According to NFPA 54, which piping material is not allowed to be used with natural gas?

According to NFPA 54, which piping material is not allowed to be used with natural gas?

• A. Cast iron
• B. Copper
• C. Plastic
• D. Steel

Answer: (D)

NFPA 54 limits natural gas piping to materials that are proven to withstand the gas environment, pressure, and installation conditions. Cast iron is not allowed for natural gas piping because it is brittle and prone to cracking or breaking under gas service, ground movement, or impact, which can lead to leaks. Modern gas piping uses steel, copper, or listed plastics because these materials provide the needed strength, reliability, and compatible joints for safe gas distribution. Copper and certain plastics are permitted in specific configurations and sizes, while steel is the common choice for many portions of a gas system. So the material you would not use for natural gas is cast iron.

NFPA 54 limits natural gas piping to materials that are proven to withstand the gas environment, pressure, and installation conditions. Cast iron is not allowed for natural gas piping because it is brittle and prone to cracking or breaking under gas service, ground movement, or impact, which can lead to leaks. Modern gas piping uses steel, copper, or listed plastics because these materials provide the needed strength, reliability, and compatible joints for safe gas distribution. Copper and certain plastics are permitted in specific configurations and sizes, while steel is the common choice for many portions of a gas system. So the material you would not use for natural gas is cast iron.