Start from the rated walls on the life safety or code plan, then check that each window, interior lite, or glass block panel in those walls is scheduled as a rated assembly with matching glazing, frame, and test basis in the specifications. AI can flag conflicts; the architect, the glazing supplier, and the authority having jurisdiction decide compliance.
What does NFPA 257 cover?
NFPA 257 is the Standard on Fire Test for Window and Glass Block Assemblies. NFPA’s page states that the standard establishes test protocols to measure how well window and glass block assemblies prevent or slow the spread of fire, providing a standardized method for comparing the relative performance of different fire window assemblies.
NFPA’s official NFPA 257 page identifies the 2022 edition as current when checked on October 11, 2026. Confirm the edition, local amendments, and project scope that actually govern the work. The publisher’s newest edition does not establish local adoption.
NFPA 257 is a test method; the rating a wall needs, and whether glazing is allowed in it, come from the adopted building code covered in the IBC Chapter 7 guide. Installation of fire windows follows the NFPA 80 guide. Glazing in doors is part of the door assembly, covered in the NFPA 252 guide.
Gather the glazing documents and the rated walls
Collect the life safety or code plans, the floor plans and interior elevations, the window and storefront schedules, the interior glazing or borrowed-lite schedule, the glass block details, the frame details, the wall types, the glazing and framing specifications, and the supplier’s submittal with labels and listings.
Interior lites are often drawn only on interior elevations. Upload them with the plans so a lite added in a rated corridor wall is not missed.
Match each glazed opening in a rated wall
| Review question | Sources to compare | Decision to record |
|---|---|---|
| Openings in rated walls | Life safety plan, floor plans, interior elevations | Find windows, sidelites, and borrowed lites that sit in walls the code plan shows as rated. |
| Schedule ratings | Window or glazing schedule, life safety plan | Check that each glazed opening in a rated wall carries a rating in its schedule. |
| Glazing product | Glazing schedule, specifications, supplier submittal | Confirm the glass type for each rated opening is the same in the schedule, specifications, and submittal. |
| Frames | Frame details, specifications, storefront schedule | Match each rated lite’s frame with a labeled frame in the specifications rather than a standard storefront. |
| Glass block | Glass block details, wall types, specifications | Ask the architect to confirm whether glass block panels in rated walls are specified as tested assemblies. |
| Exterior openings | Exterior elevations, code plan, window schedule | Identify exterior windows the code plan marks as protected that the window schedule lists as ordinary units. |
The window schedule checklist and the glazing specifications guide follow the same openings from the schedule side, and exterior wall openings connect to the IBC Chapter 14 guide.
Example: a borrowed lite in a rated corridor
Hypothetical example. An office fit-out adds a borrowed lite between a conference room and a rated corridor. The interior elevation shows the new lite, while the glazing schedule lists ordinary tempered glass in a standard aluminum frame and the life safety plan still shows the corridor wall as rated.
The interior elevation adds a borrowed lite in the rated corridor wall, but the glazing schedule lists ordinary tempered glass in a standard frame. Please confirm whether the opening is permitted and, if so, coordinate a rated glazing assembly and frame.
The architect confirms the opening with the code plan and revises the glazing schedule. Compliance is decided by the architect and the authority having jurisdiction.
Review fire-rated glazing with Groundbook
Upload the current project PDFs and relevant specifications to Groundbook. Identify the governing issues and add the applicable NFPA 257 reference from a copy you are licensed to use, where the license permits uploading it. State the edition, amendments, review area, and known exclusions in your instructions.
Compare the life safety plans, floor plans, interior and exterior elevations, window, storefront, and interior glazing schedules, glass block details, frame details, wall types, glazing specifications, and supplier submittals. Flag glazed openings in rated walls without a rated assembly and glazing, frames, or ratings that differ between sources. Use the supplied NFPA 257 edition and adopted building code where applicable and cite both sources.
Groundbook links each potential finding to the sheets involved and the reference you uploaded.
Document review does not test or label glazing, verify a listing, or decide whether an opening is permitted. Those decisions remain with the architect, the supplier, and the authority having jurisdiction.