Techline CV Design Guide

TYPES OF LAYOUTS:

There are two layout methods we recommend - "GRID" and "LITE". Both accomplish the same goal, but one method will be the preferred method based on what and how you are irrigating.

"GRID":

• This is the preferred method for installing Techline CV subsurface

• This method uses supply and exhaust headers with rows of Techline CV connected at each end

• The Supply Header delivers water to each row of Techline CV

• The Exhaust Header forms a continuous loop, or return leg, so all rows of Techline CV are being supplied from both ends

• This interconnection of the piping network comprises the term "Grid layout." This evens out the flow, helps ensure water is being delivered downstream of any break in the laterals, and allows for much easier repairs of any line breaks.

"LITE":

• The LITE layout is used exclusively on-surface

• It is the fastest and easiest layout method because no supply and exhaust headers are used

• The dripperline simply weaves back and forth throughout the zone in evenly spaced rows.

WHAT DO THESE LAYOUTS HAVE IN COMMON?

• Both methods assume even row spacings will be maintained
• Both methods are designed to flow water in a loop manner

BASIC "GRID" LAYOUT:

• Headers should be indented 2" - 4" from hardscapes and planting areas.

• Headers may be PVC, polyethylene or in zones under 5-GPM, Techline CV or Techline CV Blank

• Headers must be sized to accommodate the flow of the zone without exceeding 5 feet per second velocity. (For Zone Water Requirement calculations - click here).

• Start rows of Techline CV 2" - 4" away from the edge of hardscapes, and move across the area with equal row spacing that does not exceed the recommendations of Table 1. (The 2" setback will help provide enough moisture to prevent heat damage to plant material generated by hardscapes such as asphalt). Start rows about 4" away from planting beds.

BASIC "LITE" LAYOUT:

• Water being supplied to the zone is split with a Techline fitting into two directions. Use a TL075FTEE or TL2W075MA fitting.

• Weave the Techline CV back and forth throughout the planting area with evenly spaced rows.

• Indent the tubing 2" - 4" from hardscapes and planting areas.

• Because water is being split into two separate paths that meet in the middle, the maximum length of the lateral can be twice the stated limit in Table 2.

• Therefore, to determine the maximum amount of Techline CV you can use in the zone, simply double the maximum length stated in Table 2.

How to Calculate Equal Techline CV Row Spacing

Example:

• 5 feet x 12 inches = 60 inches
• 60 inches - 8 inches (2 edges x 4" setback) = 52"
• Following recommended Techline CV Row Spacing for this example, assume 18 inches from Table 1
• 52" ÷ 18" = 2.89 spaces between Techline CV rows
• 2.89 is not a whole number, so round up to the next whole number, which is 3 (spaces)
• Add 1 (one) to the number of spaces to determine the number of Techline CV rows
• Determine equal spacing between Techline CV rows. 52 inches ÷ 3 = 17.3 inches

NOTE:
HOW TO QUICKLY DETERMINE THE AMOUNT OF TECHLINE CV IN A ZONE
(Square Footage of Zone x 12) ÷ Minimum Recommended Row Spacing

LENGTH OF TECHLINE CV ROWS:

• As with overhead irrigation, friction losses through pipe determine how long a length of pipe can be.

• You do not need to go through friction loss calculations for Techline CV laterals. It has already been done for you.

• Table 2 shows the maximum length of a single Techline CV lateral within a zone.

• The chart also determines what the operating pressure of the zone needs to be. Example - If you have a 322' lateral of 0.6 GPH/12" Techline CV, it will need 35 psi to operate properly. If it is from 323' - 369', it will need 45 psi. Note: We will discuss further how to regulate your pressure in the Pressure Regulating Valve section - click here.

• Once the zone is laid out, note the pressure you will need somewhere on the design. We will need this information later to size the Pressure Regulating Valve.

CENTER FEED GRID LAYOUTS:

• You can increase the length of laterals by center-feeding the zone. By doing so, you can have a length of Techline CV as called out in Table 2 going in each direction, effectively doubling the maximum lateral length. This is just like we discussed with the LITE layout - click here.

• Where layout flexibility exists, Center Feed layouts are an excellent design method.

• They allow for the most even flow of water through the zone.

• They are an excellent option for median strips and other large, homogenous areas.

OTHER GRID LAYOUT CONSIDERATIONS:

• When branching out or joining rows of Techline CV, one of two rules apply:

Rule #1: When branching out Techline CV from the supply header, add up all "branched out" dripperline and check it against the maximum lateral length listed in Table 2.

Rule #2: When joining laterals from the supply header, check only the longest lateral against the maximum allowable in Table 2.

• To reduce the number of glue joints, saddles or insert fittings in a header, transition to Techline CV and Techline fittings to make up subheaders.

• Make sure to follow the guideline of not exceeding 5 GPM in the "sub-header" zone.

ZONE WATER REQUIREMENTS:

• Once the Techline CV is laid out, we need to identify total zone flow. This will help determine mainline, submain as well as supply and exhaust header sizing, valve, filter, and pressure regulator selection.

• There are two ways to determine the flow in a Techline CV zone.

• Because Techline CV is pressure-compensating, the flow rate per 100' is the same over a wide pressure range.

• Table 3 shows an easy way to determine total zone flow:
- Add up the amount of Techline CV (in hundreds of feet) and
- Multiply that figure by the corresponding dripperline GPM to determine zone flow.