IRC R308: Safety Glazing

Safety glazing is glass made to break safely, and Section R308 of the International Residential Code (IRC) decides where your house has to use it. The reason is blunt: people walk into glass doors, slip in showers, and trip on stairs, and ordinary annealed glass breaks into long knife-edged shards. Tempered glass breaks into small dull cubes that rarely cut deep. This page lists the "hazardous locations" R308 flags and the exact distances that trigger the requirement, because that is what gets caught at inspection.

What R308 requires

R308 names specific hazardous locations where glazing must be safety glass, meaning tempered or laminated glass that carries a permanent maker's mark in the corner. The common triggers in a house:

• Glass in any door, including sliding, swinging, and bifold doors.
• Glass next to a door, where the bottom edge is under 60 inches off the floor and the glass is within 24 inches of the door's edge in the plane of the door.
• Glass at tubs, showers, spas, and pools, where the bottom edge of the glass is less than 60 inches above the standing or walking surface.
• Glass at the bottom of a stairway, within a 60-inch arc and less than 36 inches above the landing.
• Large low panes: glass bigger than 9 square feet whose bottom edge is under 18 inches and top edge over 36 inches above the floor, where you could walk into it.

Here is the door clause that drives most callouts:

Glazing in fixed and operable panels of swinging, sliding and bifold doors shall be considered to be a hazardous location.

What it means for an Arizona custom home

Arizona custom homes are heavy on glass, so R308 shows up everywhere. Multi-slide and pocket glass walls onto a patio are all doors, so every panel is tempered. The fixed sidelight beside the front door is tempered if it sits within 24 inches of the door. Frameless glass shower enclosures, a near-universal feature in Scottsdale and Paradise Valley primary baths, are tempered top to bottom. A window beside a soaking tub is tempered if its sill is under 60 inches above the tub deck.

For example, on a Paradise Valley home with a glass wall in the great room and a freestanding tub set against an exterior window, the plan check will flag both the slider panels and the tub window for tempered glass before the permit issues. Catch it in the window schedule and the cost is small; miss it and you replace installed glass. Note that safety glazing and low-e glass are different things: low-e controls heat, tempering controls breakage, and a desert window often needs both.

Edition note

The hazardous-location list and the trigger distances (24 inches beside a door, 60 inches at wet areas, the 9-square-foot large-pane rule) are stable across the 2018, 2021, and 2024 IRC. The 2021 edition refined the stairway and railing glazing provisions in R308.4.6 and R308.4.7, but the everyday door, tub, and shower triggers did not move. Confirm the edition your city enforces on the Arizona building code editions by city page.

How it connects

R308 protects the glazed openings that R303 light and ventilation requires and that the home's fenestration schedule lays out. It pairs with the guard and fall rules in R312 and the stair safety rules in R311.7 stairways . All three get verified at the final inspection in the sequence required when building a house in Arizona .

Source

Read the section on the official ICC site: 2021 IRC R308 on codes.iccsafe.org . The ICC I-Codes are copyrighted, so only the short door clause is excerpted; the explanation is ours.