FDNY Fire Life & Safety Director Practice Test

The spray pattern of the water discharged from a sprinkler head is determined primarily by the deflector. The deflector is a crucial component of the sprinkler system that shapes and directs the water spray as it is expelled from the sprinkler head. Its design influences how the water is distributed over the area, which is essential for effective fire suppression.

When water is released from the sprinkler, it passes through the deflector, which alters both the angle and the distribution pattern of the water droplets. This helps ensure adequate coverage of the intended area to extinguish or control the fire effectively.

While factors like water pressure can influence the force and reach of the water, it is the deflector that fundamentally defines how that water is spread out, making it central to the sprinkler's functionality. Other components, such as hose shape and pipe size, may affect overall system performance but do not control the specific pattern of water distribution from the sprinkler head.