GPT Installation Techniques 2 — Questions and Answers
Question 1: What is the minimum clearance required between a gas pipe and an electrical conduit running parallel in the same enclosure?
- 1 inch (Correct answer)
- 2 inches
- 3 inches
- 6 inches
Correct answer: 1 inch
Gas piping must maintain at least 1 inch of clearance from electrical conduit when running parallel to prevent heat transfer and potential hazards.
Question 2: When installing a gas meter riser, which pipe orientation is required for the drip leg (sediment trap)?
- Horizontal with end cap
- Vertical drop with end cap (Correct answer)
- Angled at 45 degrees
- Coiled horizontal section
Correct answer: Vertical drop with end cap
A drip leg must be installed as a vertical drop with an end cap to collect moisture and debris before they reach the meter or appliances.
Question 3: Which thread sealant is NOT acceptable for use on gas piping connections in the US?
- Yellow PTFE tape rated for gas
- Two-part anaerobic pipe dope
- Standard white PTFE plumber's tape (Correct answer)
- Gas-rated pipe thread compound
Correct answer: Standard white PTFE plumber's tape
Standard white PTFE tape (plumber's tape) is not rated for gas service and can degrade, creating leak paths; only yellow gas-rated PTFE tape or gas-rated compounds are acceptable.
Question 4: When trenching for underground gas service, what material must be placed beneath the pipe to provide bedding support?
- Crushed rock only
- Native soil compacted
- Clean sand or fine-grain bedding (Correct answer)
- Concrete encasement
Correct answer: Clean sand or fine-grain bedding
Clean sand or fine-grain bedding material is required beneath underground gas pipe to provide uniform support and prevent point loading that could damage the pipe.
Question 5: A gas line passes through a concrete foundation wall. What must be installed around the pipe at the penetration point?
- Pipe insulation wrapped in tape
- A wall sleeve with an annular seal (Correct answer)
- Extra pipe hangers on both sides
- A union fitting inside the wall
Correct answer: A wall sleeve with an annular seal
A wall sleeve with an annular seal (or escutcheon) must be installed at foundation penetrations to allow for pipe movement and prevent corrosive contact with concrete.
Question 6: What is the correct procedure when installing a tee fitting in an existing pressurized gas main during a live tap?
- Shut down the entire system and depressurize
- Use a stopple fitting and hot-tap machine with proper authorization (Correct answer)
- Quickly replace the section with a union on each side
- Apply thread sealant and install while gas flows at low pressure
Correct answer: Use a stopple fitting and hot-tap machine with proper authorization
A live tap on a pressurized gas main requires a specialized hot-tap machine and stopple fitting, performed only by authorized personnel following strict procedures.
Question 7: According to IFGC standards, what is the maximum length of a flexible appliance connector in a residential installation?
- 3 feet
- 5 feet
- 6 feet (Correct answer)
- 8 feet
Correct answer: 6 feet
IFGC limits flexible appliance connectors to a maximum of 6 feet in residential installations to reduce failure risk from repeated movement and stress.
GPT Installation Techniques 2
What is the minimum clearance required between a gas pipe and an electrical conduit running parallel in the same enclosure?