NFPA 58 LPG Code Practice Exam 2026 – Complete Test Preparation

Liquefied propane gas primarily consists of propane, which is classified as a three-carbon alkane (C3H8). In addition to propane, liquefied petroleum gas (LPG) can also contain other hydrocarbons, but the specific components can vary depending on the source and processing methods.

Ethane, a two-carbon alkane (C2H6), is not a component of liquefied propane gas itself. While it may be present in natural gas and can sometimes appear in trace amounts in certain mixtures, it is not classified as an ingredient or constituent of liquefied propane gas. This distinction is crucial for understanding the composition of LPG and its applications.

On the other hand, butane and isobutane are both part of the broader category of LPG and can be blended with propane for specific applications. Propylene is a byproduct derived from the processing of propane and is sometimes included in LPG formulations. Therefore, ethane is accurately identified as the hydrocarbon not found in liquefied propane gas.