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Chapter 4 — SPECIAL DETAILED REQUIREMENTS BASED ON OCCUPANCY AND USE

Section 409 — MOTION PICTURE PROJECTION ROOMS

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.

409.1 General.

The provisions of Sections 409.1 through 409.5 shall apply to rooms in which ribbon-type cellulose acetate or other safety film is utilized in conjunction with electric arc, xenon or other light-source projection equipment that develops hazardous gases, dust or radiation. Where cellulose nitrate film is utilized or stored, such rooms shall comply with NFPA 40.

409.1.1 Projection room required. Every motion picture machine projecting film as mentioned within the scope of this section shall be enclosed in a projection room. Appurtenant electrical equipment, such as rheostats, transformers and generators, shall be within the projection room or in an adjacent room of equivalent construction.

409.2 Construction of projection rooms.

Every projection room shall be of permanent construction consistent with the construction requirements for the type of building in which the projection room is located. Openings are not required to be protected. The room shall have a floor area of not less than 80 square feet (7.44 m [2] ) for a single machine and not less than 40 square feet (3.7 m [2] ) for each additional machine. Each motion picture projector, floodlight, spotlight or similar piece of equipment shall have a clear working space of not less than 30 inches by 30 inches (762 mm by 762 mm) on each side and at the rear thereof, but only one such space shall be required between two adjacent projectors. The projection room and the rooms appurtenant thereto shall have a ceiling height of not less than 7 feet 6 inches (2286 mm). The aggregate of openings for projection equipment shall not exceed 25 percent of the area of the wall between the projection room and the auditorium. Openings shall be provided with glass or other approved material, so as to close completely the opening.

409.3 Projection room and equipment ventilation.

Ventilation shall be provided in accordance with the California Mechanical Code.

409.3.1 Supply air. Each projection room shall be provided with adequate air supply inlets so arranged as to provide well-distributed air throughout the room. Air inlet ducts shall provide an amount of air equivalent to the amount of air being exhausted by projection equipment. Air is permitted to be taken from the outside; from adjacent spaces within the building, provided that the volume and infiltration rate are sufficient; or from the building air-conditioning system, provided that it is so arranged as to provide sufficient air when other systems are not in operation.

409.3.2 Exhaust air. Projection rooms are permitted to be exhausted through the lamp exhaust system. The lamp exhaust system shall be positively interconnected with the lamp so that the lamp will not operate unless there is the required airflow. Exhaust air ducts shall terminate at the exterior of the building in such a location that the exhaust air cannot be readily recirculated into any air supply system. The projection room ventilation system is permitted to also serve appurtenant rooms, such as the generator and rewind rooms.

409.3.3 Projection machines. Each projection machine shall be provided with an exhaust duct that will draw air from each lamp and exhaust it directly to the outside of the building. The lamp exhaust is permitted to serve to exhaust air from the projection room to provide room air circulation. Such ducts shall be of rigid materials, except for a flexible connector approved for the purpose. The projection lamp or projection room exhaust system, or both, is permitted to be combined but shall not be interconnected with any other exhaust or return system, or both, within the building.

409.4 Lighting control.

Provisions shall be made for control of the auditorium lighting and the means of egress lighting systems of theaters from inside the projection room and from not less than one other convenient point in the building.

409.5 Miscellaneous equipment.

Each projection room shall be provided with rewind and film storage facilities.

4-30 2025 CALIFORNIA BUILDING CODE

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

SPECIAL DETAILED REQUIREMENTS BASED ON OCCUPANCY AND USE

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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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