Different Types Of Risers and Their Uses
This article explains how to install sprinkler heads at variable heights using risers. You have to account for the variable heights of the pipe. 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. This is why you use risers, to install sprinkler heads at various heights. There are a variety of different kinds of risers, and each has its own features and benefits. But the basic function and purpose are the same; to connect the lateral pipe (carrying the water from the mainline and through the valve) to your sprinkler of choice flush with the surface of the ground.
Simple “Nipple” Risers
The most basic and inexpensive style of sprinkler riser is the Simple Pipe Riser or “Nipple.” Nipple risers come in a variety of different materials, but most are durable poly plastic. A standard Nipple style riser has two male ends with threaded ends. This allows the riser to screw into a threaded tee and the bottom of the sprinkler. You can purchase these types of risers in a variety of lengths and sizes. The downside is that these types of risers break easy. Therefore, if there’s a chance that they might be run over by heavy equipment, swing joints are recommended instead.
Poly Cut-Off Risers for Installing Sprinkler Heads at Variable Heights
Poly Cut-Off Risers take the concept & design of a simple “nipple” style riser and improve upon it greatly. These sprinkler risers are more flexible and have a series of threaded sections. You can cut these to various sizes as needed. 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. Swing joints are a single length of a PVC pipe with dual 90-degree fittings on both ends. The fittings 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 a slightly flexible piece 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 the flush installation of any sprinkler head while also compensating for potential flex or movement of the sprinkler head. Rigid style risers have one longer section of rigid PVC pipe connected with articulating joints on either end. Various combinations are available, which permit almost universal installation options.
Rigid arm risers are preferable 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 flexible riser sections can bend in 90-degree angles. You can even tie it in a knot and it will still remain fully functional! Flexible risers are available for purchase 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.
DIY 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 is soft 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 challenge your face using flex pipe and individual joints.