A coffee mate fireball

Coffee mate is a powdered coffee that you would mix with water (hot or cold) to make a cup of coffee. But who knew that it was flammable! Coffee mate would not ignite when on a tea spoon but when it is suspended in the air the surface area is increased. Therefore a greater amount of oxygen can react with the coffee mate so it can be ignited and produce a fireball. A fireball is cause due to the individual particles of coffee mate catching alight and then producing enough heat to catch the nearby particles producing a chain reaction. Coffee mate behaves just like flour or corn flour in terms of it being a fugitive dust, which Harwood (p19) defines as a ‘combustible particle of a particular size’. The U.S. EPA states that a suspended particle can have an aerodynamic diameter of not greater than 30 micrometers

Here are two videos to show the ignition and combustion of corn flour and then white flour; white flour for this demonstration had to be sieved to gain the find powdered needed:

Corn Flour from 1veritasium (2012)

White Flour from Science fix (2011)

Fugitive dust can be extremely dangerous and can be explosive in the right conditions and settings. Both the Saif Corporation (p3) and Harwood give an example of a ‘Dust fire and Explosion Pentagon’. This gives us the five things we need for a dust explosion: ‘Ignition’, ‘confinement of dust cloud’, ‘oxygen in air’, ‘combustible dust’ and ‘dispersion of dust particulates’. Once all these factors are present a dust explosion will occur, this is known as the primary dust explosion. If there is any dust suspended in the air nearby or a large amount of settled dust nearby a secondary explosion can take place; this secondary explosion can be far more powerful than the first. The diagram below from Harwood (p10) shows how the primary explosion can serve as an ignition for the secondary explosion: 

This just shows how dangerous it was in flour mills will all that flour dust hanging round in the air in the confined space; just like a time bomb ready to explode...

 Biography

Harwood, S. Combustible Dust: Safety and Injury Prevention. Kirkwood Community College: Community Training and Response Center. [Online].
Available at: http://www.osha.gov/dte/grant_materials/fy08/sh-17797-08/cd_instructor_manual.pdf (accessed 12 March 2013).

 Saif Corporation. (2011) Combustible dust. SAIF Corporation: Industrial Hygiene. [Online]
Available at: http://www.saif.com/_files/SafetyHealthGuides/Combustible_Dust.pdf (Accessed 19th April 2013).

 Sciencefix (2011) Flour Fireball.
Available at: http://www.youtube.com/watch?v=64Ej0sQveT8 (accessed 6th April 2013).

 U.S. EPA. Fugitive Dust Sources. US Environmental Protection Agency. [Online]
Available at: http://www.epa.gov/ttnchie1/ap42/ch13/final/c13s02.pdf (accessed 7th April 2013).

1veritasium (2012) Corn Flour Fireball.
Available at: http://www.youtube.com/watch?v=uWEp_4fHX4Y (accessed 10th April 2013).