Boulder County Building Publications
Emergency Escape and Rescue Openings - B10

Emergency Escape & Rescue Openings
Per 2021 IRC section R310

Basements and every sleeping room shall have at least one operable emergency escape and rescue opening. At the time of inspection, if windows installed in rooms requiring emergency escape and rescue openings do not meet the requirements, the windows will have to be removed and replaced with code-conforming windows. This includes new construction, remodels, and window replacements.

Operational Constraints and Opening Control Devices (R310.1.1)

Emergency escape and rescue openings shall be operational from the inside of the room without the use of keys, tools or special knowledge. Window opening control devices and fall prevention devices complying with ASTM F2090 shall be permitted for use on windows serving as a required emergency escape and rescue opening and shall be not more than 70 inches (178 cm) above the finished floor.

Minimum Dimension Requirements for Emergency Escape and Rescue Openings

Minimum Size (R310.2.1)

Emergency escape and rescue openings shall have a net clear opening area of not less than 5.7 square feet. Grade floor openings shall have a minimum net clear opening of 5 square feet.

Minimum Dimensions (R310.2.2)

The minimum net clear openable height dimension shall be 24 inches (610 mm). The minimum net clear openable width dimension shall be 20 inches (508 mm). The net clear opening dimensions shall be the result of normal operation of the opening.

Minimum Height from Floor (R310.2.3)

Emergency escape and rescue openings shall have the bottom of the clear opening not greater than 44 inches above the floor.

Emergency Escape and Rescue Openings under Decks, Porches and Cantilevers (R310.2.4)
Emergency escape and rescue openings installed under decks, porches and cantilevers shall be fully openable and provide a path not less than 36 inches (914 mm) in height and 36 inches (914 mm) in width to a yard or court.

Emergency Escape and Rescue Doors (R310.2.4)
Where a door is provided as the required emergency escape and rescue opening, it shall be a side-hinged door or a sliding door

Foundation wall cuts for Egress Windows require an engineer’s design and/or inspection. The document shall be signed, sealed, and dated by a Colorado Licensed design professional.

Area Wells for Emergency Escape and Rescue Openings

Area Wells (R310.4)

An emergency escape and rescue opening where the bottom of the clear opening is below the adjacent grade shall be provided with an area well in accordance with Sections R310.4.1 through R310.4.4.

Minimum Size (R310.4.1)

The horizontal area of the area well shall be not less than 9 square feet (0.9 m2), with a horizontal projection and width of not less than 36 inches (914 mm). The size of the area well shall allow the emergency escape and rescue opening to be fully opened. Except when a ladder or steps are required by Section R310.4.2, they can encroach not more than 6 inches (152 mm) into the required dimensions of the area well.

Ladder and Steps (R310.4.2)

Area wells with a vertical depth of greater than 44 inches shall be equipped with an approved permanently affixed ladder or steps. The ladder or steps shall not be obstructed by the emergency escape and rescue opening where the window or door is in the open position. Ladders or steps required by this section shall not be required to comply with Section R311.7 for means of egress.

Ladders (R310.4.2.1)

Ladders and rungs shall have an inside width of not less than 12 inches (305 mm), shall project not less than 3 inches (76 mm) from the wall and shall be spaced not more than 18 inches (457 mm) on center vertically for the full height of the area well.

Steps (R310.4.2.2)

Steps shall have an inside width of not less than 12 inches (305 mm), a minimum tread depth of 5 inches (127 mm) and a maximum riser height of 18 inches (457 mm) for the full height of the area well.

Drainage (R310.4.3)

Area wells shall be designed for proper drainage by connecting to the building’s foundation drainage system required by Section R405.1. Except when a drainage system for area wells is not required where the foundation is on well-drained soil or sand-gravel mixture soils in accordance with the United Soil Classification System, Group I Soils, as detailed in Table R405.1 (good drainage characteristics).

Bars, Grilles, Covers and Screens (R310.4.4)

Where bars, grilles, covers, screens or similar devices are placed over emergency escape and rescue openings, bulkhead enclosures or area wells that serve such openings, the minimum net clear opening size shall comply with Sections R310.2 through R310.2.2 and R310.4.1. Such devices shall be releasable or removable from the inside without the use of a key or tool or force greater than that required for the normal operation of the escape and rescue opening.

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