NOTE This standard covers fire-rated glazing assemblies used as opening protectives in fire-resistance-rated walls and partitions, including the glass and its complete tested-and-listed framing system. (1.1)

NOTE The platform of products in scope is broad: any place a building code requires a rated opening protective and the design wants vision glass within it. The defining characteristic of every product in this standard is that it carries a fire-resistance or fire-protection rating established by a listed test, and that the glass and frame are listed together as one assembly. A piece of fire-rated glass alone is not a rated opening protective; the listing always belongs to the glass-plus-frame-plus-installation system as a whole. (1.2)

NOTE Applicable assembly types (1.3)

NOTE This standard governs the following product forms, each set into a fire-resistance-rated wall or partition: (1.4)

NOTE Occupancies served (1.5)

NOTE Fire-rated glazing is required across healthcare, education, commercial office, multi-family residential, institutional, and industrial occupancies wherever the International Building Code mandates a rated opening protective with vision glass -- most commonly at corridor walls, stairway and exit enclosures, fire barriers separating occupancies or hazards, and fire partitions between dwelling or sleeping units. (1.6)

NOTE The W-rated versus OH-rated distinction governs every selection decision in this standard. (1.7)

NOTE Two fundamentally different product classes share the loose label "fire-rated glass," and confusing them is the single most consequential error in this discipline: (1.8)

NOTE Where the code calls for a fire-resistance-rated assembly -- fire barriers and fire walls -- only W-rated glazing qualifies, regardless of the hourly number on an OH label. (1.9)

NOTE Excluded from this standard (1.10)

NOTE The following are deliberately out of scope and are governed elsewhere: (1.11)

NOTE The marking designations referenced throughout this standard derive from IBC Section 716.1.2.2 and Table 716.1(2). (2.4)

NOTE Fire-rated glazing assemblies are marked with a sequence of letter designations that the specifier must understand to schedule the product correctly: (2.5)

NOTE A marking is followed by the rating in minutes, for example `W-60` or `OH-45`. The full designation drives both the procurement and the code-compliance review. (2.6)

NOTE The glass, the framing system, and the installation method shall together constitute the listed assembly; substitution of any component outside the listing is prohibited. (4.2)

NOTE The listing is indivisible. A W-rated glass product set into a frame that was not part of the same test is not a W-rated assembly, and the Authority Having Jurisdiction will reject it. This is why a glazing schedule must call out a complete assembly, not merely a glass product. (4.3)

NOTE Mock-ups (4.5)

NOTE For large fire-rated glass-wall installations, a project-specific mock-up of a representative bay verifies frame alignment, glazing-tape continuity, and the perimeter joint condition before production fabrication, and resolves the common field conflict between the listed frame and the adjacent non-rated finishes. (4.6)

NOTE The glazing classification (fire-protective versus fire-resistive) shall be selected to match the wall type per IBC Table 716.1(2). (5.1)

NOTE The hourly rating alone does not determine which product is acceptable. The wall type determines whether radiant-heat limitation (W-rating) is required. Selecting the wrong class is the most common and most expensive error in this discipline, because an OH product that "matches" the hourly number is still non-compliant in a fire barrier. (5.2)

NOTE Glazing classification (5.3)

NOTE The glazing classification is the primary product decision. It is set by the wall type, not by the specifier's preference, and it determines whether the product limits radiant heat. (5.4)

NOTE Required fire-protection rating (5.5)

NOTE The rated period is determined by IBC Table 716.1(2) from the fire-resistance rating of the wall containing the opening. The 45-minute rating is the most common value for corridor and fire-partition windows, which is why it is the default; the project's specific wall ratings govern. (5.6)

NOTE Marking designation (5.7)

NOTE The marking designation is the code-compliance handle for the assembly. It must appear on the glazing schedule so that the installer, the inspector, and the Authority Having Jurisdiction read the same requirement. (5.8)

NOTE Hose stream requirement (5.9)

NOTE The hose stream test, applied immediately after the fire exposure, verifies that the heated assembly does not collapse under the thermal shock and impact of a fire-hose stream. Under NFPA 257, 20-minute assemblies are exempt from the hose stream test; 45-minute and higher assemblies must pass it. This requirement eliminates many traditional wire-glass products from 45-minute and higher applications. (5.10)

NOTE Temperature-rise rating for door applications (5.11)

NOTE For certain rated door openings in corridors and exit enclosures, the IBC requires that the temperature rise on the unexposed face not exceed a defined limit at 30 minutes, protecting occupants who may contact the assembly while egressing. Where a temperature-rise door is required, the glazed lite within the leaf must also carry the temperature-rise (T) designation; a fire-rated lite that does not meet the temperature-rise criterion cannot be used in a temperature-rise door. (5.12)

NOTE Each glazing product shall be selected from a type whose listed assembly satisfies the required classification, rating, and marking for its opening. (6.1)

NOTE Four product families dominate the listed-assembly market, each with a distinct combination of classification, rating range, and physical form. The selection follows from the classification decision above and from the required light size. (6.2)

NOTE Wire glass (6.3)

NOTE Wire glass is a legacy fire-protective product limited under the current IBC to 20-minute applications, with individual lights limited to 1,296 square inches. It cannot be used at 45 minutes or higher because it does not pass the hose stream test at those ratings. Many older specifications still carry wire-glass language for higher ratings; that language generates an RFI when the installer cannot find a compliant product. (6.4)

NOTE Ceramic glass (fire-protective) (6.5)

NOTE Specialty fire-rated ceramic glazing is a clear, hose-stream-tested, fire-protective (OH-rated) product available in single lites from 45 to 90 minutes. It is the standard choice for fire-protective vision panels above 20 minutes where radiant-heat limitation is not required, and is available in clear and low-iron forms. (6.6)

NOTE Laminated fire-resistive glazing (6.7)

NOTE Fire-resistive (W-rated) glazing uses intumescent interlayers or multi-laminate constructions that turn opaque and absorb heat under fire exposure, limiting both flame passage and radiant heat. It is rated 45 to 120 minutes, has no IBC per-lite size limit, and is the only product class permitted in fire barriers and fire walls. It is available as monolithic laminates and as insulating glass units for thermal performance. (6.8)

NOTE Glass product type (6.9)

NOTE The glass product type follows from the classification and rating already selected. Laminated fire-resistive glazing is the default because it is the broadest-application, no-size-limit product and is increasingly the design default in occupied buildings. (6.10)

NOTE Maximum light size and glazed area (6.11)

NOTE Fire-protective (OH-rated) glazing carries a maximum individual light size of 1,296 square inches with no dimension exceeding 54 inches under NFPA 80, absent a larger tested assembly, and is subject to IBC aggregate-area limits per wall type. Fire-resistive (W-rated) glazing removes the per-lite size limit, but the IBC still imposes maximum aggregate glazed-area limits on fire partitions and corridor walls based on wall length; the W-rating does not remove all area restrictions. (6.12)

NOTE Vision-lite dimensions and opening locations (6.13)

NOTE The size of each vision lite and the location of each rated opening are coordination items fixed on the drawings rather than universal field selections. (6.14)

NOTE The framing system shall be the system listed as part of the complete tested assembly for the required classification and rating. (7.1)

NOTE The frame is not a separate trade decision from the glass. Steel, specialty thermally-broken steel, and listed aluminum framing systems each carry their own assembly listings, and the frame profile, anchorage, and glazing method are part of what was tested. The choice of framing material is usually driven by the aesthetic match to adjacent non-rated framing and by the rating required. (7.2)

NOTE Framing material (7.3)

NOTE Steel framing remains the most widely listed option across the full rating range, which is why it is the default. Listed thermally-broken aluminum framing is selected where the design wants a storefront aesthetic at the rated opening and a listed aluminum assembly exists for the required rating. (7.4)

NOTE Framing finish (7.5)

NOTE The frame finish is an architectural selection coordinated with adjacent doors and storefronts. It does not affect the listing provided the finish system is one accepted by the assembly listing. (7.6)

NOTE Profile and sightline (7.7)

NOTE The visible frame width (sightline) is selected to coordinate with adjacent non-rated framing. The value below covers common listed steel and aluminum profiles; the specific listed profile governs. (7.8)

NOTE Glazing infill method (7.9)

NOTE The glazing method -- the tapes, setting blocks, glazing stops, and any intumescent glazing materials -- is part of the listed assembly. Substituting a glazing compound or tape outside the listing voids the assembly just as substituting the glass or frame does. (7.10)

NOTE Glazing within a fire-rated door leaf shall carry a door-assembly listing, not a window-assembly listing. (8.1)

NOTE A vision lite set into a fire door leaf is tested as part of a door assembly under UL 10B, UL 10C, or NFPA 252, not as a window under UL 9. The glazing product, the lite frame (door light kit), and the door leaf must all be part of the same door-assembly listing. This standard governs only the glazed infill and its lite frame; the door leaf, hollow-metal frame, and hardware are governed by Doors Frames And Hardware. (8.2)

NOTE Positive-pressure testing of door assemblies (8.3)

NOTE NFPA 80 and many state codes require fire-door assemblies to be tested under positive pressure to UL 10C or NFPA 252, which more realistically represents fire behavior than the neutral-pressure UL 10B test. Specifying only a UL 10B-listed assembly in a jurisdiction that mandates positive-pressure testing produces a non-compliant installation, so the required test method must be confirmed with the Authority Having Jurisdiction. (8.4)

NOTE Fire-rated glazing in a hazardous location shall simultaneously meet the applicable safety-glazing standard and carry both the fire-rating and safety-glazing labels. (9.1)

NOTE Hazardous locations under IBC Section 2406 -- within 24 inches of a door, low sidelights, and floor-level panels -- require impact-rated safety glazing. Not all fire-rated products are also impact-safety rated, so the glazing schedule must call out both labels (for example, `OH-60 + ANSI Z97.1 Class A`); otherwise the installer will not know that both certifications are required, and a fire-only product may be installed where safety glazing is mandatory. (9.2)

NOTE Safety-glazing certification (9.3)

NOTE The safety-glazing certification class is selected by the hazardous-location condition. Class A (the higher impact category) is the conservative default for fire-rated glazing in hazardous locations because many fire-rated products are tested to it. (9.4)

NOTE Where energy-code compliance is required at an exterior rated opening, an insulating-glass fire-rated assembly shall be provided. (10.1)

NOTE Single-lite ceramic and monolithic fire-resistive glazing have very poor thermal performance, with U-factors commonly between 0.8 and 1.2. At exterior openings subject to energy-code envelope requirements, a fire-rated insulating glass unit (W-rated or OH-rated, thermally-broken) is required to meet the U-factor target. These specialty IGU assemblies have long lead times that must be reflected in the project schedule. (10.2)

NOTE Assembly U-factor (10.3)

NOTE The U-factor requirement applies only at exterior rated openings. The default reflects a typical fire-rated insulating glass unit; the project energy model governs the required value. (10.4)

NOTE Each assembly shall be installed in strict accordance with the installation instructions of its listed assembly. (11.1)

NOTE The installation method is part of the tested assembly. The anchorage spacing, the glazing-bite dimension, the setting-block placement, and the clearances are all defined by the listing; deviating from them voids the rating just as substituting the glass would. (11.2)

NOTE The perimeter joint between the listed framing system and the surrounding rated wall shall be closed with a tested firestop joint system. (11.3)

NOTE The joint between a listed fire-rated frame and the rated wall around it is a rated joint in its own right and must be closed with a tested firestop joint system, typically listed under UL 2079. This work is frequently orphaned between the glazing contractor and the firestopping contractor; the specification must assign responsibility. Detailed firestop joint requirements are governed by Firestopping. (11.4)

NOTE Coordination with adjacent assemblies (11.5)

NOTE Fire-rated glazing meets several adjacent trades whose work defines its opening and its rating continuity. (11.6)

NOTE Each installed assembly shall be inspected to confirm that it matches its listed assembly and retains a legible fire-rating label. (12.1)

NOTE Because the rating depends on the as-installed condition, a field inspection verifies that no substitution occurred during construction, that the perimeter firestop joint is complete, and that every label remains legible. (12.2)

NOTE Installed fire-rated glazing shall be protected and cleaned without damaging the rated assembly. (13.1)

NOTE Some fire-rated products have surface films or coatings that can be damaged by abrasive cleaners or sharp tools. Cleaning must use only agents and methods compatible with the specific product so the rating and clarity are preserved. (13.2)

NOTE The Contractor shall provide manufacturer warranties for the glazing and framing. (14.1)

NOTE The warranty period for fire-rated glazing and framing reflects standard architectural glazing practice; insulating glass units carry a separate seal warranty against fogging. (14.2)