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Home / Code Guides / Window Fall Protection

Window Fall Protection Code — The 24-Inch and 72-Inch Triggers

Window fall protection has two triggers and both have to be true before anything is required. Once they are, the code offers exactly two ways out.

RequirementModel Code StandardSection
First triggerThe bottom of the clear opening sits less than 24 in. above the finished floorIRC R312.2.1
Second triggerAnd the opening is more than 72 in. above the finished grade or surface belowIRC R312.2.1
Option oneLimit the opening so a 4 in. diameter sphere cannot pass through it when the window is opened to its largest positionIRC R312.2.1
Option twoOr fit a window opening control device that complies with ASTM F2090IRC R312.2.1
Egress interactionWhere the window also serves as an emergency escape and rescue opening, releasing the control device must leave an opening that still meets the escape requirementsIRC R312.2.2
Escape dimensionsThose requirements are 5.7 sq ft of net clear opening — 5.0 sq ft at grade level — with a clear height of 24 in., a clear width of 20 in., and a sill no higher than 44 in.IRC R310.2.1, R310.2.2

Worth knowing

  • The 2021 edition changed the datum. Earlier editions started at the top of the sill; the 2021 rule keys off the clear opening instead, and its lowest edge is what you measure down to the floor. That pulls some windows into the rule that sat outside it before.
  • The 2021 edition also retitled the subsections, so R312.2.1 is now “Window opening height” and R312.2.2 is “Emergency escape and rescue openings.” Older citations by title will not match.
  • ASTM F2006 is not an option for dwellings. It covers devices without an egress release, and the ICC Commentary excludes it from residential use. F2090 devices reset automatically when the window closes.
  • The IRC states no release force in pounds. Any force figure you see belongs to ASTM F2090, not to the code, and should be attributed that way.
  • Replacement windows are a separate question, handled by IRC Appendix AJ and by the existing-building code — and IRC appendices apply only where a jurisdiction specifically adopts them.

Common questions

What does the code say about first trigger for Window Fall Protection?

The bottom of the clear opening sits less than 24 in. above the finished floor. (IRC R312.2.1)

What does the code say about second trigger for Window Fall Protection?

And the opening is more than 72 in. above the finished grade or surface below. (IRC R312.2.1)

What does the code say about option one for Window Fall Protection?

Limit the opening so a 4 in. diameter sphere cannot pass through it when the window is opened to its largest position. (IRC R312.2.1)

Adopted edition by state

Base-code year from BuildSpec’s adoption records. States often amend the base code, and your city or county may differ, so confirm with your building department.

Related sections and guides

This guide is BuildSpec’s own summary, not code text. It cites the 2021 International Residential Code and the 2023 National Electrical Code as model standards. The IRC 2021 text itself is in the Code Library for signed-in members; BuildSpec publishes no NEC text, which is at nfpa.org.Neither is an adoption record: your state may be on a different edition with amendments — check your jurisdiction page or get an Address Report.
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