. Section 403 — HIGH-RISE BUILDINGS AND GROUP I-2 OCCUPANCIES HA…
    4. Section 404 — ATRIUMS
    5. Section 405 — UNDERGROUND BUILDINGS
    6. Section 406 — MOTOR-VEHICLE-RELATED OCCUPANCIES
    7. Section 407 — GROUP I-2
    8. Section 408 — GROUP I-3
    9. Section 409 — MOTION PICTURE PROJECTION ROOMS
    10. Section 410 — STAGES, PLATFORMS AND TECHNICAL PRODUCTION AREAS
    11. Section 411 — SPECIAL AMUSEMENT AREAS
    12. Section 412 — AIRCRAFT-RELATED OCCUPANCIES
    13. Section 413 — COMBUSTIBLE STORAGE
    14. Section 414 — HAZARDOUS MATERIALS
    15. Section 415 — GROUPS H-1, H-2, H-3, H-4 AND H-5
    16. Section 416 — SPRAY APPLICATION OF FLAMMABLE FINISHES
    17. Section 417 — DRYING ROOMS
    18. Section 418 — ORGANIC COATINGS
    19. Section 419 — ARTIFICIAL DECORATIVE VEGETATION
    20. Section 420 — GROUPS R-1, R-2, R-2.1, R-2.2, R-3, R-3.1 AND R-4
    21. Section 421 — HYDROGEN FUEL GAS ROOMS
    22. Section 422 — AMBULATORY CARE FACILITIES
    23. Section 423 — STORM SHELTERS
    24. Section 424 — PLAY STRUCTURES
    25. Section 425 — HYPERBARIC FACILITIES
    26. Section 427 — MEDICAL GAS SYSTEMS
    27. Section 435 — SPECIAL PROVISIONS FOR LICENSED 24-HOUR CARE FAC…
    28. Section 436 — GROUP I-4 [SFM]
    29. Section 437 — RESERVED
    30. Section 438 — RESERVED
    31. Section 439 — ROAD TUNNELS, BRIDGES AND OTHER LIMITED-ACCESS H…
    32. Section 440 — HORSE RACING STABLES [SFM]
    33. Section 441 — PET KENNELS AND PET BOARDING FACILITIES [SFM]
    34. Section 442 — COMBUSTION ENGINES AND GAS TURBINES [SFM]
    35. Section 443 — FIXED GUIDEWAY TRANSIT AND PASSENGER RAIL SYSTEM…
    36. Section 444 — EXPLOSIVES [SFM]
    37. Section 445 — RESERVED
    38. Section 446 — WINERY CAVES [SFM]
    39. Section 447 — RESERVED
    40. Section 448 — RESERVED
    41. Section 449 — PUBLIC LIBRARIES [SL AND SFM]
    42. Section 450 — GROUP C [SFM]
    43. Section 451 — RESERVED
    44. Section 452 — SCHOOL FACILITIES FOR KINDERGARTEN THROUGH 12TH …
    45. Section 453 — GROUP L [SFM]
    46. Section 454 — RESERVED
    47. Section 455 — LARGE FAMILY DAY-CARE HOMES [SFM]
  5. Chapter 5 — GENERAL BUILDING HEIGHTS AND AREAS
  6. Chapter 6 — TYPES OF CONSTRUCTION
  7. Chapter 7 — FIRE AND SMOKE PROTECTION FEATURES
  8. Chapter 7A — MATERIALS AND CONSTRUCTION METHODS FOR EXTERIOR W…
  9. Chapter 8 — INTERIOR FINISHES
  10. Chapter 9 — FIRE PROTECTION AND LIFE SAFETY SYSTEMS
  11. Chapter 10 — MEANS OF EGRESS
  12. Chapter 11 — RESERVED
  13. Chapter 11A — HOUSING ACCESSIBILITY
  14. Chapter 11B — ACCESSIBILITY TO PUBLIC BUILDINGS, PUBLIC ACCOMM…
  15. Chapter 12 — INTERIOR ENVIRONMENT
  16. Chapter 13 — ENERGY EFFICIENCY
  17. Chapter 14 — EXTERIOR WALLS
  18. Chapter 15 — ROOF ASSEMBLIES AND ROOFTOP STRUCTURES
  19. Chapter 16 — STRUCTURAL DESIGN
  20. Chapter 16A — STRUCTURAL DESIGN
  21. Chapter 17 — SPECIAL INSPECTIONS AND TESTS
  22. Chapter 17A — SPECIAL INSPECTIONS AND TESTS
  23. Chapter 18 — SOILS AND FOUNDATIONS
  24. Chapter 18A — SOILS AND FOUNDATIONS
  25. Chapter 19 — CONCRETE
  26. Chapter 19A — CONCRETE
  27. Chapter 20 — ALUMINUM
  28. Chapter 21 — MASONRY
  29. Chapter 21A — MASONRY
  30. Chapter 22 — STEEL
  31. Chapter 22A — STEEL
  32. Chapter 23 — WOOD
  33. Chapter 24 — GLASS AND GLAZING
  34. Chapter 25 — GYPSUM PANEL PRODUCTS AND PLASTER
  35. Chapter 26 — PLASTIC
  36. Chapter 27 — ELECTRICAL
  37. Chapter 28 — MECHANICAL SYSTEMS
  38. Chapter 29 — PLUMBING SYSTEMS
  39. Chapter 30 — ELEVATORS AND CONVEYING SYSTEMS
  40. Chapter 31 — SPECIAL CONSTRUCTION
  41. Chapter 31A — SYSTEMS FOR WINDOW CLEANING OR EXTERIOR BUILDING…
  42. Chapter 31B — PUBLIC POOLS
  43. Chapter 31C — RADIATION
  44. Chapter 31D — FOOD ESTABLISHMENTS
  45. Chapter 31F — MARINE OIL TERMINALS
  46. Chapter 32 — ENCROACHMENTS INTO THE PUBLIC RIGHT-OF-WAY
  47. Chapter 33 — SAFEGUARDS DURING CONSTRUCTION
  48. Chapter 34 — RESERVED
  49. Chapter 35 — REFERENCED STANDARDS
  50. Appendix A — EMPLOYEE QUALIFICATIONS
  51. Appendix B — BOARD OF APPEALS
  52. Appendix C — GROUP U—AGRICULTURAL BUILDINGS
  53. Appendix D — FIRE DISTRICTS
  54. Appendix E — RESERVED
  55. Appendix F — RODENTPROOFING
  56. Appendix G — FLOOD-RESISTANT CONSTRUCTION
  57. Appendix H — SIGNS
  58. Appendix I — PATIO COVERS
  59. Appendix J — GRADING
  60. Appendix K — GROUP R-3 AND GROUP R-3.1 OCCUPANCIES PROTECTED B…
  61. Appendix L — EARTHQUAKE RECORDING INSTRUMENTATION
  62. Appendix M — TSUNAMI-GENERATED FLOOD HAZARDS
  63. Appendix N — REPLICABLE BUILDINGS
  64. Appendix O — PERFORMANCE-BASED APPLICATION
  65. Appendix P — SLEEPING LOFTS
  66. Appendix Q — EMERGENCY HOUSING

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