As the irrigation season ramps up, commercial contractors are busy with start-ups and a backlog of installation work from the winter months. We checked in with Dave Shane, our Commercial Sales Manager, to discuss several common questions commercial contractors face on a regular basis in design/build installation work and various solutions.
1. Question: Should I install a master valve?
Answer: Yes! When the point of connection is pressurized potable water, a master valve is a worthwhile investment. It can protect the landscape from uncontrolled mainline breaks that can go undetected for days, weeks or longer.
Master valves are available in two configurations: normally closed and normally open.
- Normally closed valves are activated automatically by the controller whenever any station or program operates.
- Normally open valves are less common and are activated by the controller only when there is excess flow, making it necessary to shut down the mainline. A flow sensor is needed to determine excess flow and if it is in a lateral or the mainline.
Be sure to select the correct controller if designing with a normally open valve or a flow sensor. If in doubt, ask us. Central is here to help!
Some things to watch out for:
- Normally closed valves keep the main depressurized when zones are not operating. This prevents water waste in case of a mainline break when no flow sensor is used. But be careful: the mainline must recharge every time a program operates. That means high velocity while the main fills. High velocity can decrease the effective lifespan of the pipe and mainline fittings. In large systems where it may take five or more minutes for the main to reach adequate pressure, the zones that operate first essentially lose those minutes of effective irrigation.
- The master valve needs to be open when quick coupler valves are used. It can be opened manually – not the best choice – or from the controller by operating a blank station. Many commercial controllers can open the master valve automatically at user-defined times for hand watering when no irrigation is scheduled.
- Normally open valves keep the main constantly pressurized, increasing the pipe lifespan and providing easy access to water through quick couplers. The main should be protected by a flow sensor and a controller capable of activating the valve for excess flow caused by a break.
Be aware that normally open valves hardly ever operate, sometimes only once a year or every several years. They can potentially fail to operate when called on to save the day. Some controllers can “exercise” the valve at user-defined intervals, perhaps every 30 days for two minutes when no irrigation is scheduled.
2. Question: Where should I locate the controller?
Answer: The controller should always be in a secure location but also needs to be accessible for programming, manual operation, and maintenance. Controllers could be wall-mounted indoors or outdoors or pedestal-mounted, along a roadway or another convenient location away from a building.
Several factors should be considered when picking a controller location:
- Is it a two-wire or conventionally wired system? Two-wire can run further than conventional wire, so the controller location relative to its valves is not as critical.
- How often will the controller be accessed? It could take a lot of valuable time to gain entry to a secure location. When operating from a remote or cloud-based app, location is not as critical.
- How will the controller communicate with cloud software? Ethernet may be available in an indoor location or the outside wall of a building. If the controller is pedestal-mounted away from a building, it may be possible to extend Ethernet through a Wi-Fi hub. A cell modem may be necessary in more remote locations, or when the client will not allow the controller on the network. If considering a cell modem, a wireless test will determine feasibility and antenna type.
- Are there environmental factors to consider? A very humid indoor location is not ideal for controller electronics. A nearby VFD or large transformer could cause electronic interference in the controller, making it randomly unreliable. I’ve seen controllers installed in underground vaults subject to flooding, at ground level where it is virtually impossible to program or operate them, on poles 10 or 12 feet high and in traffic circles where it is dangerous to get to them. My all-time favorite was the one at a private zoo in the lion’s den. No thanks, I was unavailable to help with that one!
3. Question: Should I install quick coupler valves, and if so, how many?
Answer: Yes! A quick coupler is a convenient way to access water from the main for hand watering or washdown of sidewalks. Commercial quick couplers can have locking covers and are sized for ¾” or 1” hose. A compatible key and hose swivel is required. Locking covers and locking valve boxes should be used to limit access and liability.
Quick coupler size and quantity should be based on the type of hose used by the maintenance staff. If they use ¾” hose in 50’ lengths, then ¾” quick couplers placed no more than 100’ apart should be installed.
The mainline fitting the quick coupler is connected to is subject to unusual stress when the quick coupler key is inserted, pushed, and twisted. A swing joint specifically designed for quick couplers should always be used. It can be secured with lengths of rebar driven into undisturbed earth below the main. This keeps the quick coupler secure while still providing the required flexibility to minimize stress on the mainline fitting.
4. Question: Should I downsize laterals further away from the zone valve?
Answer: Yes, there are sound design principals on why this can be done. It’s all about water velocity not exceeding 5 feet per second: the pipe after each head will carry less water than the pipe before the head, so it is possible to downsize, decrease pipe cost, and still not exceed 5 feet per second.
Downsizing laterals is more common in residential installation where three or more lateral sizes are often used. Lots of reducer fittings are required. In commercial production work just one or two lateral sizes are more common. This is especially true when zones are center fed and there is typically less need for larger pipe.
A good rule in commercial work is to have no more than two lateral sizes with 1” being the minimum. Of course, there are exceptions to every rule: a large end-fed zone on a sports field with 1” rotors may start with 2.5”, transition to 2” and then 1.5”.
At Central Turf, we are experienced in commercial design and projects. Ask us your toughest product and installation questions; we are here to assist and help make you more efficient, competitive, and profitable in your commercial work.
About Dave Shane
Dave has more than three decades of experience in the irrigation industry in both distribution and manufacturing roles. He specializing in commercial project solutions with an emphasis on controls to meet complex requirements. He is an excellent resource for any technical questions about irrigation systems and finding the right solutions for efficient irrigation systems.