The “Creamer Cannon” a Lesson on Combustible Dust Explosions

Posted: June 1, 2015 in Fire Investigation, Fire Science
Tags: , , , , ,

by: Jason A. Sutula

Last week, I enjoyed an excellent presentation by a colleague on the explosive power of combustible dust. The presentation started off with several case studies throughout history that all told a similar tale. One of the most interesting cases was also one of the earliest on record: “The Account of a Violent Explosion which Happened in a Flour-Warehouse, at Turin, December the 14th, 1785, to which are added some Observations of Spontaneous Inflammations.” (Printed in its entirety in Eckhoff, 2003) Even more interesting was that this incident was investigated by a local official, Count Morozzo, who took the time to do as scientific of an investigation as was possible for his time. He even wrote an account of his findings.

According to Count Morozzo, at about 6:00 p.m. an explosion took place in the house of Mr. Giacomelli, a Baker in the city of Turin. The explosion was powerful enough to blow out the windows and window frames of the building, and produced a noise that was as loud as a “large cracker.” At the moment of the explosion, Count Morozzo reported that a very bright flame was observed that only lasted for a few seconds. Further investigation revealed that the “inflammation” had started in the flour warehouse, which was located in the rear of the structure over top of the bakery shop. A boy was stirring flour in this area while using the light from a lamp. As a result of the fire, the boy sustained burns to his face and hands, and his hair had been burned off.

Without the benefit of chemistry and modern fire and explosion dynamics, Count Morozzo was able to use logical arguments to piece together many of the components that led to the incident. He correctly deduced that the flour needed to be in the air (dust suspended in air), that atmospheric air was mixed with the flour (oxidizer), that the event was confined within a small room in the bakery (confinement of the dust cloud), and that the ignition occurred from the light next to the boy (heat source for ignition). These are four of the five components necessary for a dust explosion to occur. The remaining component is the dust itself (the fuel). Count Morozzo was unable to link this component to the event because fuel chemistry was not understood at the time, and he believed that “inflammable air” was confined within the flour and could be released without changing the makeup of the flour itself.

The good news is that the boy recovered from his injuries within a fortnight (14 days). The bad news is that even with Count Morozzo’s account, the process industry did not learn from these types of case studies until more recently in the modern era. It can also be argued that there is still plenty of work left to do today.

In an effort to demonstrate what that poor boy in Mr. Giacomelli’s Bakery must have experienced, take the time to watch the above YouTube video. Mythbusters produced this non-dairy creamer cannon demonstration for Season 07, Episode 03. It is the perfect visual for understanding the power of a dust explosion.

Eckhoff, Rolf, Dust Explosions in the Process Industries, Third Edition, Boston, Gulf Professional Publishing, 2003.

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