A California duplex (two-family dwelling) falls under the California Residential Code, which requires each dwelling unit to have a continuous, unobstructed egress path to a required egress door that does not pass through a garage; that door must open to a public way or to a yard/court that opens to a public way (§ 1.1.3; § R318.1). Each unit must have not less than one side-hinged egress door with a clear opening of at least 32 inches (813 mm) wide and 78 inches (1981 mm) high, readily openable from inside without a key or special knowledge (§ R318.2). Every sleeping room, habitable attic, and qualifying basement must also have an operable emergency escape and rescue opening (EERO) that opens to a public way, or to a yard/court that opens to a public way, with a minimum net clear opening of 5.7 sq ft (0.530 m²) (grade-floor EEROs may be 5.0 sq ft (0.465 m²)) and minimum clear dimensions of 20 inches (508 mm) wide by 24 inches (610 mm) high (§ R319.1; § R319.2.1; § R319.2.2).
Required door, path, and landings
- Egress must be a continuous path within each dwelling unit to the required egress door; travel through a garage is not permitted (§ R318.1).
- The egress door must be side-hinged, provide at least 32 inches clear width and 78 inches clear height, and be openable from inside without a key or special knowledge (§ R318.2).
- A landing is required on each side of each exterior door; minimum landing depth is 36 inches (914 mm) in the direction of travel, and the slope may not exceed 2% (§ R318.3).
Emergency escape and rescue openings (EEROs)
- Provide at least one EERO in every sleeping room, and in habitable attics and basements with sleeping rooms; openings must lead to a public way or to a yard/court that opens to a public way (§ R319.1).
- Minimum opening sizes: net clear area 5.7 sq ft (or 5.0 sq ft at grade), with clear width 20 inches and clear height 24 inches (§ R319.2.1; § R319.2.2).
- Bars, grilles, or covers over EEROs must be releasable from the inside without keys or tools; release mechanisms must be maintained operable (§ R319.1.1; § R319.4.4).
- Notable exceptions include certain small or nonhabitable basements and alternatives for sprinklered basements (§ R319.1 Exceptions).
Ramps serving egress
- Ramps serving the required egress door may not exceed a slope of 1:12 (8.3%); other ramps may be up to 1:8 (12.5%). Landings are required at the top and bottom and where doors open onto ramps; landing depth must be at least 36 inches. Handrails are required on at least one side where slope exceeds 1:12 (§ R318.8.1; § R318.8.2; § R318.8.3).
What this does not address: The source text does not specify corridor width or exit travel distance limits for duplexes, and it does not include detailed stair geometry; those items, if applicable, would appear in other CRC sections not included here.