Sprinkler Head Types
As soon as water passes through a valve from the main line, it enters a "zone line." This line connects directly to the sprinkler head and is sometimes referred to as a "swing line."
Each zone line is attached to the main line with a connective device called a "saddle-T" that directs the water immediately to the sprinkler head itself. As soon as a sprinkler head is activated by the water flow, it extends upward, directing a spray of water onto the surrounding area.
Rotor sprinkler heads rotate to cover wide sections of lawn and are generally used for larger, open areas. The spray range of a micro-sprayer can be set at bubble-size or expanded to a 10-foot, 360-degree radius. These sprinklers are generally used in flowerbeds, or other limited spaces that don't require large amounts of water.
In planning any irrigation system, it's essential to determine the right type of sprinkler head for each zone in the layout. Sprinkler heads are sold in a wide variety of sizes, styles and spray patterns, so background research is essential to ensure that you select the right type(s) for the needs of your lawn.
Pop-up rotor heads have a lower, wider portion that is inserted into the ground. When this sprinkler head is activated, the upper portion rises into position to emit the spray of water. The distance to which a sprinkler can spray is often referred to as its "throw."
A 6-inch pop-up rotor head will generally have a 30- to 35-foot throw, and is ideal for use in open lawn areas and along hard lines (curbs, sidewalks, etc.) When planning the placement of individual sprinkler heads, begin with large areas first; then work inward from hard lines toward the smaller sections of the landscape.
With an average throw around 45 feet, an impact sprinkler head is ideal for larger open spaces. Impact sprinklers are named for the action that propels them: the actual spray is "impacted" by a mechanical arm that helps distribute the streaming water. The mechanism of this sprinkler type has the familiar, ticking sound often heard on golf courses. However, the open design of impact sprinklers doesn't protect the inner mechanism from debris. Therefore, this type of sprinkler isn't a good choice for lawns with grasses that grow on "stringers" (zoysia and Bermuda varieties, for example). These grasses can easily become tangled in the spray mechanism and disrupt its motion.
Pop-up heads, by comparison, are gear-driven and self-contained (and therefore won't be obstructed by grass or other debris). If this type of sprinkler will be used in an area where the spray needs to extend over a small obstacle -- a flowerbed or small grouping of rocks, for example -- simply select a taller model, such as the 12" version.
Variable arc nozzles have adjustable heads, turn open to whatever angle is needed; and have a constant spray, meaning they have higher precipitation rates than rotor sprinklers. They are useful in areas that need extra water, or in regular areas part of the time. On average they have a 15-foot throw or radius. Variable arc nozzles stand at a 12" height for obstacles.