RMGA Gas Distribution Systems 1 — Questions and Answers
Question 1: What is the typical operating pressure range for a low-pressure natural gas distribution system serving residential customers?
- 0.25 to 2 psig (Correct answer)
- 50 to 100 psig
- 200 to 400 psig
- 500 to 1000 psig
Correct answer: 0.25 to 2 psig
Low-pressure residential distribution systems typically operate between 0.25 and 2 psig to safely supply gas to home appliances.
Question 2: What material is most commonly used for new natural gas distribution mains installed in the United States?
- Cast iron
- Steel
- Polyethylene (PE) (Correct answer)
- Copper
Correct answer: Polyethylene (PE)
Polyethylene pipe is the dominant material for new gas distribution mains due to its corrosion resistance, flexibility, and ease of installation.
Question 3: What is the purpose of a service line in a natural gas distribution system?
- To carry gas from the transmission line to the distribution main
- To connect the distribution main to the customer's meter (Correct answer)
- To carry gas from the wellhead to a processing plant
- To bypass a pressure regulator during maintenance
Correct answer: To connect the distribution main to the customer's meter
A service line is the piping that connects the distribution main to the customer's meter set assembly.
Question 4: What does the acronym 'PE' stand for when referring to gas distribution pipe material?
- Pressure Elevated
- Polyethylene (Correct answer)
- Pipeline Engineering
- Pre-qualified Equipment
Correct answer: Polyethylene
PE stands for polyethylene, a thermoplastic material widely used for natural gas distribution piping.
Question 5: What is the purpose of installing a curb valve on a gas service line?
- To regulate pressure entering the building
- To isolate the service line at the property line for emergency shutoff (Correct answer)
- To measure gas consumption
- To prevent backflow from the building to the main
Correct answer: To isolate the service line at the property line for emergency shutoff
A curb valve allows the utility or emergency responders to quickly shut off gas supply at the property boundary without entering the building.
Question 6: What is the minimum burial depth for a polyethylene gas distribution main in a normal excavated trench?
- 6 inches
- 12 inches
- 18 inches (Correct answer)
- 24 inches
Correct answer: 18 inches
49 CFR Part 192 requires a minimum cover of 18 inches for plastic gas mains in normal conditions to protect against damage.
RMGA Gas Distribution Systems 1
What is the typical operating pressure range for a low-pressure natural gas distribution system serving residential customers?