Purpose

The California Residential Code regulates emergency escape or rescue windows in residential buildings. Because most fires occur when occupants are asleep, the likelihood that people will first try to exit from these openings is very high. Therefore, the code has established that basements in residential dwellings and all sleeping rooms below the fourth story have windows and doors that may be used for emergency escape or rescue. Extensive research done by fire department personnel has determined the minimum allowed dimensions for the emergency openings to adequately allow rescue personnel and equipment in and out access to serve both rescue and escape.

Design Provisions

Location

The emergency escape and egress openings shall be located on the exterior of the building. This is intended for fire personnel to rescue the occupants from the exterior and for occupants to exit directly out of the building without having to re-enter it.

Types/Sizes of Window Allowed

Emergency escape or rescue windows must have the following characteristics:

  • Must be operable
  • Must be of a usual type such as double-hung, horizontal sliding or casement windows operated by the turn of a crank and does not require special knowledge or effort to operate
  • Must have a net clear opening width of 20 inches and net clear opening height of 24 inches
  • Have a minimum net clear openable area of 5.7 sq. ft. and upper floors and 5.0 sq. ft. and grade floor openings.
  • Have the bottom of the clear opening not greater than 44 inches measured from the floor.

Window Wells

For emergency escape windows with a finished sill height below the adjacent ground elevation, these shall be provided with a window well with the following characteristics:

  1. The clear horizontal dimension shall allow the window to be fully opened, provide a minimum accessible net clear opening of 9 sq. ft. with a 36 inch minimum dimension; and
  2. For window wells with more than 44 inches of vertical depth, provide an approved permanently affixed ladder or stairs accessible with the window in the fully open position (the ladder/stairs cannot encroach into the required dimensions of the window well by more than 6 inches.

Security Devices

Emergency windows, doors or window wells may be provided with security devices such as grilles, bars and steel shutters provided:

  1. The devices are equipped with approved release mechanisms that are openable from the inside without the use of a key or special knowledge or effort and the release mechanism shall be maintained operable at all times.
  2. Such bars, grills, grates or any similar devices shall be equipped with an approved exterior release devise for use by the fire department only when required by the authority having jurisdiction.

Emergency Escape and Exit Windows Elevation

Emergency Escape Windows Elevation Diagram

Single Casement:

  • 2-4 x 4-0
  • 2-6 x 3-6

Double Casement:

  • 4-8 x 4-0

Casement/Fixed Combo:

7-0 x 4-0

Slider:

  • 4-0 x 4-0
  • 5-0 x 3-6
  • 6-0 x 3-0

Slider/Fixed Combo:

  • 8-0 x 4-0
  • 10-0 x 4-0
  • 12-0 X 3-0

Single/Double Hung:

  • 3-0 x 5-0
  • 3-0 x 5-6
  • 3-4 x 5-0
  • 3-8 x 5-0
  • 4-0 x 5-0

Diagram of required window openings

  • 20 inches Minimum Clear Width
  • 24 inches Minimum Clear Height
  • 5.7 Sq. Ft. Min. Openable Area at Upper Floors
  • 5.0 Sq. Ft. Min. Openable Area at Grade Floors

Permit Processing

A permit is required to replace or install new windows and/or doors.

For plan submittal and permit processing information, please visit our Minor Residential Building Permits webpage. 

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