Introduction:

 

This minimum Standards document has been provided to assist in promoting quality irrigation design and installation.  This document is subject to revision.

Please forward comments and suggestions to the Gateway Irrigation Association.

 

 

SYSTEM DESIGN CHARACTERISTICS:

 

1. Unless otherwise specified, plans and specifications are intended to include everything for the proper installation and completion of work.
2. Irrigation plans are intended to show all components and their locations within a specific job site.  The plans show backflow preventer location, pipe locations, pipe sizes, valves, timer and sprinkler locations along with nozzle sizes.
3. Design and construction of irrigation system must meet all applicable codes.  Components of irrigation system shall be designed and installed in accordance with guidelines set forth by manufactures.
4. Pressure regulation devices will be installed to allow entire system including all remote control valves and all sprinkler heads to operate at optimum pressure designated by product manufacturer.  Pressure regulation devices may include one or all of the following:

1—pressure regulation valve at main line POC

2—pressure regulation device on/at remote control valve

3—pressure regulation device on individual sprinkler heads

4—regulation of low volume drip/micro systems.

5. Booster pumps shall be installed on systems where supply pressure does not meet minimum recommended pressures of sprinkler manufactures.
6. Systems shall be able to complete watering in 10 hours or less per night. (Applies to post established landscapes.)
7. Provide separate zones for turf, shrubs, and drip.
8. Provide separate zones for different exposures. (i.e. north side of building vs. south side)
9. Provide separate zones for sloped areas.  When irrigating slopes, take runoff at slope bottom into consideration.  Run lateral lines parallel to slope.
10. Systems shall contain check valves to prevent low point drainage where applicable.
11. Provide separate zones for variations in site soil types.
12. Design and/or install with reduced head spacing or low angle nozzles for windy conditions.
13. No single zone shall be designed or installed with sprinklers of differing pressure requirements or precipitation rates. (Rotors, spray heads, drip emitters should not be mixed within a zone.)
14. All sprinkler heads shall be spaced at a maximum of 50% of design performance diameter of the sprinkler.  It is recommended spacing shall be reduced below 50% of design performance diameter when conditions demand.to ensure complete “head to head” coverage.
15. All systems shall include a port by which the system can be winterized with  compressed air.

 

 

POINT OF CONNECTION & BACKFLOW DEVICE

 

1. Recommended Point of Connection component installation order: 1-connection to source, 2-shut off, 3-backflow preventer, 4-master valve where applicable.
2. Point of Connection & Backflow Device shall be installed in accordance with all state & local plumbing codes and performed by the appropriate licensed and qualified individuals.
3. The backflow preventer shall be place a minimum of 12” above grade and a minimum of 6” laterally away from any wall, fixture or obstruction.
4. The backflow preventer shall be oriented in a position to allow easy access to test cocks for testing and winterizing.
5. A shock arrestor shall be installed when required by local code.

 

 

CONTROLLER/COMMUNICATION WIRE

 

1. Controller and wire installation shall be installed in accordance with all state & local electrical codes.
2. Controller shall be able to provide separate programs for turf zones, shrub zones, and drip zones.
3. Controllers shall be capable of temporarily shutting down system by utilizing internal/external options (such as rain, wind, freeze devices)
4. Controller shall be programmable for multiple start times for repeat and rest periods, and shall be capable of water budget adjustment.
5. Power wire and control wire shall not be contained in the same conduit.
6. Controller wiring at outside exposure shall be contained in solid or flexible conduit.
7. Remote control valve wiring shall be a minimum of 18 gauge, solid, single conductor copper UL rated.  14 gauge wire shall be used for wire runs exceeding 1000’.
8. All wire connections shall be made with UL approved watertight connectors and contained in valve box.
9. Provide 12” of slack wire at each remote control valve in valve box.
10. Remote control valve wiring shall be installed with the main line pipe where possible.
11. Remote control valve wiring shall have separate colors for common, control, and spare. White is recommended color for common wire.
12. Provide minimum of one spare wire for every six remote control valves in system.  Spare wire shall be available at all valve manifolds.  All spare wires shall be “home run” to the respective controller.
13. Outdoor controllers shall be lockable and weather resistant.
14. All wiring under hardscaping shall be contained in sleeving.
15. Two wire systems shall adhere to all codes and manufactures installation recommendations.

 

 

PIPING / FITTINGS

 

1.      All PVC pipe shall be continuously and permanently marked with the manufacturer’s name, material, size and schedule or type. Pipe shall conform to U.S. Department of Commerce Commercial Standard CS 207-06, or latest revision.

2.      Material shall conform to all requirements of Commercial Commerce CS 256-63, or latest revision

3.      Minimum recommended standards for PVC pipe: Class 200 for 1”.  Class 160 for 11/4” and above.

4.      Maximum flow velocity in any pipe shall not exceed five feet per second.

5.      It is recommended all piping under hardscape shall be contained in sleeving twice the size of the sleeved pipe.

6.      Minimum pipe depths: lateral pipe 12” cover, main line 18” cover, sleeving 18” cover. In extreme rock conditions, pipe should be installed as deep as possible and owner/client should be notified of depth.

7.      Suggested Maximum flow rates for PVC pipe sizes are as follows:

2-1/2”            = 85 GPM                1-1/4”            = 27 GPM

2”            = 60 GPM                1”            = 20 GPM

1-1/2”            = 35 GPM                1” Poly= 14 GPM

8.       Where trenching, piping will be backfilled with clean material, settled and compacted to proper finish grade.

9.      All solvent weld joints to be installed according to manufacturer specifications.

10.  All insert fittings shall be installed according to manufacturer specifications.

11.  PVC main line shall use a minimum of Schedule 40 fittings or better.

 

VALVES

 

1.      Remote control valves shall be sized according to the zone demand requirement, lateral piping downstream and manufacturer’s specifications.

2.      Control valves will be installed in an irrigation industry manufactured valve/meter box.

3.      Remote control valve in valve box shall have ample space for service and to remove valve cover.

4.      Recommended valve to valve box size is as follows

1-     1” valve  = 6” valve box            1- 1-1/2” valve = 10” valve box

2-     1” valves = 10” valve box            2- 1-1/2” valves = 12” valve box

3-     1” valves = 12” valve box            1- 2” valve = 10” valve box

4-     1” valves = 12” valve box

Single Drip manifold assembly = 12” valve box

 

Any larger or additional manifolds should use 16” “Jumbo Box”.

Tops of all valve boxes will be set even with and match adjacent grade.

 

SPRINKLER HEADS

 

1.      All sprinkler heads shall be attached to lateral line pipe with a riser or flexible/adjustable swing assembly.

2.      Athletic field heads shall be installed with approved swing joint assembly.

3.      Spray heads shall pop up a minimum of 4” in turf areas.

4.       Sprinkler heads adjacent to hardscape paving shall be spaced a minimum of 1”  away from paving. Sprinklers adjacent to walls, buildings, fences or other structures shall be spaced a minimum of 6” away from the aforementioned.

5.      All sprinklers within a zone shall have matched precipitation rates.

6.      Shrub heads located adjacent to pedestrian areas shall be of pop up variety.

7.      Sprinklers in turf areas shall be fully spring retractable and pop up a minimum of 4”.

8.      Shrub heads should be 6” or 12” pop ups, appropriate to future plant height and allow for even distribution of water.

 

TESTING THE SYSTEM

 

1.      Mainline shall be pressurized and hold tight.

2.      The entire system shall be tested at the normal system working pressure or at the rated pressure of the pipe, whichever is lower.

3.      Upon visual inspection of the ground, should any leak be found, it shall be promptly repaired. The line shall then be retested until satisfactory with system requirements.

 

RECORD DRAWING

 

1.     After completion of the system installation, the Contractor shall furnish a scaled “Record Drawing” showing location of point of connection, system shut-off, backflow preventer, controller, sprinkler heads, valves, drains, and pipelines and all other components of the irrigation system.

2.     All valves and wire splice locations shall be shown using dimensions from a fixed point.

3.     Instruction sheets and operating manuals covering all operating equipment shall be furnished to the owner/owner’s personnel.