Single Hung vs. Casement vs. Horizontal Roller — FBC/IRC R310 emergency escape & rescue openings · Majestic Permits
Estimation tool only — not for permit submission. Net clear opening dimensions vary by manufacturer, frame material, and hardware. This uses simplified, generalized deductions to compare how operating type affects egress — always confirm actual net clear opening against the specific product's tested egress chart or NOA/FPA documentation before specifying a window for a required egress opening.
Opening Inputs
Max allowed is 44 in.
How Net Clear Opening Is Estimated
Single Hung: width − 4", height ÷ 2.
Casement: width − 4", full height.
Horizontal Roller: (width − 4") ÷ 2, full height.
Code Minimums Being Checked (FBC/IRC R310)
Net clear opening height: 24 in minimum.
Net clear opening width: 20 in minimum.
Net clear opening area: 5.7 sq ft minimum (5.0 sq ft for grade-floor openings).
Sill height above floor: 44 in maximum.
All four must pass for an opening to qualify as code-compliant egress.