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Group Title: Circular - University of Florida Institute of Food and Agricultural Sciences ; 434
Title: Handbook of irrigation tables and useful formulas
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00067094/00001
 Material Information
Title: Handbook of irrigation tables and useful formulas
Series Title: Circular
Physical Description: 17, 1 p. : ill. ; 23 cm.
Language: English
Creator: Harrison, D. S ( Dalton Sidney ), 1920-
Overman, Allen R., 1937-
Florida Cooperative Extension Service
Publisher: Florida Cooperative Extension Service
Place of Publication: Gainesville Fla
Publication Date: 197-
 Subjects
Subject: Sprinkler irrigation -- Tables   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: Dalton S. Harrison and Allen R. Overman.
General Note: Cover title.
General Note: Chiefly tables.
General Note: "10-10M-77"--p. 18
Funding: Circular (Florida Cooperative Extension Service) ;
 Record Information
Bibliographic ID: UF00067094
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 20570267

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Full Text





HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida





Circular 434


~ _-7
"--


Handbook of Irrigation Tables

and Useful Formulas
Dalton S. Harrison and Allen R. Overman

Professor (Agricultural Engineer) and Associate Professor (Associate Agricultural Engi-
neer), Department of Agricultural Engineering, IFAS, University of Florida, Gainesville.


Florida Cooperative Extension Service
Institute of Food and Agricultural Sciences
University of Florida, Gainesville
John T. Woeste, Dean for Extension


Li









Table of Contents


Pressure Loss in Aluminum Irrigation Pipe, Table 1 page 2
Pressure Loss in Asbestos-Cement Irrigation Pipe, Table 2 page 3
Pressure Loss in PVC (125 and 160 psi rated) Irrigation
Pipe, Table 3 page 4
Pressure Loss in Ordinary Rubber Hose, Table 4 page 5
Pressure Loss in Valves and Fittings, Table 5 page 5
Pressure Loss Through Water Meters, Table 6 page 6
Quantity of Water Available from a City Service Line,
Table 7 page 7
Irrigation Rate for Traveling Sprinklers (guns), Table 8 page 8
Depth of Water applied by Traveling Sprinklers (guns),
Table 9 page 9
Application Rate For Planning Irrigation Systems Table 10 page 10
Precipitation Rate Necessary for Cold Protection, Table 11 page 11
Electric Motor Data for Irrigation Pumping, Table 12 page 12
Conversion Factors, Table 13 page 13
Conversion of Metric Units To English Units, Table 14 page 14
Performance Characteristics and Speed of Operation
(pumps) page 15
Determination of BHP, Pumping Rate and Application
Rate page 16
Estimated Flows From Pipes, Fig. 1 page 17













INTRODUCTION


This handbook has been assembled for use by engineers and
others concerned with design, installation and operation of sprink-
ler irrigation systems.
Particular emphasis has been given to estimation of pressure
loss in pipes, selection of pumps and calculation of application
rates. Conversion factors have been included to aid in calculation
of standard units and for converting between English and metric
units.
Selection of sprinkler heads and nozzles has not been included
since these are adequately covered in tables provided by the
manufacturers of commercial units.
Many of these contributions have been, and are in existence in
numerous periodicals and handbooks. They are simply condensed
under one cover for easy, quick reference.













TABLE 1. PRESSURE (FRICTION) LOSS, IN FEET PER 100 FEET, FOR
PORTABLE ALUMINUM IRRIGATION PIPE WITH COU-
PLINGS. (BASED ON SCOBEY'S FORMULA Kg = 0.40, AND
30-FT. PIPE LENGTHS).*



Pipe Diameters
Gallons
Per 3-in. OD 4-in. OE 5-in. OD 6-in. OD0 7-in. OD 8-in. OD 10-in. OD
Minute 2.914 ID 3.906 It 4.896 ID 5.884 ID 6.872 ID 7.856 ID 9.818 ID


.658
1.006
1.423
1.906
2.457
3.073
3.754
5.307
7.113
9.169
11.47
14.01
16.79
19.81
23.06
26.55
30.27
34.22
38.39
42.80
47.43
52.28


.157
.239
.339
.449
.584
.731
.893
1.263
1.693
2.182
2.729
3.333
3.996
4.713
5.488
6.316
7.203
8.142
9.137
10.18
11.29
12.44
13.65
14.57
16.23
17.59
19.01
22.79
26.88
31.30
36.03
41.08


.150
.193
.242
.295
.417
.560
.721
.967
1.102
1.321
1.558
1.814
2.089
2.381
2.692
3.020
3.366
3.731
4.113
4.513
4.930
5.364
5.815
6.284
7.532
8.886
10.35
11.91
13.58
15.35
17.22
19.20
21.28
23.45
28.11
31.75


.120
.170
.227
.293
.366
.448
.537
.633
.737
.849
.967
1.094
1.227
1.368
1.516
1.671
1.833
1.988
2.179
2.363
2.554
3.060
3.611
4.204
4.839
5.517
6.237
6.999
7.801
8.645
9.530
11.42
13.58
15.69
18.06
20.59
23.28
26.12


.209
.251
.296
.344
.397
.452
.511
.573
.639
.708
.781
.857
.936
1.019
1.104
1.193
1.430
1.687
1.965
2.262
2.520
2.915
3.271
3.646
4.041
4.454
5.338
6.298
7.333
8.441
9.264
10.88
12.21
13.61
15.08
16 62


.235
.265
.298
.332
.368
.399
.445
.486
.529
.573
.620
.742
.876
1.020
1.174
1.339
1.513
1.698
1.893
2.097
2.312
2.771
3.269
3.806
4.382
4.996
5.648
6.337
7.064
7.829
8.630


.136
.149
.163
.177
.192
.208
.249
.294
.342
.394
.449
.507
.569
.635
.703
.775
.929
1.096
1.277
1.470
1.675
1.894
2.125
2.369
2.625
2.894


*From SPRINKLER IRRIGATION, 3rd Ed.


.6 62 8e630














TABLE 2. PRESSURE LOSS IN ASBESTOS-CEMENT IRRIGATION PIPE
(psi per 100 feet of Pipe). C=140.


PIPE SIZE
Il ow Flow
gpm 2 2-1/2 3 4 6 8 10 pm
40 1.5 .53 .21 .06 40
45 1.9 .70 .27 .07 45
50 2.2 .80 .33 .08 50
60 3.2 1.1 .45 .11 60
75 4.9 1.7 .69 1.6 75
100 2.9 1.1 .28 .04 100
120 4.2 i.6 .39 .06 120
150 6.5 2.5 .60_ .09 150
200 4.2 1.0 .14 200
250 6.4 1.5 .22 250
300 2.2 .31 .08 300
350 2.9 .40 .10 350
400 3.7 .52 .13 400
450 4.6 .64 .16 450
500 5.6 .78 .19 .07 500
550 .93 .23 .08 550
600 1.1 .27 .09 600
650 1.3 .31 .10 650
700 1.5 .36 .12 700
750 1.7 ,41_ .14 750
800 1.9 .46 .16 800
850 2.1 .51 .17 850
900 2.3 .57 .19 900
950 2.6 .63 .21 950
1000 2.9 .70 .23 1000
1200 .97 .33 1200
1500 __ 1.5 .50 1500
2000 NOTE: Values below dotted lines ?.5 .86 2000
3000 are at velocities over 5 ft. per 1.8 3000
4000 second and should be selected with caution 3.1 4000

The values in this table are based on William & Hazen formula, coefficient of
flow C = 140 which is commonly used by engineers for design purposes and
allows some factor of safety for plastic, asbestos-cement, and cement lined
pipe.








TABLE 3. PRESSURE LOSS IN PVC PLASTIC IRRIGATION PIPE (125 and 160 psi rated) (psi per 100 feet of pipe, C=150)
PIPE SIZE
1/2" 3/4" "1 /4" 1/2" 2" 2 1/2" 3" 4"



S3.4 4.4 .3 .43 .3 .
z U) >. U) > U) t 0) 4- 40 4 4. 4- 4-4 4-

8 6.30 )9.87 3.78 2.84 2.29 .84 1.39 .24 1.06 .13 0 w4 .*68 .04 a) W c w4 U 4- w
040>0 0.~0. >0. P..". $4 >0 P.r 0. -
410 > > N P, > r P4 P A, C1 > 14 C11 Q _
5 3.94 4.14 2.36 1.19 1.43 .35. .87 .10 .67 .05 ______ _____ -
6 4.73 5.80 2.83 1.67 1.72 .49 1.04 .14 .80 .08
8 6.30 9.87 3.78 2.84 2.29 .84 1.39 .24 1.06 .13 .68 .04
10 7.88 14.91 4.72 4.29 2.86 1.27 1.74 .37 1.33 .20 .85 .07 .58 .03
15 7.08 9.08 4.29 2.68 2.61 .78 2.00 .41 1.27 .14 .87 .05
20 9.44 15.46 5.72 4.57 3.49 1.33 2.66 .70 1.70 .24 1.16 .09 .78 .04
25 7.15 6.90 4.35 2.01 3.33 1.06 2.12 .36 1.45 .14 .97 .05
30 8.58 9.67 5.22 2.81 4.00 1.49 2.55 .50 1.74 .20 1.17 .08
35 6.10 3.74 4.66 1.98 2.98 .67 2.03 .27 1.35 .10
40 6.95 4.79 5.33 2.54 3.40 .86 2.32 .34 1.56 .13 .94 .04
45 6.00 3.16 3.84 1.06 2.61 .42 1.75 .16 1.06 .05
50 6.66 3.84 4.25 1.29 2.90 .51 1.95 .19 1.18 .06
60 8.00 5.38 5.10 1.81 3.48 .72 2.33 .27 1.41 .08
70 9.32 7.15 5.95 2.41 4.06 .96 2.72 .36 1.65 .11
80 6.80 3.08 4.64 1.23 3.11 .46 1.88 .14
90 ______ 7.65 3.84 5.22 1.53 3.50 .58 2.12 .17
100 8.50 4.66 5.80 1.85 3.89 .70 2.35 .20
125 10.60 7.04 7.25 2.80 4.86 1.06 2.94 .31
150 8.80 3.93 5.81 1.48 3.53 .43
175 10.15 5.22 6.81 1.97 4.11 .58
200 7.78 2.60 ". .2.&
225 8.75 3.17 5.29 .92
250 9.73 3.81 5.88 1.12
275 10.70 4.55 6.46 1.33
300 7.05 1.56
325 7.64 1.81

NOTE: Values below dotted lines are at velocities over 5 feet per second and should be selected with caution.







TABLE 4. PRESSURE LOSS IN ORDINARY RUBBER HOSE. (psi per
100 feet of hose).



Flow NOMINAL HOSE SIZE (IN.) Flow

pm 1/2 5/8 3/4 1 1 1 1 1 1/2 2 gpm


0.5
1.5
2.5
5
10

15
20
25
30
35

40
45
50
60
70

80
90
100
125
150

175
200
225
250
275

300
325
350
375
400


1.01
2.58
9.37
33.20

71.00
121.00


0.42
1.08
3.86
13.80

29.60
50.30
76.50
108.00
142.00


0.95
3.38

7.25
12.40
18.70
26.50
34.80

44.70
55.00
67.50
94.30
126.00


0.32
1.41

2.45
4.15
6.34
8.96
11.80

15.10
18.60
22.80
31.80
42.50

54.60
67.50
81.50
124.00


0.13
0.47

1.01
1.71
2.60
3.68
4.83

6.20
7.65
9.35
13.10
17.50

22.50
27.80
33.50
50.60
72.10

94.50
122.00


0.12

0.25
0.42
0.64
0.90
1.18

1.52
1.87
2.28
3.19
4.25

5.48
6.80
8.19
12.40
17.60

23.10
29.60
36.80
44.60
53.30

62.50
72.50
83.20
94.50
107.00


0.5
1.5
2.5
5
10

15
20
25
30
35

40
45
50
60
70

80
90
100
125
150

175
200
225
250
275

300
325
350
375
400


TABLE 5. PRESSURE LOSS IN VALVES & FITTINGS (In Terms of
Equivalent Length in Ft. of Standard Steel Pipe)


Pipe Globe Angle Sprinkler Gate Side Outlet Run of
Std. 45
Size Valve Valve Angle Va e Valve Std. Tee Std. Tee Elbow Elbow


1/2 17 9 2 .4 4 1 2 1
3/4 22 12 3 .5 5 2 3 1
1 27 15 4 .6 6 2 3 2
1 1/4 38 18 5 .8 8 3 4 2
1 1/2 45 22 6 1.0 10 3 5 2
2 50 28 7 1.2 12 4 6 3
2 1/2 70 35 9 1.4 14 5 7 3
3 90 45 11 1.8 18 6 8 4
4 120 60 15 2.3 23 7 11 5
6 170 85 20 3.3 33 12 17 8













TABLE 6. PRESSURE LOSS THROUGH CITY WATER METERS. (psi)


Flow METER SIZE (IN.) Flow

gpm 5/8 3/4 1 1 1/2 2 3 4 Rpm


7.2 3.1 1.1


12.3 4.1
15.0 4.9
7.2
9.8
12.8

16.1
20.0



NOTE: Greatest flow shown for each
meter is maximum safe flow capacity
for meter.


45
50
60
70
.7 80


350 Generally, it is not practical to 10.0 350
select meter size such that the resultant
400 pressure loss is greater than 10% of the 13.0 400
450 static water pressure at the main service 16.2 450
500 line. In no case should flows greater 20.0 500
than 75% of the maximum safe flow capacity
of the meter be used for irrigation design
purposes.














TABLE 7. QUANTITY OF WATER AVAILABLE FROM A CITY SERVICE
LINE


Length of Dia. of Size of gpm
Service Line (ft.) Service Line (in.) Meter (in.) available

50 3/4 5/8 10

50 3/4 3/4 12

50 1 1 18

50 1 1 22

50 1 1/4 1 30

50 1 1/2 1 35

50 1 1/2 1 1/2 45

50 2 1 1/2 60

50 2 2 75

50 3 3 160



This is intended as a guide in determining the approximate water supply
available for a sprinkler system.
This information is based on a pressure drop of approximately 10 psi from
the city main through the service line and the meter. For example, if the
static pressure in the city main is 60 psi, then a 50 ft. 1" service line with a
U" meter should be capable of delivering 18 gpm at 50 psi.
In order to assure adequate water for household needs, normally not more
than 50 to 80 percent of the available water should be used by the sprinkler
system. An automatic sprinkler system set to operate during the low demand
hours (late at night or very early in the morning) can use a higher percentage
of the total water supply available.













TABLE 8. IRRIGATION RATE FOR TRAVELING SPRINKLERS (GUNS)*



Travel Travel Lane Spacing (Feet Hours
Speed 165 200 240 270 300 330 Required
(Ft. per Min.) Acres Irrigated Per our Per 1/4 mi. run

0.4 0.09 0.10 0.13 0.15 0.16 0.18 55.0
0.5 0.11 0.14 0.16 0.19 0.21 0.23 44.0
1.0 0.22 0.27 0.33 0.37 0.41 0.45 22.0
2.0 0.45 0.54 0.66 0.75 0.82 0.90 11.0
4.0 0.90 1.10 1.32 1.49 1.65 1.81 5.0
6.0 1.36 1.65 1.98 2.23 2.48 2.72 3.7
8.0 1.81 2.20 2.64 2.97 3.30 3.63 2.7
10.0 2.27 2.75 3.30 3.72 4.13 4.54 2.2


Acres
Irrigated
Per 1/4
Mile Travel 5.0 6.0 7.3 8.2 9.1 10.0


Formulae: Acres Irrigated Travel Speed, Ft./Min. x
per Hour 726


Spacing Between Runs, Ft.


Acres Irrigated Spacing, Ft.
per Mile Travel 33

Hours Required 22
per % Mile Travel Travel Speed, Ft./ Min.


*From L. R. Nelson Mfg. Co. Traveling Sprinkler System Planning Guide.













TABLE 9. DEPTH OF WATER APPLIED BY TRAVELING SPRINKLERS
(GUNS), IN INCHES.*


Spacing
Sprink- Between
ler Travel TRAVEL SPEED FEET ER MINUTE
gpm Lanes Ft. 0.4 0.5 1 2 4 6 8 10

100 165 2.4 1.9 1.0 5.0 0.24 0.16 0.12 0.09
200 165 4.9 3.9 2.0 1.0 0.5 0.32 0.24 0.19
200 4.0 3.2 1.6 0.8 0.4 0.27 0.20 0.16
300 200 6.0 4.8 2.4 1.2 0.6 0.40 0.30 0.24
270 4.4 3.6 1.8 0.9 0.4 0.30 0.22 0.18
400 240 6.7 5.3 2.7 1.3 0.7 0.44 0.33 0.27
300 5.3 4.3 2.1 1.1 0.5 0.36 0.27 0.21
500 270 7.4 6.0 3.0 1.5 0.7 0.50 0.37 0.29
330 6.1 4.9 2.4 1.2 0.6 0.40 0.30 0.24
600 270 8.9 7.1 3.6 1.8 0.9 0.6 0.45 0.36
S 330 7.3 5.8 2.9 1.5 0.7 0.5 0.36 0.29
700 270 10.4 8.3 4.2 2.1 1.0 0.7 0.5 0.42
330 8.5 6.8 3.4 1.7 0.8 0.6 0.4 0.34
800 300 10.7 8.5 4.3 2.1 1.1 0.7 0.5 0.43
S 360 8.9 7.1 3.6 1.8 0.9 0.6 0.4 0.36
900 300 12.0 9.6 4.8 2.4 1.2 0.8 0.6 0.5
S360 10.0 8.0 4.0 2.0 1.0 0.7 0.5 0.4
1000 330 12.2 9.7 4.9 2.4 1.2 0.8 0.6 0.5
S400 10.0 8.0 4.0 2.0 1.0 0.7 0.5 0.4

Formula: Average Water Depth = 1.605 x Sprinkler gpm
Applied, Inches Lane Spacing, Ft. x Travel Speed, Ft./ Min.


*From L. R. Nelson Mfg. Co. Traveling Sprinkler System Planning Guide.











TABLE 10. APPLICATION RATE FOR PLANNING IRRIGATION SYSTEMS (Inches Per Hour)


Gallons Per Minute from each Sprinkler
)_________________ __________________________________________


1 12 13 14 5S


.96
.64
.48
.40
.32
.61
.43
.32
.25
.21
.24
.19
.16
.12
.15
.13
.11
.11


6 8 10 112 15 118 [20 |25 30 1 35 | 40


1.44
.96
.72
.60
.48
.92
.64
.48
.38
.32
.36
.29
.24
.18
.23
.19
.17
.16
.14
.12
.12
.10


20x20
20x30
20x40
20x50
20x60
25x25
30x30
30x40
30x50
30x60
40x40
40x50
40x60
40x80
50x50
50x60
50x70
60x60
60x70
60x80
70x70
70x80
70x90
80x80
80x90
80x100
100x100


1.60
1.20
1.00
.80
1.54
1.07
.80
.64
.53
.60
.48
.40
.30
.39
.32
.28
.27
.23
.20
.20
.17
.15
.15
.13
.12
.10


1.93
1.45
1.20
.96
1.85
1.28
.96
.76
.64
.72
.58
.48
.36
.46
.39
.33
.32
.27
.24
.24
.21
.18
.18
.16
.14
.12


2.00
1.60

2.14
1.61
1.28
1.07
1.20
.96
.80
.60
.77
.64
.55
.53
.46
.40
.39
.34
.30
.30
.27
.24
.19


2.00


2.01
1.60
1.54
1.50
1.20
1.00
.75
.96
.80
.69
.67
.57
.50
.49
.43
.37
.38
.33
.30
.24


1.81
1.50
1.20
2.31
1.61
1.20
.96
.80
.90
.72
.60
.45
.58
.48
.41
.40
.34
.30
.29
.26
.23
.23
.20
.18
.14


2.17
1.80
1.44

1.93
1.45
1.15
.96
1.08
.86
.72
.54
.69
.58
.49
.48
.41
.36
.35
.31
.28
.27
.24
.22
.17


2.40
1.92
1.61
1.80
1.44
1.20
.90
1.15
.96
.82
.80
.69
.60
.59
.52
.46
.45
.40
.36
.29


2.14
2.40
1.92
1.60
1.20
1.54
1.28
1.10
1.07
.92
.80
.79
.69
.61
.60
.53
.48
.39


S45 50


2.16
1.80
1.35
1.73
1.44
1.24
1.20
1.03
.90
.88
.77
.69
.68
.60
.54
.43


2.00
1.50
1.92
1.60
1.37
1.34
1.15
1.00
.98
.86
.76
.75
.67
.60
.48


Sprinkler
Spacing(ft,


1.87
2.10
1.68
1.40
1.05
1.35
1.12
.96
.93
.80
.70
.69
.60
.53
.53
.47
.42
.34


1 12 13 14 1












TABLE 11. PRECIPITATION RATE (INCHES PER HOUR) NECESSARY
FOR COLD PROTECTION.



Temp.
of a WIND SPEED (mph)
Dry Leaf* 0 to 1 2 to 4 5 to 8 0 to 14 1 to 22 30
oF

27 0.10 0.10 0.1 0.1 0.2 0.3


26 0.10 0.10 0.14 0.2 0.4 0.6


24 0.10 0.16 0.3 0.4 0.8 1.6


22 0.12 0.24 0.5 0.6 1.2 1.8


20 0.16 0.3 0.6 0.8 1.6 2.4


18 0.20 0.4 0.7 1.0 2.0 3.0


15 0.26 0.5 0.9 1.3 2.6 4.0


11 0.34 0.7 1.2 1.7 3.4 5.0


*The temperature of a dry leaf is the expected minimum leaf temperature on
an unprotected leaf. This will range from 1'F below air temperature on
nights with light wind to 3-4F on very calm nights.


(Data from Ext. Circular 287).












TABLE 12. ELECTRIC MOTOR DATA FOR IRRIGATION PUMPING.


REQUIRED


DIRECT CURRENT ALTERNATING CURRENT
SINGLE-PHASE 3-PHASE


Amps (hp, E, pf 746 (hp) 746 (hp) 746 (hp)
and Eff. are (E) (Eff) E (Eff) (pf) 1.73 (E) (Eff) (pf)
known)

Amps (KW,E,pf 1000 (KW) 1000 (KW) 1000 (KW)
are known) E E (pf) 1.73 (E) (pf)

Amps (KVA and E 1000 (KVA) 1000 (KVA)
E 1.73 (E)


KW (I,E, and pf (I) (E) (E) (1) (pf) 1.73 (I) (E) (pf)
are known 1000 1000 1000

KVA (I, E are known) (I) (E) 1.73(1) (E)
1000 1000


HP Output (I,E,Eff.
and pf are known)


(I) (E) (Eff.)
746


(I) (E) (pf) (Eff.)
746


1.73 (I) (E) (pf) (Eff.)
746


I- amperes
E volts
Eff = efficiency (as a decimal)
hp = horsepower


pf = power factor*
KW = kilowatts
KVA = kilovolt amperes


*That factor by which the volt-ampere product must be multiplied in order to
obtain the actual power. It is never greater than 1, and may range between
0.50 and 0.90 (depending on full, % or 'A load) for 1-100 hp rated motors.

Example: Assume a 20 hp, 3-phase, 220 v., VHS Motor with an efficiency of
88 percent and a power factor of .90 at full load, then:

Amps 746 (20) i 49
1.73 x 220 x .88 x .90









TABLE 13. CONVERSION FACTORS


LENGTH
= 0.03937 inch
= 0.3937 inch
= 39.37 inches
3.2808 feet
= 3,280.8 feet
= 5,280 feet
= 1.60935 kilometers
= 16.5 feet
= 100 links or 66 feet
= 7.92 inches

AREA
= 43,560 feet
= 3.1416 x radius2
= 1/ altitude x base


1 acre
Area of a circle
Area of a triangle


1 acre-inch
1 gallon of water


1 cubic foot of water

1 litre
1 cubic meter
Volume of a cylinder


VOLUME
= 27,154 gallons
= 231.0 cubic inches
= 0.1337 cubic foot
= 3.7853 litres
= 7.48 gallons
= 28.316 litres
= 0.2642 gallon
= 264.0 gallons
= 3.1416 x radius x height


1 cfm
1 acre-inch/hr
1 cfs or second foot (or 1 cfs)


1 gallon of water
1 cubic foot of water


Degrees C
Degrees F


1 atmosphere

1 foot of water
1 psi
1 foot of water
1 inch of Mercury (Hg)


1 horsepower

1 kilowatt


RATE OF FLOW
= 7.48 gpm
= 452.57 gpm
= 448.83 gpm
= acre-inch/hr.

WEIGHTS
= 8.326 pounds
= 62.428 pounds


TEMPERATURE
= 5/9 (F 32")
= 9/5 (C + 32)

PRESSURE
= 14.7 psi
= 33.947 feet of water
= 0.433 psi
= 2.31 feet of water
= 0.883 inches of Mercury (Hg)
= 1.133 feet of water

MECHANICAL AND ELECTRICAL
= 745.7 watts
= 33,000 foot pounds per minute
= 1,000 watts
= 1.341 horsepower


1 millimeter
1 centimeter
1 meter

1 kilometer
1 mile

1 rod
1 chain
1 link












TABLE 14. CONVERSION OF METRIC UNITS TO ENGLISH UNITS


Measure Metric Units
length centimeters (cm) x
kilometers (km) x
area hectares (ha) x
volume hectoliters (hi) x
mass metric tons x
kilograms (kg) x
yield kilograms/hectare x
metric tons/hectare x
hectoliters/hectare x
temperature centigrade (c)
pressure atmospheres (atm) x


Multiplier
0.394
0.621
2.471
2.838
1.102
2.205
0.891
0.446
1.15
9/5 x c 32
14.70


English Units
inches (in)
miles (mi)
acres (acr)
bushels (bu)
English tons
pounds (Ib)
pounds/acre
English tons/acre
bushels/acre
Fahrenheit (F)
pounds/'











PERFORMANCE CHARACTERISTICS OF CENTRIFUGAL (KINETIC) PUMPS:

The performance of a centrifugal pump varies with the speed of rotation.
The capacity or rate of flow varies directly as the change in speed; that is, if
the speed is increased by 50 percent the capacity is increased by 50 percent.
The pressure head that the pump will develop, however, varies as the square
of the ratio of the new speed to the old speed. Thus, an increase of 50
percent in the speed means that the developed head will increase/ .5. or
2.25 times.

Further, the required horsepower increases as the cube of the ratio of change.
This means that by increasing the speed by 50 percent the required horse-
power will increase (1.5\ or 3.38 times that required at the lower speed.



EFFECT OF SPEED CHANGE ON PUMP PERFORMANCE:

Theoretically, varying the pump speed will result in changes in capacity,
head and brake horsepower according to the following formulae:

rpm2 x gpm1 = gpm2
rpm2
rpm x gp = gpm

rpm22
_rp_ x H1 = H2 (in feet)
rpm1


rpm__2 x bhpl = bhp2

rpm/

If the pump is driven by a constant speed electric motor connected
directly to its shaft, the pump must turn at the same speed as the motor. The
pump speed can be changed by connecting it to the motor through an in-
direct drive or a speed change gear. This arrangement, however, provides
only a different fixed speed and not a variable speed.
When the pump is driven directly by an internal combustion engine, it is
possible to vary its speed of operation within the speed range of which the
engine is capable; however, this will often change the efficiency. Also, the
horsepower capacity of an engine varies when the rpm of the engine is
changed.






.16





Determination of Brake Horsepower required at the pump shaft:

gpm x tdh
bhp 3960 x eff = brake horsepower required by the pump. (To this must
be added the power consumed by mechanical friction
in the bearings, gears, etc. in order to arrive at the
continuous bhp required at the input shaft)

where tdh total dynamic head, gpm = gallons per minute
eff = hydraulic efficiency of the pump, expressed as a decimal



Pumping Rate Determination for Irrigation Systems:
453 x I x A
gpm HxD

where I inches of water (gross) to be applied each irrigation
A total acres to be irrigated
H = number of hours of operation per day
D number of days to complete one irrigation. (This should not
exceed 75% of the irrigation frequency.)


Pumping Rate of Permanent Systems:

Application Rate Desired (gross) gpm/acre
0.10 inches/hr 45
0.15 inches/hr 67.5
0.20 inches/hr 90
0.25 inches/ hr 112.5


Application or Precipitation Rate for Sprinkler Systems:

gpm/sprinkler x 96.3
AR = SxL

where S spacing of sprinklers along the lateral (in feet)
L spacing between laterals (in feet)

(This applies to square, rectangular, or triangular spacing.)
AR inches per hour










FIG. 1. ESTIMATED FLOW FROM PIPES.

The gpm flow from pipes may be approximated by measuring the distance
"X" in inches when the vertical distance is 12" (or 6", see note below table)
and find value in Table 15.


FOR PIPES FLOWING FULL


TABLE 15. GALLONS PER MINUTE


Dia. _Horizontal Distance ="X"
Pipe = D 12" 14" 16" 18" 20" 22" 24" 26" 28" 30"
2" 41 48 55 61 68 75 82 89 96 102
3" 90 105 120 135 150 165 180 195 210 225
4" 150 181 207 232 258 284 310 336 361 387
6" 352 410 470 528 587 645 705 762 821 880
8" 610 712 813 915 1017 1119 1221 1322 1425 1527
10" 960 1120 1280 1440 1600 1760 1920 2080 2240 2400
12" 1378 1607 1835 2032 2300 2521 2760 2980 3210 3430


APPROXIMATE FLOWS FROM PIPE RUNNING FULL
IF 6" VERTICAL DISTANCE IS USED MULTIPLY GPM BY 1.4

FOR PIPES FLOWING PARTIALLY FULL


MEASURE SX
a UJ
I 1 -------------------


"\\\
V\ \\'
v\\\


Flow from partially filled pipes.
Divide "E" by "D" for percent factor. Multiply
flow for full pipe of "D" diameter (Table 15)
by factor obtained from Table 16. E Measure
of empty portion of pipe. D -Measure of inside
diameter of full pipe.

TART.H 1


E/D Factor E/D Factor
10 0.95 50 0.50
20 0.86 60 0.38
25 0.81 65 0.31
30 0.75 70 0.25
35 0.69 80 0.14
40 0.63 90 0.05
45__ 0.56 100 0.00


Inclined Pipe


Horizontal Pipe






























Single copies are free to residents of Florida and may be obtained
from the County Extension Office. Bulk rates are available upon
request. Please submit details of the request to C.M. Hinton, Publi-
cation Distribution Center, IFAS Building 664, University of
Florida, Gainesville, Florida 32611.



10-10M-77



COOPERATIVE EXTENSION WORK IN AGRICULTURE AND HOME ECONOMICS
(Acts of May 8 and June 30, 1914)
Cooperative Extension Service, IFAS, University of Florida
and United States Department of Agriculture, Cooperating
K. R. Tefertiller, Director


This publication was printed at a cost of $722 or 7.2
cents per copy as a handbook for use by engineers
concerned with sprinkler irrigation systems.




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