Irrigation Terminology
Atmospheric Vacuum Beaker (AVB)
A backflow prevention device installed between the remote control valve and sprinklers in non continuous pressure applications.
Backflow Prevention Device
A device required by law, on an irrigation system that prevents water from re-entering the potable water line once it flows into the irrigation pipes
Manifold
A group of control valves located together in the same area.
Station
A group of sprinklers that is controlled by the same remote control valve; same as a zone.
Zone
A group of sprinklers that operate together and are controlled by the same remote control valve.
PVC Pipe
Poly Vinyl Chloride pipe; the most common used pipe in irrigation systems.
Head to Head Spacing
Refers to the spacing distances of sprinklers when they do not exceed the radius of the sprinklers.
FPS
The abbreviation for "feet per second;" refers to the velocity of water in pipes.
GPM
The abbreviation for "gallons per minute;" unit of measure for water flow.
POC
The abbreviation for "point of connection." This is the location on the irrigation system where a tap is made for connection of a backflow prevention device or water meter.
PSI
The abbreviation for "pounds per square inch;" which is a unit of measure for water pressure.
Evaporation
The change by which any substance is converted from a liquid state to a vapor.
Radius
The circular area extending from the center of a circle to the outside curve.
Water Main
The city water pipe located in the street or right of way.
Shut Off Valve
The component in the irrigation system that allows manual shut off of water to all components downstream.
Remote Control Valve
The component in the irrigation system that regulates the On/Off of water from the main line to the sprinkler heads; activated by the controller; same as in-line valve.
In Line Valve
The component in the irrigation system that regulates the On/Off of water from the main line to the sprinkler heads; activated by the controller; same as remote control valve.
Timer
The device that sends timing commands to remote control valves for actuation; same as controller.
Controller
The device that sends timing commands to remote control valves for actuation; same as timer.
Spacing
The distance between sprinklers.
Water Pressure
The force of water that exists in a piping system; measured in pounds per square inch (PSI).
Water Hammer
The impact created by water and air moving through the piping system at high velocities and suddenly stopping. *Water comes to a T section at 8.3 pounds and stops when it splits to go one way or another.
Friction Loss
The loss of pressure (force) as water flows through the piping system.
Flow
The movement of water through the irrigation piping system; causing friction loss.
Coverage
The pattern of water applied to an area by a sprinkler head.
Supply Manifold
The pipe connected to the remote control valves that supplies water to the sprinklers.
Lateral
The pipe in an irrigation system located downstream from the remote control valve. Lateral pipes carry water directly to the sprinklers.
Main Line
The pipe in an irrigation systems that delivers water from the backflow prevention device to the remote control valves. This is usually the largest pipe on the irrigation system, generally under constant pressure and located upstream from the remote control valves.
Service Line
The pipe supplying water from the city water main to the water meter.
Designed Operating Pressure
The pressure a designer uses to determine spacing distances and flow for sprinkler heads. The designed operating pressure is determined by subtracting estimated friction losses from the static water pressure.
Dynamic Pressure
The pressure reading in a pipeline system with water flowing.
Static Water Pressure
The pressure that exists in a piping system when there is no flow; measure in pounds per square inch. (PSI).
Precipitation Rate (PR)
The rate at which sprinkler heads apply water to a specific area of coverage, over a given period of time, measured in inches per hour.
Working Pressure
The remaining pressure in an irrigation system when all friction losses are subtracted from the static pressure.
Velocity
The speed at which water flows through the piping system; Measured in feet per second (FPS). *Make sure the velocity will not make a water hammer when zone is turned on.
Matched Precipitation Rate (MPR)
The uniform delivery of water across each square foot of an irrigate area. Each sprinkler's coverage provides every blade of grass with no more and no less water than the next. The result is high-precision application.
Potable Water
Water used for drinking purposes.
