Syttymis

Syttymis is a Finnish term that denotes ignition, the process by which a material begins to burn and enters into combustion. In technical contexts it is used to describe the onset of a flame when heat, fuel and an oxidizer come together to support sustained chemical reaction.

Ignition requires sufficient energy input to raise the material to its ignition temperature or to initiate a self-sustaining reaction with oxygen. The classic framework for understanding ignition is the fire triangle, consisting of heat, fuel, and oxygen. If any one of these elements is removed, ignition cannot be maintained.

There are two main ignition pathways. External ignition occurs when an external source such as a flame, spark, hot surface, or friction provides the energy necessary to start burning. Self-ignition, or spontaneous ignition, happens when the material heats itself through internal exothermic reactions or slow oxidation until the temperature reaches a level that sustains rapid combustion, without an external heat source. Materials have characteristic properties such as ignition temperature and autoignition temperature that determine how easily they ignite.

Ignition behavior is central to fire safety, risk assessment, and material handling. Proper control of ignition sources, ventilation, temperature, and storage conditions reduces the likelihood of unwanted syttymis.