Learn irrigation then buy a kit
HOME

RAINO IRRIGATION COMPANY
Parolical,Kottayam-686562,Kerala, ,
Phone:-0481-2792365
PREVIOUS
GO TO MAIN
NEXT
 
IRRIGATION  SYSTEM
    (FROM USA)  DEALER   See Demo
                 
CLIMATE P.E.T. TABLE "A"
TABLE "A" P.E.T.
*Climate
Inches Daily

Cool Humid
.10-.15
Cool Dry
.15-.20
Warm Humid
.15-.20
Warm Dry
.20-.25
Hot Humid
.20-.30
Hot Dry
  .30-.45
(Worst Case
PLANT FACTOR TABLE "B"
TABLE B PLANT FACTOR

Plant
Factor
Mature Tree
.80
Vines & Shrubs
(over 4 ft.)
.70
Small Shrubs
(under 4 ft.)
1.00

Arid Climate
Native Plants
.35

Climate

Decimal Equivalent

Warm/Hot Dry
0.85
Moderate
0.90
Humid
0.95
DRIP IRRIGATION FREQUENCY*
(Rough Guideline for Maximum Intervals)

Plant Type
Frequency

Small shrubs, vines
2-3 Days
Large shrubs, small trees
3-4 Days
Medium to large trees
5-6 Days
SOIL TYPE TABLES
AREA WETTED PER EMITTER

Soil Type

Area in
Sq. Ft.
Diameter Range in Feet
Sandy
(coarse soil)
5-21

2.5-5

Loan
(medium soil)
21-65

5-9

Clay (fine soil)
65-161
9-14+
TABLE I
No.of Outlets

Factor

No.of Outlets

Factor

No.of Outlets

Factor

1
1
5
.380
30
.350
2
.512
10
.365
40
.349
3
.434
15
.357
50
.348
4
.405
20
.354
100
.347
TABLE II
Friction Loss Chart for 1/2" Class 315 Pipe
(Loss in PSI per 100' of pipe at flows shown)
Flow In G.P.H.

Loss In P.S.I

Flow In G.P.H.

Loss In P.S.I

Flow In G.P.H.

Loss In P.S.I

15
.017
70
.29
200
2.00
20
.028
80
.37
220
2.39
25
.043
90
.46
240
2.82
30
.06
100
.56
260
3.26
35
.08
120
.78
280
3.73
40
.10
130
.90
300
4.26
45
.13
150
1.18
320
4.78
50
.15
170
1.48
340
5.34
60
.22
180
1.65
360
5.97
Summary

Now that you are familiar with the various segments of the drip irrigation system design process, here is an outline of the steps in order.

1. Obtain climate and site data.

2. Calculate the gallons per plant required per day for each size plant on (or to be planted on) the project.

3. Determine the number of emitters for each plant size.

4. Space the emitters for each plant.

5. Select the emitter flow rates and establish the running time per day.

6. Circuit the emitters into valve groups.

7. Select either pipe or tubing as the circuit lateral and calculate friction loss and pressure requirement.

8. Select control head components and make final loss and pressure calculations to provide proper flow and pressure to the circuit.

9. Because steps one through five are for all the emitters and plants on the project, complete steps 6 through 8 for all other circuits in the drip system.


Formulas & Tables
Gallons Per Plant Per Day = .623 x plant area x plant factor x P.E.T.
                                          The decimal equivalent of drip irrigation efficiency for the given climate type.

Plant Area Formula
Step 1. Measure the diameter of the canopy of the plant from one edge of the drip line across to the opposite edge.
Step 2. Multiply the diameter measurement times itself (diameter squared).
Step 3. Multiply your previous answer by .7854 and you have the plant area number in square feet. For example, a 15 foot diameter tree calculation would be:
15' x 15' x .7854 = 176.71 square feet.

Emitter Per Plant Formula
Number of Emitters Per Plant
                                      The Formula
Emitter #= Area per plant x % to be wetted (as a decimal)
Area wetted per emitter




















*"Cool" equals under 70degree F as an average midsummer high. "Warm" equals between 70 degree and 90 degree F as mid-summer highs. "Hot" equals over 90 degree F."Humid" equals over 50% as average mid-summer relative humidity (dry=under 50%)
DRIP IRRIGATION EFFICIENCY TABLE
DRIP IRRIGATION EFFICIENCY*












Note: "Moderate" refers to the cool but dry climates.
*Efficiencies when surface wet spot per emitter does not exceed two feet in diameter.















*Always consider climate/soil/root depth data when establishing watering frequency for the various plants on your project. The goal is to maintain optimum levels of subsurface moisture for the plant root zone.
If excessive drying, run off or puddling occur, adjust the watering time and interval to eliminate the problem and still meet the plant water requirement.