1 Scope
1.1This standard governs the selection, documentation, and field verification of building assemblies that carry a code-required hourly fire-resistance rating.
NOTE This standard applies to every assembly that IBC Chapter 7 requires to resist the passage of fire and heat for a rated duration: walls, partitions, floor-ceiling assemblies, roof-ceiling assemblies, columns, beams, and structural frame members. (1.1.1)
NOTE The governing rating for an assembly may originate from any of several code provisions, and the same physical wall can be subject to more than one at once. (1.1.2)
NOTE The hourly rating may be set by the construction-type minimums of IBC Table 601, the exterior-wall separation requirements of Table 602, an occupancy separation under Section 707, a corridor under Section 1020, a shaft enclosure under Section 713, or a fire wall, fire barrier, or fire partition designation. Where two provisions apply to the same element, the more stringent rating governs. (1.1.3)
NOTE This standard is the master coordination layer: it selects the tested assembly, cites the governing design number, and delegates material installation to the discipline standards. (1.1.4)
NOTE The work of furring, fastening, and finishing a rated gypsum partition belongs to
Gypsum Board Assemblies; shaft-wall system materials to
Gypsum Shaft Wall Assemblies; spray-applied fireproofing on structural steel to
Fireproofing; and restoration of the rating at penetrations and joints to
Firestopping. This standard establishes which tested assembly is required and how its rating is documented and verified.
(1.1.5) 1.1.6Fire-resistance-rated assemblies shall be selected and documented for every project on which the construction type, occupancy separation, corridor protection, shaft enclosure, or fire wall, fire barrier, or fire partition designation imposes a minimum hourly rating.
1.1.7The required rating, the assembly classification, and the specific tested design number for each rated assembly shall be shown on the Contract Documents.
NOTE This standard is not intended for the material installation of gypsum partitions, shaft walls, ceilings, fireproofing, firestopping, rated doors, or dampers, each of which is governed by its own SynC standard. (1.1.8)
2 Referenced Standards
2.1Assemblies, materials, and documentation shall comply with the latest adopted edition of each of the following unless a specific edition is cited or adopted by the Authority Having Jurisdiction.
2.2Where referenced standards or code provisions conflict, the more stringent requirement shall govern unless the Authority Having Jurisdiction or the Engineer of Record directs otherwise in writing.
| Standard |
Title |
| ASTM E119 |
Standard Test Methods for Fire Tests of Building Construction and Materials |
| UL 263 |
Fire Resistance of Building and Construction Materials |
| ASTM E84 |
Standard Test Method for Surface Burning Characteristics of Building Materials |
| IBC Chapter 7 |
International Building Code — Fire and Smoke Protection Features |
| IBC Table 601 |
Fire-Resistance Rating Requirements for Building Elements |
| IBC Table 602 |
Fire-Resistance Rating Requirements for Exterior Walls Based on Fire Separation Distance |
| IBC Section 703 |
Fire-Resistance Ratings and Fire Tests |
| IBC Section 707 |
Fire Barriers |
| IBC Section 708 |
Fire Partitions |
| IBC Section 713 |
Shaft Enclosures |
| IBC Section 1020 |
Corridors |
| NFPA 101 |
Life Safety Code |
| NFPA 5000 |
Building Construction and Safety Code |
| GA-600 |
Fire Resistance and Sound Control Design Manual (Gypsum Association) |
| GA-216 |
Application and Finishing of Gypsum Panel Products (Gypsum Association) |
| UL Fire Resistance Directory |
UL Fire Resistance Directory (online, continuously updated) |
| ICC-ES AC23 |
Acceptance Criteria for Spray-Applied Fire-Resistive Materials |
NOTE NFPA 251 was withdrawn in 2010 and shall not be referenced; the current fire-resistance test standards are ASTM E119 and UL 263, both accepted by IBC Section 703.2. (2.2.1)
NOTE GA-600 is a design resource that catalogs tested gypsum assemblies; it is not itself a test standard. (2.2.2)
NOTE It is published by the Gypsum Association and provides fire-resistance and sound-rated designs (WP-series numbers) usable as an alternative to UL listings where the IBC accepts gypsum association designs. (2.2.3)
3 Selection of the Governing Rating
3.1The rating required for each assembly is derived from the code provision that applies to that element, not assumed by analogy to other walls on the project.
NOTE Construction type fixes the baseline ratings for structural and enclosure elements. (3.1.1)
NOTE IBC Table 601 sets minimum hourly ratings for the structural frame, floor construction, roof construction, and bearing walls by construction type from Type I-A through Type V-B. These ratings have been stable across the 2018, 2021, and 2024 IBC editions. Type I-A imposes a 3-hour structural frame and 2-hour floors; Type I-B imposes 2-hour frame and floors; Types II-A, III-A, IV-HT, and V-A impose 1-hour frame, floor, and roof; Types II-B, III-B, and V-B impose no rating on these elements. (3.1.2)
3.1.3The construction type for the project shall be established from the Contract Documents before any assembly rating is selected.
Type I-A
Type I-B
Type II-A
Type II-B
Type III-A
Type III-B
Type IV-HT
Type V-A
Type V-B
NOTE Table 601 ratings are minimums and may be exceeded by other provisions or local amendments; the Authority Having Jurisdiction may require a higher rating based on occupancy separation, mixed-use conditions, or local code amendments. (3.1.4)
3.1.5The governing rating shall always be confirmed with the Authority Having Jurisdiction before being locked onto the Contract Documents.
NOTE Each rated assembly shall be classified as a fire wall, fire barrier, fire partition, horizontal assembly, or shaft enclosure, because continuity and opening-protection rules differ by classification. (3.1.6)
Fire wall (IBC 706)
Fire barrier (IBC 707)
Fire partition (IBC 708)
Horizontal assembly (IBC 711)
Shaft enclosure (IBC 713)
Exterior wall (IBC Table 602)
Structural frame member (IBC Table 601)
3.1.7The required hourly rating for each assembly shall be selected from the code section applicable to that element.
20-minute
1-hour
2-hour
3-hour
4-hour
NOTE One-hour is the default for most commercial interiors, but it is a starting point, not a substitute for the code analysis. (3.1.8)
NOTE One-hour ratings govern fire partitions under Section 708, shaft walls connecting fewer than four stories, and the floor and roof of Type II-A, III-A, and V-A construction. Two-hour ratings govern occupancy separations under Section 707 and shaft walls connecting four or more stories. Three-hour and four-hour ratings are reserved for fire walls and for the structural frame and floors of Type I-A construction. (3.1.9)
3.2 Corridor and Shaft Rules
NOTE In a fully sprinklered building, corridor walls for most occupancies require no fire-resistance rating. (3.2.1)
NOTE IBC Section 1020 requires 0 hours for corridor walls in fully sprinklered Group A, B, E, F, M, S, and U occupancies, and 1 hour in non-sprinklered buildings and in Group I-2 and I-3 occupancies regardless of sprinklers. The 80-percent case in modern fully-sprinklered commercial work is a 0-hour corridor, which still must satisfy smoke-partition continuity even though it carries no fire-resistance rating. (3.2.2)
● Fully sprinklered (NFPA 13)
○ Not fully sprinklered
3.2.3Corridor wall ratings shall be confirmed against the building's sprinkler status before any corridor wall is designated as rated.
NOTE Rating inflation on the drawings shall be avoided; an assembly shall not be labeled rated where the governing code section requires no rating. (3.2.4)
NOTE Labeling every corridor 1-hour in a fully sprinklered building where Section 1020 requires 0 hours needlessly raises cost and forces firestopping coordination at every conduit, pipe, and cable penetration that crosses the wall. (3.2.5)
3.2.6Shaft enclosure ratings shall follow IBC Section 713.4 based on the number of stories the shaft connects.
NOTE A shaft connecting fewer than four stories requires a minimum 1-hour enclosure; a shaft connecting four or more stories requires a minimum 2-hour enclosure. (3.2.7)
● Shaft connects fewer than 4 stories — 1-hour
○ Shaft connects 4 or more stories — 2-hour
NOTE The sprinkler substitution that reduces a 2-hour separation to 1-hour does not apply universally. (3.2.8)
NOTE IBC Section 707.3.10 permits substituting a 1-hour fire barrier for a 2-hour occupancy separation in a fully sprinklered building, but the substitution does not apply to corridors in Group I-2, and it never applies to fire walls. The substitution shall not be applied to fire walls or to Group I-2 corridors. (3.2.9)
4 Assembly Test Basis and Design Number
4.1A rated assembly is established by a specific tested design, and the design number is the contractual instrument that defines it.
NOTE Fire-resistance ratings are established by furnace testing to a standard time-temperature curve. (4.1.1)
NOTE ASTM E119 and the UL-owned equivalent UL 263 expose a full-scale assembly to the standard time-temperature curve for the rated duration — 1, 2, 3, or 4 hours. For walls and partitions rated 1-hour and above, a hose-stream test is applied after the fire exposure; floor-ceiling assemblies are not typically subject to the hose stream. (4.1.2)
4.1.3Each rated assembly shall be constructed to a specific tested design listed in the UL Fire Resistance Directory or GA-600, or to a calculated fire resistance per IBC Section 722, or to an alternative protection method approved under IBC Section 104.2.3.
● Tested assembly (UL 263 / ASTM E119 listed design)
○ Calculated fire resistance (IBC Section 722)
○ Alternative protection method (IBC Section 104.2.3, AHJ approval)
4.1.4The specific design number shall be cited on the Contract Documents for every rated assembly.
● UL Fire Resistance Directory design number
○ GA-600 design number
○ Proprietary tested assembly (third-party listed)
4.1.5The design number shall be recorded in the assembly schedule for each rated assembly.
Per drawings — fire-rated assembly schedule
NOTE A rating specified without a design number invites substitution and generates RFIs. (4.1.6)
NOTE A note on the drawings that reads only "1-hour fire-rated" leaves the contractor free to select any listed design, which may carry different stud gauges, board counts, or framing requirements than the architect assumed. The design number removes that ambiguity. (4.1.7)
NOTE UL design numbers are organized by a prefix that identifies the element type, which the specifier shall use to confirm the design matches the element being rated. (4.1.8)
NOTE The prefix groups are: U, V, and W for walls and partitions; L for floor-ceiling assemblies; P for roof-ceiling assemblies; J for beams; X for columns; and D for composite assemblies. Selecting an L-series design for a wall, or a U-series design for a floor, is a fundamental misapplication. (4.1.9)
NOTE The UL Fire Resistance Directory is online and continuously updated; the cited design shall be confirmed current at the time of construction. (4.1.10)
NOTE Listings are revised and occasionally withdrawn. The directory at the UL online product database is the authoritative source, and a design number copied from an old project may no longer be valid. (4.1.11)
5 Assembly Material Family and Configuration
5.1The material family of the rated assembly determines which tested designs are available and which discipline standard governs installation.
5.1.1The assembly material family shall be selected to match the tested design, because each family follows a different installation standard.
Gypsum board on steel framing
Gypsum shaft-wall system
Concrete masonry unit (CMU)
Cast-in-place or precast concrete
Composite steel deck and beam with spray fireproofing
NOTE Gypsum-board-framed assemblies are the most common interior rated construction, and their rating is sensitive to every component. (5.1.2)
NOTE The achieved rating depends on the stud gauge and spacing, the number and type of board layers, the board thickness, the fastener schedule, and any cavity insulation. Changing any one of these from the tested design can invalidate the rating or move the assembly to a different design number. (5.1.3)
NOTE Framing gauge and spacing shall match the tested design number; substituting a lighter or wider-spaced stud changes the applicable design and may reduce the rating. (5.1.4)
20-gauge at 16 in. o.c.
20-gauge at 24 in. o.c.
25-gauge at 16 in. o.c.
25-gauge at 24 in. o.c.
5.1.5Board layer count, type, and thickness shall match the tested design number.
Single layer 5/8 in. Type X each face
Double layer 5/8 in. Type X each face
Single layer 5/8 in. Type C each face
Double layer 5/8 in. Type C each face
NOTE A 5/8-inch Type X board layer contributes roughly 30 minutes of fire resistance per layer per side, but the exact contribution shall be taken only from the cited design. (5.1.6)
NOTE This rule of thumb explains why most 1-hour partitions use a single layer each face and most 2-hour partitions use a double layer, but it is a heuristic only — the specific tested construction, not the heuristic, establishes the rating. (5.1.7)
5.1.8Where cavity insulation is part of the tested design, its presence, type, and thickness shall match that design.
NOTE Insulation affects both fire-resistance and acoustic performance in many UL and GA designs; substituting or omitting it can invalidate the listed rating. (5.1.9)
None (per design)
Mineral wool batt
Glass-fiber batt
NOTE Non-symmetrical assemblies require a design that covers the exact two-sided configuration. (5.1.10)
NOTE A wall finished differently on each face — gypsum board on one side and brick veneer, tile backer, or masonry on the other — shall be constructed to a UL design that lists that exact configuration, or to a separate engineering judgment from a qualified party. A symmetrical design number does not cover a non-symmetrical wall. (5.1.11)
5.2 Common Rated Configurations
NOTE The following configurations represent the assemblies most frequently specified in commercial construction; the cited design number always governs the exact construction. (5.2.1)
- 1-hour steel-stud gypsum partition: 3-5/8 in. 20-gauge studs at 24 in. o.c., single layer 5/8 in. Type X each face — the most common interior fire partition.
- 2-hour steel-stud gypsum partition: 3-5/8 in. 20-gauge studs, double layer 5/8 in. Type X each face — standard corridor and occupancy-separation wall in higher-rated conditions.
- 1-hour shaft wall: 1 in. coreboard or E-stud system with Type X board — standard vertical shaft enclosure under four stories.
- 2-hour shaft wall: double-layer Type X on E-stud chassis or solid coreboard — for four-or-more-story shafts per IBC 713.
- 1-hour CMU bearing wall: 6 in. normal-weight CMU, ungrouted, no additional protection at most densities.
- 2-hour CMU: 8 in. normal-weight CMU or solid-grouted lighter units.
- 1-hour composite floor-ceiling: steel beam and deck with spray fireproofing, ubiquitous in Type II-B floors.
- 2-hour composite floor: deck-and-beam with SFRM thickness set by the beam W/D ratio, common in Type I-B high-rise.
- 2-hour fire wall: structurally independent masonry or concrete, continuous through the roof.
NOTE Composite floor-ceiling and structural-frame ratings depend on spray-applied fireproofing whose thickness is set by the structural member, requiring coordination with the structural drawings. (5.2.2)
NOTE The SFRM thickness for a composite beam-and-deck floor is governed by the W/D ratio (weight-to-heated-perimeter) of the specific beam section in the cited UL design. The structural engineer must provide the beam sizes, and the fireproofing specification under
Fireproofing must coordinate to those sizes. Specifying the rating without coordinating the framing produces field conflicts.
(5.2.3) 6 Continuity and Opening Protectives
6.1A rated assembly performs only if it is continuous and its openings are protected; both are part of the rating, not afterthoughts.
6.1.1Fire barriers and fire partitions shall extend from the floor to the underside of the structural deck above, or to a fire-rated floor-ceiling assembly above.
6.1.2Fire barriers and fire partitions shall be continuous through concealed spaces, including plenums and interstitial spaces.
NOTE Stopping a rated partition at the acoustic-tile ceiling is a common and serious code violation. (6.1.3)
NOTE IBC Sections 707.5 and 708.4 require continuity to the deck or to a rated horizontal assembly above. A 1-hour partition that dies at the lay-in ceiling provides no rated separation in the plenum and is routinely flagged during inspection. (6.1.4)
6.1.5Openings in a rated assembly shall be protected by opening protectives whose rating corresponds to the assembly rating per IBC Table 716.1.
NOTE A 1-hour barrier requires a 3/4-hour door; a 2-hour barrier requires a 1.5-hour door; a 3-hour barrier requires a 3-hour door or shutter; a 20-minute partition requires a 20-minute door. (6.1.6)
20-minute door (in 20-minute partition)
3/4-hour door (in 1-hour barrier)
1.5-hour door (in 2-hour barrier)
3-hour door or shutter (in 3-hour barrier)
NOTE Opening protectives — rated doors, frames, glazing, and dampers — are governed by their own standards and shall be coordinated, not specified here. (6.1.7)
NOTE Rated door, frame, and hardware assemblies are governed by
Doors Frames And Hardware; fire and combination fire/smoke dampers in rated duct penetrations are governed by
Hvac Ductwork. This standard establishes the required opening-protective rating; those standards establish the products.
(6.1.8) NOTE The gap between the top track and the structural deck is not part of the wall design and requires a separate fire-resistive joint system. (6.1.9)
NOTE The head-of-wall joint between a rated wall and the deck above is a movement joint that a UL wall design does not cover. It requires a tested fire-resistive joint system per UL 2079, governed by
Firestopping. Specifiers routinely omit this and the firestopping subcontractor inherits unexpected scope.
(6.1.10) 6.1.11Through-penetrations of a rated assembly by pipe, conduit, cable, and duct shall be sealed with a tested firestop system that restores the assembly rating, per Firestopping. NOTE The finish rating of a tested design shall be observed where combustible structural elements are framed within the assembly. (6.1.12)
NOTE A UL design carries both a fire rating and a finish rating; the finish rating is the time before the unexposed face of the protective membrane reaches an average 250°F rise, and it is the life-safety metric that protects combustible framing inside the cavity. Overlooking the finish rating on a wood-framed rated wall is a substitution pitfall. (6.1.13)
7.1The rated performance is defined by the failure criteria of the test, which the selected assembly must have demonstrated for the required duration.
NOTE Each rated assembly shall demonstrate the ASTM E119 / UL 263 endpoint criteria for the full required rating duration. (7.1.1)
NOTE The fire test fails the assembly when the unexposed surface temperature rise, the passage of flame or hot gases, or (for load-bearing assemblies) the loss of structural capacity exceeds the standard limits before the rated time elapses. The selected design number must have passed for at least the required duration. (7.1.2)
7.1.3For protected structural connections, the temperature rise shall not exceed the IBC Section 703.2.3 limits for the duration equal to the required rating of the connected element.
NOTE IBC Section 703.2.3 sets a single fixed limit for protected structural connections: an average temperature rise of 250°F and a maximum temperature rise of 325°F at any point on the unexposed face of the connection. These values are not project-selectable; they apply universally to any assembly whose rating is based on protection of a structural connection. (7.1.4)
7.1.5Materials placed within a rated assembly cavity shall meet the surface-burning requirements of ASTM E84 where required by the IBC for interior finishes and concealed insulation.
Class A (flame spread ≤ 25, smoke developed ≤ 450)
Class B (flame spread 26–75)
Not applicable (noncombustible)
8 Submittals
8.1 Action Submittals
8.1.1The Contractor shall submit the following action submittals for each rated assembly before fabrication or installation:
- Schedule of all rated assemblies, keyed to the drawings, listing classification, required rating, and the cited design number for each.
- The complete tested design listing (UL or GA-600 page) for every cited design number.
- Product data confirming each component of the assembly matches the cited design — stud gauge and spacing, board type and thickness, layer count, insulation, and fasteners.
- Shop drawings of head-of-wall and intersection conditions identifying the separate fire-resistive joint systems required.
- Engineering judgment documentation for any non-listed condition, signed by a qualified party.
☐ Rated assembly schedule (classification, rating, design number)
☐ Tested design listings (UL / GA-600 pages)
☐ Component product data matched to cited design
☐ Head-of-wall and intersection shop drawings
☐ Engineering judgment for non-listed conditions
8.2.1The Contractor shall submit the following informational submittals:
- Manufacturer certification that supplied components are the listed components of each cited design.
- Qualification documentation for any special inspector engaged for fireproofing or rated-assembly verification.
- Coordination drawings reconciling rated assemblies with structural framing, mechanical penetrations, and ceiling lines.
☐ Manufacturer certification of listed components
☐ Special inspector qualifications
☐ Coordination drawings (structural / MEP / ceiling)
8.3 Closeout Submittals
8.3.1The Contractor shall submit the following closeout submittals:
- Inspection records documenting verification of each rated assembly before concealment.
- As-built rated assembly schedule reflecting any approved substitutions and the final design number for each assembly.
- Record copies of all engineering judgments and Authority Having Jurisdiction approvals.
☐ Pre-concealment inspection records
☐ As-built rated assembly schedule
☐ Engineering judgments and AHJ approvals
9 Quality Assurance
9.1Documentation, substitution control, and field verification protect the rating from the gap between what is tested and what is built.
NOTE Substituting any component of a listed assembly invalidates the tested rating unless a revised design number is selected. (9.1.1)
NOTE Changing the gypsum board manufacturer or thickness, the stud gauge, the insulation type, or the fastener schedule from what the listed design specifies breaks the chain of evidence that the assembly will perform. Each component shall match the cited listing, or a different design number that covers the substitution shall be selected and documented. (9.1.2)
9.1.3Any proposed substitution of a listed component shall be submitted as a revised design number with supporting listing documentation, and shall not be made in the field.
9.1.4A qualified party shall prepare an engineering judgment for any rated condition not covered by a published tested design, subject to Authority Having Jurisdiction acceptance.
NOTE Field verification of SFRM thickness and density shall follow ICC-ES AC23 and the applicable AWCI procedures where spray fireproofing establishes the rating. (9.1.6)
NOTE For composite floor-ceiling and structural-frame assemblies, the rating depends on the as-applied thickness and density of the SFRM. These are verified in the field against the cited UL design; the installation itself is governed by
Fireproofing.
(9.1.7) 10 Field Verification and Concealment
10.1A rated assembly must be inspected and documented while it is still visible, because concealment hides the components the rating depends on.
10.1.1Rated assemblies shall be inspected and documented before being concealed by drywall, ceiling tile, or other finish, per IBC Section 110.3.4.
NOTE Concealment before inspection is a frequent schedule conflict and a code violation. (10.1.2)
NOTE IBC Section 110.3.4 prohibits covering rated assemblies — especially fireproofing on structural steel — before inspection by the Authority Having Jurisdiction or the special inspector. Framing and finish trades that move quickly often close up walls and ceilings before the inspection hold point is released; this requires the work to be reopened. (10.1.3)
10.1.4Inspection hold points for each rated assembly shall be established in the construction schedule and released in writing before concealment.
● Required for all rated assemblies
○ Required only for structural fireproofing
10.1.5Each rated assembly shall be field-verified against its cited design number for stud gauge and spacing, board layers, fastener schedule, insulation, and continuity to the deck before sign-off.
NOTE There is no published field-inspection standard specific to rated drywall assemblies; verification relies on the cited design, the Authority Having Jurisdiction's visual inspection, and contractor documentation. (10.1.6)
NOTE Unlike spray fireproofing, which has thickness and density verification procedures, rated gypsum assemblies are confirmed by comparing the as-built construction to the cited listing and recording that comparison. The documentation is the evidence of compliance. (10.1.7)
11 Identification and Labeling
11.1A rated assembly that is not labeled cannot be maintained or verified after the building is occupied.
11.1.1Rated walls and barriers shall be permanently identified in concealed spaces above ceilings and in accessible shafts with stenciled or labeled signage stating the assembly rating, per IBC Section 703.7.
☐ Stenciled rating text in plenum and concealed spaces
☐ Markings spaced not more than 30 ft on center
☐ Letters not less than 3 in. high
11.1.2Marking text shall identify the wall as a fire or smoke-resistant assembly and state the hourly rating in a contrasting color legible from the accessible space.
12 Coordination with Other Standards
12.1This standard selects and documents the assembly; the installation, protection, and openings are executed under the discipline standards.
12.1.1Installation of rated gypsum partitions, ceilings, and area-separation walls shall be executed under Gypsum Board Assemblies to the design number cited under this standard. 12.1.3Spray-applied fire-resistive materials on structural steel and concrete shall be executed under Fireproofing to the thickness required by the cited design. 12.1.4Through-penetration firestops and fire-resistive joint systems that restore the rating at openings and gaps shall be executed under Firestopping. 13 Warranty
13.1Warranty obligations cover the documentation and installation that this standard controls, not the inherent fire resistance of code-compliant materials.
13.1.1The Contractor shall warrant that each rated assembly was constructed to the cited tested design and that no component was substituted without an approved revised design number, for the project warranty period.
13.1.2Defects in rated-assembly construction discovered during the warranty period — including missing continuity, unprotected openings, or substituted components — shall be corrected at no cost to the Owner.
NOTE The fire-resistance rating of a code-compliant listed assembly is established by test, not by a manufacturer's warranty; the warranty here covers conformance of construction to the cited design. (13.1.3)