New Mexico GF-9 Utility Lines Exam: Complete Questions
And Correct Detailed Answers (Expert Verified Exam)
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SECTION 1: DEFINITIONS & GENERAL INSTALLATION (Q1–Q25)
Q1. What is the maximum allowable pressure drop for a low-pressure (under 14" w.c.) gas
system from the meter outlet to the farthest appliance?
A) 0.3" w.c.
B) 0.5" w.c.
C) 1.0" w.c.
D) 2.0" w.c.
Explanation: NFPA 54 Table 6.3.1 – design pressure loss must not exceed 0.5" w.c. for low-
pressure systems to ensure appliance burner efficiency.
Q2. A sediment trap (drip leg) is required at which location?
A) Every appliance connector
B) At the inlet to the appliance regulator
C) At the gas meter outlet
D) At every vertical rise over 10 feet
,Explanation: NFPA 54 5.5.3 requires a sediment trap ahead of the appliance regulator
where sediment may collect.
Q3. What minimum size must a sediment trap be?
A) 1/2 inch
B) 3/4 inch
C) Not smaller than the pipe size of the inlet to the appliance
D) A minimum of 1 inch always
Q4. When threading steel pipe, how many threads should be exposed after tightening?
A) 1-2 threads
B) 3-4 threads
C) 5-6 threads
D) No threads should be exposed
Q5. What is the minimum distance a gas meter must be installed from an electrical meter?
A) 1 foot
B) 2 feet
C) 3 feet
D) 5 feet
Explanation: NM state amendments require 3 feet of horizontal clearance between gas and
electric meters to prevent arc ignition.
,Q6. Gas piping installed in a concealed location must be:
A) Brazed
B) Threaded only
C) Continuous without fittings where possible, and protected from physical damage
D) Painted red
Q7. Flexible gas connectors are permitted for:
A) Any fixed appliance over 400,000 BTU/h
B) Residential appliances only and must be 6 feet or less
C) Commercial kitchens only
D) Any outdoor appliance
Q8. What is the maximum length for an unshielded flexible appliance connector?
A) 3 feet
B) 6 feet
C) 9 feet
D) 12 feet
Q9. CSST (Corrugated Stainless Steel Tubing) must be bonded to the electrical grounding
system with a minimum wire size of:
A) #14 AWG
B) #6 AWG
, C) #8 AWG
D) #10 AWG
Explanation: CSST bonding is critical to prevent lightning damage; NFPA 54 requires a #6
AWG copper wire to the grounding electrode.
Q10. Where a gas pipe passes through a concrete wall, the pipe must be:
A) Wrapped with electrical tape
B) Installed in a protective sleeve
C) Welded continuous
D) Painted with anti-corrosion paint
Q11. The minimum working pressure for natural gas supplied to a residential building is
generally:
A) 3.5" w.c.
B) 4.0" w.c.
C) 7.0" w.c.
D) 14.0" w.c.
Q12. A union is required at the gas meter outlet and at the appliance. Which fitting is not
allowed to be used as a union in a concealed space?
A) Dielectric union
B) Flanged union
And Correct Detailed Answers (Expert Verified Exam)
|Already Graded A+||Brand New!!
SECTION 1: DEFINITIONS & GENERAL INSTALLATION (Q1–Q25)
Q1. What is the maximum allowable pressure drop for a low-pressure (under 14" w.c.) gas
system from the meter outlet to the farthest appliance?
A) 0.3" w.c.
B) 0.5" w.c.
C) 1.0" w.c.
D) 2.0" w.c.
Explanation: NFPA 54 Table 6.3.1 – design pressure loss must not exceed 0.5" w.c. for low-
pressure systems to ensure appliance burner efficiency.
Q2. A sediment trap (drip leg) is required at which location?
A) Every appliance connector
B) At the inlet to the appliance regulator
C) At the gas meter outlet
D) At every vertical rise over 10 feet
,Explanation: NFPA 54 5.5.3 requires a sediment trap ahead of the appliance regulator
where sediment may collect.
Q3. What minimum size must a sediment trap be?
A) 1/2 inch
B) 3/4 inch
C) Not smaller than the pipe size of the inlet to the appliance
D) A minimum of 1 inch always
Q4. When threading steel pipe, how many threads should be exposed after tightening?
A) 1-2 threads
B) 3-4 threads
C) 5-6 threads
D) No threads should be exposed
Q5. What is the minimum distance a gas meter must be installed from an electrical meter?
A) 1 foot
B) 2 feet
C) 3 feet
D) 5 feet
Explanation: NM state amendments require 3 feet of horizontal clearance between gas and
electric meters to prevent arc ignition.
,Q6. Gas piping installed in a concealed location must be:
A) Brazed
B) Threaded only
C) Continuous without fittings where possible, and protected from physical damage
D) Painted red
Q7. Flexible gas connectors are permitted for:
A) Any fixed appliance over 400,000 BTU/h
B) Residential appliances only and must be 6 feet or less
C) Commercial kitchens only
D) Any outdoor appliance
Q8. What is the maximum length for an unshielded flexible appliance connector?
A) 3 feet
B) 6 feet
C) 9 feet
D) 12 feet
Q9. CSST (Corrugated Stainless Steel Tubing) must be bonded to the electrical grounding
system with a minimum wire size of:
A) #14 AWG
B) #6 AWG
, C) #8 AWG
D) #10 AWG
Explanation: CSST bonding is critical to prevent lightning damage; NFPA 54 requires a #6
AWG copper wire to the grounding electrode.
Q10. Where a gas pipe passes through a concrete wall, the pipe must be:
A) Wrapped with electrical tape
B) Installed in a protective sleeve
C) Welded continuous
D) Painted with anti-corrosion paint
Q11. The minimum working pressure for natural gas supplied to a residential building is
generally:
A) 3.5" w.c.
B) 4.0" w.c.
C) 7.0" w.c.
D) 14.0" w.c.
Q12. A union is required at the gas meter outlet and at the appliance. Which fitting is not
allowed to be used as a union in a concealed space?
A) Dielectric union
B) Flanged union
