The time, in seconds, required for the flaming front of a fire to pass a stationary point at the surface of the fuel. The total length of time that the flaming front of the fire occupies one point.

A written or oral agreement between and among agencies/organizations and/or jurisdictions that provides a mechanism to quickly obtain assistance in the form of personnel, equipment, materials, and other associated services. The primary objective is to facilitate the rapid, short-term deployment of support prior to, during, and/or after an incident.

The size of a piece of fuel, often expressed in terms of size classes.

Delineated area surrounding a base which can be reached first by the ground or air attack units assigned to the base.

Computed gross weight for an aircraft, obtained from the appropriate performance chart, which is the maximum gross weight appropriate to the applicable circumstance of configuration and/or environmental conditions.

The part of a fire within which continuous flaming combustion is taking place. Unless otherwise specified, the fire front is assumed to be the leading edge of the fire perimeter. In ground fires, the fire front may be mainly smoldering combustion.

That zone of a moving fire where the combustion is primarily flaming. Behind this flaming zone combustion is primarily glowing or involves the burning out of larger fuels (greater than about 3 inches in diameter). Light fuels typically have a shallow flaming front, whereas heavy fuels have a deeper front.

In meteorology, the boundary between two air masses of differing atmospheric properties.

The ratio of liquid foam concentrate to water, usually expressed as a percent.

The appropriate ratio of liquid foam concentrate to water recommended by the chemical manufacturer for each class of fire, usually expressed as a percent (such as 0.5%).