Spontaneous combustion fires do not occur as often as fires from other sources, but can cause major losses to property when they do occur. According to the National Fire Protection Association (NFPA), “fires caused by spontaneous combustion or chemical reactions accounted for an estimated average of 14,070 fires per year between 2005 and 2009.”
In home fires, the garage was the location most common, while in commercial sites, laundry and dry cleaning businesses were the businesses most affected. For storage properties, 35% of fires started in an outbuilding or shed. Interestingly, most happen between 6pm and midnight.
WHAT IS SPONTANEOUS COMBUSTION?
According to NFPA, "Spontaneous combustion is a byproduct of spontaneous heating, which occurs when a material increases in temperature without drawing heat from its surroundings. If the material reaches its ignition temperature, spontaneous ignition or combustion occurs."
Graph courtesy of NFPA
"The statistics in this report are derived from the United States Fire Administration’s National Fire Incident Reporting System, (NFIRS), as well as the NFPA annual survey. NFIRS provides the details of fires, and has a code for the “heat source” field which is “Spontaneous combustion, chemical reaction”.
One of the most susceptible to this kind of combustion are oily rags. Oily rags not only come from working on cars. Rags soaked in linseed oil, or turpentine, used in the refinishing of furniture and other do-it-yourself projects, are also very hazardous sources of spontaneous combustion fires.
One of the reasons that oily rags are such a danger is that most people are not aware that they can spontaneously catch on fire. If the rags you are using for your project are folded or wadded up and thrown on the floor, the oil drying on the rags produces heat and the air inside the folds of the cloth produces a combustible mixture, while the rag itself provides the fuel. That is why oily rags must be stored or disposed of in a way that will prevent a fire.
STORAGE AND PROPER DISPOSAL OF OILY RAGS
The first step in safely disposing of oily rags is to DRY THEM OUT COMPLETELY. Hang them up or spread them out flat and weigh them down outside. Do NOT wad them up or place them in a pile! Once they are completely dry, you can dispose of them or reuse them.
For the commercial user, oily rags should be placed in a designated oily waste container and emptied by a private contractor.
For a do-it-yourselfer who uses the rags regularly, placing rags in an airtight metal container and covering with water as well as using a detergent that breaks down oil. Secure the lid tightly and store outside. Such containers can then be disposed of during a special hazardous waste collection day.
Knowing how to prevent these type of fires by properly handling oily rags can make all the difference!