Irrigation Design Basics

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1. SIZE INDIVIDUAL SPRINKLER SUPPLY PIPE (LATERAL)

PIPE SIZE	MAX. GPM
16 mm	1.7
20 mm	4.0
1/2"	6.0
3/4"	8.0
1"	14.0
1-1/4"	10.0

(Total No. Sprinklers or Drip Tubes) x (Capacity in GPH) =
Total GPH

Total GPH Ö 60 = Capacity in GPM (Gallons Per Minute)

Example: (40) Sprinklers @ 19.0 GPH x 760 = Total GPH
Example: 760 GPH Ö 60 = 12.7 Total GPM

Select supply pipe size from Chart No. 1

2. SIZE DISTRIBUTOR PIPE

PIPE SIZE	MAX. GPM
3/4"	10.0
1"	14.0
1-1/4"	20.0

Add Total GPM for all sprinkler supply pipes.

Example: (2) Drip Line @ 2.5 GPM = 5.0 GPM
Example: (1) Sprinkler Line @ 4.0 GPM = 4.0 GPM
Example: Total GPM = 9.0 GPM
Select supply pipe size from Chart No. 2

3. SIZE MAIN LINE PIPE

PIPE SIZE	MAX. GPM
3/4"	10.0
1"	14.0
1-1/4"	20.0

Add Total GPM for all distributor lines

Example: (1) Distributor Line @ 9.0 GPM = 9.0 GPM
Example: (1) Distributor Line @ 7.5 GPM = 7.5 GPM
Example: Total GPM = 16.5 GPM
Select supply pipe size from Chart No. 3

4. SELECT PRESSURE REGULATOR, FILTERS AND
4. FERTILIZER INJECTOR BASED ON TOTAL
4. SYSTEM GPM IN MAIN LINE PIPE.