Wick effect

The wick effect is the name given to the partial destruction of a human body by fire, when the clothing of the victim soaks up melted human fat and acts like the wick of a candle. The wick effect is a phenomenon that has been proven to occur under certain conditions, and thoroughly observed. It is one commonly offered explanation for the alleged phenomenon of spontaneous human combustion (SHC).

The wick effect theory essentially says that a person is burned through his/her own fats after being ignited, accidentally or otherwise. The clothed human body acts like an "inside-out" candle, with the fuel source (human fat) inside and the wick (the clothing of the victim) outside. Hence there is a continuous supply of fuel in the form of melting fat seeping into the victim's clothing. Fat contains a large amount of energy due to the presence of long hydrocarbon chains.

Examples of the wick effect

David Gee's wick effect experiment

In 1965 Professor David Gee recounted an experiment with a wick effect situation. He took a small portion of human fat and wrapped it in cloth to simulate clothing. He then applied a Bunsen burner flame to the 'candle'. Due to the high water content of human fat he had to hold the flame on the 'candle' for over a minute before it would catch on fire:

"One end of the candle was ignited by a Bunsen flame, the fat catching fire after about a minute. Although the Bunsen was removed at this point, combustion of the fat proceeded slowly along the length of the roll, with a smoky yellow flame and much production of soot, the entire roll being consumed after about one hour."

This gives some indication of the slow speed with which the wick effect will proceed.

John De Haan's Example

The following case is recorded by American fire investigator John De Haan, author of Kirk's Fire Investigation (first published in 1969), one of the most widely read and accepted textbooks in the field of fire investigation:

In February 1991, in woodland near Medford, Oregon, USA, two hikers came across the burning body of a female adult, lying faced down in fallen leaves. They alerted the officials and a local deputy sheriff soon arrived. The victim was described as "well nourished"—a common pathologist's euphemism for minor to substantial overweight. She had been stabbed several times in the upper regions of the chest and back. Both arms were spread outwards from the torso. The lower legs and surface of the neck showed signs of fire damage. The soft tissues of the right arm, torso and upper legs were consumed. The majority of bones of these parts retained their integrity, although friability was increased. Between mid-chest and knees the fleshy parts of the body were mostly destroyed. Crime scene personnel reported that the pelvis and spine were "not recoverable", having been reduced to a grey powder. Her killer had soaked the clothes and corpse in nearly a pint of barbecue starter fluid and set her on fire. In the well-oxygenated outdoor environment, this combination of circumstances—an immobile and clothed body with a high fat-to-muscle ratio, accelerant (lighter fluid), and artificial ignition—made it prime for the wick effect to occur. The murderer was arrested and made a full confession. He claimed to have set the body alight some thirteen hours before it was discovered.

1998 experiment

A larger scale experiment conducted for the BBC television program "QED" by Dr John de Haan of the California Criminalistic Institute involved a pig's body being wrapped in a blanket and placed in a furnished roomfn|2. The blanket was lit with the aid of a small amount of petrol. The body took some time to ignite and burned at a very high temperature with low flames. The heat collected at the top of the room and melted a television. However, the flames caused very little damage to the surroundings, and the body burned for a number of hours before it was extinguished and examined. On examination it was observed that the flesh and bones in the burned portion had been destroyed.

Confusion with Spontaneous Human Combustion

Since both wick effect and SHC involve the incineration of bodies, and therefore the melting and combustion of body fat, there are many similarities between the known phenomenon (wick effect) on the one hand and the alleged phenomenon (SHC) on the other. Many cases of the wick effect have been mistaken for SHC. The uncertainty is over how many.

ee also

* Spontaneous human combustion

Notes

*fnb|1 Gee, Professor David (1965): "A Case of Spontaneous Human Combustion". In "Medicine, Science and the Law" (vol 5, 1965)
*fnb|2 Full information regarding this program is unknown, however a web based BBC news report from 1998 is available.

References

*cite visual | crew=Unknown | date=1998 | title=QED | medium=TV-Series | location=London | distributor=BBC
*cite web | title=New light on human torch mystery | url=http://web.archive.org/web/20030418222504/http://news.bbc.co.uk/2/hi/uk_news/158853.stm | accessmonthday=February 9 | accessyear=2006