1204 Lighting — 2025 California Building Code

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.

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.

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.

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.

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

See California Green Building Standards Code, Chapter 5, Division 5.1 for additional light pollution reduction requirements.

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.