About Spontaneous Combustion
A "normal" combustion process involves a material, like wood, to which an external source of heat is applied. The temperature inside the material rises to a point where ignition takes place. Once this happens, oxygen from the air further feeds the process. In cases of spontaneous combustion, certain materials ignite all on their own.
Other People Are Reading
-
Identification
-
Unlike the normal combustion process, cases involving spontaneous combustion occur without any outside intervention. This happens because of a slow oxidation process that takes place inside a substance. Oxidation occurs when oxygen combines with a material. As this takes place, heat builds up inside the material causing it to get hotter and hotter. If there is nowhere for the heat to escape, the material will catch on fire, or spontaneously combust, all by itself.
Pyrophoric Materials
-
Substances that are physically capable of spontaneous combustion are called "pyrophoric." Some examples of pyrophoric materials are alkali metals, phosphorous, plutonium, sodium and potassium. The physical composition of these materials makes them highly volatile when they are exposed to air or water. The temperature at which a material will set on fire is its ignition point. A pyrophoric material has an automatic ignition point that is actually lower than room temperature. Pyrophoric materials, by design, have a larger surface area than less-combustible materials. A larger surface area means bumps and crevices are present on the surface, which increases the amount of contact these materials can have with air or water.
-
Combustible Materials
-
A combustible material--like coal--is naturally inclined to build up internal heat. When there is little to no ventilation for this heat to escape, it will eventually ignite. Different materials will spontaneously combust under certain conditions. Linseed oil can become combustible when exposed to hot conditions. Rags soaked in this oil undergo a slow oxidation process and can potentially ignite when heated conditions are present. Large quantities of pistachio nuts are another material capable of spontaneous combustion when stored in a confined container. Other similar materials include grain dust and haystacks.
Spontaneous Human Combustion
-
The concept of spontaneous human combustion is a phenomenon that has met with much controversy. A number of theories have been presented to explain its occurrence, and several incidents have been recorded. Eyewitness accounts, which detail how these events occurred, date back as far as 1763. An actual explanation for this event has yet to be given. Some theories have proposed that this phenomenon include static electricity build-up, flammable chemicals present in the digestive system and divine intervention.
The Wick Effect
-
The Wick Effect theory is, as of yet, the most scientific explanation for spontaneous human combustion events. The theory attributes spontaneous human combustion to the interaction that takes place between body fat and clothing materials. When exposed to a flame, the clothing's fabric can become soaked with body fat (a highly flammable substance). In effect, the clothing acts as a wick to the fat. The person ignites and continues to burn because of the contact between clothing and flesh.
-
References
Resources
- Photo Credit flickr.com/photos/aussiegall/843849383/
