Journeyman Plumbers Exam Gas Piping Systems 3 — Questions and Answers
Question 1: What is the required pressure test for new gas piping before placing it in service under the International Fuel Gas Code?
- 10 psi for 15 minutes
- 3 psi for 10 minutes (Correct answer)
- 1.5 times the operating pressure for 10 minutes
- 50 psi for 1 hour
Correct answer: 3 psi for 10 minutes
New gas piping systems must be pressure tested at no less than 3 psi gauge for a minimum of 10 minutes to verify there are no leaks before the gas is turned on.
Question 2: A gas appliance connector flexible hose may NOT be used to connect which type of appliance?
- Gas range
- Water heater
- Built-in oven (Correct answer)
- Gas dryer
Correct answer: Built-in oven
Built-in ovens are considered permanently installed appliances and must be connected with rigid piping, not flexible appliance connectors.
Question 3: When gas piping passes through a wall, floor, or ceiling, it must be protected by:
- A rubber grommet
- A sleeve or protective coating (Correct answer)
- A metal conduit pipe
- No protection is required
Correct answer: A sleeve or protective coating
Gas piping penetrating walls, floors, or ceilings must be protected with a sleeve or protective coating to prevent abrasion damage to the pipe.
Question 4: What is the specific gravity of propane compared to air?
- 0.55 (lighter than air)
- 1.0 (same as air)
- 1.5 (heavier than air) (Correct answer)
- 2.5 (much heavier than air)
Correct answer: 1.5 (heavier than air)
Propane has a specific gravity of approximately 1.5, making it heavier than air, which causes it to settle in low areas such as basements and pits.
Question 5: The BTU content of one cubic foot of natural gas is approximately:
- 500 BTU
- 1,000 BTU (Correct answer)
- 2,500 BTU
- 5,000 BTU
Correct answer: 1,000 BTU
Natural gas contains approximately 1,000 BTU per cubic foot, a value used in load calculations when sizing gas piping and meters.
Question 6: Which of the following joints is NOT acceptable for use in gas piping systems?
- Threaded joints with approved sealant
- Welded joints
- Solvent-cemented plastic pipe joints (Correct answer)
- Flared joints on copper tubing
Correct answer: Solvent-cemented plastic pipe joints
Solvent-cemented joints on plastic pipe are not acceptable for gas distribution inside buildings, as they are not rated for gas service in above-ground applications.
Question 7: A manual shutoff valve must be installed within what distance of each gas appliance?
- 3 feet
- 5 feet
- 6 feet (Correct answer)
- 10 feet
Correct answer: 6 feet
The IFGC requires a manual shutoff valve to be installed within 6 feet of each gas appliance to allow for quick isolation in an emergency.
