Cremation of a dead body is carried out at a temperature ranging between 1400 to 1800 degrees Fahrenheit. The intense heat helps reduce the body to its basic elements and dried bone fragments.
The process takes place in a cremation chamber, also known as a retort, of a crematory. The chamber is preheated at a set point and then body is placed is quickly transferred there through a mechanized door to avoid heat loss.
Here’s a video showing the cremation of human body.
During incineration, the body is exposed to a column of flames produced by a furnace fueled by natural gas, oils, propane, etc.
As the corpse is placed in a casket or container (preferably prepared from a combustible material), the container burns down.
Next, the heat dries the body, burns the skin and hair, contracts and chars the muscles, vaporizes the soft tissues, and calcifies the bones so that they eventually crumble. The gases released during the process are discharged through an exhaust system.
The bodies are mostly burned one at a time. There is usually no smell because the emissions are processed to destroy the smoke and vaporize the gases that would smell.
Some crematories have a secondary afterburner to help burn the body completely. Otherwise, the cremation technician may have to crush the partially cremated remains with the help of a long hoe-like rod.
As a result, the corpse is reduced to skeletal remains and bone fragments. It is then collected in a tray or pan (tiny residue may still remain in the chamber and mix with the particles from subsequent cremations) and allowed to cool for sometime.
These remains, however, also contain non-consumed metal objects such as screws, nails, hinges, and other parts of the casket or container.
In addition, the mixture may contain dental work, dental gold, surgical screws, prosthesis, implants, etc. These objects are removed with the help of strong magnets and/or forceps after manual inspection. All these metals are later disposed of as per the local laws.
Mechanical devices, pacemakers, in particular, are removed beforehand because they may explode due to the intense heat and damage the cremation equipment and staff.
It is suggested to remove jewelry items like rings, wrist washes, and other similar objects, too, as they are likely to break down during the process.
Moreover, the metal pieces are removed before the next process because they may damage the equipment used for pulverization.
Finally, the dried bone fragments are further ground into a finer sand-like consistency. The machine used for this pulverization is called cremulator.
On an average, it takes about one to three hours to cremate a human body, thereby reducing it to 3-7 pounds of cremains. The cremation remains are usually pasty white in color.
These remains are transferred in a cremation urn and given to the relative or representative of the deceased. If you do not have an urn, the crematorium may return the ashes in a plastic box or default container.
Factors Affecting Cremation Time
The duration of a cremation process usually depends on certain factors. They are:
- weight or size of the body
- percentage of body fat to lean muscle mass
- the performance of cremation equipments used
- operating temperature of the cremation chamber
- the type of cremation container or casket in which the body is placed