ICC 93 TALL MASS TIMBER BUILDINGS EXAMINATION: 200 PRACTICE QUESTIONS
WITH VERIFIED ANSWERS AND RATIONALES (2026 EDITION)
SECTION 1: CONSTRUCTION TYPES AND CLASSIFICATIONS (Questions 1–30)
1. The 2021 International Building Code (IBC) introduced which three new construction
types to accommodate tall mass timber buildings?
A) Type III-A, III-B, III-C
B) Type IV-A, IV-B, IV-C
C) Type V-A, V-B, V-C
D) Type II-A, II-B, II-C
Correct Answer: B
Rationale: The 2021 IBC added Type IV-A, Type IV-B, and Type IV-C as new mass timber
construction classifications alongside the existing Type IV-HT (Heavy Timber). These new
types establish different levels of fire-resistance ratings, encapsulation requirements, and
allowable heights, enabling taller wood buildings than previously permitted.
2. Which construction type allows the tallest mass timber building under the 2021 IBC?
A) Type IV-HT
B) Type IV-C
C) Type IV-B
D) Type IV-A
Correct Answer: D
Rationale: Type IV-A permits the greatest height, up to 18 stories and 270 feet, as it
requires noncombustible protection for all mass timber elements. Type IV-B allows 180
feet (12 stories), while Type IV-C and Type IV-HT are limited to 85 feet.
3. What is the maximum building height in feet for a building of Type IV-C construction
under the 2021 IBC?
A) 85 feet
B) 120 feet
,C) 180 feet
D) 270 feet
Correct Answer: A
Rationale: IBC Section 602.4 explicitly limits Type IV-C construction to 85 feet in building
height, although it permits full timber exposure. This is the lowest height tier among the
new mass timber construction types.
4. What is the maximum allowable number of stories for tall mass timber buildings under
Type IV-A construction?
A) 6 stories
B) 9 stories
C) 12 stories
D) 18 stories
Correct Answer: D
Rationale: Type IV-A construction allows up to 18 stories total. This is the highest tier of
mass timber construction with the most stringent fire protection requirements.
5. What is the maximum building height permitted for Type IV-B mass timber construction
under the 2021 IBC?
A) 85 feet
B) 120 feet
C) 180 feet
D) 270 feet
Correct Answer: C
Rationale: Type IV-B construction is permitted up to 180 feet in height (approximately 12
stories). This is the mid-range option for mass timber buildings, balancing height allowance
with reduced encapsulation requirements compared to Type IV-A.
6. Which Type IV classification allows the most exposed mass timber surfaces with the
least encapsulation?
A) Type IV-A
B) Type IV-B
C) Type IV-C
D) Type IV-HT
Correct Answer: C
Rationale: Type IV-C permits maximum exposed timber surfaces but still requires some
,fire protection through sprinklers and char calculations. Type IV-A requires the most
encapsulation, while Type IV-B allows limited exposed timber.
7. Under the 2024 IBC, what percentage of exposed timber ceilings is permitted in Type IV-B
construction?
A) 20%
B) 40%
C) 80%
D) 100%
Correct Answer: D
Rationale: The 2024 IBC permits 100% exposed timber ceilings in Type IV-B construction, a
significant increase from the 20% allowance in the 2021 IBC. This change, based on fire
testing results, provides more design flexibility.
8. Which of the following is NOT one of the new mass timber construction types introduced
in the 2021 IBC?
A) Type IV-A
B) Type IV-B
C) Type IV-C
D) Type IV-HT
Correct Answer: D
Rationale: Type IV-HT (Heavy Timber) existed prior to the 2021 IBC. The 2021 IBC
introduced Type IV-A, IV-B, and IV-C as new classifications alongside the existing Type IV-
HT.
9. What is the primary difference between Type IV-A and Type IV-B construction regarding
fire protection?
A) Type IV-A requires 2-hour fire resistance while Type IV-B requires 1-hour
B) Type IV-A requires noncombustible protection on all mass timber elements while Type
IV-B allows limited exposed timber
C) Type IV-A allows more exposed timber than Type IV-B
D) Type IV-A has no fire resistance requirements
Correct Answer: B
Rationale: Type IV-A requires noncombustible protection such as gypsum wallboard on all
mass timber elements, providing 2- and 3-hour fire resistance. Type IV-B permits limited
exposed mass timber while still providing 2-hour fire resistance.
, 10. Type IV-B construction permits a maximum of how many stories above grade?
A) 6 stories
B) 9 stories
C) 12 stories
D) 18 stories
Correct Answer: C
Rationale: Type IV-B construction allows up to 12 stories above grade. This is the mid-tier
option for tall mass timber buildings.
11. Type IV-C construction permits a maximum of how many stories above grade?
A) 6 stories
B) 9 stories
C) 12 stories
D) 18 stories
Correct Answer: B
Rationale: Type IV-C construction allows up to 9 stories above grade. This is the lowest tier
among the new mass timber construction types.
12. Which construction type requires the most stringent fire-resistance rating for the
primary structural frame?
A) Type IV-HT
B) Type IV-C
C) Type IV-B
D) Type IV-A
Correct Answer: D
Rationale: Type IV-A is the most fire-resistive mass timber construction type. According to
IBC Table 601, the primary structural frame in Type IV-A construction requires a 3-hour fire-
resistance rating.
13. What is the minimum fire-resistance rating for floor assemblies in Type IV-A
construction?
A) 1 hour
B) 2 hours
C) 3 hours
D) 4 hours
WITH VERIFIED ANSWERS AND RATIONALES (2026 EDITION)
SECTION 1: CONSTRUCTION TYPES AND CLASSIFICATIONS (Questions 1–30)
1. The 2021 International Building Code (IBC) introduced which three new construction
types to accommodate tall mass timber buildings?
A) Type III-A, III-B, III-C
B) Type IV-A, IV-B, IV-C
C) Type V-A, V-B, V-C
D) Type II-A, II-B, II-C
Correct Answer: B
Rationale: The 2021 IBC added Type IV-A, Type IV-B, and Type IV-C as new mass timber
construction classifications alongside the existing Type IV-HT (Heavy Timber). These new
types establish different levels of fire-resistance ratings, encapsulation requirements, and
allowable heights, enabling taller wood buildings than previously permitted.
2. Which construction type allows the tallest mass timber building under the 2021 IBC?
A) Type IV-HT
B) Type IV-C
C) Type IV-B
D) Type IV-A
Correct Answer: D
Rationale: Type IV-A permits the greatest height, up to 18 stories and 270 feet, as it
requires noncombustible protection for all mass timber elements. Type IV-B allows 180
feet (12 stories), while Type IV-C and Type IV-HT are limited to 85 feet.
3. What is the maximum building height in feet for a building of Type IV-C construction
under the 2021 IBC?
A) 85 feet
B) 120 feet
,C) 180 feet
D) 270 feet
Correct Answer: A
Rationale: IBC Section 602.4 explicitly limits Type IV-C construction to 85 feet in building
height, although it permits full timber exposure. This is the lowest height tier among the
new mass timber construction types.
4. What is the maximum allowable number of stories for tall mass timber buildings under
Type IV-A construction?
A) 6 stories
B) 9 stories
C) 12 stories
D) 18 stories
Correct Answer: D
Rationale: Type IV-A construction allows up to 18 stories total. This is the highest tier of
mass timber construction with the most stringent fire protection requirements.
5. What is the maximum building height permitted for Type IV-B mass timber construction
under the 2021 IBC?
A) 85 feet
B) 120 feet
C) 180 feet
D) 270 feet
Correct Answer: C
Rationale: Type IV-B construction is permitted up to 180 feet in height (approximately 12
stories). This is the mid-range option for mass timber buildings, balancing height allowance
with reduced encapsulation requirements compared to Type IV-A.
6. Which Type IV classification allows the most exposed mass timber surfaces with the
least encapsulation?
A) Type IV-A
B) Type IV-B
C) Type IV-C
D) Type IV-HT
Correct Answer: C
Rationale: Type IV-C permits maximum exposed timber surfaces but still requires some
,fire protection through sprinklers and char calculations. Type IV-A requires the most
encapsulation, while Type IV-B allows limited exposed timber.
7. Under the 2024 IBC, what percentage of exposed timber ceilings is permitted in Type IV-B
construction?
A) 20%
B) 40%
C) 80%
D) 100%
Correct Answer: D
Rationale: The 2024 IBC permits 100% exposed timber ceilings in Type IV-B construction, a
significant increase from the 20% allowance in the 2021 IBC. This change, based on fire
testing results, provides more design flexibility.
8. Which of the following is NOT one of the new mass timber construction types introduced
in the 2021 IBC?
A) Type IV-A
B) Type IV-B
C) Type IV-C
D) Type IV-HT
Correct Answer: D
Rationale: Type IV-HT (Heavy Timber) existed prior to the 2021 IBC. The 2021 IBC
introduced Type IV-A, IV-B, and IV-C as new classifications alongside the existing Type IV-
HT.
9. What is the primary difference between Type IV-A and Type IV-B construction regarding
fire protection?
A) Type IV-A requires 2-hour fire resistance while Type IV-B requires 1-hour
B) Type IV-A requires noncombustible protection on all mass timber elements while Type
IV-B allows limited exposed timber
C) Type IV-A allows more exposed timber than Type IV-B
D) Type IV-A has no fire resistance requirements
Correct Answer: B
Rationale: Type IV-A requires noncombustible protection such as gypsum wallboard on all
mass timber elements, providing 2- and 3-hour fire resistance. Type IV-B permits limited
exposed mass timber while still providing 2-hour fire resistance.
, 10. Type IV-B construction permits a maximum of how many stories above grade?
A) 6 stories
B) 9 stories
C) 12 stories
D) 18 stories
Correct Answer: C
Rationale: Type IV-B construction allows up to 12 stories above grade. This is the mid-tier
option for tall mass timber buildings.
11. Type IV-C construction permits a maximum of how many stories above grade?
A) 6 stories
B) 9 stories
C) 12 stories
D) 18 stories
Correct Answer: B
Rationale: Type IV-C construction allows up to 9 stories above grade. This is the lowest tier
among the new mass timber construction types.
12. Which construction type requires the most stringent fire-resistance rating for the
primary structural frame?
A) Type IV-HT
B) Type IV-C
C) Type IV-B
D) Type IV-A
Correct Answer: D
Rationale: Type IV-A is the most fire-resistive mass timber construction type. According to
IBC Table 601, the primary structural frame in Type IV-A construction requires a 3-hour fire-
resistance rating.
13. What is the minimum fire-resistance rating for floor assemblies in Type IV-A
construction?
A) 1 hour
B) 2 hours
C) 3 hours
D) 4 hours
