What two variables primarily affect the reach of fire streams?

The reach of fire streams is primarily influenced by two physical forces: air resistance and gravity.

Air resistance, or drag, opposes the motion of the fire stream as it moves through the atmosphere. The faster the water travels, the more air resistance it encounters, which can reduce its distance. This is particularly significant for fire streams, as the nozzle design and the angle at which the stream is projected can impact how effectively it can overcome this resistance.

Gravity is the second crucial factor, acting on the water as it is projected into the air. As the water rises, gravity pulls it down, affecting the trajectory of the stream. The angle of elevation used when operating the nozzle affects how high and far the water can reach before succumbing to gravity's pull.

Together, air resistance and gravity determine not only how far a fire stream can reach but also the shape of its trajectory, which is vital for effectively combating fires from a safe distance. Understanding these principles allows fire apparatus engineers to optimize their equipment and techniques for maximum effectiveness in firefighting operations.