Safety Glazing Hazardous Location Check (IRC R324.4)
Whether a lite of glass is in a hazardous location and so must be safety glazing.
Example
You enter
- Where the glazing is window
- Exposed area of the pane (sq ft; windows) 12
- Bottom exposed edge above the floor or walking surface (in) 12
- Top edge above the floor (in; windows) 70
- Horizontal distance to the door edge, walking surface, water's edge or nosing (in) 24
- Beside a door: where the glazing is plane
- Exception that applies none
You get
- Conditions met 4
- Conditions checked 4
- Section R324.4.3
No published worked example is on file for this calculation. It is checked against a hand-worked derivation of its method and an independent reference test.
Details, formula, and sources
Scopeby the seven locations of IRC 2024 R324.4 (R308.4 in IRC 2021, the same criteria). Pick where the glass is and give the distances that location turns on, and it answers hazardous or not with the conditions it checked and any exception that cleared it. Glass in a door or a guard is hazardous at any size. Beside a door it is hazardous when the bottom edge is under 60 in and it is within 24 in of the door, in the door's plane or on the hinge side of an in-swinging door. A window must meet all four conditions: a pane over 9 sq ft, bottom under 18 in, top over 36 in, and a walking surface within 36 in, so a 12 sq ft pane 12 in off the floor beside a hallway is hazardous and the same pane at 8 sq ft is not. Near a tub, shower, spa or pool any glass with its bottom under 60 in is hazardous unless it is more than 60 in from the water's edge; beside a stair or ramp, a bottom edge under 36 in up and less than 36 in away; at the bottom landing, 36 in up within a 60 in arc of the bottom nosing. A screen, not a code-official determination.
Formula or tableR324.4.1 door panel: always (exceptions: 3 in sphere, decorative); R324.4.2 beside a door: bottom < 60 in AND within 24 in AND (in the door's plane OR hinge side of an in-swinging door); R324.4.3 window: area > 9 sq ft AND bottom < 18 in AND top > 36 in AND walking surface <= 36 in; R324.4.4 guard: always; R324.4.5 wet: bottom < 60 in AND <= 60 in from the water's edge; R324.4.6 stair or ramp: bottom < 36 in AND < 36 in horizontally; R324.4.7 bottom landing: < 36 in up AND within a 60 in arc of the bottom nosing.
Source and editionIRC 2024 (International Residential Code). Sections R324.4.1 through R324.4.7 and R324.1 (R308.4.1 through R308.4.7 and R308.1 in IRC 2021), both read at codes.iccsafe.org on 2026-10-19: the criteria are the same, only the section numbers moved.
Free accessFree to read at codes.iccsafe.org.
What governsEstimate. AHJ and licensed structural engineer govern.
API field nameslocation, area_sqft, bottom_in, top_in, distance_in, door_relation, exception, conditions_met, conditions_checked, section
- One location at a time a lite that sits in two locations (beside a door and near a tub) is checked under eachstated assumption
- Exceptions asserted by the reader the tile does not judge whether glazing is decorative or a barrier is permanentstated assumption
- Residential code only the IBC Section 2406.4 locations are not checked herestated scope