IBC Glass and Glazing Requirements: Safety Glazing, Wind Loads and Skylights

TL;DR — Key Takeaways

• IBC Chapter 24 governs all glazing — windows, curtain walls, storefronts, glass doors, skylights, sloped glazing, and decorative glass.

• Safety glazing (§2406) is required in hazardous locations — near doors, in low locations (below 18 inches above floor), in wet areas, and in impact-prone locations — and must be labeled per CPSC 16 CFR Part 1201 or ANSI Z97.1.

• Wind resistance (§2404.1): Glass in exterior openings must be designed to resist the design wind pressure for the building's location, using the load tables in §2404 or engineering analysis per ASTM E1300.

• Curtain wall systems must be designed as complete assemblies resisting wind, seismic, and serviceability requirements; all tested assemblies must have approval documentation (AAMA, ASTM, ICC-ES).

• Sloped glazing (§2405): Glass installed at a slope less than 75 degrees from horizontal must be laminated safety glazing — if it breaks, it remains in place rather than raining shards on occupants below.

• Fire-resistance-rated glazing (§716.2.1): Where glass is used in fire-rated partitions, the glass must be rated (wired glass in approved frames, or fire-rated tempered or ceramic glass per the assembly listing).

• Hurricane protection: In wind-borne debris regions (Florida coastal areas, Gulf Coast), windows and glazed openings must meet impact resistance standards (ASTM E1886/E1996 — the "impact + pressure" two-stage test).

• Skylights (§2405.5): Must use laminated glass or glass with plastic sheeting on the hazard side to prevent fallout; curb height, flashing, and drainage requirements apply.

Safety Glazing — Where Required (§2406)

Safety glazing is required at locations where human impact is likely or where broken glass would pose exceptional danger. IBC §2406.4 lists the mandatory hazardous locations:

§2406.4.1 — Glazing in swinging doors:

All glazing in storm doors, entry doors, interior doors, and sliding glass doors must be safety glazing regardless of size.

§2406.4.2 — Glazing adjacent to doors:

Any glazing panel within 24 inches of the edge of a door and within 60 inches of the floor must be safety glazing. The panel must be in the same wall plane as the door and within the door's swing path.

§2406.4.3 — Glazing in windows at low elevations:

Glazing where the exposed area of a single pane is more than 9 square feet, the bottom edge of the glazing is within 18 inches of the floor, and the top edge is more than 36 inches above the floor — and the glazing is within 36 inches of a walking surface — must be safety glazing.

§2406.4.4 — Glazing in railings and balustrades:

All glazing used as railings (glass guardrails), balustrades, or handrail infill panels must be safety glazing.

§2406.4.5 — Glazing in wet areas:

Glazing adjacent to bathtubs, showers, hot tubs, and pools within 60 inches of the water's edge must be safety glazing.

§2406.4.7 — Sports facilities:

Glazing near squash courts, handball courts, and similar sporting facilities.

Safety Glazing Products

Three products commonly used to meet safety glazing requirements:

Tempered glass: Heat-treated to increase strength — when broken, shatters into small, relatively blunt fragments rather than sharp shards. The most common safety glazing product. Tempered glass cannot be cut or drilled after tempering.

Laminated glass: Two or more glass lites bonded with a plastic interlayer (PVB or SGP). When broken, the fragments adhere to the interlayer. Laminated glass is preferred where glazing must remain in place after breakage (sloped glazing, overhead glazing, hurricane glazing).

Wire glass: Glass with embedded wire mesh — historically used in fire-rated assemblies. Largely superseded by fire-rated tempered and ceramic glazing products. Wire glass is NOT a safety glazing product in §2406 terms — it fails the ANSI Z97.1 impact test.

Wind Resistance of Glazing (§2404)

Design Pressure Calculation

Glazing in exterior openings must resist the design wind pressure for the building, calculated per ASCE 7 Chapter 30. The wind pressure on glazing depends on:

• Basic wind speed (from ASCE 7 wind maps for the project location)

• Building height

• Exposure category (B, C, or D)

• Zone location (field, perimeter, corner — corners have the highest pressure)

Glass Thickness Design — ASTM E1300

The required glass thickness for a given panel size and design pressure is determined using ASTM E1300 (Standard Practice for Determining Load Resistance of Glass in Buildings). The standard provides charts and procedures to select glass type and thickness based on:

• Panel dimensions (width × height)

• Design pressure (positive and negative)

• Glass type (annealed, heat-strengthened, tempered)

• Edge support conditions

Curtain wall manufacturers typically provide pre-engineered systems with tested pressure ratings (ASTM E330 structural test) — the design team specifies the required pressure class and selects a system with equal or higher tested performance.

Curtain Walls and Storefronts (§2403)

Curtain wall systems (aluminum framing with glass infill panels, typically exterior of the structure) must comply with §2403. Requirements:

• Structural performance: The curtain wall system must support gravity loads, resist wind pressure, and accommodate building movement (inter-story drift, thermal expansion) without glass breakage, leakage, or structural failure.

• Air infiltration: Tested per ASTM E283 at a specified pressure differential.

• Water infiltration: Tested per ASTM E331 — water must not infiltrate at the design test pressure.

• Thermal cycling: AAMA 501.5 test for condensation resistance.

Certification and listing:

Curtain wall and storefront systems are listed by AAMA (American Architectural Manufacturers Association) ratings:

• AAMA Gold Label: Most comprehensive certification — structural, air, water, and operation tests

• Certified Products Directory at amaanet.org provides listed systems

Hurricane impact glazing (§2404.1.5):

In wind-borne debris regions (areas with basic wind speeds ≥130 mph or within 1 mile of the coastline per ASCE 7), all glazed openings must have impact-resistant glazing (ASTM E1886/E1996) or be protected by approved impact-resistant shutters or panels.

Sloped Glazing (§2405)

Glazing installed at an angle less than 75 degrees from horizontal (essentially all skylights and most sloped roof glazing) must use laminated safety glazing or be protected with a screen below the glass per §2405.2. The purpose: if the glass breaks, fragments must remain in place or be caught — shards falling on occupants below are the hazard.

Specific requirements (§2405):

• All overhead glazing (0–75 degrees): Laminated glass with PVB interlayer, OR glass with plastic film on the bottom surface, OR wired glass (in fire-rated assemblies only — wired glass fails the safety glazing test and cannot be used in other overhead applications)

• Laminated glass for overhead applications must meet ANSI Z97.1 after heat aging test

Skylights (§2405.5)

Curb-mounted skylights have additional requirements:

• Curb height minimum: 4 inches above the roof surface at the skylight perimeter (to prevent water infiltration during rain events)

• Condensation drainage: Skylights must have a drainage system or condensation gutter to handle interior condensation

• Flashing: Compliant with §1503.2 (roofing flashing requirements) at all curb-to-roof intersections

Fire-Resistance-Rated Glazing (§716.2.1)

Where glass is installed in fire-rated walls, partitions, or doors, it must be fire-resistance-rated as part of the assembly. The common fire-rated glazing products:

Wired glass in labeled frames: Provides up to 45-minute fire rating in fire doors and fire windows. Wired glass does NOT meet safety glazing requirements — it cannot be used in hazardous locations per §2406 unless specifically excepted.

Fire-rated tempered glass (pyroborosilicate): Products like Schott Pyran and similar — rated for 20 to 180 minutes depending on the assembly. Must be installed in listed frames.

Fire-rated laminated glass (intumescent interlayer): The PVB interlayer swells when heated, blocking radiant heat transfer. Some products provide up to 120-minute ratings. Commonly used in protected openings between high-value or high-occupancy spaces.

Tested assemblies required: The glazing unit alone is not a fire-rated assembly — the complete assembly (glass + frame + hardware + installation) must be tested and listed per NFPA 252 (fire doors) or NFPA 257 (fire windows).

Research Glazing Requirements for Your Project

Glazing selection requires balancing wind pressure design, safety glazing location requirements, fire ratings, and energy performance (U-factor from IECC). Melt Code lets you search IBC Chapter 24, ASTM E1300 references, and your jurisdiction's amendments together.

Search glazing requirements for your building on Melt Code Try Melt Code →

Frequently Asked Questions

Q: Is tempered glass always required near doors?

Any glazing within 24 inches of the door edge AND within 60 inches of the floor must be safety glazing per §2406.4.2 — tempered glass is the most common option. Safety glass can also be laminated glass. The panel doesn't have to be large — even a narrow glass sidelight within 24 inches of the door swing requires safety glazing.

Q: Can I use regular glass in a storefront?

All glass in exterior doors must be safety glazing per §2406.4.1. For the fixed glass panels in a storefront system, safety glazing is required if the panel meets the hazardous location criteria (size, height, proximity to walking surfaces). Many storefront panels will require safety glazing. In practice, storefront systems are almost universally glazed with tempered glass.

Q: What is the minimum glass thickness for a window?

There is no single IBC minimum thickness — the required thickness depends on the panel dimensions and design wind pressure per ASTM E1300. For a typical 24" × 48" residential window at 25 psf design pressure, 1/8" annealed glass may be adequate. For a large commercial window (48" × 96") at 40 psf, 1/4" or 5/16" tempered glass may be required. Use ASTM E1300 charts or manufacturer load resistance data.

Q: Is impact-rated glazing required everywhere in Florida?

Not everywhere. Impact-rated glazing (ASTM E1886/E1996) is required in "wind-borne debris regions" per Florida Building Code — typically coastal areas within 1 mile of the shoreline with basic wind speeds ≥130 mph, and inland areas with basic wind speeds ≥140 mph. Other areas of Florida may use standard glazing with impact-rated shutters as an alternative.