International Code Council 93-Tall-Mass-Timber-Buildings 93-Tall-Mass-Timber-Buildings Exam Dumps: Updated Questions & Answers (October 2026)

When the footnotes are disregarded, the fire-resistance ratings assigned to the principal building elements of Type IV-A construction correspond to those of Type I-A construction . Option A is therefore correct.

IBC Table 601 assigns both Type I-A and Type IV-A a 3-hour rating for the primary structural frame , 3 hours for exterior and interior bearing walls, 2 hours for floor construction and associated secondary structural members , and 1½ hours for roof construction and associated secondary structural members . Interior nonbearing walls and partitions are generally rated zero by Table 601 unless another code provision requires a rating. Exterior nonbearing walls are governed separately based on fire separation distance.

The similarity in Table 601 ratings does not mean Type I-A and Type IV-A are otherwise equivalent construction types. Type I-A relies principally on noncombustible structural construction, whereas Type IV-A permits mass timber subject to the substantial noncombustible protection requirements of Section 602.4.1.

Types II-A, III-A, IV-C, and IV-HT have materially different Table 601 requirements, so options B, C, and D do not provide a complete rating match.

References/Topics: 2021 IBC Section 601 and Table 601; Types I-A and IV-A fire-resistance ratings.

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A proprietary field-glued mass timber beam splice requires special inspection because the connection relies on a field-applied adhesive process that is not covered as a routine prescriptive mass timber connection in Table 1705.5.3. The controlling mechanism is IBC Section 1705.1.1, which authorizes the building official to require special inspection for unusual materials, systems, or installation procedures, particularly where compliance depends on additional manufacturer installation instructions.

The ICC code-development rationale for the tall mass timber provisions specifically identifies field-glued mass timber beam or panel splices as an example of work for which special inspection can be required. Inspection must address the approved evaluation report and manufacturer’s instructions, including substrate preparation, moisture and temperature limits, adhesive storage and expiration, mixing or proportioning, application quantity, open time, member alignment, clamping or pressure, and curing conditions.

Approval by the permit applicant has no regulatory significance. Verification by the registered design professional may supplement the inspection program but does not replace the approved special inspector. A building official may observe the work, but routine field verification by that official is not the prescribed quality-control procedure.

References/Topics: 2021 IBC Sections 1704.2, 1704.3 and 1705.1.1; special cases; proprietary field-glued mass timber splices.

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Option C is the incorrect statement. The sealing inspection requirements in IBC Section 1705.20 do not automatically apply to every item classified as a “joint” under Section 202. They apply specifically where a sealant or adhesive required by Section 703.7 is installed on mass timber building elements identified in the approved construction documents.

Section 703.7 addresses abutting edges and intersections of fire-resistance-rated mass timber elements and intersections between mass timber and other materials where both elements require a fire-resistance rating. These conditions require periodic special inspection because continuity of the air seal affects the fire performance assumed for the timber assembly.

Option A is correct: qualifying sealants must comply with ASTM C920. Option B is also correct: adhesives used for this purpose must comply with ASTM D3498. Option D reflects the required inspection of sealant applications at the prescribed abutting edges and intersections, although the technically precise term is “mass timber building elements.”

Fire-resistant joint systems are governed separately by IBC Section 715 and may require inspection under Section 1705.18. The two inspection categories must not be treated as interchangeable.

References/Topics: 2021 IBC Sections 703.7, 715, 1705.18 and 1705.20; ASTM C920; ASTM D3498.

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The 1/2-inch lag screws attaching the structural steel ledger require fire protection, making option D correct. These fasteners are structural components of the ledger-to-CLT connection and therefore form part of the connection whose fire performance must be maintained for the required duration.

AWC Technical Report 10 states that wood structural connections—including their connectors, fasteners, and participating members—must be protected from fire exposure for the required fire-resistance time . Protection may be provided by wood cover, fire-rated gypsum board, other approved materials, or a combination.

TR10 distinguishes structural connection fasteners from small fasteners used merely to hold sacrificial protection in place. The report specifically explains that fasteners attaching protective wood strips need not themselves be protected, provided they are sufficiently long to keep the protection in position throughout the required exposure.

In the illustrated ledger connection, the 1/2-inch lag screws transfer structural load between the steel ledger and CLT wall. Their thermal protection is therefore integral to maintaining connection capacity.

References/Topics: AWC Technical Report No. 10 Sections 4.5 and connection examples; thermal protection of structural connectors and fasteners.

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A 7/16-inch wood structural panel is not one of the prescriptively acceptable fireblocking materials listed by IBC Section 718.2.1. Therefore, option C is correct.

Section 718.2.1 permits fireblocking to consist of several specified materials. These include one-half-inch gypsum board; properly secured batts or blankets of mineral wool, mineral fiber, or other approved materials; and mass timber complying with Section 2304.11. Options A, B, and D are consequently valid.

For wood structural panels, however, the IBC requires a substantially greater thickness: a single thickness of approximately 0.719 inch , conventionally represented as 23/32 inch, with joints backed by material of the same required thickness. A 7/16-inch panel is only approximately 0.438 inch thick and therefore does not satisfy that prescriptive fireblocking provision.

Fireblocking is intended to interrupt concealed draft openings and restrict the movement of flame and hot gases through concealed combustible spaces. It should not be confused with a tested firestop system used at penetrations through fire-resistance-rated assemblies.

Special inspection should confirm that the installed material, thickness, joint backing, retention, and location conform to the approved construction documents and the applicable code provision.

References/Topics: 2021 IBC Sections 718.2 and 718.2.1; Section 2304.11; permitted fireblocking materials.

Option A reproduces one of the two permitted exterior gypsum-board fastening methods in 2021 IBC Section 722.7.2.2. Type X gypsum board used as noncombustible protection on the exterior side of mass timber walls may be attached using galvanized nails of minimum 12 gage with a 7/16-inch head and sufficient length to penetrate the mass timber at least 1 inch .

The code also permits ASTM C1002 Type S, W, or G screws, but those screws must likewise penetrate the mass timber a minimum of 1 inch . Options C and D are therefore incorrect because they specify only 3/4-inch and 7/8-inch penetration, respectively. Option B is incorrect because it substitutes 16-gage nails for the minimum 12-gage requirement.

Section 722.7.2.2 additionally requires exterior Type X gypsum-board layers to be fastened 12 inches on center each way and 6 inches on center at joints or ends. Panel-edge fasteners must be located at least 1 inch and not more than 2 inches from the edge.

These fastening details are part of the conditions necessary to claim the protection contribution in Table 722.7.1(2).

References/Topics: 2021 IBC Sections 722.7.1 and 722.7.2.2; exterior Type X gypsum-board protection.

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Option D is the incorrect statement. IBC Section 722.7.2.1 requires the panel edges of the face layer , rather than the base layer, to be taped and finished with joint compound. Fastener heads on the face layer must also be covered with joint compound.

The other three provisions accurately reproduce the code. Each gypsum-board layer must be secured with Type S drywall screws long enough to penetrate the mass timber at least 1 inch when driven flush. Screws for the base layer are installed at 12 inches on center in both directions . Subsequent layers use the same general spacing but are offset from screws in the preceding layer. In addition, the panel edges of each succeeding layer must be offset 18 inches from the panel edges of the previous layer.

These details are not merely workmanship recommendations. They form part of the installation conditions under which the protection contributions in Table 722.7.1(2) can be credited.

References/Topics: 2021 IBC Section 722.7.2.1, Items 1–9; fastening, panel-edge offset, and finishing of Type X gypsum protection.

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Option A correctly reflects the required noncombustible protection for protected Type IV-A mass timber. Under IBC Section 602.4.1.2.1, the noncombustible protection applied to interior faces of Type IV-A mass timber must contribute the protection time determined by the applicable provisions of Section 722.7, but not less than 80 minutes .

The broader Type IV provisions are particularly important for interior exit and elevator hoistway enclosures. In qualifying tall mass timber buildings with an occupied floor more than 75 feet above the lowest level of fire department access, mass timber interior exit and elevator hoistway enclosures are permitted up to the specified height limits only where protected in accordance with Section 602.4.1.2. For a two-hour, 120-minute-rated enclosure, at least 80 minutes must therefore come from the prescribed noncombustible protection.

Type IV-B likewise uses an 80-minute minimum for protected interior mass timber, so option B ' s 40-minute value is incorrect. Type IV-C has different exposure allowances and shaft-protection provisions, but option C does not state the controlling tall-building enclosure requirement tested here. Type IV-HT is not governed by the Type IV-A tall mass timber enclosure protection rule.

References/Topics: 2021 IBC Sections 602.4 and 602.4.1.2 through 602.4.1.2.1; Section 722.7.

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For the illustrated two-layer protection system, the 5/8-inch Type X gypsum-board layer directly adjacent to the connection is assigned 20 minutes, while the second layer is assigned 40 minutes. Therefore, option C is correct.

The standard assigned protection time for one layer of 5/8-inch Type X gypsum board is 40 minutes. However, the thermal-separation methodology applies a 0.50 reduction factor to the final or base Type X layer located directly against the protected connection. That layer therefore contributes 20 minutes. The outer layer retains its full 40-minute assigned value, producing a combined assigned protection time of 60 minutes for the two-layer configuration.

The layers are not interchangeable for calculation purposes because the reduced contribution applies specifically to the layer adjacent to the protected connection. Options A and B incorrectly assign the same value to both layers, while option D reverses the required allocation.

During inspection, the special inspector should verify layer sequencing, board thickness and type, fastening, joint staggering, edge support, protection at corners, and continuity around the connection. Missing or incorrectly sequenced layers can invalidate the calculated thermal-separation time.

References/Topics: AWC Technical Report 10; AWC 2021 Fire Design Specification Section 3.5.2.1; assigned protection time for Type X gypsum board.

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The governing standard is ANSI/APA PRG 320, Standard for Performance-Rated Cross-Laminated Timber. Therefore, option A is correct. The 2021 IBC requires structural glued cross-laminated timber to be manufactured and identified in accordance with PRG 320, and Type IV provisions require CLT to bear a label demonstrating conformity with that standard.

PRG 320 addresses essential manufacturing and qualification requirements, including panel construction, layup, structural performance, adhesive qualification, dimensional tolerances, product marking and quality assurance. Product identification is particularly important to the special inspector because visual similarity alone does not establish that a panel is code compliant.

DOC PS 2 applies primarily to wood structural panels such as plywood and oriented strand board and is not the manufacturing standard for CLT. ANSI/AITC or ANSI/APA A190.1 applies to structural glued-laminated timber, commonly called glulam. ASTM D5055 covers the establishment and monitoring of structural capacities for prefabricated wood I-joists.

The inspector should verify that CLT panels retain legible identification and that the manufacturer, grade, layup and panel designation correspond to the approved construction documents.

References/Topics: 2021 IBC Sections 602.4 and 2303.1.4; Chapter 35; ANSI/APA PRG 320-2019.

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