Which is a two-dimensional fire?

A two-dimensional fire occurs on a flat surface and spreads outward, primarily in two dimensions rather than three. The ignited flammable liquid spill on open ground exemplifies this concept well, as it spreads laterally across the surface of the ground, creating a fire that is primarily confined to a flat area.

In this scenario, the flammable liquid typically burns on the surface, affecting the ground area around it but not penetrating into a vertical dimension or confined space. This characteristic of spreading out on a horizontal plane makes it a clear example of a two-dimensional fire since there is minimal height or depth involved in the burning material.

In contrast, ground cover fires typically involve vegetation and can be affected by both horizontal and vertical dimensions; the fire moves through grasses, shrubs, and trees and can rise as it climbs those structures. A roof fire involves burning materials on a vertical surface, significantly broadening the spatial dimension of the fire. Lastly, a fire contained within a void space is often constrained in height and width but can exist in multiple dimensions due to the enclosure, thereby not fitting the definition of a two-dimensional fire.