CNI-020 Emergency Escape and Rescue Windows, California Residential Code
Basements, habitable attics, and every sleeping room shall have at least one operable window or door for emergency escape and rescue opening. Such openings shall open directly into a public way or to a yard or court that opens to a public way. The emergency door or window shall be operable from the inside to provide a full clear opening without the use of separate tools. (R310)
The following shall apply for new residential buildings, new sleeping rooms, and for new windows in existing residential buildings.
Minimum window size requirements:
- The net clear opening shall be no less than 5.7 square feet (5.0 square feet when at grade-floor).
- The net clear openable height dimension shall be no less that 24 inches.*
- The net clear openable width dimension shall be a minimum of 20 inches.*
- The finished sill height shall be not more that 44 inches above the floor.
*Note: Using both minimum figures will not obtain the required minimum openable area.
The Figure below depicts the dimensional requirements for minimum openable areas (5.7 square feet) at bedrooms.
The following chart provides minimum width/height requirements that will achieve the required minimum openable area of 5.7 square feet.
The following chart provides minimum width/height requirements that will achieve the required minimum openable area of 5.0 square feet.
Replacement windows are exempt from these requirements if the window is the manufacturer’s largest standard size window that will fit within the existing frame or rough opening and provides for an equal or greater window opening area than the existing window. (R310.2.5)
Where the sill height is below grade a window well in accordance with R310.2.3 shall be provided.