Replacement Windows in Emergency Escape and Rescue Openings

October 29, 2015

Questions about replacing windows where new construction would require Emergency Escape and Rescue Openings are common. While a recent column discussed new provisions for replacement windows in the 2015 International Codes, it did not address all possible scenarios.

EEROs are required in all basements and sleeping rooms below the fourth floor of single family homes, townhouses and apartment buildings. EEROs must provide a minimum clear opening height of 24 inches and clear opening width of 20 inches. If they are located on the ground floor, they must also provide a minimum total clear opening area of 5.0 square feet, while those on a floor above grade (second or third floor) must provide a minimum total clear opening area of 5.7 square feet.


With regard to replacement windows and EEROs in existing buildings, there are basically four possible scenarios.

1. The opening is not required to be an EERO.

In this case, there is no concern about the size of opening provided by the replacement window.

2. The opening is required to be an EERO, but the existing opening is large enough to accommodate a replacement window that meets the EERO size requirements.

In this case, an appropriate size window is installed and there is not further concern.

3. The opening would be required to be an EERO if occurring in new construction, but the existing opening is not large enough to meet the size specification.

In this case, it is not possible to provide a replacement window of the same operator type in the same frame that will meet the EERO requirement. The provisions of the International Residential Code for existing structures govern in this situation. These provisions state that the legal occupancy of any structure that exists at the time of enactment of that code shall be permitted to continue. It further states, however, that alterations to the existing building shall comply with the requirements of the code for new construction.

Enlargement of an existing window opening to meet EERO requirements would not be required unless the window is being replaced as part of the remodeling of an existing building and the project creates a new requirement for an EERO. For example, if an existing room or space that did not previously serve as a sleeping room is being altered or enlarged to make it a sleeping room, the requirement for a new EERO is created. This requirement may be met by adding a new opening that meets the emergency escape requirements or by enlarging an existing window opening.

4. The opening is required to be an EERO and meets the size requirements with the existing window in place, but placing a new window of the same operator type within the existing frame will not meet the size specification.

Here, again, the provisions of the IRC for existing buildings come into play. In addition to the provisions discussed above, the IRC also states that alterations shall not adversely affect the performance of the existing building. Replacing an existing window that meets EERO requirements with one that does not is considered to diminish the overall life safety of the building, and therefore to adversely affect its performance.

Sometimes it is difficult to replace an existing window with one of the same or similar operator type without reducing the size of the resulting opening below that required for EERO. For this reason, new provisions in the 2015 IRC permit the installation of a replacement window that is the same operator type as the window being replaced, if it is the manufacturer’s largest standard size window of that operator type that will fit within the existing frame.

A different operator type that provides an equal or greater size opening may also be used. Use of an operator type different than the original that would reduce the size of the opening provided, however, cannot occur. Also, this provision cannot be used if the replacement of the window is part of an addition or alteration that creates a new requirement for an EERO.

Finally, the actual requirements being enforced depend upon what the jurisdiction has adopted. As is always the case, the local jurisdiction has the final authority with regards to enforcement of construction code.

Code Arena is brought to you by the America Architectural Manufacturers Association. Julie Ruth may be reached through AAMA at 847/303-5664 or via e-mail at

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