Landscape Irrigation

Based upon the book Rain Bird Irrigation Design

Manual

Types of Pipe

Polyethylene – PE Often used in mid-west and eastBlack Usually barbed fittings

Polyvinyl chloride – PVCMost commonly used in So. Cal.White or grayTypically glued and/or threaded fittings

Polyethylene – PE Pipe

Polyethylene – PE Pipe

Flexible, lightweightCuts easily with tubing cuttersUses barbed fittings – no glueCan be installed with pipe puller – reduces laborNot shovel- or pocket gopher-friendly

Barbed Fittings

Pipe Puller

Pipe Puller

PVC Pipe

Rigid, fairly lightweightCuts easily with PVC cutters or sawsChemically welded connectionsDurable & Buriable Resists shovels and gophersSome UV resistant

PVC Pipe Ratings

Divided into two groupsSchedule rated (Schedule or Sch)Pressure Rated (Class or Cl)Not UV resistant must be buried or painted

Schedule Rated Pipe

Thick walledSame dimensions as iron pipeUsed in pressurized main line situationsPressure ratings change as sizes changeSchedule 40 (Sch 40) (white)Schedule 80 (Sch 80) (dark gray)

Guaranteed Pressure Rating

Remember: pressure rating changes with pipe size

& larger diameter pipes sustain less pressure

Sch 40typical

forirrigatio

nuses

Schedule 80

Gray plasticThick wallsThreadableVery strongUsed as transition from valves to pipeOutside diameter same as white PVC PVC nipples typically Sch 80

Schedule 40

White plasticThinner walls than Sch 803/4” to 1-1/4” as main- or service-line (under pressure)Pipe sizes – based on O.D. – “nominal”

Pressure Rated PVC Pipe

1/2” or 1-1/2” and larger used as service-, or main-line3/4” and larger used as lateral linePressure rated instead of schedule ratedWhich means a uniform pressure rating regardless of sizeBuilt-in 2:1 safety factor for surges

Standard Dimension Ratio (SDR-PR)

The ratio of wall thickness to O.D. is same throughout each classSDR is a relationship of wall thickness to O.D. = SDR

PR = Pressure Rated

Outside Diameter

Wall Thickness

1120, 1220 – Some Data Code

Raw materials and stress 11 = Type 1 & Grade 1

Suitable for irrigation

12 = Type 1 & Grade 2Suitable for drainage

20 = material tensile strength (in 100s)

Material can hold up to 2,000 psi in pulling stress

Pressure Rated PVC PipeTypically used in landscape irrigationClass 315 (Cl 315) – rated at 315 psiClass 200 (Cl 200) – rated at 200 psiEasily cut - resists damageStrong and durable (*except Cl 125 & Cl 160 – too thin to safely use)Class 160* (Cl 160) – rated at 160 psiClass 125* (Cl 125) – rated at 125 psi

Guaranteed Pressure Rating

Pressure stays the same regardless in change of diameter or wall thickness

Pressure Rated PVC Pipe

Class 315 Main line or service line — 1-1/2” and largerLateral line — 1-1/2” and larger

Class 200 Lateral line — 3/4” and larger

ASTM

American Society for Testing and MaterialsASTM D-1785 – tests schedule rated pipeASTM D-2241 – tests pressure rated pipeSelect ONLY PVC produced under ASTM standards

Some Other Stuff

“Purple pipe” – for reclaimed waterOlson Tubing® or Funny Pipe ® – swing joints

A Review of a Few TermsCity water main Underground pipe – under streets, alleys, etc.Supplies water to houses and business

Static pressure dependent uponDistance from pumping stationAge of pipeTime of dayNumber of customers on the line

A Review of a Few TermsWater serviceBetween the home or business and the water meterUnder constant pressure Can be:

Polyethylenegalvanized steelType L copper or PVC – Sch 40 or Class 315

Covered by at least 18” of soil

A Reminder

When replacing a metal water service (galvanized or copper) for a plastic one

MAKE SURE THE HOUSE’S ELECTRICAL SYSTEM IS GROUNDED!

A Review of a Few TermsIrrigation service line – from point of connection (POC)Under constant pressureCan be: Polyethylenegalvanized steelType L copperor PVC – Sch 40 or Class 315

Covered by at least 18” of soil

Still More Terms (ad nauseam)Lateral lineCarries water from the irrigation valves to the sprinkler headsUnder pressure when valves are openTypically PVC Class 315 for 1/2” Class 200 for 3/4” and larger

Covered by at least 12” of soil

Priceless Information

The industry standard for the maximum safe velocity in feet per second (fps) through pipePlastic pipe – not to exceed 5 fpsMetal pipe – not to exceed 7.5 fps

Still More Terms (ad nauseam)

Threads on pipe and fittingsFemale threads – on inside of fittingsMale threads – on outside of pipe or fittings

Fittings

PVC Slip Fittings

Sch 40 PVCWhite plastic Slip by slip fittings (SxS) gluedaka (socket x socket) configurationI.D. of fitting matches O.D. of corresponding pipe size

PVC Slip Fittings

Common Sch 40 fittings

Tee SxSxS

divides flow of water two

ways

Coupling SxS

Connects two pieces of pipe

90º Elbow (Ell) SxS

Changes direction of water

PVC Slip x Thread FittingsSchedule 40 Slip by thread fittings (SxT) or (SxMIPT or SxFIPT)Glued joint and threaded joint on same fittingThreaded ends same size and type as metal pipe threads – tapered threadI.D. of fitting matches O.D. of corresponding PVC pipe size

PVC Slip x Thread Fittings

SxT 90º Elbow (Ell)

Female Adapter SxT

Male Adapter SxT

90º Street Elbow SxT Tee SxSxT

PVC Thread x Thread FittingsSchedule 40 Thread by thread fittings (TxT) (MIPT or FIPT)Two threaded joints on same fittingThreaded ends same size as metal pipe threadsI.D. of fitting matches O.D. of corresponding pipe sizeNot commonly used in PVC

PVC Pipe Nipples

Pipe threaded at both endsPVC nipples typically Sch 80Used to make transition from thread to glue

TxT Close Nipple

TxT Nipple

Slip Fix

An irrigation miracle!Used to repair broken PVC linesTypically SxSTelescopes to extend

Compression Fittings

Used to connect PVC to metal pipeSlips over and tightens with compression washers

Compression Couplings

Compression Tee