Techline CV Design Guide

SLOPES AND BERMS:

Techline CV has a check valve built into each dripper. This allows the dripperline to hold back up to a 4 1/2 feet column of water. As such, designing Techline CV on slopes and berms is very easy.

• Techline CV should be installed perpendicular to (across) slopes

• In the upper 2/3 of the slope, space Techline CV per TABLE 1, click here.

• In the lower 1/3 of the slope, increase the distance between rows by 25%.

• For every 4 1/2 feet of elevation change, either:

- Split the slope into separate zones, or
- Install a Netafim "TLCV" inline check valve.

Techline Check Valve (TLCV):

• Designed to hold back up to a 13' column of water

• Rule of Thumb: Every 1' of water exerts 0.433 psi of pressure at the base of the column. As such, a 100' column of water exerts 43.3 psi at the base.

TLCV Specifications:

• Flow Range: 0.9 - 4.4 GPM (200 - 1,000 I/h)
• Closing Pressure: 5.7 psi (4m)
• Opening Pressure: 7.1 psi (5m)
• Can hold back a 13' column of water (5.7 ÷ .433)
• Connection: 17mm insert

TREES:

• It is important to provide trees with adequate water at the rootball, while also planning for the tree's needs as it grows.

NOTE: When trees are transplanted, the soil in the rootball and the native soil are different. You must ensure that there are sufficient drippers irrigating both soils because water will not migrate from one soil type to the other.

• A loop of Techline CV close to the rootball, with more Techline CV surrounding the estimated dripline of the tree when mature will provide sufficient water.

PRESSURE & FLOW CHECKS:

• One of the best means of ensuring a Techline CV zone is operating properly is to test the pressure at regular intervals.

• By taking and recording the pressure while the zone is running, you can ensure that the zone is working as installed.

• Take the reading as far away from the source as possible to ensure that pressures throughout the rest of the zone are at least that high.

• If readings are lower than normal, a line break, clogged filter, dirty remote control valve, clogged PRV, or reduced line pressure are possible causes.

NOTE: Always take the readings at the same time of day, from the same spot. This reduces the chance of faulty readings due to other factors.

• If a water meter is available, check the flow of each zone.

• Record the information at least once per year on a "System Inspection Checklist" (an example is provided - click here).

CALCULATING PRECIPITATION RATES:

• Method 1: See the "Techline CV Application Rate Tables" - click here.

• Method 2: If there is some variation in your design, (for instance, when we had to decrease the distance between the rows in our earlier example) then rely on the formula below.

CAUTION: Though the precipitation rates of rotors, fixed sprays and Techline CV can be very close in many situations, we do not recommend tying dripperline into spray or rotor zones. Techline CV has an irrigation application rate efficiency greater than sprays or rotors. Even when calculations make it appear that the application rates are the same, a Techline CV zone will actually be delivering more water since none of it is evaporating or landing where it can't be used.