What Are the Egress Window Laws?

SECTION R310 - EMERGENCY ESCAPE AND RESCUE OPENINGS

R310.1 Emergency escape and rescue opening required.

Habitable attics, basements, and every sleeping room must have at least one operable rescue opening and emergency escape route. If the basement contains more than one sleeping room, each room must have its own rescue opening. These rescue openings and emergency escapes must open directly into a public area, or to a yard that opens to a public area. Exception: basements or storm shelters that are only used to house mechanical equipment, of 200 square feet (18.58 m2) or less total floor area.

R310.1.1 Operational constraints and opening control devices.

All rescue openings and emergency escape routes must be operational from inside the room, without the need for special knowledge, tools, or keys. For windows serving as the required emergency escape, opening control devices are permitted for use only if in compliance with ASTM F 2090.

R310.2 Emergency escape and rescue openings.

Rescue openings and emergency escape openings must have minimum dimensions, as specified in this section. 

R310.2.1 Minimum opening area.

Escape, rescue, and emergency openings must have a net clear opening of 5.7 square feet (0.530 m2) or larger. These specified net clear openings must be easily obtained by normal operation of the rescue opening from the inside. The net clear width of the opening must be 20 inches (508 mm) or greater, and the net clear height must be 24 inches (610 mm) or greater.

Exception: Grade floor or below grade openings must have at least a 5-square-foot (0.465 m2) net clear opening.

R310.2.2 Window sill height.

When a window serves as the rescue or emergency escape opening, it must have a sill height of 44 inches (1118 mm) or less from the floor. If sill height is below grade, a window well must be provided, in accordance with Section R310.2.3.

R310.2.3 Window wells.

For a window well, the horizontal area must be 9 square feet (0.9 m2) or greater, with a width and horizontal projection of 36 inches (914 mm) or greater. The window well area must allow full opening of the rescue and emergency escape opening.

Exception: Steps or ladders required by Section R310.2.3.1 are permitted to encroach 6 inches (152 mm) or less into the window well dimensions.

R310.2.3.1 Ladder and steps.

For window wells with a vertical depth of more than 44 inches (1118 mm), a permanently affixed ladder or steps must be accessible while the window is fully open. These ladders or steps, as required by this section, are not required to comply with Sections R311.7 and R311.8. These ladders or rungs must have an inner width of 12 inches (305 mm) or more, and must project from the wall by at least 3 inches (76 mm). They must also be spaced 18 inches (457 mm) or less on center, vertically for the window well height.

R310.2.3.2 Drainage.

Window wells must be connected to the building’s foundation drainage system (as required by Section R405.1 or other approved method), for proper drainage. Where the foundation is built upon a sand-gravel mixture or well-draining soil, a window well drainage system is not mandatory. This soil must be in accordance with the United Soil Classification System, Group I Soils, as seen in Table R405.1.

R310.2.4 Emergency escape and rescue openings under decks and porches.

Rescue openings and emergency escape openings may be installed under porches and decks, as long as the location of the porch or deck allows the openings to reach full opening capacity, and offers a path of at least 36 inches (914 mm) high to a yard or public court.

R310.2.5 Replacement windows.

For buildings meeting the scope of this code, replacement windows may be exempt from the sill height requirements of Sections R310.1 and Sections R310.2.1 and R310.2.2, as long as that window meets these conditions: the replacement window is the largest manufactured size that will fit within existing opening or frame. The replacement window is of the same operating style, or a style that offers greater window opening, than the current window. The replacement window is not related to an occupancy change.

R310.3 Emergency escape and rescue doors.

For emergency escape and rescue openings where a door is provided, the door must be either on a slider or a side-hinge system. If the opening is below ground height, the door must be provided with a bulkhead enclosure.

R310.3.1 Minimum door opening size.

For any door that is used for a rescue or emergency escape opening, it must meet the net clear height opening as outlined in Section R310.2.1.

R310.3.2 Bulkhead enclosures.

Bulkhead enclosures must meet the minimum net clear opening equal to the door in full opened position. These enclosures must provide direct access from the basement. 

R310.3.2.1 Drainage.

Bulkhead enclosures must be connected to the building’s foundation drainage system (as required by Section R405.1 or other approved method), for proper drainage. Where the foundation is built upon a sand-gravel mixture or well-draining soil, a bulkhead drainage system is not mandatory. This soil must be in accordance with the United Soil Classification System, Group I Soils, as seen in Table R405.1.

R310.4 Bars, grilles, covers and screens.

For rescue openings, emergency escape openings, window wells, and bulkhead enclosures, the use of covers, grilles, screens, bars, or similar devices is allowed, as long as the minimum net clear opening size is in compliance with Sections R310.1.1 to R310.2.3. Additionally, these devices must be removable from the inside, without the need for special knowledge, a key or other tool, and without force greater than what is required for normal operation of the emergency escape opening itself. 

R310.5 Dwelling additions.

Any addition to a dwelling that includes sleeping rooms, each new sleeping room must have one or more emergency escape or rescue openings. If the dwelling addition has a basement, the new basement must include the required number of rescue openings or emergency escape openings. Exceptions: If the basement sleeping room already has a rescue opening or emergency escape opening, a new opening is not required. If the new basement is attached to and accessible by an existing basement that already has an emergency escape or rescue opening, a new rescue opening or emergency escape opening is not required. 

R310.6 Alterations or repairs of existing basements.

Rescue openings and emergency escape openings are not required, where an existing basement undergoes repairs or alterations. Exception: if the alteration or repair includes the addition of a new sleeping room, a rescue opening or emergency escape opening must be provided in accordance with Section R310.1.