BGE Natural Gas Systems & Pipelines 1 — Questions and Answers
Question 1: What is the typical operating pressure range for natural gas low-pressure distribution mains serving residential customers?
- 0.25 to 2 psig (Correct answer)
- 50 to 100 psig
- 10 to 20 psig
- 200 to 400 psig
Correct answer: 0.25 to 2 psig
Low-pressure residential distribution mains typically operate between 0.25 and 2 psig, which is safe for household appliances.
Question 2: Which material is most commonly used for new natural gas distribution pipelines installed in residential areas?
- Cast iron
- Polyethylene (PE) (Correct answer)
- Galvanized steel
- Copper
Correct answer: Polyethylene (PE)
Polyethylene pipe is the industry standard for new residential gas distribution due to its corrosion resistance, flexibility, and ease of fusion joining.
Question 3: What odorant is added to natural gas to make leaks detectable, and what does it smell like?
- Methanol — sweet alcohol scent
- Mercaptan (THT) — rotten egg or sulfur smell (Correct answer)
- Acetylene — garlic-like odor
- Propane — faint oily odor
Correct answer: Mercaptan (THT) — rotten egg or sulfur smell
Mercaptan (tetrahydrothiophene) is injected into natural gas to produce the distinctive rotten egg smell that alerts people to leaks.
Question 4: What is the primary purpose of cathodic protection systems installed on underground steel gas pipelines?
- To increase gas flow velocity
- To prevent electrochemical corrosion of the pipe (Correct answer)
- To detect gas leaks electronically
- To regulate operating pressure
Correct answer: To prevent electrochemical corrosion of the pipe
Cathodic protection applies an electrical current to counteract the electrochemical reactions that cause corrosion on buried metal pipelines.
Question 5: Which federal regulation establishes the minimum safety standards for natural gas distribution pipeline systems?
- OSHA 29 CFR Part 1910
- 49 CFR Part 192 (Correct answer)
- NFPA 54
- DOT 40 CFR Part 60
Correct answer: 49 CFR Part 192
49 CFR Part 192 (Transportation of Natural and Other Gas by Pipeline) is the federal regulation governing safety standards for natural gas pipeline systems.
Question 6: What is the primary function of a pressure regulating station (PRS) in a natural gas distribution system?
- To add odorant to the gas supply
- To reduce high transmission pressure to safe distribution pressure (Correct answer)
- To measure customer usage for billing
- To remove moisture and contaminants from gas
Correct answer: To reduce high transmission pressure to safe distribution pressure
A pressure regulating station steps down high-pressure gas from transmission lines to the lower operating pressures required for safe distribution to customers.
Question 7: In a natural gas distribution system, what does the term 'Maximum Allowable Operating Pressure' (MAOP) refer to?
- The minimum pressure needed to serve customers during peak demand
- The highest pressure at which a pipeline segment may be continuously operated (Correct answer)
- The pressure at which a relief valve automatically opens
- The standard test pressure applied during hydrostatic testing
Correct answer: The highest pressure at which a pipeline segment may be continuously operated
MAOP is the highest pressure at which a pipeline or segment is legally authorized to operate, as established by design, testing, and federal regulations.
BGE Natural Gas Systems & Pipelines 1
What is the typical operating pressure range for natural gas low-pressure distribution mains serving residential customers?