G33 Master Gas Pipe Fitter Exam | Comprehensive Practice Test | 100 Q&A
Subject/Course: Plumbing, HVAC, Mechanical Trades, Licensing Exams, Gas Fitting
Tags: Master Gas Fitter, G33 License, Gas Piping, Natural Gas, Propane, Fuel Gas
Code, NFPA 54, ICC, IPC, IFGC, Pipe Sizing, Leak Test, Practice Exam
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G33 MASTER GAS PIPE FITTER - PRACTICE EXAMINATION
1. The model code most commonly adopted as the basis for state and local fuel
gas regulations in the United States is:
A) ASME B31.3
B) NFPA 54 / ANSI Z223.1 (National Fuel Gas Code)
C) Uniform Plumbing Code (UPC)
D) International Plumbing Code (IPC)
Correct Answer: B) NFPA 54 / ANSI Z223.1 (National Fuel Gas Code)
Explanation: NFPA 54, also known as the National Fuel Gas Code, is the
predominant model code for the installation of fuel gas piping systems,
appliances, and equipment.
2. A Master Gas Fitter license (G33) typically authorizes the holder to:
A) Design gas piping systems only
B) Install, repair, and supervise gas piping and appliances without restriction
C) Only install piping up to 1 inch in diameter
D) Only work on residential systems
,Correct Answer: B) Install, repair, and supervise gas piping and appliances without
restriction
Explanation: The Master level license is the highest grade, allowing the holder to
perform all gas fitting work and supervise Journeyman and Apprentice gas fitters.
3. The maximum operating pressure for natural gas in a residential building,
downstream of the meter, is typically:
A) 0.5 psig (14" w.c.)
B) 2 psig
C) 5 psig
D) 10 psig
Correct Answer: A) 0.5 psig (14" w.c.)
Explanation: The gas utility typically supplies gas to the meter at about 7" w.c.
(0.25 psi). Inside the residence, the pressure is further regulated at each appliance
or at a second-stage regulator to the appliance manifold pressure, usually 3.5"
w.c. The distribution pressure within the house piping is generally maintained
below 0.5 psig (14" w.c.).
4. The minimum depth for underground steel gas piping to protect against
accidental damage is:
A) 6 inches
B) 12 inches
C) 18 inches
D) 24 inches
Correct Answer: B) 12 inches
,Explanation: NFPA 54 requires a minimum cover of 12 inches for steel gas piping.
Plastic piping may have different depth requirements, and local codes may
require greater depth.
5. When a gas line must be run through an air duct or plenum, the piping must be:
A) PVC schedule 40
B) Uncoated black steel
C) Galvanized steel
D) Sealed in a gastight, noncombustible sleeve
Correct Answer: D) Sealed in a gastight, noncombustible sleeve
Explanation: This prevents any potential gas leakage from contaminating the
airstream. The sleeve must extend beyond the duct and be sealed at both ends.
6. The primary purpose of a drip leg (sediment trap) in a gas line is to:
A) Increase gas pressure
B) Catch moisture, dirt, and pipe scale before they enter the appliance controls
C) Act as a pressure relief device
D) Provide a point to add odorant
Correct Answer: B) Catch moisture, dirt, and pipe scale before they enter the
appliance controls
Explanation: Drip legs are required at the inlet to each appliance to protect
sensitive valves and orifices from debris that can cause malfunction or unsafe
conditions.
7. The minimum size of a drip leg is:
A) 1/2 inch
, B) 3 inches in length
C) The same size as the pipe serving the appliance
Correct Answer: C) The same size as the pipe serving the appliance
Explanation: NFPA 54 requires the drip leg to be the same nominal size as the
connecting pipe to the appliance. Its length must be at least 3 inches.
8. The maximum allowable pressure drop from the meter to the farthest
appliance under maximum load conditions is:
A) 0.3" w.c.
B) 1.0" w.c.
C) 5.0" w.c.
D) 10% of the inlet pressure
Correct Answer: A) 0.3" w.c.
Explanation: For natural gas systems operating at 7" w.c. or less, the code
typically limits the pressure drop from the outlet of the meter to the appliance
regulator to 0.5" w.c. A common design target is 0.3" w.c. to ensure proper
appliance operation.
9. When sizing gas piping using the "Longest Length Method," the length used is:
A) The actual measured length of pipe
B) The length from the meter to the farthest appliance only
C) The equivalent length, which includes allowances for fittings
D) The shortest run in the system
Correct Answer: C) The equivalent length, which includes allowances for fittings
Subject/Course: Plumbing, HVAC, Mechanical Trades, Licensing Exams, Gas Fitting
Tags: Master Gas Fitter, G33 License, Gas Piping, Natural Gas, Propane, Fuel Gas
Code, NFPA 54, ICC, IPC, IFGC, Pipe Sizing, Leak Test, Practice Exam
---
G33 MASTER GAS PIPE FITTER - PRACTICE EXAMINATION
1. The model code most commonly adopted as the basis for state and local fuel
gas regulations in the United States is:
A) ASME B31.3
B) NFPA 54 / ANSI Z223.1 (National Fuel Gas Code)
C) Uniform Plumbing Code (UPC)
D) International Plumbing Code (IPC)
Correct Answer: B) NFPA 54 / ANSI Z223.1 (National Fuel Gas Code)
Explanation: NFPA 54, also known as the National Fuel Gas Code, is the
predominant model code for the installation of fuel gas piping systems,
appliances, and equipment.
2. A Master Gas Fitter license (G33) typically authorizes the holder to:
A) Design gas piping systems only
B) Install, repair, and supervise gas piping and appliances without restriction
C) Only install piping up to 1 inch in diameter
D) Only work on residential systems
,Correct Answer: B) Install, repair, and supervise gas piping and appliances without
restriction
Explanation: The Master level license is the highest grade, allowing the holder to
perform all gas fitting work and supervise Journeyman and Apprentice gas fitters.
3. The maximum operating pressure for natural gas in a residential building,
downstream of the meter, is typically:
A) 0.5 psig (14" w.c.)
B) 2 psig
C) 5 psig
D) 10 psig
Correct Answer: A) 0.5 psig (14" w.c.)
Explanation: The gas utility typically supplies gas to the meter at about 7" w.c.
(0.25 psi). Inside the residence, the pressure is further regulated at each appliance
or at a second-stage regulator to the appliance manifold pressure, usually 3.5"
w.c. The distribution pressure within the house piping is generally maintained
below 0.5 psig (14" w.c.).
4. The minimum depth for underground steel gas piping to protect against
accidental damage is:
A) 6 inches
B) 12 inches
C) 18 inches
D) 24 inches
Correct Answer: B) 12 inches
,Explanation: NFPA 54 requires a minimum cover of 12 inches for steel gas piping.
Plastic piping may have different depth requirements, and local codes may
require greater depth.
5. When a gas line must be run through an air duct or plenum, the piping must be:
A) PVC schedule 40
B) Uncoated black steel
C) Galvanized steel
D) Sealed in a gastight, noncombustible sleeve
Correct Answer: D) Sealed in a gastight, noncombustible sleeve
Explanation: This prevents any potential gas leakage from contaminating the
airstream. The sleeve must extend beyond the duct and be sealed at both ends.
6. The primary purpose of a drip leg (sediment trap) in a gas line is to:
A) Increase gas pressure
B) Catch moisture, dirt, and pipe scale before they enter the appliance controls
C) Act as a pressure relief device
D) Provide a point to add odorant
Correct Answer: B) Catch moisture, dirt, and pipe scale before they enter the
appliance controls
Explanation: Drip legs are required at the inlet to each appliance to protect
sensitive valves and orifices from debris that can cause malfunction or unsafe
conditions.
7. The minimum size of a drip leg is:
A) 1/2 inch
, B) 3 inches in length
C) The same size as the pipe serving the appliance
Correct Answer: C) The same size as the pipe serving the appliance
Explanation: NFPA 54 requires the drip leg to be the same nominal size as the
connecting pipe to the appliance. Its length must be at least 3 inches.
8. The maximum allowable pressure drop from the meter to the farthest
appliance under maximum load conditions is:
A) 0.3" w.c.
B) 1.0" w.c.
C) 5.0" w.c.
D) 10% of the inlet pressure
Correct Answer: A) 0.3" w.c.
Explanation: For natural gas systems operating at 7" w.c. or less, the code
typically limits the pressure drop from the outlet of the meter to the appliance
regulator to 0.5" w.c. A common design target is 0.3" w.c. to ensure proper
appliance operation.
9. When sizing gas piping using the "Longest Length Method," the length used is:
A) The actual measured length of pipe
B) The length from the meter to the farthest appliance only
C) The equivalent length, which includes allowances for fittings
D) The shortest run in the system
Correct Answer: C) The equivalent length, which includes allowances for fittings
