What does the term "K-factor" refer to in sprinkler design?

In sprinkler design, the term "K-factor" specifically refers to a constant that relates the flow rate of water through a sprinkler head to the pressure applied to the head. This factor is determined by the size and shape of the sprinkler's orifice. The K-factor is critical in calculating the flow rate that will be discharged by the sprinkler head when a certain pressure is applied, allowing for proper system design to ensure that sufficient water is delivered to control a fire effectively.

Understanding the K-factor enables designers and installers to choose the right type of sprinkler heads based on the requirements of the particular application. It directly impacts the effectiveness of sprinkler operation in a fire scenario, ensuring that the fire suppression system meets codes and standards for safety.

The other options refer to different aspects of fire sprinkler systems: the pressure at which a sprinkler activates is related to its activation settings, the radius of coverage pertains to the area that a sprinkler can effectively cover, and the size of the water storage tank indicates the capacity of the system to supply water. While related to system functionality, these do not define the K-factor itself.