Glossary of Terms

News | Glossary of Terms


Back Flow
Any unwanted flow of used or non-potable water or substance from any domestic, industrial or institutional piping system into the pure, potable water distribution system. The direction of flow under these conditions is in the reverse direction from that intended by the system and normally assumed by the owner of the system.

Backflow Prevention Device (BPD)
Safety device which prevents the flow of water from the water distribution system back to the water source. Types of devices include atmospheric vacuum breaker (AVB), pressure vacuum breaker (PVB), and reduced pressure principle assembly (RP, RPA, RPZ)

Best Management Practice (BPM)
An irrigation BMP is a voluntary irrigation practice that is both economical and practical and is designed to reduce water consumption and protect water quality while maintaining a healthy, functional landscape.

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Certified Irrigation Contractor (CIC)
The Certified Irrigation Contractor is an irrigation professional whose principle business is the execution of contracts and subcontracts to install, repair and maintain irrigation systems. The CIC must conduct business in such a manner that projects meet the specifications and requirements of the contract.

Certified Irrigation Designer (CID)
The IA Certified Irrigation Designer engages in the preparation of professional irrigation designs. They evaluate site conditions and determine net irrigation requirements based on the needs of the project. The designer is then responsible for the selection of the most effective irrigation equipment and design methods. The objective of a CID is to establish specifications and design drawings for the construction of an irrigation project.

Certified Landscape Irrigation Auditor (CLIA)
The Certified Landscape Irrigation Auditor is involved in the analysis of landscape irrigation water use. Auditors collect site data, make maintenance recommendations and perform water audits. Through their analytical work at the site, these irrigation professionals develop monthly irrigation base schedules. Prior to certification examination, auditors are required to take an Irrigation Association approved preparatory course.

An electric timing device that operates each (irrigation) zone for a predetermined time and frequency. An automatic timing device that sends an electric signal for automatic valves to open or close according to a set irrigation schedule.

Cross Connection
Any actual or potential connection or structural arrangement between a public or private potable water system and any other source or system through which it is possible to introduce into any part of the potable system any used water, industrial fluids, gas, or substance other than the intended potable water with which the potable system is supplied. By-pass arrangements, jumper connections, removable sections, swivel or change-over arrangements or other "temporary" arrangements through which backflow could occur are considered to be cross-connections. See also backflow.

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Drip Irrigation
Micro-irrigation system (low pressure and low volume) wherein water is applied to the soil surface as drops or small streams through emitters.

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gpm (Gallons Per Minute)
Acronym for gallons per minute.

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Head to Head Spacing
Spacing of sprinkler heads so that each sprinkler throws water to the adjacent sprinkler.

Hose Bib
Just another name for a faucet outside of your house.

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Irrigation Audit
Procedure to collect and present information concerning the uniformity of application, precipitation rate, and general condition of an irrigation system and its components.

Irrigation Schedule
Determining when to irrigate and how much water to apply, based upon measurements or estimates of soil moisture or crop water used by a plant.

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Lateral Lines
This is a term used to describe the pipes downstream from each station valve. Any particular lateral line will not be under pressure unless that particular station is being watered.

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Main Line
The pipe which carries water to the station valves.

Master Valve
A electric valve which opens whenever any station is watering, and closes when no station valves are on, shutting off the pressure in the main line. A master valve will greatly reduce any water loss due to a leaky station valve because the leaky station valve can only leak while the master valve is providing pressure to the system. Also, if you damage the irrigation main line, a master valve will control water loss so the main can be repaired without shutting off the water supply. A master electric valve is typically the same type of valve as you would use for your station valves, but rather than being installed downstream from your main line and connected to a station output in your controller it is installed upstream at the front of the main line and connected to the "master" or "pump" connection in your controller. Not all controllers support a mater valve or pump- be sure to check the features before buying a controller.

Moisture Sensor
A sensor, usually installed in the ground, which disables watering when the soil is wetter than the setpoint for the sensor.

Multiple Start Times
A controller feature that allows a program to pe operated multiple times on the same watering day. This is important to allow the water time to soak in on steep slopes of clay soils.

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The part of a sprinkler that defines the spray pattern.

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psi (Pounds Per Square Inch)
Acronym for pounds per square inch.

PVC (Poly Vinyl Chloride)
A type of plastic used for irrigation pipe and fittings.

Point of Connection (POC)
Location where irrigation system is connected to a (potable) water supply.

Polyethylene (PE, Poly Pipe)
Flexible (usually black) plastic material used to make irrigation pipe and other items.

Precipitation Rate
The depth of water distributed on the ground over a given period of time. A typical precipitation rate for pop-up spray sprinklers is two inches per hour, about equal to a hard rain.

Pressure Reducing Spray (PRS)
A Rain Bird sprinkler feature which controls pressure at the head to reduce misting and protects against extreme water loss in the event a nozzle falls off of the sprinkler stem.

Professional Grade Parts
Parts made especially for irrigation industry professionals. These are the parts that irrigation companies install, and they are higher quality and more reliable than the parts typically sold through large retail hardware warehouses.

Pump Start Relay
A controller feature which turns on a pump or master valve whenever a station is watering.

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The distance from the middle to the edge of a circle. For a sprinkler, this is the distance from the sprinkler to the edge of the spray pattern.

Rain Shut-Off Device
A switch that opens the common line and interrupts watering as long as the rain switch is moist after a rain. Watering is automatically enabled several days after a rain. Some rain switches have an adjustable disable period.

A fixture, usually used in shrub areas, on which a nozzle is attached. Risers do not move up and down at the beginning and end of the watering cycle.

A type of sprinkler where a stream of water is moved back and forth across the area being watered. While the watering is not uniform at any one instant, it is uniform over a period of several minutes or longer.

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Scheduling (same as Program)
A predefined list of stations which operate sequentially each time the program is scheduled. The best controllers have three or more programs which can be operated on different schedules.

Seal-a-Matic (SAM)
A Rain Bird sprinkler feature (essentially a check valve) which prevents the loss of water from low heads after watering is stopped.

Shut-Off Valve
A valve, usually a ball valve or gate valve, used to shut off the supply to a sprinkler system. The shut-off valve is located near the connection to the main water supply.

Electromagnet which is connected to a controller and facilitates the opening and closing of automatic control valves (or valve-in-head sprinklers).

Spray Head
Sprinkler head that does not rotate.

Sprinkler (Head)
Device for distributing water under pressure. Nozzle or device, which may or may not rotate, for distributing water under pressure through the air.

Static Pressure
Pressure in a closed system, without any water movement. Water pressure when the water is at rest.

Circuit on a controller which has the ability to be programmed with a run time unique and separate from other circuits and provides power to one or more remote control valves (or valve-in-head sprinklers).

Swing Joint
An assembly of three ells and a nipple to provide for convenient height adjustment of a sprinkler, and to reduce the chance of damage when a sprinkler is run over by a vehicle.

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Device to control flow of water in a pipeline in only one direction of which there are many types.

Valve Box
A plastic enclosure which surrounds an underground valve to protect it yet still allow access to the valve.

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Water Hammer
The sudden spike in water pressure observed when moving water is stopped suddenly. This occurs when the kinetic energy in the moving water is converted into potential energy. Pressure spikes due to water hammer are larger when schedule 40 pipe is used as opposed to SDR ("class") pipe. This is primarily because the inside diameter of SDR pipe of a given nominal size is larger than the inside diameter of schedule 40 pipe, resulting in a lower water velocity, and therefore less kinetic energy. A secondary reason is that SDR pipe is more elastic than schedule 40 pipe (since it has a thinner wall thickness in the common sizes) and absorbs the kinetic energy, reducing the maximum pressure during the water hammer spike.

Water Meter
Device used to measure the flow of water.

Process of removing water from the irrigation system before the onset of freezing temperatures.

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Section of an irrigation system served by a single control valve. Zones are comprised of similar sprinkler types and plant material types with similar water requirements and types.

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The Irrigation Association

Travis Irrigation