Persons or work for which employment is less than 12 months (excluding firefighters hired for a particular fire).

Pressure due to elevation of water. Equals 0.433 pounds per square inch (PSI) per foot of elevation. (Approximately 0.5 PSI is required to lift water 1 foot in elevation)

Attacking a fire by working along the flanks either simultaneously or successively from a less active or anchor point and endeavoring to connect two lines at the head.

A hose-coupling device having two female swivel couplings to permit joining two male hose nipples of the same size and thread type when lines are laid with couplings in opposite or reverse directions.

Aircraft in which maximum certified gross weight at take-off exceeds 12,500 pounds.

The fuels, weather and topographical conditions of a specific fire scene or area of the fire scene at the time of fire passage.

Photographs from a lookout point, bearing azimuth and vertical angle scales, to assist in locating fires with a firefinder.

Weight of an aircraft/engine including the structure, power plant, all fixed equipment, all fixed ballast, unusable fuel, undrainable oil, and total quantity of hydraulic fluid.

That part of the fire on which work is started when suppression crews arrive.

Condition of the atmosphere in which the temperature decrease with increasing altitude is less than the dry adiabatic lapse rate. In this condition, the atmosphere tends to suppress large-scale vertical motion.