CodeMandatory

Egress window net opening dimensions

IRC R310.2

Description

Emergency escape and rescue openings must have a net clear opening of not less than 5.7 sq ft (5.0 sq ft at grade-floor openings), with minimum opening height of 24 inches and minimum opening width of 20 inches. Sill height not more than 44 inches above the finished floor.

Why this exists

The 5.7 sq ft / 24×20 / 44-in sill numbers come from firefighter rescue research — these are the minimums that let a fully-equipped firefighter pass through with breathing apparatus, AND that an adult can climb out of unaided. Smaller openings have killed people in fires.

Measurements

Property	Operator	Value	Unit	Note
`minOpeningArea`	min	5.7	sq_ft	Net clear opening area (5.0 sq ft at grade).
`minOpeningHeight`	min	24	in
`minOpeningWidth`	min	20	in
`maxSillHeight`	max	44	in	Maximum sill height above finished floor.

Applies to

Room types: bedroom, master_bedroom

Source

ICCno manifest entry

International Residential Code (2024)

Section: R310.2.1, R310.2.2

Published 2024-01-01 · last verified 2026-05-09

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Solver enforcement

Browsable only — the solver does not currently enforce this directive (no spec-level data to check against). This entry exists so the architect personas can cite it in conversation and the user can read what the rule says.

Backed by research

Every sleeping room must have at least one operable egress window with a net clear opening of 5.7 sq ft (5.0 sq ft at grade), minimum 24 in height, 20 in width, and a sill not more than 44 in above the finished floor.
Council (2024), ICC — R310.2.1, R310.2.2 — view source ↗

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