Installing Sprinkler Heads At Variable Heights Using Risers
No two sprinkler systems are the same. Each and every sprinkler system has its own obstacles and challenges. One area specifically is the placement of the sprinklers themselves. It is not uncommon to have variations in the distance from the Lateral Pipe to the surface of the ground. For this reason, sprinkler head risers have been developed. There are a variety of different kinds of risers, and each has its own features and benefits. But the basic function and purpose is the same; to connect the lateral pipe (carrying the water from the mainline and through the valve) to the your sprinkler of choice flush with the surface of the ground.
Simple “Nipple” Risers
The most basic and inexpensive style of riser is the Simple Pipe Riser or “Nipple”. Nipples are available in a variety of different materials, but most are made from a durable poly plastic. A standard Nipple style riser has two male ends with threaded ends allowing the riser to be easily attached to the lateral pipe and the other side screwed directly into the bottom of the sprinkler. You can purchase these type risers in a variety of lengths and sizes. This style of riser is not recommended for installations where the sprinkler head may come in contact with any foreign objects because they can break easily.
Poly Cut-Off Risers
Poly Cut-Off Risers take the concept & design of a simple “nipple” style riser and improve upon it greatly. They are made from a softer more felxible material and are molded to include a series of threaded sections. The riser can be cut to fit the needs of the installation. The soft poly-plastic material lets the riser flex under pressure instead of breaking. Additionally, thread tape or sealants are not necessary for installation.
Swing-Joint Style Risers
One of the more common riser designs is the swing joint riser. It is made up of a single length of a PVC pipe fitted with dual 90-degree fittings (on both ends) which articulate, allowing for universal applications. Simply install the Swing Joint Riser inline between the sprinkler head and the lateral pipe. The center section of this style riser pipe is made from a slightly flexible peice of pipe — it is firm but it also has a memory. This means that the joint riser will absorb movement or impact without resulting in damage. Swing-Arm risers are an inexpensive and effective way to install sprinkler heads. It is the style we most recommend for residential and non-commercial applications. Pre-assembled swing-are risers are preferable to others because the joints have proven over time to remain flexible and durable.
Rigid Style Risers
Similar to flexible swing joint risers, rigid arm risers also allow for a flush installation of any sprinkler head while also compensating for potential flex or movement of the sprinkler head.It is comprised of one longer section of rigid PVC pipe connected with articulating joints on either end (various combinations are available) which permit for almost universal installation options.
Rigid arm risers are preferred when dealing with industrial and larger scale installations. Rigid Swing Joints, although much more heavy duty are more susceptible to freeze damage than any other design due to the rigid nature of their construction and the PVC materials.
Pre-Made Flexible Risers
As the name suggests, flexible risers forego the use of joints in favor of different flexible materials that resist breaking when bent. In fact most flexble riser sections can be bent in 90-degree angles, even tied in a knot and still remain fully functional! Flexible risers can be purchased as a complete unit with threaded ends in various lengths — ready to use. One of the shortcomings of this style riser is that it is unable to handle high pressure.
D-I-Y Flexible Risers
When ready made options are not available or you have a situation requiring a custom made design, it is possible to make your own flexible riser. The most basic version of a flexible riser would incorporate a section of flex pipe (i.e. funny pipe or swing pipe) and two fittings, one on each end appropriate for your needs. Flex pipe is a softer type of pipe and commonly has a blue stripe running along its length. It issoft and flexible enough that it can be easily cut with a common pocket knife. Because of the negligible cost between the pre-made swing joint risers, flexible risers and making your own flexible riser, it is probably easier and preferable to buy a pre-made unit. However, in situations where various angles or obstacles prevent an easy swing joint riser installation, it may be best to make a custom flexible riser specifically to fit the exact specifications or challenges your face using flex pipe and individual joints.