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Evaluation Worksheet:
Sprinkler System Information:
Inputs Shaded.
Nozzle
Size:
Lateral Spacing, feet:
(30-45 feet)
Pressure
Measurements:
First
Head(psi) Last Head(psi)
Lateral 1:
Lateral 2:
Lateral 3:
Lateral 4:
Lateral 5:
Lateral 6:
Evaluation Month:
Evaluation
Wind Conditions:
Estimated Windspeed, mph:
By using this worksheet
, you will be able to determine with reasonable accuracy the
field DU and necessary set time of your sprinkler system as currently
operated. You also can estimate the effects of any changes you
choose to evaluate. The worksheet will guide you in combining the
factors that have the greatest effects on sprinkler system DU to arrive at your systems's
DU. The field DU can then be applied to the systems's flow rate to
deteremine optimum set time. Other links are available that
deal with with sprinkler evaluations from another point of
view.
Getting Started:
Most of the necessary information to complete an
evaluation can be gathered in less than one hour by inspecting you system
in
operation. With
the
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Results:
Estimated DUcc:
Pressure Diff.
Flow Adj.:
Miscellaneous Losses
Adjustment:
Mixed Nozzles, 0-25%, 3%
Leakage, 0-10%, 1.5%
Nozzle Sand Wear, 0-5%,
1.5%
Pipe Drainage, 0-4%, 1%
Sprinklers Not Rotating, 0-2%, 0.5%
Plugged Nozzles, 0-10%, 0.5%
Total Miscellaneous Losses Adj.:
Est. Field
DU:
Est. Avg. Sprinkler Flow, gpm:
Est. Gross App.
Rate, in/hr:
Est. Net App. Rate, in/hr:
water off, use a feeler gauge or drill bit to measure nozzle orifices for
sand wear and check for mixed sizes. You will also need a gauge with a pitot
tube to take water
pressure measurements at the beginning and the end of your pipeline and
laterals. The remaining information, lateral spacing, leakage,
nonrotating sprinklers. and plugged nozzles should be readily
apparent. The only other requirements are a clipboard and a sharp
pencil.
Note: The equipment required to measure pressures at
the sprinkler head is a Pitot Tube attached to a Liquid Field Pressure
Gauge. One possible source is the Rainbird part number A90917 and
D22810, respectively. This reference is given because it is readily
available and no recommendation is intended.
September 2003
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