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100+ Free MS Ductwork HVAC Practice Questions

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2026 Statistics

Key Facts: MS Ductwork HVAC Exam

70%

Passing Score

PSI MS Contractor Bulletin 4/23/2026

60 Q

Official Exam Questions

PSI MS Contractor Bulletin 4/23/2026

2 hours

Time Allowed

PSI MS Contractor Bulletin 4/23/2026

$120

PSI Exam Fee

PSI MS Contractor Bulletin 4/23/2026

Open book

Exam Format

PSI MS Contractor Bulletin 4/23/2026

MS Ductwork HVAC PSI trade exam: 60 questions, 70% pass, 2 hours, fee $120. Open-book MSBOC classification (bulletin 4/23/2026).

Sample MS Ductwork HVAC Practice Questions

Try these sample questions to test your MS Ductwork HVAC exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Per the 2021 International Mechanical Code, metallic HVAC ducts shall be constructed as specified in which standard?
A.ASHRAE Standard 62.1 only
B.SMACNA HVAC Duct Construction Standards—Metal and Flexible
C.NFPA 13
D.ASTM A36 structural steel specification
Explanation: IMC 2021 Section 603.4 requires metallic ducts to be constructed as specified in the SMACNA HVAC Duct Construction Standards—Metal and Flexible. That is the same third-edition SMACNA standard listed as an approved reference for the Mississippi ductwork examination. The dwelling-unit thickness table in IMC 603.4 is a limited exception, not the commercial construction method.
2A 12-inch by 12-inch rectangular duct carries air at 800 feet per minute. What is the airflow?
A.800 cubic feet per minute
B.400 cubic feet per minute
C.1,200 cubic feet per minute
D.96 cubic feet per minute
Explanation: Airflow is CFM = V × A, with area in square feet. A 12-inch by 12-inch duct has an area of 144 / 144 = 1.00 square foot. Multiplying 800 fpm by 1.00 ft² gives 800 CFM. Convert both dimensions to feet, or divide the product of the inch dimensions by 144, before multiplying by velocity.
3What is the aspect ratio of a 36-inch by 12-inch rectangular duct?
A.2:1
B.3:1
C.4:1
D.1:3
Explanation: Aspect ratio is the long side divided by the short side: 36 / 12 = 3, or 3:1. SMACNA construction and fitting pressure-loss data assume the designer keeps aspect ratio moderate; values above about 4:1 waste metal and increase friction for a given area. Always use the two inside cross-section dimensions, not length of the run.
4In the U.S. sheet-steel gauge system used for galvanized duct, what happens as the gauge number increases?
A.The metal becomes thicker
B.The metal becomes thinner
C.The zinc coating weight increases
D.The yield strength doubles
Explanation: For steel sheet, gauge is an inverse thickness system: a larger gauge number means thinner metal. Twenty-six gauge is thinner than 24 gauge, which is thinner than 22 gauge. SMACNA construction tables therefore list heavier (lower) gauges as duct size or pressure class increases.
5What is the circumference of a 20-inch inside-diameter round duct?
A.31.42 inches
B.62.83 inches
C.314.16 inches
D.125.66 inches
Explanation: Circumference is π times diameter: 3.1416 × 20 = 62.83 inches. That stretch-out is the blank width of the duct wrapper before any Pittsburgh, snap-lock, or grooved-seam allowance is added. Using radius instead of diameter, or computing area, produces the common wrong answers.
6Which SMACNA longitudinal seam is commonly used to close the long side of rectangular galvanized duct?
A.Drive cleat
B.S-slip
C.Pittsburgh lock
D.Companion-angle flange
Explanation: The Pittsburgh lock is a machine-formed longitudinal seam: one edge is a pocket and the opposite edge is a flange that is inserted and hammered over. Drive cleats and S-slips are transverse (end-to-end) connectors, not the long-seam closer. Companion-angle or TDC/TDF flanges are also transverse joints.
7On a low-pressure rectangular duct joint, which pair of connectors is typically used together as the transverse joint?
A.Pittsburgh lock and grooved seam
B.S-slip on the long sides and drive cleats on the short sides
C.TDC flange and a welded standing seam
D.Button-punch snap lock and an ACME lock
Explanation: The conventional low-pressure rectangular transverse joint uses S-slips (or standing S) on the two wide sides and drive cleats on the two narrow sides. The installer slides the S-slips on first, then drives the cleats to draw the joint tight. Pittsburgh and snap-lock seams close the longitudinal wrapper, not this end joint.
8Per the 2021 IMC, how shall the male end of a crimped round-metal duct joint be oriented?
A.The male end shall extend into the adjoining duct in the direction of airflow
B.The male end shall face upstream against airflow
C.The male end may face either way if three screws are used
D.The male end must be welded and orientation does not matter
Explanation: IMC 2021 Section 603.4.2 requires crimp joints for round and oval metal ducts to be lapped not less than 1 inch, with the male end extending into the adjoining duct in the direction of airflow. That orientation keeps the downstream section from peeling the joint open and reduces leakage at the lap. Three equally spaced screws or rivets are a separate fastening rule in 603.4.1.
9Per the 2021 IMC, a round metallic duct joint shall be mechanically fastened with a minimum of how many sheet-metal screws or rivets?
A.One screw at the top of the joint
B.Two screws 180 degrees apart
C.Three screws or rivets spaced equally around the joint
D.Eight screws regardless of duct size
Explanation: IMC 2021 Section 603.4.1 requires not less than three sheet-metal screws or rivets spaced equally around a round metallic duct joint. Equal spacing prevents a hinge effect if one side of the joint opens. Where part of the joint is inaccessible, the three fasteners are equally spaced on the exposed portion.
10If a designer does not specify a construction pressure class, SMACNA HVAC Duct Construction Standards treat the duct as which default class?
A.1/2 inch water gauge
B.1 inch water gauge
C.3 inches water gauge
D.10 inches water gauge
Explanation: SMACNA HVAC Duct Construction Standards retain a default-to-1-inch-water-gauge pressure class when the contract documents do not assign a class. The shop must still build to a listed SMACNA class of 1/2, 1, 2, 3, 4, 6, or 10 inches wg, positive or negative. Using the 1-inch default keeps gauge, reinforcement, and seal class from being guessed.

About the MS Ductwork HVAC Exam

Mississippi Ductwork for Heating, A/C and Ventilation Contractor Examination is a classification trade examination administered by PSI for the Mississippi State Board of Contractors. The official open-book exam has 60 questions, a 70% passing standard, and 2 hours allowed. PSI examination fee is $120 per portion (bulletin updated 4/23/2026). This English-language MCQ bank is a study aid for the official content outline; it is not an official PSI form, does not replace the required Law and Business Management exam, and is not a substitute for MSBOC application review or the official open-book examination.

Questions

60 scored questions

Time Limit

2 hours

Passing Score

70%

Exam Fee

$120 (PSI Services LLC (for Mississippi State Board of Contractors))

MS Ductwork HVAC Exam Content Outline

65%

Ducts

Duct design, fabrication, and installation

10%

Hoods and Ventilation Equipment and Devices

Kitchen hoods and ventilation equipment

17%

General Knowledge

HVAC ductwork general knowledge

8%

Safety

Sheet metal and HVAC safety

How to Pass the MS Ductwork HVAC Exam

What You Need to Know

  • Passing score: 70%
  • Exam length: 60 questions
  • Time limit: 2 hours
  • Exam fee: $120

Keys to Passing

  • Work through all 100 available questions
  • Review every answer and explanation
  • Track weak areas and revisit them
  • Use our AI tutor for tough concepts

MS Ductwork HVAC Study Tips from Top Performers

1Study only the approved references listed for this classification in the current PSI Mississippi Contractor bulletin (updated 4/23/2026)
2Practice open-book navigation with permanent tabs and indexes before test day
3Drill OSHA 29 CFR 1926 topics that appear across nearly every trade outline
4Confirm MSBOC classification scope and eligibility at msboc.us before scheduling with PSI
5All applicants must also pass Law and Business Management unless it is waived

Frequently Asked Questions

How many questions are on the MS Ductwork HVAC exam?

The official PSI examination has 60 scored questions (plus possible unscored experimental items). Passing is 70% within 2 hours.

How much does the MS Ductwork HVAC exam cost?

PSI lists $120 per examination portion (Candidate Information Bulletin updated 4/23/2026). MSBOC application fees are separate: $400 commercial or $50 residential. Additional classifications are $100 each.

Is the Mississippi contractor exam open book?

Yes. PSI administers MSBOC classification exams as open book. Only bulletin-listed approved references are allowed; temporary tabs such as Post-it notes are prohibited.

Do I still need the Law and Business Management exam?

Yes. MSBOC requires the Mississippi Law and Business Management exam (50 questions, 70%, 2 hours) of all applicants. Reciprocity may waive a trade exam in some cases but does not waive Law and Business.