93-Tall-Mass-Timber-Buildings Exam Dumps : 93-Tall-Mass-Timber-Buildings

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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Minimum prescriptive dimensions are not themselves a component added into a calculated fire-resistance time. Therefore, option A is the exception.

IBC Section 602.4 states that a mass timber element’s required fire resistance can be based on the fire-resistance contribution of the mass timber, the noncombustible protection, or a combination of those two components. Options B, C, and D reflect those permitted approaches.

Minimum dimensions under Section 2304.11 serve a different function. They establish the minimum cross-sectional size and construction characteristics required for qualifying heavy timber or mass timber elements. A member can satisfy the minimum dimensional requirement without automatically achieving every required one-, two-, or three-hour fire-resistance rating. The structural fire calculation must evaluate the remaining effective section after charring, elevated-temperature effects, applied loading, and any credited protective materials.

The inspector must therefore verify both requirements independently: the installed member must meet the minimum code dimensions and must match the approved fire-resistance design. Increasing a member to the minimum prescriptive size does not by itself replace the required calculation, tested assembly, or approved protection system.

References/Topics: 2021 IBC Sections 602.4, 703.2, 722.7 and 2304.11; calculated mass timber fire resistance.

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The figure depicts an unprotected portion of the mass timber ceiling . For Type IV-B construction, Section 602.4.2.2.2, Exception 1.1, limits unprotected ceiling areas—including attached mass timber beams—to 20 percent of the floor area of the applicable dwelling unit or fire area. Option B is therefore correct.

The percentage is based on floor area rather than total ceiling surface area. For example, where the associated fire area contains 1,000 square feet of floor area, the maximum ceiling exposure permitted under this particular exception would be 200 square feet, subject to the additional separation and mixed-exposure provisions.

The 40-percent value in option D applies to mass timber walls, including attached columns , rather than ceilings. The 15-percent and 30-percent values are not the prescribed Type IV-B ceiling exposure limitations in the 2021 IBC.

The inspector must additionally determine whether another exposed wall or ceiling region exists nearby. Section 602.4.2.2.4 imposes a 15-foot separation requirement, and Section 602.4.2.2.3 controls situations where both wall and ceiling surfaces are intentionally exposed.

References/Topics: 2021 IBC Sections 602.4.2.2.2 through 602.4.2.2.4; Type IV-B ceiling exposure limitations.

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