Free International Code Council 93-Tall-Mass-Timber-Buildings Practice Exam with Questions & Answers | Set: 2

The permitted reduction is one hour. Table 601 assigns a two-hour base fire-resistance rating to exterior and interior bearing walls in Type IV-C construction. Footnote “a” to the table permits the ratings of the primary structural frame and bearing walls to be reduced by one hour where those elements support a roof only.

Accordingly, a Type IV-C bearing wall that supports only roof construction may be assigned a one-hour rating after application of the permitted reduction. The allowance recognizes that the element is not carrying occupied floor levels above and therefore presents a lower consequence of progressive structural failure than a wall supporting one or more floors.

The reduction is not automatic merely because a bearing wall is located at the upper story. The approved structural documents must establish that the wall supports only the roof and does not carry floor loads, transfer loads, elevated mechanical platforms, occupied rooftop structures, or other construction that invalidates the condition.

Options A and B are not reductions specified by Table 601. Option D would eliminate the entire two-hour rating and is not permitted. The inspector should verify the applicable rating and the precise load path before accepting reduced fire protection at the top story.

References/Topics: 2021 IBC Table 601, Footnote “a”; Type IV-C bearing walls and roof-support rating reduction.

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The construction detail identifies a 1/2-inch tolerance between the steel beam web and the adjacent CLT panel. Therefore, option B is correct.

This is principally a construction-document interpretation question rather than a generic prescriptive IBC dimension. The 2021 IBC does not establish one universal steel-web-to-CLT clearance applicable to every mass timber connection. The required clearance is project specific and is established by the registered design professional through the approved structural drawings and connection details.

The tolerance provides erection clearance for placement of the prefabricated CLT around the steel member while accounting for fabrication and installation variation. It must not be arbitrarily reduced or increased because the gap can affect panel fit, bearing conditions, fastener alignment, fire-protection continuity, acoustic treatment and any specified joint-filling material.

Under the special-inspection framework, the inspector must compare the installed connection directly with the approved construction documents. Any condition that does not maintain the specified 1/2-inch clearance—or any undocumented field modification to the CLT or steel connection—must be reported and resolved through the registered design professional rather than accepted solely on the contractor’s direction.

References/Topics: Approved structural details; 2021 IBC Sections 1704.2 and 1705.5; inspection of mass timber erection, anchorage and connections.

Type IV-C generally permits interior mass timber surfaces to remain exposed, but shaft and elevator hoistway enclosures are a specific exception to that broad exposure allowance. Section 602.4.3.6 requires shafts, elevator hoistways, and interior exit stairway enclosures constructed with mass timber to receive noncombustible protection having a minimum assigned protection time of 40 minutes . Option A is therefore correct.

Critically, protection is required on both the inside and outside of the shaft enclosure . The 40-minute value is an assigned contribution from the noncombustible protection; the complete enclosure must still satisfy whatever overall fire-resistance rating is required by Sections 713, 713.4, Table 601, or other applicable provisions.

Option B incorrectly applies the general Type IV-C exposed-interior allowance to a specifically regulated shaft condition. Option C is incomplete because 1/2-inch Type X gypsum board provides only 25 minutes under Table 722.7.1(2), not the required 40 minutes. A 5/8-inch Type X board provides a recognized 40-minute contribution when installed in accordance with Section 722.7.2. Option D does not state the prescribed Type IV-C shaft requirement.

References/Topics: 2021 IBC Sections 602.4.3.2 and 602.4.3.6; Tables 722.7.1(1) and 722.7.1(2).

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The required minimum rating is two hours. Under 2021 IBC Table 601, the primary structural frame in Type IV-C construction must provide a two-hour fire-resistance rating. A structural connection joining members of that frame cannot be permitted to fail before the members it connects; consequently, the connection must remain functional for the same required period.

The protection requirement applies to the complete connection assembly. This includes steel plates, hangers, bolts, screws, dowels, fasteners, welds, bearing regions, and portions of the connected timber that form part of the connection. Compliance can be achieved through tested construction, calculated wood cover, Type X gypsum protection, another approved noncombustible system, or a combination documented by the registered design professional.

Option A is insufficient because it would leave a one-hour weakness in a two-hour structural load path. Option B similarly falls short of the required Table 601 rating. Option D is the Type IV-A primary-frame rating and is not required for the stated Type IV-C condition.

The special inspector must verify protective-cover dimensions and installation before connection hardware becomes concealed, including any project-specific inspection required for calculated wood-cover protection.

References/Topics: 2021 IBC Table 601 and Section 2304.10.1; AWC Fire Design Specification, protection of structural connections.

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The calculation begins with 2021 IBC Table 506.2. Because the building is a Group B occupancy, has more than one story, and is protected throughout by an automatic sprinkler system complying with Section 903.3.1.1, the applicable tabular classification is “SM”—a multistory, fully sprinklered building.

For Group B and Type IV-A construction, Table 506.2 assigns an SM allowable area factor of 324,000 square feet. However, this is not the final total allowable building area. Section 506.2.1 requires a single-occupancy building with more than three stories above grade plane to use Equation 5-2. Where no frontage increase is stated, the calculation is:

324,000 square feet × 3 = 972,000 square feet.

The story-area multiplier is limited to three even though the building contains 15 stories. The code does not permit multiplying 324,000 square feet by all 15 stories. Additionally, the actual area of an individual story cannot exceed its calculated allowable area. Option A represents a different construction-type area factor, while option B does not result from the required IBC multistory calculation. The building is not automatically unlimited merely because it is Type IV-A and sprinklered.

References/Topics: 2021 IBC Sections 506.2 and 506.2.1; Equation 5-2; Table 506.2, Group B, Type IV-A, SM area factor.

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Adhesives installed to resist air passage at qualifying mass timber interfaces must comply with ASTM D3498. Therefore, option C is correct. IBC Section 703.7 applies this requirement to Types IV-A, IV-B, and IV-C at prescribed abutting edges and intersections of building elements that require fire-resistance ratings.

ASTM D3498 addresses adhesives used for field-gluing wood-based structural components. Compliance is significant because the adhesive must retain adequate bond performance under the environmental and service conditions associated with the approved application. The special inspector should verify product identification, compatibility with the timber substrate, manufacturer instructions, storage conditions, shelf life, surface preparation, application temperature, coverage, and curing.

UL 263 is a fire-resistance test standard for building assemblies and structural elements; it is not the product standard for the adhesive. ASTM A653 applies to metallic-coated steel sheet. ASTM F1575 concerns pressure-sensitive safety glazing films and is unrelated to sealing mass timber interfaces.

Where the adhesive is required by Section 703.7, its installation is subject to periodic special inspection under Section 1705.20 unless the applicable code exception removes the sealing requirement.

References/Topics: 2021 IBC Sections 703.7 and 1705.20; ASTM D3498; Type IV-C sealing requirements.

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The IFC does not require daily inspection documentation to be stored in a fire- and water-resistant safe. Therefore, option C is the exception.

The owner or the owner’s authorized agent must establish and maintain the required construction-site fire-prevention program and designate a site safety director. The site safety director is responsible for completing a daily fire-safety inspection covering the building and exterior project areas. The results must be documented, retained on-site until the certificate of occupancy is issued, and made immediately available to the fire code official upon request. Options A, B, and D accurately reflect these administrative requirements.

The purpose is not merely record retention. Daily inspections are intended to identify conditions such as obstructed fire apparatus access, blocked hydrants or fire department connections, exposed temporary wiring, improper hazardous-material storage, uncontrolled combustible debris, unavailable extinguishers, impaired standpipes, and deficient hot-work controls.

A special inspector is not automatically the site safety director. However, observations involving installed passive protection or unsafe construction conditions should be communicated through the approved reporting process. The owner remains accountable for implementing the site safety plan and maintaining the required documentation.

References/Topics: 2021 IFC Sections 3303.1 through 3303.3; site safety director and daily fire-safety inspection records.

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The applicable requirement is found in 2021 IBC Section 504.3 and Table 504.3. The table regulates building height in feet above grade plane by occupancy, construction type, and sprinkler condition. For a Group I-4 occupancy equipped throughout with a Section 903.3.1.1 sprinkler system, the applicable row is the sprinklered “S” row.

Reading across that row to Type IV-B construction gives a maximum building height of 120 feet. Therefore, option B is correct. The 180-foot value applies to Type IV-A construction for the same occupancy and sprinkler condition. The 85-foot value, which is not offered, applies to Type IV-C and Type IV-HT. The 270-foot value generally appears for certain lower-hazard occupancies—such as Groups A, B, E, F, M, S and U—when constructed as sprinklered Type IV-A, but it is not permitted for Group I-4.

This distinction reflects the additional life-safety considerations associated with custodial-care occupancies. A special inspector should verify that the approved construction documents identify both the correct occupancy classification and construction type because either classification directly changes the permitted height.

References/Topics: 2021 IBC Section 504.3; Table 504.3, Group I-4, sprinklered Type IV-B construction; Section 903.3.1.1.

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The intended answer is ANSI/AWC NDS Chapter 16. The video option uses “AWS,” but the correct standards organization is the American Wood Council—AWC . Option D is therefore correct based on its intended reference.

IBC Section 722.1 expressly permits exposed wood members and wood decking to have their calculated fire resistance determined in accordance with Chapter 16 of the ANSI/AWC National Design Specification for Wood Construction. The method evaluates charring, the effective char depth, the reduced residual cross section, elevated-temperature effects, loading, and the remaining structural capacity for the required exposure period.

ACI 216.1 applies to concrete and masonry fire resistance. TMS 0216 addresses masonry assemblies. ASCE 29 Chapter 5 provides procedures for calculating the fire resistance of structural steel assemblies. Those references are code-recognized methods, but they apply to different construction materials.

For mass timber inspection, the approved calculations should identify the exposed surfaces, required rating, timber species or product, member dimensions, design loads, protective contribution, and connection treatment. Field reductions in member dimensions can invalidate the calculated fire resistance.

References/Topics: 2021 IBC Section 722.1; ANSI/AWC NDS Chapter 16; calculated fire resistance of exposed wood members and decking.

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Steel plates are not themselves a fire-protective material for the connection; therefore, option A is the exception. Steel plates frequently form part of mass timber structural connections, but because steel is highly thermally conductive, exposed steel can rapidly transmit heat into fasteners and adjacent wood. Consequently, the steel connection components are normally the items that require protection , not the material relied upon to provide that protection.

AWC guidance recognizes wood cover, fire-rated gypsum board, and other approved protection materials as valid means of shielding structural connections. TR10 specifically provides calculation procedures and worked examples using sacrificial wood cover and Type X gypsum wallboard. An approved protective coating can also be used where its documented fire-performance characteristics establish the required endurance under the approved design.

The distinction is important for inspection. A concealed steel plate does not automatically mean a protected connection. The special inspector must verify whether sufficient wood cover, gypsum protection, approved coating, or another engineered protection system surrounds the steel for the required duration. Hardware geometry, exposed edges, gaps, and penetrations can all materially affect thermal performance.

References/Topics: AWC Technical Report No. 10, protection of structural connections; 2021 IBC Section 2304.10.1; AWC guidance that connection protection can be provided by wood cover, gypsum board, or other approved material.

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