BGE Natural Gas Systems & Pipelines 2 — Questions and Answers
Question 1: Which instrument is most commonly used by BGE technicians to detect natural gas leaks along distribution mains and service lines?
- Infrared thermometer
- Combustible gas indicator (CGI) (Correct answer)
- Clamp-on ammeter
- Insulation resistance tester
Correct answer: Combustible gas indicator (CGI)
A combustible gas indicator (CGI) detects the presence of flammable gas vapors in air, making it the standard tool for locating natural gas leaks.
Question 2: What is the Lower Explosive Limit (LEL) of natural gas (methane) in air, below which ignition cannot occur?
- 1% by volume
- 5% by volume (Correct answer)
- 15% by volume
- 25% by volume
Correct answer: 5% by volume
Natural gas (methane) has a LEL of approximately 5% by volume in air; below this concentration the mixture is too lean to ignite.
Question 3: When excavating near marked underground gas facilities, what is the required hand-digging tolerance zone on each side of the marked line per PHMSA guidelines?
- 6 inches
- 18 inches (Correct answer)
- 24 inches
- 36 inches
Correct answer: 18 inches
Federal and industry guidelines require hand-digging within 18 inches on each side of a marked underground gas facility to avoid striking the pipe.
Question 4: What is the 'squeeze-off' procedure used for in natural gas operations?
- Testing pipeline integrity under high pressure
- Temporarily stopping gas flow by mechanically compressing a PE pipe (Correct answer)
- Connecting a new service line to an active main
- Purging air from a newly installed gas line
Correct answer: Temporarily stopping gas flow by mechanically compressing a PE pipe
Squeeze-off uses a specialized tool to flatten and compress polyethylene pipe walls together, temporarily stopping gas flow without cutting the pipe or shutting a valve.
Question 5: What action should a BGE technician take FIRST upon discovering a natural gas leak inside an occupied building?
- Call the supervisor to report the leak before taking any action
- Evacuate the building and call 911 from a safe distance (Correct answer)
- Attempt to locate and shut the gas valve inside the building
- Open windows to ventilate the space and monitor with a CGI
Correct answer: Evacuate the building and call 911 from a safe distance
Life safety is the top priority; immediate evacuation and calling 911 from outside ensures occupants are safe before any technical response begins.
Question 6: What does yellow-colored warning tape buried above an underground gas pipeline indicate to excavators?
- High-voltage electric line below
- Caution — gas line below (Correct answer)
- Fiber optic cable below
- Potable water main below
Correct answer: Caution — gas line below
Yellow is the APWA (American Public Works Association) standard color for gas and oil lines; yellow warning tape signals the presence of a gas facility below.
Question 7: Which type of valve is most commonly installed as the emergency shut-off device at a natural gas meter set on a residential service?
- Gate valve
- Ball valve (Correct answer)
- Butterfly valve
- Globe valve
Correct answer: Ball valve
Ball valves provide a reliable quarter-turn shutoff with a visible open/closed indicator, making them the preferred emergency shutoff at residential meter sets.
BGE Natural Gas Systems & Pipelines 2
Which instrument is most commonly used by BGE technicians to detect natural gas leaks along distribution mains and service lines?