Indiana Sheet Metal Contractor Practice
Exam
Questions And Correct Answers
(Verified Answers) Plus Rationale 2026
Q&A| Instant Download Pdf
1. Which gauge of galvanized steel is most commonly used for residential
HVAC ductwork?
A. 16 gauge
B. 18 gauge
C. 26 gauge
D. 14 gauge
Correct answer is 26 gauge because it provides sufficient strength for
residential air distribution systems while remaining easy to fabricate
and install.
2. What is the primary purpose of turning vanes in rectangular duct
elbows?
A. Reduce duct size
B. Increase airflow noise
C. Improve airflow efficiency and reduce turbulence
D. Strengthen duct joints
Turning vanes guide airflow smoothly through changes in direction,
reducing pressure loss and noise.
,3. Which SMACNA standard governs HVAC duct construction quality?
A. NEC
B. IPC
C. HVAC Duct Construction Standards – Metal and Flexible
D. NFPA 13
SMACNA standards define materials, reinforcement, sealing, and
fabrication methods for HVAC ducts.
4. What type of joint is most commonly used for rectangular duct
connections?
A. Lap joint
B. Riveted seam
C. Slip and drive connection
D. Welded joint
Slip and drive connections are standard because they are secure,
economical, and easy to assemble.
5. Which fastener is typically required for transverse duct joints?
A. Wood screws
B. Nails
C. Sheet metal screws
D. Bolts only
Sheet metal screws provide secure mechanical fastening suitable for
thin-gauge metal.
6. What is the primary function of duct insulation?
A. Strengthen ducts
B. Improve appearance
C. Reduce heat loss/gain and control condensation
D. Increase airflow
, Insulation maintains thermal efficiency and prevents moisture-
related issues.
7. Which type of insulation is commonly wrapped around metal ducts?
A. Foam board
B. Cellulose
C. Fiberglass blanket insulation
D. Spray polyurethane only
Fiberglass wrap is flexible, effective, and widely accepted for duct
insulation.
8. What does a fire damper do in a duct system?
A. Controls airflow volume
B. Reduces noise
C. Prevents fire spread through ducts
D. Supports duct weight
Fire dampers close automatically to maintain fire-rated barriers.
9. At what location are fire dampers typically required?
A. At all diffusers
B. Where ducts penetrate fire-rated walls or floors
C. At outdoor air intakes
D. At return grilles only
Fire-rated assemblies must remain intact where ducts pass through
them.
10. Which code primarily regulates fire protection requirements for
ducts?
A. IPC
Exam
Questions And Correct Answers
(Verified Answers) Plus Rationale 2026
Q&A| Instant Download Pdf
1. Which gauge of galvanized steel is most commonly used for residential
HVAC ductwork?
A. 16 gauge
B. 18 gauge
C. 26 gauge
D. 14 gauge
Correct answer is 26 gauge because it provides sufficient strength for
residential air distribution systems while remaining easy to fabricate
and install.
2. What is the primary purpose of turning vanes in rectangular duct
elbows?
A. Reduce duct size
B. Increase airflow noise
C. Improve airflow efficiency and reduce turbulence
D. Strengthen duct joints
Turning vanes guide airflow smoothly through changes in direction,
reducing pressure loss and noise.
,3. Which SMACNA standard governs HVAC duct construction quality?
A. NEC
B. IPC
C. HVAC Duct Construction Standards – Metal and Flexible
D. NFPA 13
SMACNA standards define materials, reinforcement, sealing, and
fabrication methods for HVAC ducts.
4. What type of joint is most commonly used for rectangular duct
connections?
A. Lap joint
B. Riveted seam
C. Slip and drive connection
D. Welded joint
Slip and drive connections are standard because they are secure,
economical, and easy to assemble.
5. Which fastener is typically required for transverse duct joints?
A. Wood screws
B. Nails
C. Sheet metal screws
D. Bolts only
Sheet metal screws provide secure mechanical fastening suitable for
thin-gauge metal.
6. What is the primary function of duct insulation?
A. Strengthen ducts
B. Improve appearance
C. Reduce heat loss/gain and control condensation
D. Increase airflow
, Insulation maintains thermal efficiency and prevents moisture-
related issues.
7. Which type of insulation is commonly wrapped around metal ducts?
A. Foam board
B. Cellulose
C. Fiberglass blanket insulation
D. Spray polyurethane only
Fiberglass wrap is flexible, effective, and widely accepted for duct
insulation.
8. What does a fire damper do in a duct system?
A. Controls airflow volume
B. Reduces noise
C. Prevents fire spread through ducts
D. Supports duct weight
Fire dampers close automatically to maintain fire-rated barriers.
9. At what location are fire dampers typically required?
A. At all diffusers
B. Where ducts penetrate fire-rated walls or floors
C. At outdoor air intakes
D. At return grilles only
Fire-rated assemblies must remain intact where ducts pass through
them.
10. Which code primarily regulates fire protection requirements for
ducts?
A. IPC
