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Chapter 12 — INTERIOR ENVIRONMENT

Section 1204 — LIGHTING

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.

1204.1 General.

Every space intended for human occupancy shall be provided with natural light by means of exterior glazed openings in accordance with Section 1204.2 or shall be provided with artificial light in accordance with Section 1204.3. Exterior glazed openings shall open directly onto a public way or onto a yard or court in accordance with Section 1205.

[HCD 1] Glazed openings may open into a passive solar energy collector provided the area of exterior glazed openings in the passive solar energy collector is increased to compensate for the area required by the interior space.

1204.2 Natural light.

The minimum net glazed area shall be not less than 8 percent of the floor area of the room served.

1204.2.1 Adjoining spaces. For the purpose of natural lighting, any room is permitted to be considered as a portion of an adjoining room where one-half of the area of the common wall is open and unobstructed and provides an opening of not less than onetenth of the floor area of the interior room or 25 square feet (2.32 m [2] ), whichever is greater.

Exception: Openings required for natural light shall be permitted to open into a sunroom with thermal isolation or a patio cover where the common wall provides a glazed area of not less than one-tenth of the floor area of the interior room or 20 square feet (1.86 m [2] ), whichever is greater.

1204.2.2 Exterior openings. Exterior openings required by Section 1204.2 for natural light shall open directly onto a public way, yard or court, as set forth in Section 1205.

Exceptions:

  1. Required exterior openings are permitted to open into a roofed porch where the porch meets all of the following criteria:

1.1. Abuts a public way, yard or court. 1.2. Has a ceiling height of not less than 7 feet (2134 mm). 1.3. Has a longer side at least 65 percent open and unobstructed. 2. Skylights are not required to open directly onto a public way, yard or court.

1204.3 Artificial light.

Artificial light shall be provided that is adequate to provide an average illumination of 10 footcandles (107 lux) over the area of the room at a height of 30 inches (762 mm) above the floor level.

1204.4 Stairway illumination.

Stairways within dwelling units and exterior stairways serving a dwelling unit shall have an illumination level on tread runs of not less than 1 footcandle (11 lux). Stairways in other occupancies shall be governed by Chapter 10.

1204.4.1 Controls. The control for activation of the required stairway lighting shall be in accordance with the California Electrical Code.

1204.5 Emergency egress lighting.

The means of egress shall be illuminated in accordance with Section 1008.1.

1204.6 Light pollution reduction.

1204.6 Light pollution reduction. [BSC-CG] See California Green Building Standards Code, Chapter 5, Division 5.1 for additional light pollution reduction requirements.

1204.7 Campus lighting for parking facilities and primary walkways at California state…

colleges. [BSC] Artificial light shall be provided for parking facilities and primary walkways at California State Universities, colleges and community colleges in accordance with provisions of this subsection. This subsection shall not apply to the University of California unless the Regents of the University of California, by resolution, make it applicable.

1204.7.1 Lighting requirements. Based on the recommendations of the most current edition of the Illumination Engineering Society lighting handbook, the following lighting standards shall be used for all new construction of open parking facilities, covered parking facilities and primary walkways: 1. Open and covered parking facilities. 1.1. Medium-level activity usage when medium usage is present. 1.2. High-level activity usage when high usage is present. 2. Primary campus walkways. 2.1. Medium-level activity usage when medium usage is present. 2.2. High-level activity usage when high usage is present.

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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…
  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
    Overview
    1. Section 1201 — GENERAL
    2. Section 1202 — VENTILATION
    3. Section 1203 — TEMPERATURE CONTROL
    4. Section 1204 — LIGHTING
    5. Section 1205 — YARDS OR COURTS
    6. Section 1206 — SOUND TRANSMISSION
    7. Section 1207 — ENHANCED CLASSROOM ACOUSTICS
    8. Section 1208 — INTERIOR SPACE DIMENSIONS
    9. Section 1209 — ACCESS TO UNOCCUPIED SPACES
    10. Section 1210 — TOILET AND BATHROOM REQUIREMENTS
    11. Section 1211 — UV GERMICIDAL IRRADIATION SYSTEMS
    12. Section 1212 — [HCD 1 & HCD 2]—GARAGE DOOR SPRINGS
    13. Section 1213 — [HCD 1]—POLLUTANT CONTROL
    14. Section 1214 — RESERVED
    15. Section 1215 — RESERVED
    16. Section 1216 — RESERVED
    17. Section 1217 — RESERVED
    18. Section 1218 — RESERVED
    19. Section 1219 — RESERVED
    20. Section 1220 — RESERVED
    21. Section 1221 — RESERVED
    22. Section 1222 — RESERVED
    23. Section 1223 — RESERVED
    24. Section 1224 — [OSHPD 1]—HOSPITALS
    25. Section 1225 — [OSHPD 2]-SKILLED NURSING AND INTERMEDIATE-CARE…
    26. Section 1226 — [OSHPD 3]-CLINICS
    27. Section 1227 — [OSHPD 4]-CORRECTIONAL TREATMENT CENTERS
    28. Section 1228 — [OSHPD 5]—ACUTE PSYCHIATRIC HOSPITALS
    29. Section 1229 — [OSHPD 6] — CHEMICAL DEPENDENCY RECOVERY HOSPIT…
    30. Section 1230 — [BSCC] — MINIMUM STANDARDS FOR JUVENILE FACILIT…
    31. Section 1231 — [BSCC] — LOCAL DETENTION
    32. Section 1232 — RESERVED
    33. Section 1233 — RESERVED
    34. Section 1234 — RESERVED
    35. Section 1235 — [DPH]—SANITARY CONTROL OF SHELLFISH (PLANTS AND…
    36. Section 1236 — [DPH]—LABORATORY ANIMAL QUARTERS
    37. Section 1237 — [DPH]—WILD ANIMAL QUARANTINE FACILITIES
    38. Section 1238 — RESERVED
    39. Section 1239 — RESERVED
    40. Section 1240 — [AGR]—MEAT AND POULTRY PROCESSING PLANTS
    41. Section 1241 — [AGR]—COLLECTION CENTERS AND FACILITIES
    42. Section 1242 — [AGR]—RENDERERS
    43. Section 1243 — [AGR]—HORSEMEAT AND PET FOOD ESTABLISHMENTS
    44. Section 1244 — RESERVED
    45. Section 1245 — RESERVED
    46. Section 1246 — RESERVED
    47. Section 1247 — RESERVED
    48. Section 1248 — RESERVED
    49. Section 1249 — RESERVED
    50. Section 1250 — [CA]—PHARMACIES
    51. Section 1251 — [CA]—VETERINARY PREMISES
    52. Section 1252 — [CA]—BARBER COLLEGES AND SHOPS
    53. Section 1253 — [CA]—SCHOOLS OF COSMETOLOGY, COSMETOLOGICAL EST…
    54. Section 1254 — [CA]—ACUPUNCTURE OFFICES
  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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