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100+ Free NV C-21C Sheet Metal Practice Questions

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2026 Statistics

Key Facts: NV C-21C Sheet Metal Exam

60 Q

Official Exam Questions

PSI Nevada Contractor CIB updated 3/25/2026

70%

Passing Score

PSI Nevada Contractor CIB updated 3/25/2026

2.5 hours

Time Allowed

PSI Nevada Contractor CIB updated 3/25/2026

USD 95

PSI Exam Fee (one portion)

PSI Nevada Contractor CIB updated 3/25/2026

Open Book

Book Policy

PSI Nevada Contractor CIB updated 3/25/2026

Nevada C-21C Sheet Metal Contractor Examination is the official NSCB/PSI open book exam: 60 questions, 70% (42 of 60 points), 2.5 hours, USD 95 (bulletin 270, updated 3/25/2026). Official delivery: English.

Sample NV C-21C Sheet Metal Practice Questions

Try these sample questions to test your NV C-21C Sheet Metal exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Under NAC 624.380, which work is authorized for a Nevada C-21C sheet metal contractor but expressly excluded from the classification?
A.Fabrication and installation of HVAC ducts, flashings, and metal roof systems, but not equipment that uses refrigeration as an integral part of the system
B.Installation of complete refrigeration condensing units and refrigerant piping
C.Charging and recovery of refrigerant in packaged air-conditioning equipment
D.Replacement of compressors, expansion valves, and filter-driers
Explanation: NAC 624.380(3)(c) authorizes C-21C fabrication and installation of sheet metal, including cornices, flashings, gutters, leaders, downspouts, pans, food service equipment, ducts, louvres, patented chimneys, flues, and metal roof systems. The same subsection excludes fabrication or installation of equipment that uses refrigeration as an integral part of the system. C-21C is the HVAC sheet-metal specialty inside the C-21 family, not a refrigeration mechanic license.
2Why is lock-forming-quality galvanized steel the usual material for low-pressure HVAC supply and return ducts under UMC 2018 Chapter 6?
A.It is listed as a Type I grease-duct metal without welding
B.It forms Pittsburgh and snap-lock seams, resists ordinary indoor corrosion, and meets SMACNA HVAC Duct Construction Standards
C.It is approved as a clothes-dryer exhaust liner without joints
D.It may be used as a masonry chimney flue liner without listing
Explanation: UMC 2018 Chapter 6 requires metal ducts to be constructed to SMACNA HVAC Duct Construction Standards — Metal and Flexible (2005). G-60/G-90 lock-forming galvanized sheet is the SMACNA base metal because it takes Pittsburgh, snap-lock, and TDC/TDF seams and resists ordinary indoor corrosion. It is not a substitute for the heavier carbon or stainless steel required for Type I grease ducts.
3What is the relationship used to size HVAC duct airflow from a known cross-section and velocity?
A.CFM equals static pressure times duct gauge
B.CFM equals duct perimeter times velocity
C.CFM equals cross-sectional area in square feet times velocity in feet per minute
D.CFM equals duct length times aspect ratio
Explanation: The continuity equation for incompressible air is Q = A × V. Convert the inside width and height (or πr² for round duct) from square inches to square feet by dividing by 144, then multiply by face velocity in fpm. That product is cubic feet per minute. Gauge, perimeter, and length do not replace area in the airflow equation.
4Which longitudinal seam is the standard shop-formed lock on rectangular galvanized HVAC duct?
A.Pittsburgh lock
B.Butt weld with no overlap
C.Soldered flat lock used on copper gutters
D.Standing-seam roof clip
Explanation: SMACNA HVAC Duct Construction Standards treat the Pittsburgh lock as the ordinary longitudinal seam on rectangular galvanized duct. One side is formed into a pocket and the other into a flange that is hammered or button-punched closed. It is a mechanical HVAC seam, not a grease-duct weld or an architectural roof seam.
5On a low-pressure rectangular HVAC duct, which pair of fittings makes the ordinary transverse joint?
A.A cricket and a saddle
B.A Type B storm collar and a firestop spacer
C.A conductor head and an expansion joint
D.An S-slip on the long sides and drive cleats on the short ends
Explanation: SMACNA low-pressure rectangular duct uses an S-slip (or standing S) along the longer dimension and drive cleats on the shorter ends. The drives lock the joint and square the duct. Higher-pressure work more often uses TDC/TDF four-bolt flanges instead of slip-and-drive.
6Factory-made flexible air ducts used on a UMC 2018 HVAC system must be listed and labeled to which standard?
A.UL 1978 grease-duct listing only
B.UL 181 as Class 0 or Class 1 air ducts or connectors
C.ASTM E108 roof-covering fire test
D.UL 103 factory-built chimney listing
Explanation: UMC 2018 Section 603.4 requires factory-made air ducts and connectors to be listed and labeled to UL 181 and installed to their listing, the manufacturer’s instructions, and SMACNA. Class 0 has a zero flame-spread rating; Class 1 is limited to flame spread 25. UL 1978 and UL 103 are grease-duct and chimney listings, not HVAC flex listings.
7A C-21C installer is connecting a return-air duct to a central HVAC unit. From which of the following spaces does UMC 2018 prohibit taking return air?
A.A habitable living room with no fuel-fired appliance
B.A corridor used only as a required egress path in some occupancies, if the designer so specifies
C.A bathroom, toilet room, kitchen, closet, or garage
D.An interior hallway that is part of the conditioned dwelling
Explanation: UMC 2018 return-air rules keep contaminants and combustion products out of the circulating system. Return openings are not taken from bathrooms, toilet rooms, kitchens, closets, garages, or similar spaces where moisture, odor, vehicle exhaust, or products of combustion collect. Habitable conditioned rooms are the ordinary return source.
8Under UMC 2018 Section 603.4, factory-made flexible air ducts shall not do which of the following?
A.Serve as a short runout to a ceiling diffuser in a one-story dwelling
B.Be used as an elbow at a terminal device
C.Be listed to UL 181 Class 1
D.Penetrate a fire-resistance-rated assembly
Explanation: UMC 2018 Section 603.4 states that factory-made air ducts shall not penetrate a fire-resistance-rated assembly or construction and shall not be used as vertical risers serving more than two stories. A listed fire damper and rigid duct are required at a rated penetration. Short residential runouts and a flex elbow at a terminal device are expressly contemplated.
9On an externally insulated cooling-supply duct, where is the vapor retarder installed?
A.On the outside (warm) face of the insulation, sealed at joints and hangers
B.Against the cold metal, under the insulation
C.Only on the inside liner of the duct
D.Vapor retarders are omitted on all cooling ducts
Explanation: A cooling duct runs below ambient dew point. Moisture in room air tries to move inward, so the vapor retarder belongs on the warm outer face of the insulation and must be continuous at seams, punctures, and hangers. UMC 2018 duct-covering rules also require the covering to meet flame-spread and smoke limits and to be suitable for the service temperature.
10When a galvanized HVAC duct passes through a fire-resistance-rated wall or floor, UMC 2018 requires which device unless an exception applies?
A.A listed fire damper installed in the plane of the assembly, with an access door
B.A Type B gas-vent firestop spacer
C.A grease-duct access panel rated 1500°F
D.A standing-seam roof clip
Explanation: UMC 2018 fire-and-smoke-damper provisions require a listed fire damper (UL 555) where a duct penetrates a fire-resistance-rated assembly, unless a specific exception applies (for example certain steel ducts in some partitions). An access door is required so the damper can be inspected and reset. Flex duct cannot make that penetration.

About the NV C-21C Sheet Metal Exam

The Nevada C-21C Sheet Metal Contractor Examination is the official Nevada State Contractors Board trade examination administered by PSI Services LLC. The official exam has 60 scored questions. Passing is 70% (42 of 60 points) in 2.5 hours. The examination is open book. Uniform Mechanical Code, 2018 and International Building Code, 2018 (allowed in center). PSI lists USD 95 for one examination portion and USD 140 if taken with CMS; otherwise USD 95 per trade exam (Candidate Information Bulletin 270, updated 3/25/2026). NSCB requires a separate CMS examination for most new applicants, plus a USD 300 application fee and a USD 600 biennial license fee. This English-language MCQ bank is a study aid, not an official PSI form. It does not replace required trade experience, board approval, fingerprints, bonding, or the official examination.

Assessment

Open Book computer-based multiple-choice. Uniform Mechanical Code, 2018 and International Building Code, 2018 (allowed in center)

Time Limit

2.5 hours

Passing Score

70% (42 of 60 points)

Exam Fee

USD 95 (PSI Services LLC (for the Nevada State Contractors Board))

NV C-21C Sheet Metal Exam Content Outline

33%

Ducts

Ducts (20 items)

13%

Chimneys, Flues, and Vents

Chimneys, Flues, and Vents (8 items)

17%

Hoods, Ventilation, Equipment, and Food Service Equipment

Hoods, Ventilation, Equipment, and Food Service Equipment (10 items)

17%

Metal Roofing Systems, Flashing, and Architectural Metals

Metal Roofing Systems, Flashing, and Architectural Metals (10 items)

8%

Gutters and Downspouts

Gutters and Downspouts (5 items)

7%

Tools and Equipment

Tools and Equipment (4 items)

5%

Safety

Safety (3 items)

How to Pass the NV C-21C Sheet Metal Exam

What You Need to Know

  • Passing score: 70% (42 of 60 points)
  • Assessment: Open Book computer-based multiple-choice. Uniform Mechanical Code, 2018 and International Building Code, 2018 (allowed in center)
  • Time limit: 2.5 hours
  • Exam fee: USD 95

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

NV C-21C Sheet Metal Study Tips from Top Performers

1Distribute study time to the official bulletin 270 content outline (updated 3/25/2026)
2Use only the PSI-listed references; temporary tabs such as Post-it notes are prohibited
3Confirm NSCB experience documentation before scheduling with PSI
4This bank is an English-language MCQ study aid, not an official PSI form

Frequently Asked Questions

How many questions are on the Nevada C-21C Sheet Metal Contractor Examination?

The official PSI examination has 60 scored questions. Passing is 70% (42 of 60 points) within 2.5 hours (Candidate Information Bulletin 270, updated 3/25/2026).

How much does the NV C-21C exam cost?

PSI lists USD 95 for one examination portion. Two portions cost USD 140 only if the second portion is CMS. NSCB charges a separate USD 300 application fee and USD 600 biennial license fee.

Is the NV C-21C exam open book?

Yes. PSI lists this examination as open book. Uniform Mechanical Code, 2018 and International Building Code, 2018 (allowed in center)

Do I still need the CMS examination?

CMS is the required Nevada business-and-law examination. Most new applicants must pass CMS and a trade examination for the requested classification. In most cases you will not retake an exam if you have actively served as a qualified employee in the same classification within the last four years.