American Architectural Manufacturers Association

Window Sill Heights Discussed at Final Action Code Hearings

The May International Code Council Group A+ final action hearings held in Dallas, TX, provided many favorable outcomes for our industry. One topic of discussion was that of window sills.

For residential occupancies built under the 2012 International Building Code, the required height of operable window sills that are more than 72 inches above exterior grade will be 36 inches or more above the interior floor, while for the same occupancies built under the 2012 International Residential Code the required height will be 24 inches. This requirement won’t apply if the window is equipped with a window guard or window opening control device (WOCD) that complies with ASTM F2090 or if the window can’t be opened more than 4 inches under normal operation.

WOCDs are intended to limit initial opening of the window to no more than 4 inches, but then release with no more than 15 pounds of force so that the window can open further, especially important in case of emergency egress.

The scope of the International Residential Code is limited to one and two family dwellings and townhouses three stories or less in height. While the International Building Code also has provisions for these types of buildings, its scope also covers all other types of building. Since the majority of single family homes and townhouses are built under the International Residential Code it is anticipated the impact of the 36 inch sill height will be greatest for residential buildings greater than 3 stories in height such as high rise apartment buildings.

 Acceptance of the use of window opening control devices as an alternative to the minimum sill height will provide both window manufacturers and home builders with more options to comply with these new code requirements.

Group B of the Final Action Hearings are scheduled to begin October 25 in Charlotte, NC.

Please contact Julie Ruth, AAMA Code Consultant, or Chuck Anderson, AAMA Codes and Industry Affairs Manager, if you have any questions.

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