What defines a competent ignition source in fire investigation?

In fire investigation, a competent ignition source is characterized by its ability to provide sufficient energy, temperature, and time to ignite a fuel source. The key factors here are energy output, which must be adequate for the ignition of the materials present, and the temperature achieving the ignition point of those fuels. Additionally, the time element is crucial; the ignition source must maintain its heat long enough to allow for ignition to occur.

This concept is central to determining how and why a fire started, as not just any heat source can cause ignition. For instance, a match held too briefly against a combustible material may not ignite it, whereas a pilot light or an electrical arc that sustains heat could. Thus, understanding the characteristics of a competent ignition source is vital for fire investigators in establishing fire causation during their analyses.