Design Guide

■ Step 8: Locate and size both the supply and flush manifolds in each
zone. Both manifolds should be sized to accommodate the
entire flow of the zone in GPM. (For details, refer to the Toro
Technical Data Book, Form No. 490-1737).
■ Step 9: Determine the number and location of the flush caps for
each zone at a minimum of 10 PSI. One flush cap is required
for each 15 gallons per minute of zone flow. Place the flush
caps at the hydraulic center of the flush manifold(s) (see
details 15 and 16, p. 30).
■ Step 10: (Subsurface installations only) Calculate the total number of
air/vacuum relief valves from the following table.
One air vacuum relief valve is required per footage
length indicated in the chart above. For example, two
air vacuum relief valves are needed for 1,500’ of
dripline with 0.5 GPH flow and 12” emitter spacing.
Place air vacuum relief valve(s) at the highest point(s) of each
zone. Using an air vacuum relief lateral, connect the air
vacuum relief valve to all dripline laterals within the elevated
area (see details 15 and 16, p. 30). If the supply and flush
manifolds are at the same depth as the dripline, and are at
the highest point in the zone, they can be used as the air
relief lateral.
Landscape Dripline Design _____________________________________________________________
■ Typical Design Procedures
NOTES:
1⁄2” AIR VACUUM RELIEF VALVE (Item No. T-YD-500-34)
Dripline Nominal Flow 12” Emitter Spacing 18” Emitter Spacing
DL2000 0.5 GPH 750’ 1,125’
DL2000 1.0 GPH 390’ 585’
TABLE 2.8
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