Landscape Architect & Specifier News

JUL 2017

LASN is a photographically oriented, professional journal featuring topics of concern and state-of-the-art projects designed or influenced by registered Landscape Architects.

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78 Landscape Architect and Specifier News i r r i g a t i o n continued from page 26 between the backflow preventer and the mainline, allowing the backflow preventer to experience the benefits of the constant lower pressure. A typical installation will have the PRV installed on the upstream riser leading up to the backflow preventer. If the local code does not allow components installed in line before the backflow preventer, the PRV can be installed in line after the backflow preventer. A benefit of this installation is the backflow preventer is isolated from any water hammer effects created by the irrigation control valves. Typical installations will have the PRV installed on the downstream riser after the backflow preventer, as seen in the installation drawing below. Another common installation practice is to install the PRV below grade in an irrigation box. This installation could have the PRV installed in a separate box or on the main line of the manifold before the control valves. In either case, it is required to use a sealed cage PRV model designed for below grade installations to prevent water from entering the PRV bell housing. Aesthetically, the single PRV solution does not have a negative impact on the beauty of the landscaping. The installation is either on existing piping risers connected to the backflow preventer, or installed below grade and not visible in the landscape. Installations of this type reduce the overall cost, as the contractor labor required to add the PRV into the system is reduced. This water saving solution is also aesthetically pleasing on retrofit or remodel designs as the visible system changes are not extreme and do not require major changes to the existing irrigation piping. Existing backflow enclosures should have enough space around the risers to cover the newly installed PRV. July is "Smart Irrigation Month," an initiative of the Irrigation Association. Zurn Industries is a proud sponsor of Smart Irrigation Month and promotes efficient landscape watering. The start of summer is a perfect time to evaluate landscape irrigation systems, current design criteria and typical installation practices. If the water pressure to the irrigation system is too high, adding a PRV at the point of connection of the system is a direct and cost effective approach for increasing watering efficiency. The higher efficiency will result in water savings and cost savings to property owner without sacrificing the beauty of the landscape. Typical irrigation installations will have the pressure reducing valves (PRVs) installed on the downstream riser after the backflow preventer, as seen in the installation drawing. I n f o r m a t i o n R e q u e s t # 6 0 6

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