Is Kerosene Flammable or Combustible?

Kerosene, sometimes referred to as paraffin, is a popular and versatile fuel used around the world in a variety of functions. As a planet, humanity burns through (no pun intended) 1.2 million barrels of kerosene every day on average, or around 250 million litres. Kerosene has a wide range of applications outside of being utilised as a fuel, and has been used as a pesticide, a cleaning substance, and for pyrotechnics. But is kerosene a flammable or combustible fuel?

Flammable vs Combustible: What’s The Difference?

For those of you who don’t know, flammable and combustible fuels have some differences between them, although they share many features. Both flammable and combustible liquids will set alight and burn, which is why they’re both useful as fuels. Yet, they require different conditions to do so.

The terms flammable and combustible refer to how easily a substance will ignite. This is determined by examining the fuels’ respective flashpoints.

What is a Flashpoint?

First, it is important to note that although we refer to liquid fuels as flammable or combustible, it’s never actually the liquid that’s burning. The vapour given off by the slow evaporation of the liquid is what produces the fumes that can ignite so easily. The “flashpoint”, like a melting point or boiling point, is the minimum temperature at which enough vapour will be mixing with the air above the liquid to ignite.

So, what’s the difference between flammable and combustible liquids? Flammable liquids have a flashpoint that is below room temperature, while combustible liquids have a flashpoint above room temperature. Simply put, flammable liquids will burn at room temperature while combustible liquids will not; they require heating to above their flashpoint in order to ignite.

For example, dropping a lit match into a barrel of diesel would only see the match go out. But putting a container of diesel on a fire will eventually heat to the level where the fuel will ignite.

So Is Kerosene Flammable or Combustible?

Well, here’s where it gets interesting (and a little subjective). Kerosene’s minimum flash point is around 37oC, far higher than petrol at -43oC but still within the range of room temperature. In Europe and North America it is rare that temperatures exceed 37oC, yet in places like Australia, Africa, South America, and The Middle East, temperatures above 37oC are not uncommon.

This means that kerosene is both flammable and combustible, and whether you consider it one, the other, or both simply depends on the average temperatures of your country.