Newly Released International Code Council 93-Tall-Mass-Timber-Buildings Exam PDF

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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Concealed connections in Type IV-C construction require periodic special inspection under 2021 IBC Table 1705.5.3, making option B correct.

The mass timber special-inspection table specifically applies to mass timber elements in Types IV-A, IV-B, and IV-C . Among the activities listed for periodic inspection are bolted connections, concealed connections, erection of mass timber construction, screw installation, verification of required predrilling, and several other connection-related installation characteristics.

Options A and C are incorrect because they specify Type IV-HT. Table 1705.5.3 is expressly scoped to Types IV-A, IV-B, and IV-C rather than Type IV-HT. Option D involves a listed Type IV-A activity, but its inspection frequency is wrong: adhesive anchors installed horizontally or upwardly inclined to resist sustained tension loads require continuous , not periodic, special inspection.

For concealed connections, inspection must occur while the relevant components remain observable. Once CLT panels, wood cover, gypsum protection, or finishes hide the connection, critical installation details may no longer be verifiable without destructive removal.

References/Topics: 2021 IBC Section 1705.5.3 and Table 1705.5.3, Required Special Inspections of Mass Timber Construction.

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The prescribed proportion is two-thirds , making option C correct. The relationship is demonstrated directly by IBC Table 722.7.1(1). A building element requiring a one-hour fire-resistance rating must receive 40 minutes of noncombustible protection; a two-hour element requires 80 minutes; and a three-hour-or-greater element requires 120 minutes. Each of those prescribed values represents two-thirds of the corresponding one-, two-, or three-hour rating.

For Type IV-A specifically, Section 602.4.1.2 requires protection of the interior faces of all mass timber elements. Section 602.4.1.2.1 further states that the protection must contribute at least the time assigned in Table 722.7.1(1) and not less than 80 minutes .

The remaining portion of the required fire resistance is provided by the mass timber element itself. Thus, for a three-hour Type IV-A primary structural element, 120 minutes are provided through noncombustible protection and the timber must supply the remaining required endurance.

This two-component approach is fundamental to the Type IV-A fire-design methodology.

References/Topics: 2021 IBC Sections 602.4.1.2 and 602.4.1.2.1; Tables 601 and 722.7.1(1); protected Type IV-A mass timber.

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Type IV-HT construction permits concealed spaces where those spaces comply with the specific protection alternatives prescribed for traditional heavy-timber construction. One permitted method is to completely fill the concealed space with noncombustible insulation. Therefore, option D is correct.

This provision should not be confused with the concealed-space requirements applicable to the tall mass timber classifications—Types IV-A, IV-B, and IV-C. Those classifications employ dedicated noncombustible protection and assigned-time requirements intended to control the contribution of concealed combustible construction during a fire. Type IV-HT follows a different concealed-space framework and allows protection through approved alternatives, including sprinkler protection, gypsum-board enclosure, or complete filling with noncombustible insulation, as applicable.

The insulation must completely occupy the concealed volume. Merely installing partial batt insulation, leaving unprotected voids, or relying on nominally fire-resistant thermal insulation does not satisfy the provision. The inspector should verify the material’s noncombustibility, continuity, placement around obstructions, and conformance with the approved construction documents before the space becomes inaccessible.

References/Topics: 2021 IBC Section 602.4.4; concealed spaces in Type IV-HT construction; noncombustible insulation protection method.

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