The term “spontaneous combustion” strikes many as one that deals more with magic and fantasy than real life and real tragedies. In fact, spontaneous combustion is a serious source of fires in home and garage workshops, as well as on farms. According to the U.S. Fire Administration, spontaneous fires are one of the leading causes of fires in agricultural storage facilities (i.e., barns, silos, stables, etc.).
The name is a little misleading, though. Spontaneous combustion doesn’t occur out of the blue. All fires, including those ignited “spontaneously,” require three elements: fuel, oxygen and a source of heat. Normally, we think of a source of heat as something with a flame. There is no flaming ignition with spontaneous combustion. Rather, when flammable finishes like linseed or tung oil are applied to a rag, heat develops. If the heat is allowed to dissipate, it presents no problem.
But when these same rags are bunched up and piled on top of each other (see photo), heat can build to a point where it ignites this already flammable material. No matches, torches or burning cigarettes required. It’s a relatively simple process of oil oxidizing, which generates heat. If other combustible material is nearby, this little act of magic can quickly develop into a full-raging fire.
Preventing spontaneous combustion from occurring is as simple as practicing a little routine housekeeping. Anytime you have an oily rag left over after some wood-finishing or other project, hang it up to dry, preferably outdoors. You can use a clothesline or a fence, but just be sure to hang each rag by itself. Don’t pile them on top of each other. And if you need to hang them indoors, keep them away from heat sources such as water heaters or furnaces.
Photo © nalundgaard flickr/Creative Commons