Proper Sprinkler Selection

The first step in the process is to have a good understanding of the types (categories) of sprinklers available. Then, knowing what category each sprinkler fits in to, choosing the correct sprinkler becomes easier. You select a category that contains just a few sprinklers, and then you select a sprinkler within that category.

TYPES OF LANDSCAPE SPRINKLERS. Generally speaking, there are three different types, or categories, of sprinklers that are most commonly used on the smaller irrigation projects. Drip is used in some areas of the country, but it is not as widely accepted as the three categories that we will discuss in this section.

1. Bubblers
2. Sprays
3. Gear Drive Rotors

BUBBLERS. Bubblers are designed to apply a large amount of water to a small area in a short period of time. The bubbler delivers water to the area immediately around the head (umbrella bubbler), or is sprayed in thick streams a short distance from the bubbler (stream bubbler). Because of this high flow rate and close spacing requirements, bubblers are restricted to small, confined, level areas. Bubblers operate over a pressure range of 1 to 90 psi and may be used on most types of plant material with the exception of turf.

SPRAY HEADS. Fixed spray heads may be used for almost any type of landscape planting - from turf and ground cover to shrub beds and planters. The shorter radius (5 to 17 feet) of lawn and shrub fixed spray heads make for a high level of control for over-spray, but their relatively short radius also limits their usefulness to smaller areas. Spray heads typically have flow rates of up to 5½ gpm (gallons per minute) or more. This high flow rate restricts the use of the heads to relatively level areas to prevent runoff.

Stream spray heads provide a slightly larger radius. Stream spray heads have been successfully used on gentle slopes because the gpm is slightly lower, while the radius is slightly larger, reducing the risk of run-off. Caution should be exercised when using stream spray heads in shrub beds because shrub branches can block the relatively small spray streams.

The pressures for most spray heads range from 15 to 50 psi (pounds per square inch). Particular attention should be paid to situations with excess pressure, which produce severe misting and poor water distribution.

GEAR-DRIVEN ROTORS. Gear drive rotor heads are well suited for medium to large landscapes with most types of plantings. Their larger radius (15 to 74 feet) makes rotor heads a frequent choice for medium to large landscape areas.

The relatively low gpm for the area of coverage is less than spray heads and makes them useful on landscapes from level to steeply sloping. Lower flows allow more sprinklers to be operated at one time, reducing the number of zone control valves and controller stations (more area can be covered on a single zone). Additionally, less pipe and labor are necessary with rotor systems than with spray systems, which reduces the overall system installed cost.

Typically, designers want to use the largest head possible for the most efficient and the lowest cost system. Pressure requirements for rotors range from 25 to 100 psi.