Fire Safety Feature Part 2 of 5

Fuel Science

This video deals with the scientific aspects of the fuels that are commonly used in fire performance. A basic understanding of the chemical properties of the common fuels that are used to produce fire is essential for producing safe performance and creating safe fuel management practices in the context of fire performance.

In the United States, although of course there are regional variations, there are 3 or 4 fuels that are commonly used in fire performance.

1. Naptha, commonly known as Coleman Camp fuel or “white gas”
2. Paraffin, commonly known as “lamp oil”
3. Alcohol Fuels such as denatured alcohol, isopropyl alcohol, or even food grade ethanol
4. Kerosene, commonly known as “kerosene”

As you know, automotive gasoline, diesel fuel, and other unlisted fuels are not recommended due to their danger or lack of additional benefit as compared with the fuels listed above.

However, before we get to discussing each of the individual fuels, there are important characteristics common to all of the fuels as well as common terminology. All of the fuels are classified as hydrocarbons which means that they are made entirely of hydrogen and carbon, derived originally from crude oil. As with most products derived from crude oil, there is a health risk associated with coming into contact with these chemicals, whether these come in contact through the skin, are inhaled, or swallowed. Unfortunately, they are all toxic to varying degrees.

Each type of fuel has varying characteristics

• Flash point
  • The lowest temperature that a solvent gives off enough vapor to burn when a flame or spark is present
  • Ex. flash point of Automotive gasoline is -48 degrees Fahrenheit, which means that an open container of automotive gasoline will give off enough vapors to burn at that temperature.
• Vapor pressure
  • indicates how easily the fuel forms a vapor
  • important because it is actually the vapors of the fuel that is flammable, not necessarily the liquid fuel itself.
  • Ex. Automotive gas has a high vapor pressure, this is how you can smell the characteristic smell so easily.

All of this information and much more can be found in each fuel’s Material Safety Data Sheet (MSDS). These documents which are recommended to be brought to every site where liquid fuels are to be burned, are freely available online.

Naptha, ‘White Gas’, or ‘Camp Fuel’

In the United States, naptha is sold as ‘camp fuel’ or ‘white gas’, and under brand names such as Coleman, Ozark Trail, and Crown. It’s a National Fire Protection Association (NFPA) Class 1B Flammable Solvent, meaning it can ignite at temperatures less than 100°F, and that it can dissolve other substances. It has a flash point of less than 0°F, high vapor pressure, and its vapors are heavier than air. In practice, this means that naptha ignites easily at room temperatures, and makes ignitable vapors very easily which can also track along the ground and ignite at a distance from the container. The high vapor pressure also means that naptha evaporates easily, but is difficult to extinguish by fast spinning.

In the realm of fire performance, naptha is commonly used for rapid spinning props. In practical experience, it burns longer than a similar quantity of alcohol fuel, but shorter than paraffin.

Paraffin, ‘Lamp Oil’, or ‘Tiki Torch Fuel’

Sold under various brands as Lamplight Farms or Guiding Light. It is an NFPA Class 3 Combustible Liquid. It has a high flash point of 150°F and a low vapor pressure. So, in practice it means that paraffin is difficult to ignite and doesn’t evaporate well at all. It is common to use paraffin for props that don’t spin rapidly or need to remain burning for a long time. It is also used in fire breathing where the large surface area increases its ignitability. It leaves an oily residue with a long burn time but creates more smoke and soot than naptha. Fire performers often blend the two to create a hybrid fuel that ignites easily but burns longer.

Alcohol Fuel, “Denatured Alcohol”

Otherwise known as methylated spirits which general contain a bit of methanol which is poisonous if ingested. This solvent is an NFPA Class 1B withi it’s flash point and vapor pressure existing in between naptha and paraffin. In practice, this means that alcohol fuel is more ignitable than paraffin and gives off more vapors than paraffin but still less than naptha. They have a short burn time and produce a dim blue flame which is the coolest temperature flame in all fire performance, but it does absorb other chemicals easily such as boric acid.

Kerosene

In the US, generally used as a home heating liquid and also as jet fuel. It is a NFPA Class 2 Combustible liquid. It has a flash point lower than paraffin and a vapor pressure as low as paraffin. Which means that it gives off few heavy vapors making it very difficult to ignite. It has a long burn time with a smoky sooty flame and leaves a smelly oily residue.

Summary

While this is a lot of information, it is important to remember that each type of fuel has different flash points and vapor pressures which will affect when and how you use and handle them.