Texas Journeyman Plumbing Practice Test

Liquefied petroleum gas (LPG) is primarily composed of propane and butanes, which are hydrocarbons typically derived from natural gas processing and petroleum refining. The correct option highlights that LPG includes propane and butanes or their variants, such as propylene and butylenes. This mixture allows LPG to be effectively used for various applications, including heating, cooking, and as a fuel for engines.

Additionally, the inclusion of propylene and butylenes in the composition simply indicates that these substances are part of the broader category of LPG. This versatility in composition is vital for its performance as a fuel source.

To clarify, while methane is a significant component of natural gas, it is not part of LPG. Its representation in other options fails to capture the true composition of LPG, which does not consist solely of butanes or hydrogen. This understanding of LPG’s components is crucial for plumbing professionals, as it informs not only the safe handling and use of the gas but also the design of relevant gas systems.