Basements, habitable attics and every sleeping room shall have not less than one operable emergency escape and rescue opening. Where basements contain one or more sleeping rooms, an emergency escape and rescue opening shall be required in each sleeping room. Emergency escape and rescue openings shall open directly into a public way, or to a yard or court that opens to a public way.
Exception: Storm shelters and basements used only to house mechanical equipment not exceeding a total floor area of 200 square feet (18.58 m2).
Because so many fire deaths occur as a result of occupants being asleep in a residential building during a fire, the code requires that all basements, habitable attics and sleeping rooms have windows or doors that may be used for emergency escape or rescue. The requirement for emergency escape and rescue openings in sleeping rooms exists because a fire will usually have spread before the occupants are aware of the problem, and the normal exit channels may be blocked. The requirement for basements and habitable attics exists because they are so often used as sleeping rooms. A fire in a mechanical room adjacent to a stairway could engulf the only means of egress for the basement without the egress window or door.
Openings required for emergency escape or rescue must be located on the exterior of the building so that rescue can be performed from the exterior and so that occupants may escape through that opening to the exterior of the building without having to travel through the building itself. Therefore, where openings are required, they should open directly into a public street, public alley, yard or court. After the occupants pass through the emergency escape and rescue opening, their continued egress is essential. Where a basement contains sleeping rooms and a habitable space, an emergency escape and rescue opening is required in each sleeping room, but is not required in adjoining areas of the basement.
Exception: Storm shelters and basements used only to house mechanical equipment with a total floor area not exceeding 200 square feet (18.58 m2).
The dimensions prescribed in the code for emergency escape and rescue openings in Sections R310.2 through R310.2.2, and as illustrated in Commentary Figure R310.2.1, are based, in part, on extensive testing by the San Diego Building and Fire Departments to determine the proper relationships of the height and width of window openings to adequately serve for both rescue and escape. The minimum of 20 inches (508 mm) for the width is based on two criteria: the width necessary to place a ladder within the window opening and the width necessary to admit a fire fighter with full rescue equipment, including a breathing apparatus. The minimum 24-inch (610 mm) height is based on the minimum size necessary to admit a fire fighter with full rescue equipment. By requiring a minimum net clear opening size of at least 5.7 square feet (0.53 m2), the code provides for an opening of adequate dimensions. To be accessible from the interior of the sleeping room, attic or basement, Section R310.2.2 requires that the emergency escape and rescue opening be located not more than 44 inches (1118 mm) above the floor. The measurement is to be taken from the floor to the bottom of the clear opening.
Section R310.1.1 requires that the required opening dimensions be achieved by the normal operation of the window, door or hatch from the inside without the use of keys, tools or special knowledge. Section R310.1.1 also allows window opening control devices to be used on windows that serve as required emergency escape and rescue openings, provided that such devices comply with ASTM F2090. The window industry is a highly competitive market. Manufacturers are constantly developing new products that are easier to clean and possess higher thermal protection properties. It is important to keep in mind that no special knowledge for operation of the egress window is a key operational constraint. It is impractical to assume that all occupants can operate a window that requires a special sequence of operations to achieve the required opening size. Although most occupants are familiar with the normal operation to open the window, children and guests are frequently unfamiliar with special procedures necessary to remove the sashes. The time spent comprehending special operations unnecessarily delays egress from the bedroom and could lead to panic and further confusion. Thus, windows that achieve the required opening dimensions only by performing a special sequence of operations, such as the removal of sashes or mullions, are not permitted. For example, if a specific area of the window has to be depressed or manipulated to allow the sash to be removed or released to achieve the open area requirement of 5.7 square feet (0.53 m2), the window does not qualify as an egress window.
