Pass the International Code Council Special Inspector 93-Tall-Mass-Timber-Buildings Questions and answers with Dumpstech

Adhesive anchors installed horizontally to resist sustained tension loads require continuous special inspection. Therefore, option D is correct.

Continuous special inspection means that the special inspector must be present during the performance of the regulated work. This heightened oversight is necessary because horizontal or upwardly inclined adhesive-anchor installations resisting sustained tension are sensitive to installation variables such as borehole cleaning, adhesive proportioning, mixing, placement, embedment depth, temperature, cure time, and prevention of adhesive loss before curing. A concealed installation defect can substantially reduce long-term tension capacity.

The other listed activities are generally subject to periodic inspection under the mass timber special-inspection provisions. Periodic inspection allows the inspector to observe the work intermittently at appropriate stages rather than remaining present throughout the entire operation. Bolted connections, concealed mass timber connections, and anchorage of mass timber construction to deep foundation systems must still be inspected, but the code does not automatically designate each of those activities as continuous.

The inspector should also verify installer certification where required, approved adhesive-anchor evaluation documentation, expiration dates, storage conditions, drilling method, hole dimensions, and compliance with the approved structural documents.

References/Topics: 2021 IBC Sections 1705.3 and 1705.5.3; Table 1705.3; continuous inspection of adhesive anchors under sustained tension.

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Option D most accurately characterizes Type IV-B under the 2021 IBC. The default rule is that interior faces of mass timber elements—including the inside face of exterior mass timber walls and mass timber roofs—receive noncombustible protection. However, Section 602.4.2.2.2 permits specifically limited portions of walls and ceilings to remain exposed.

That combination of extensive protection plus controlled exposure is the defining practical distinction between Types IV-A, IV-B, and IV-C. Type IV-A requires essentially complete interior protection of mass timber surfaces. Type IV-B uses substantial noncombustible protection but permits limited exposed wall and ceiling areas under quantitative and separation restrictions. Type IV-C, by contrast, permits mass timber interior elements to remain unprotected generally, while retaining special requirements for exterior walls, concealed spaces, and shaft enclosures.

Option A therefore more closely describes the protection philosophy of Type IV-A. Option B invents a 50-percent rule that does not exist in the 2021 IBC. Option C more closely resembles the broad exposure philosophy of Type IV-C, though even that wording oversimplifies its specific requirements.

References/Topics: 2021 IBC Sections 602.4.1, 602.4.2 and 602.4.3; Type IV-A, IV-B and IV-C protection concepts.

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The connection detail specifies the CLT-to-glulam screws at 24 inches on center , so option D is correct. This is a construction-document interpretation question rather than a universal prescriptive screw-spacing requirement imposed by the IBC.

The approved structural detail controls the required spacing for this particular connection because the registered design professional has established the connection geometry and fastener schedule based on the applicable structural loads, CLT panel configuration, glulam member, fastener properties, and required load transfer. The 24-inch dimension must therefore be maintained in the field unless an approved revision changes the connection design.

IBC Table 1705.5.3 is directly relevant to the special inspector’s responsibilities. For screws used in Type IV-A, IV-B, or IV-C mass timber connections, periodic special inspection includes verification of diameter, length, head type, spacing, installation angle, and installation depth . The special inspector is therefore expected to compare actual field installation against precisely this type of approved connection detail.

Substituting 12-, 16-, or 20-inch spacing without design authorization would constitute a deviation from the approved documents, even if the alternate spacing appeared more conservative.

References/Topics: Approved structural connection detail shown in the exhibit; 2021 IBC Section 1705.5.3 and Table 1705.5.3, inspection of screw spacing and installation.

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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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