Connecticut (CT) SM-1 Limited Sheet
Metal Contractor Practice Exam
Questions With Complete Solutions.
1. A sheet metal shop is installing a new HVAC system. The prints call for G60 galvanized
steel. What does the "G60" designation indicate?
A) The tensile strength in ksi
B) The weight of the zinc coating in ounces per square foot
C) The thickness of the steel in gauges
D) The yield strength in pounds per square inch
Answer: B
Explanation: G60 refers to the weight of the zinc coating on both sides of the sheet,
specifically 0.60 ounces per square foot total. This is a standard for corrosion resistance
in HVAC applications. Tensile strength, gauge, and yield strength are separate
specifications.
2. When installing a spiral duct system, the maximum allowable pressure class for a
lock-seam spiral pipe made of 26-gauge steel is most commonly:
A) Positive 2" w.g.
B) Positive 4" w.g.
C) Positive 10" w.g.
D) Positive 0.5" w.g.
,Answer: A
Explanation: SMACNA standards generally limit 26-gauge lock-seam spiral duct to
positive 2 inches water gauge (w.g.). For higher pressures, heavier gauges or welded
seams are required. This ensures structural integrity under operating conditions.
3. In Connecticut, a Limited Sheet Metal Contractor (SM-1) is permitted to perform work
that includes:
A) Any type of roofing and siding
B) HVAC ductwork and kitchen exhaust systems up to specified limits
C) Full electrical and plumbing rough-ins
D) Structural steel erection for high-rise buildings
Answer: B
Explanation: The SM-1 license covers sheet metal work related to HVAC, kitchen exhaust,
and similar systems but excludes structural steel erection, roofing not incidental to
HVAC, and trades requiring separate licenses like electrical or plumbing.
4. The minimum clearance required between an uninsulated metal exhaust duct and
combustible material, per NFPA 96, is:
A) 0 inches, if double-walled
B) 1 inch
C) 6 inches
D) 18 inches
Answer: D
Explanation: NFPA 96 (Standard for Ventilation Control and Fire Protection of
Commercial Cooking Operations) requires an 18-inch clearance for uninsulated grease
ducts from combustibles. This can be reduced with approved enclosures or insulation.
5. A duct system is designed with a static pressure of 3 inches w.g. at the fan outlet.
What is the most appropriate duct construction class per SMACNA?
A) Low pressure (0-2" w.g.)
B) Medium pressure (2-6" w.g.)
,C) High pressure (6-10" w.g.)
D) Very high pressure (>10" w.g.)
Answer: B
Explanation: SMACNA classifies 2–6 inches w.g. as medium pressure. Ducts must be
constructed with additional reinforcements such as standing seams, drive slips, and
cross-breaking to prevent drumming and failure.
6. Connecticut state law requires that a sheet metal contractor carry minimum liability
insurance of:
A) $100,000
B) $250,000
C) $500,000
D) No specific minimum, but must show proof of coverage
Answer: D
Explanation: Connecticut does not set a specific dollar minimum for liability insurance
for SM-1 licensees, but you must maintain coverage and provide proof upon request.
Local jurisdictions may impose higher requirements.
7. When field-fabricating a 45-degree lateral tap into a main rectangular duct, the angle
of the tap measured from the main duct axis should not exceed:
A) 15 degrees
B) 30 degrees
C) 45 degrees
D) 60 degrees
Answer: C
Explanation: SMACNA recommends a maximum branch entry angle of 45 degrees to
minimize turbulence and pressure loss. Exceeding 45 degrees increases noise and
energy consumption significantly.
, 8. The maximum allowable leakage class (CL) for a medium-pressure supply duct in a
commercial building, tested at 4 inches w.g., per SMACNA, is:
A) CL 3
B) CL 6
C) CL 12
D) CL 48
Answer: C
Explanation: For medium pressure (2–6" w.g.), SMACNA specifies Leakage Class 12 at 4
inches w.g. for sealed ducts. Higher CL values indicate more leakage. CL 3 is for high
pressure, CL 48 for low pressure.
9. A grease duct for a commercial kitchen must be welded inside a shaft. What is the
minimum thickness of steel allowed for the duct if it is 12 inches in diameter?
A) 20 gauge (0.0359")
B) 16 gauge (0.0598")
C) 14 gauge (0.0747")
D) 10 gauge (0.1345")
Answer: B
Explanation: NFPA 96 requires minimum 16 gauge (0.0598") carbon steel for grease
ducts up to 18" diameter. For larger diameters, thicker material may be required. 20
gauge is too thin and would not meet fire safety.
10. In Connecticut, the responsible party for obtaining a building permit for sheet metal
HVAC work on a new commercial build is:
A) The sheet metal subcontractor (SM-1)
B) The general contractor
C) The property owner
D) The mechanical engineer of record
Answer: B
Explanation: Typically the general contractor pulls the permit, but the SM-1 contractor
Metal Contractor Practice Exam
Questions With Complete Solutions.
1. A sheet metal shop is installing a new HVAC system. The prints call for G60 galvanized
steel. What does the "G60" designation indicate?
A) The tensile strength in ksi
B) The weight of the zinc coating in ounces per square foot
C) The thickness of the steel in gauges
D) The yield strength in pounds per square inch
Answer: B
Explanation: G60 refers to the weight of the zinc coating on both sides of the sheet,
specifically 0.60 ounces per square foot total. This is a standard for corrosion resistance
in HVAC applications. Tensile strength, gauge, and yield strength are separate
specifications.
2. When installing a spiral duct system, the maximum allowable pressure class for a
lock-seam spiral pipe made of 26-gauge steel is most commonly:
A) Positive 2" w.g.
B) Positive 4" w.g.
C) Positive 10" w.g.
D) Positive 0.5" w.g.
,Answer: A
Explanation: SMACNA standards generally limit 26-gauge lock-seam spiral duct to
positive 2 inches water gauge (w.g.). For higher pressures, heavier gauges or welded
seams are required. This ensures structural integrity under operating conditions.
3. In Connecticut, a Limited Sheet Metal Contractor (SM-1) is permitted to perform work
that includes:
A) Any type of roofing and siding
B) HVAC ductwork and kitchen exhaust systems up to specified limits
C) Full electrical and plumbing rough-ins
D) Structural steel erection for high-rise buildings
Answer: B
Explanation: The SM-1 license covers sheet metal work related to HVAC, kitchen exhaust,
and similar systems but excludes structural steel erection, roofing not incidental to
HVAC, and trades requiring separate licenses like electrical or plumbing.
4. The minimum clearance required between an uninsulated metal exhaust duct and
combustible material, per NFPA 96, is:
A) 0 inches, if double-walled
B) 1 inch
C) 6 inches
D) 18 inches
Answer: D
Explanation: NFPA 96 (Standard for Ventilation Control and Fire Protection of
Commercial Cooking Operations) requires an 18-inch clearance for uninsulated grease
ducts from combustibles. This can be reduced with approved enclosures or insulation.
5. A duct system is designed with a static pressure of 3 inches w.g. at the fan outlet.
What is the most appropriate duct construction class per SMACNA?
A) Low pressure (0-2" w.g.)
B) Medium pressure (2-6" w.g.)
,C) High pressure (6-10" w.g.)
D) Very high pressure (>10" w.g.)
Answer: B
Explanation: SMACNA classifies 2–6 inches w.g. as medium pressure. Ducts must be
constructed with additional reinforcements such as standing seams, drive slips, and
cross-breaking to prevent drumming and failure.
6. Connecticut state law requires that a sheet metal contractor carry minimum liability
insurance of:
A) $100,000
B) $250,000
C) $500,000
D) No specific minimum, but must show proof of coverage
Answer: D
Explanation: Connecticut does not set a specific dollar minimum for liability insurance
for SM-1 licensees, but you must maintain coverage and provide proof upon request.
Local jurisdictions may impose higher requirements.
7. When field-fabricating a 45-degree lateral tap into a main rectangular duct, the angle
of the tap measured from the main duct axis should not exceed:
A) 15 degrees
B) 30 degrees
C) 45 degrees
D) 60 degrees
Answer: C
Explanation: SMACNA recommends a maximum branch entry angle of 45 degrees to
minimize turbulence and pressure loss. Exceeding 45 degrees increases noise and
energy consumption significantly.
, 8. The maximum allowable leakage class (CL) for a medium-pressure supply duct in a
commercial building, tested at 4 inches w.g., per SMACNA, is:
A) CL 3
B) CL 6
C) CL 12
D) CL 48
Answer: C
Explanation: For medium pressure (2–6" w.g.), SMACNA specifies Leakage Class 12 at 4
inches w.g. for sealed ducts. Higher CL values indicate more leakage. CL 3 is for high
pressure, CL 48 for low pressure.
9. A grease duct for a commercial kitchen must be welded inside a shaft. What is the
minimum thickness of steel allowed for the duct if it is 12 inches in diameter?
A) 20 gauge (0.0359")
B) 16 gauge (0.0598")
C) 14 gauge (0.0747")
D) 10 gauge (0.1345")
Answer: B
Explanation: NFPA 96 requires minimum 16 gauge (0.0598") carbon steel for grease
ducts up to 18" diameter. For larger diameters, thicker material may be required. 20
gauge is too thin and would not meet fire safety.
10. In Connecticut, the responsible party for obtaining a building permit for sheet metal
HVAC work on a new commercial build is:
A) The sheet metal subcontractor (SM-1)
B) The general contractor
C) The property owner
D) The mechanical engineer of record
Answer: B
Explanation: Typically the general contractor pulls the permit, but the SM-1 contractor
