The Role of the Sprinkler Riser

The Role of the Sprinkler Riser

Friction losses in the pipe from the sprinkler riser to the water supply can be estimated using the Hazen-Williams formula defined in NFPA 13. Hazen-Williams calculates friction loss per foot; this value can be multiplied by the total pipe length to determine the pressure lost.
Elevation is an important factor for pressure losses, as it takes a significant amount of pressure to overcome gravity: Consider 0.433 psi per foot of height required for this. Important features such as backflow preventers and strainers should also be considered because pressure is lost as water flows through these devices.