Full Product Manual

Table Of Contents
Because both the EDR formula and the data in Table 6-1 are based on 100%
application efficiency, you must adjust the EDR figure you use for the application
efficiency of your system in a particular climate. To do this, multiply the EDR
figure from the table and the application efficiency (percentage) that you re-
corded on your Site Data Worksheet. The result is the “adjusted EDR.”
EXAMPLE
If you are using Landscape Dripline with 0.9 GPH emitters spaced at 18” X 18”,
the EDR from table 6-1 is 0.64 inches per hour. If the climate is warm humid,
the application efficiency will be approximately 90%.
Multiply the EDR (0.64 inches per hour) by the application efficiency expressed
as a decimal (0.90). The adjusted EDR is 0.576 or 0.58 inches per hour.
Page 44 Chapter 6
1.Calculate System Run Time
The general formula for system run time is:
Run Time Per Day = Water Requirement
Flow Rate
However, since the water requirements are measured differently, you will apply
this general formula in slightly different ways for dense and sparse plantings.
In Chapter 4, you calculated the water requirement for dense plantings in inches
per day (also see Appendix B). In order to calculate the system run time, you
must also measure the flow in inches per hour. We call this flow measurement
“Emitter Discharge Rate,” (EDR). EDR is measured in inches per hour.
The formula for determining EDR is:
EDR (inches per hour) = 231.0 q
s
l
where: q = emitter flow rate (gallons per hour)
s = emitter spacing (inches)
l = lateral spacing (inches)
Dense Plantings
Table 6-1 shows the EDR for the most common Landscape Dripline spacing
schemes. For other emission devices, calculate EDR using the formula.
TABLE 6-1: EMITTER DISCHARGE RATES (EDR) FOR LANDSCAPE DRIPLINE
IN INCHES PER HOUR*
Emitter Flow Rate
Emitter Spacing Lateral Spacing 0.6 GPH 0.9 GPH
12” 12” 0.96 in./hr. 1.44 in./hr.
18” 18” 0.43 in./hr. 0.64 in./hr.
24” 24” 0.24 in./hr. 0.36 in./hr.
*At 100% Application Efficiency
®