Why It’s Called LP Gas

It’s called LP gas because it stands for “liquefied petroleum gas,” a petroleum-derived mixture—primarily propane and butane—that’s stored and transported as a liquid under moderate pressure and used as a fuel when released to vaporize. The name reflects both where it comes from (petroleum) and how it is handled (liquefied for practicality and safety), and it is widely abbreviated as LP gas or LPG in regulations and the marketplace.

What the “LP” Stands For—and What’s in It

“Liquefied petroleum” describes a family of light hydrocarbons separated from crude oil refining and natural gas processing, then compressed into liquid form for efficient storage and transport. In everyday use, LP gas most often means propane in North America and mixtures of propane and butane elsewhere.

The following points clarify the components and properties commonly associated with LP gas:

• Composition: Mainly propane (C3H8), n‑butane (C4H10), and isobutane (i‑C4H10), with traces of propylene and other light hydrocarbons depending on local specifications.
• State: Gaseous at ambient conditions but easily liquefied with modest pressure or cooling, which greatly increases energy density.
• Standards: In the U.S., “HD‑5 propane” is a common retail grade that limits propylene content to 5% for performance and safety.
• Odorization: Naturally odorless; ethyl mercaptan or similar compounds are added so leaks can be detected by smell.

Together, these characteristics explain why the industry and codes use the umbrella term “liquefied petroleum gas,” shortened to LP gas or LPG, to cover fuels with similar handling and combustion behavior.

How Liquefaction Works—and Why It Matters

LP gas is liquefied because doing so makes it practical to store and move. At room temperature, propane needs only moderate pressure (roughly 100–200 psi, varying with temperature) to become liquid. That liquid takes far less space than the equivalent gas volume, enabling cylinder, tank, and bulk transport logistics that are cost‑effective and reliable.

From Tank to Flame

In use, LP gas leaves the pressurized container, drops in pressure, and vaporizes to a gas, which is then metered by valves and regulators into appliances or engines. This pressure–vaporization cycle is central to why the “liquefied” part of the name is so important to how the fuel works day to day.

Where LP Gas Comes From

LP gas is sourced in two main ways: as a byproduct of natural gas processing (removing heavier hydrocarbons from methane) and from crude oil refining (fractionating and treating light ends). Supply shares vary by region and market conditions. Historically, LP gas was identified in the early 20th century—chemist Walter O. Snelling documented propane in 1910—and commercial distribution followed soon after as pressure‑rated containers made widespread use feasible.

How the Term Is Used Around the World

While the product is essentially the same, naming conventions differ by country and sector. Understanding these labels helps explain why “LP gas” persists as a catch‑all phrase.

Here’s how LP gas fits alongside similar fuels and the names they go by:

1. LPG/LP gas: Global/industry terms for liquefied petroleum gas. In North America, “LP gas” often implies propane-dominant fuel; elsewhere, LPG may be propane, butane, or a seasonal blend.
2. Autogas: LPG used as a road‑fuel, common in Europe, Asia, and parts of Australia, often optimized blends for vehicle performance.
3. Bottled gas: Colloquial label for LPG sold in cylinders for cooking, heating, and small appliances.
4. Not LNG: Liquefied natural gas is mostly methane chilled to about −162°C; it’s different in composition, storage temperature, and infrastructure.
5. Not CNG: Compressed natural gas is methane stored at high pressure as a gas, not a liquid, and uses different tanks and fueling systems.

These distinctions show that “LP gas” is both a technical descriptor and a practical label that separates it from natural‑gas variants and gasoline, reducing confusion across energy applications.

Why the Name Stuck in Codes and Commerce

Regulators and industry groups formalized the term early on. In the United States, NFPA 58 is titled the LP‑Gas Code, reflecting longstanding usage in safety standards, equipment rating, and inspection protocols. The label communicates key handling rules—pressurized containers, vapor‑service regulators, and temperature‑dependent pressure behavior—regardless of the exact propane–butane mix.

Bottom Line

It’s called LP gas because it is liquefied petroleum gas: a petroleum‑derived, easily liquefied fuel stored under pressure as a liquid and used as a gas at the point of consumption. The term succinctly captures both its origin and its defining physical behavior.

Summary

LP gas refers to liquefied petroleum gas—primarily propane and butane—produced from natural gas processing and oil refining. It’s stored as a liquid under moderate pressure for compact, safe transport and vaporized for use. The name “LP gas” endures globally in commerce and safety codes, distinguishing it from LNG and CNG and signaling how it must be stored, handled, and burned.

Are propane and LPG the same?

No, propane and LPG are not exactly the same, but propane is a type of LPG. LPG (liquefied petroleum gas) is a broader category of fuel that can include propane, butane, isobutane, and other related gases, while pure propane is a specific, single hydrocarbon with a distinct molecular structure (C₃H₈). The key difference is that LPG can be a mixture of different gases, whereas propane is a specific, single gas. 
What is LPG?

• A Fuel Category: LPG is a general term for a family of hydrocarbon gases that are primarily composed of propane, butane, or a mixture of both, which can be liquefied under pressure for storage and transport. 
• Composition Varies: The specific composition of LPG can vary depending on its source and the intended use. 

What is Propane?

• A Specific Gas: Propane (C₃H₈) is a particular type of liquefied petroleum gas. 
• A Common Fuel: It is a clean-burning alternative fuel widely used for heating, cooking, and powering vehicles. 
• Winter Fuel: Pure propane is a better choice for colder climates because it has a lower boiling point, allowing it to vaporize more easily in cold temperatures compared to butane. 

In Summary

• All propane is LPG, but not all LPG is propane. 
• You might use LPG that contains propane, but it could also contain other gases like butane. 
• The terms are often used interchangeably, especially in everyday use, but technically, LPG is a broader term for a class of liquefied petroleum gases. 

Is LPG actually liquid?

At normal temperature and pressure – as in your living room or garden – you will meet LPG as a gas. But when it is either cooled down or put under pressure, it changes into a liquid. Exactly the type of liquid that is filled onto the cylinders you use for your BBQ in the summer.

Why is propane called LP gas?

Liquified petroleum gas — or LP gas — is a flammable hydrocarbon gas made from propane, butane and small amounts of other hydrocarbons like propylene and butylene. Propane and butane are flammable hydrocarbons with different chemical formulas.

Can I use LP gas instead of propane?

The terms propane and liquid propane are used interchangeably in the grilling industry. In fact, propane, liquid propane, propane gas, and LP all refer to the same thing when we’re talking about grills.