A fire-rated wall assembly is a tested combination of studs, gypsum board or masonry, insulation, and fasteners that holds back fire for a set time, usually 1 or 2 hours. Its rating comes from a listed design such as UL U419. On drawings, a wall type tag points to the partition schedule, which lists the UL number and rating.
Last reviewed October 2026
Helonic is an AI construction drawing analysis platform for teams researching fire rating guide during drawing review. This guide covers common UL wall assemblies, how to read them on a drawing set, the line types used for fire walls, fire barriers, fire partitions, and smoke barriers, and the door ratings each wall needs.
These UL designs show up on partition schedules more than almost any others. Each listing is rated by fire endurance testing to UL 263 (ASTM E119), and the rating only holds when the wall is built exactly as listed.
| UL design | Type | Rating | Construction summary |
|---|---|---|---|
| UL U305 | Load-bearing wood stud wall | 1 hour | 2x4 wood studs at 16 in. on center maximum, one layer of 5/8 in. Type X gypsum board each side. |
| UL U419 | Nonbearing steel stud wall | 1, 2, 3, or 4 hours | Steel studs with 5/8 in. Type X gypsum board. One layer each side for 1 hour, two layers each side for 2 hours, more layers for 3 and 4 hours. |
| UL U465 | Nonbearing steel stud wall | 1 hour | Steel studs with one layer of 5/8 in. Type X gypsum board each side. |
Summaries only. Stud depth, gauge, spacing, fastener schedule, and permitted board products vary within each design. Verify the current listing in UL Product iQ before specifying.
A rated wall is documented in three places: the tag on the plan, the partition schedule, and the life safety plan. All three have to agree.
Fire-rated walls are shown with distinct line patterns, and those patterns vary by firm so you always check the legend.
Note: Line patterns vary by firm. These are common office conventions, not a code requirement, so always check the project's life safety legend.
Construction drawings call out fire barriers, fire partitions, fire walls, smoke barriers, and smoke partitions, each with a different rating and continuity rule.
A fire-rated wall can only accept a door or glass assembly whose rating matches the wall type, such as a 90-minute door in a 2-hour barrier.
| Wall Rating | Door Rating | Glass Rating |
|---|---|---|
| 4-Hour Fire Wall | 3-Hour (A Label) | Not permitted or 3-hr rated |
| 2-Hour Fire Wall/Barrier | 1.5-Hour (B Label) | 1.5-hour rated max |
| 1.5-Hour Fire Barrier | 1.5-Hour (B Label) | 1.5-hour rated max |
| 1-Hour Fire Barrier (shafts, exit enclosures) | 1-Hour (B Label) | 1-hour rated max |
| 1-Hour Fire Barrier (other) | 45-Minute (C Label) | 45-min rated max |
| 1-Hour Fire Partition (corridor) | 20-Minute (C Label) | 20-min rated max |
| Smoke Barrier | 20-Minute + S Label | Fire-rated with smoke seal |
Fire ratings must stay continuous from rated floor to rated floor or roof, and openings cannot drop the assembly below the required rating.
Exterior walls follow a different rule: their required rating depends on how close the wall sits to the lot line. The IBC fire separation distance guide covers those ratings and the opening limits that go with them, and the IBC construction types guide lists the ratings Table 601 sets for the structure itself.
A fire-rated wall assembly is a specific combination of studs, gypsum board or masonry, insulation, and fasteners that passed a fire endurance test (ASTM E119 or UL 263) for a set time, such as 1 or 2 hours. The assembly is only rated when it is built exactly as the listing describes.
A 2-hour fire barrier requires a 1.5-hour (90-minute) fire door assembly under IBC Table 716.1(2). The door must use listed hardware, and any vision panel must use fire-rated glazing listed for that door assembly.
Fire barriers must extend from the floor to the underside of the floor or roof deck above and be securely attached (IBC 707.5). They cannot stop at a suspended ceiling. Fire walls have stricter rules and generally continue through the roof to a parapet unless one of the exceptions in IBC 706.6 applies.
A smoke barrier (IBC 709) has a 1-hour fire-resistance rating and limits smoke movement, and its doors need smoke and draft control. A smoke partition (IBC 710) has no fire-resistance rating requirement and only has to resist the passage of smoke.
No. The UL listing covers fire endurance only. Sound transmission class (STC) comes from a separate acoustical test, so the partition schedule should list the UL design number and the STC value in separate columns.
Reference based on the 2021 IBC and the UL test standards listed above. Always verify requirements with your local Authority Having Jurisdiction (AHJ) and check the project symbol legend.
Related references for fire-rated assemblies and code compliance.
F-rating, T-rating, and firestop installation requirements.
How distance to the lot line sets exterior wall ratings and openings.
Sprinkler, standpipe, and suppression system symbols.
Fire-resistance requirements by construction type.
Best practices for reviewing fire protection plans.
AI-powered building code verification for drawings.
Compare automated and manual plan review approaches.
Tired of manually tracing fire-rated walls through multiple sheets to verify continuity and proper door ratings? Helonic's AI can scan your PDFs and identify missing or conflicting fire rating symbols in seconds. Catch life safety issues before plan check or field inspection.