Landscape Irrigation:Chpt.3 Irrigation Components
Matched Precipitation- Most sprinklers available today have matched precipitation which allow for uniform distribution of water:
" " means that all sprinkler heads within a watering zone will produce similar precipitation rates, regardless of the pattern (or arc) they cover. For example, if a full circle (360 degree) head delivers 4 gallons per minute (GPM), then a half circle (180 degree) head of the same type will produce half that amount, or 2 GPM. The full circle head has twice as much area to cover, therefore, it needs to put out twice the amount of water as the half circle head
Spray heads: Center strip pattern nozzle:
(CST) 15 ft radius
Spray heads: Left corner strip pattern nozzle :
(LCS) 4' X 15' Radius
Spray heads: Right corner strip pattern nozzle:
(RCS) 4' x 15' Radius
Rotary heads: Multi-stream rotary heads- (special application)
(such as the MP Rotator) Are gaining increased popularity for some applications because of their - uniformity - flexibility in design - water-savings and - cost
Integrated emitters: A general guide to capillary action-
(the main effect distributing water horizontally through the soil) -is as follows: Average Horizontal water movement (+/−) Sand-------1-3---feet Loam------2-4----feet Clay-------3-6----feet
Spray heads: The most common spray nozzle radii are-
* 5' * 8' * 10' * 12' and * 15 ft In fixed arc patterns that include * Full circle (360 degrees) * Three quarter (270 degrees) * Two-thirds (240 degrees) * Half circle (180 degrees) * One-third (120 degrees) and * Quarter circles (90 degrees) Toro spray heads in pic
In order to protect against backflow, backsiphonage and backpressure one or more of the following 5 methods are utilized:
* Air gap * Atmospheric vacuum breaker (AVB) * Pressure vacuum breaker (PVB) * Double check assembly (DCA) * Reduced pressure principle device (RP) These are all mechanical devices which physically block any potentially harmful element flowing back into the potable water supply
Rotary Heads: Most units are available in-
* Full circle (360 degree) and * Adjustable models which go from +/−30 to near 360 degrees
Spray heads: The advantages of plastic pop-ups-
* Higher pop-ups * Better seals * Filter screens and * Better nozzle selection Example: Rain Bird 4" quarter circle pop-up spray head
The most common types of rotary heads are the:
* Impact ( or impulse), * Gear and ball driven heads
Electric valve how it works:
* In the off position - water (from the inlet inside) fills both the bottom/a top chamber - the surface area above the diaphragm is approximately 2 1/2 times larger than the pressurized surface area below the diaphragm * This keeps the valve closed - because there is a greater force above the diaphragm than below it * To activate the valve - an electrical impulse is sent to the valve solenoid (usually located on the downstream side of the valve) * Creating an electro-magnetic field - which lifts the plunger inside the solenoid * Water in the top chamber is released - allowing the valve to open/water to flow * When the electrical impulse is shut off - the solenoid drops the plunger down over the outlet port * Causing the top chamber to fill with water again and - close the valve * The diaphragm spring - assists in the closing sequence Example: pic of how it works
PVC pipe is classified as either:
* Schedule or * Class pipe
There are many different types of sprinklers heads available from a number of manufacturer's. However, most will fall under one of these 4 Categories:
* Spray * Rotary * Bubblers (including drip irrigation) * Micro Sprays
Spray heads: Common strip heads include-
* Various end strip nozzles * Center strip nozzles and * Side strip nozzles Example: see chart →
PVC is solvent welded together:
* many contractors mistake this process for glueing - however, this is incorrect, as the solvent chemically welds the pipe together * All new irrigation systems that are installed using PVC pipe/fittings - shall be primed with a colored primer prior to applying the PVC cement in accordance with - the Uniform Plumbing Code or - the International Plumbing Code * Some of the larger PVC piping is not solvent welded and - incorporates a gasket in the bell end that prevents leakage when pressure is applied
There are 2 basic types of drip irrigation:
1). Point emitters 2). Integrated emitters
Irrigation pipes here in Tx can legally be buried
4" to 6" because our soil doesn't freeze
Because drip irrigation flow is so low/the orifices extremely small:
A filtering system is Mandatory to assure the drip system stays in good working order. Depending on your individual site requirements/which product you install - a pressure regulator (to lower pressure), - a flush valve (to flush debris from the lines) - and /or an air relief valve (which eliminates any vacuum that could result in debris or contaminants being sucked into the piping system) - may be Required for efficient operation * For drip that is installed on the surface, using mulch not only improves the appearance of your home but also holds in moisture example: pressure regulator/filter
Greater pressure at the heads will result in:
A greater flow, and throw, of each head (as seen in the sample nozzle performance chart) This is acceptable if calculated into the design.
Spray heads: Diffusion of spray nozzles is accomplished by-
A small screw located in the top of the nozzle. Diffusion should be limited to approximately 25% of the radius of the nozzle. For example, a 12 ft nozzle should not be diffused down more than 3 feet, or 25% of the 12 ft radius. Diffusing the nozzle more than 25% may affect uniformity due to radius fluctuations. Example: Toro anatomy of top view of pop-up
Valves: Angle valve-
A valve with its outlet at a 90-degree angle from its inlet
What is an air gap? Look at the sinks in your house, do you recognize the air gap?
ANSWER: An air gap is a vertical, physical separation between the end of a water supply outlet and the flood-level rim of a receiving vessel. This separation must be at least twice the diameter of the water supply outlet and never less than one inch. An air gap is considered the maximum protection available against backpressure backflow or backsiphonage but is not always practical and can easily be bypassed.
Rotary heads: Multi-stream rotary heads include the following-
Advantages: * Retrofit on any conventional spray body or shrub adapter * Provide low application rates to reduce run-off in tight soils or on slopes * Provide matched precipitation rates & high uniformity * Provide solutions for low pressure problems in repair situations * Reduced installation costs
Check Valve:
Allow water to travel in only one direction. * Water traveling in the correct direction will - move the rubber disc or hinge out of the way * When the flow is shut off - gravity or a spring will force the rubber disc or hinge to close, preventing any backflow " " are typically used on backflow prevention devices
Solid state controllers:
Although more susceptible to electrical surges * Are State-Of-The-Art when it comes to programming flexibility * Most units are compact/easy to install * Most controllers have battery back-up in case of power failure - while some of the latest controllers have a "non-volatile" memory which retains memory in the event of a power failure, even without a battery back-up * The biggest drawback - when introduced on the market was the difficulty in programming the controller - especially to home owners who had a contractor install their sprinkler system * However, in recent years - user-friendly models have become the standard Example: modular solid state controller
Air Gap:
An approved " " is the unobstructed vertical distance through free atmosphere -between the lowest point of a water supply outlet/the flood level rim of the fixture or assembly into which the outlet discharges * These vertical, physical separations must be at least twice the diameter of the water supply outlet - but never less than 1 inch For example: A common " " would be that of a typical household sink in which there is a gap between the water in the sink/the faucet above it. Picture of diagram→
Rain sensors:
Are among the most popular/are designed to shut the system off in the event of a predetermined amount of rain -thus not over-watering the plant material & wasting water. * These are very effective devices; however, - like most sensors, they have some drawbacks for instance, - if the rainfall is too intense or quick/precipitation exceeds the infiltration of the soil, most of the water runs off before it has the chance to benefit the plant material while the rain sensor proceeds in turning off the system * A " " that allows for various rain adjustments is a better choice
Pressure compensating heads, nozzles/filters:
Are another means that control the water pressure * Adjusting the flow control on the valves -offers another method in which to control excessive pressure note to self: - to conform with water conservation issues, pressure regulation should be required where the operating pressure at the head exceeds the manufacturers recommended range of operation
Rotary heads: types The pop-up impact models-
Are concealed in large canisters which are installed at ground level. Because of their large sizes, some pop-up canisters are equipped with side inlets - this minimizes the trenching depth, but creates a more difficult/timely repair if replacement is needed Because of the constant motion/force, above ground models should be mounted on rigid risers Although excellent heads The drawbacks of impact heads include * their large size when installing and * the annoying noise made while in operation.
Drip irrigation: Integrated emitters-
Are integrated into the - flexible polyethylene piping from the manufacturer - they are usually spaced * 12 inches * 18 inches, or * 24 inches apart
Hydraulic valves/how it works:
Are normally open valves * They utilize water instead of electricity - to activate the opening/closing of the valves * Water is supplied to top chamber of the valve by a water tube - hence, equalizing the pressure/allowing the diaphragm to close * To open the valve - water in the top chamber is allowed to bleed off through the tubing * Although these valves are not as common - if you've been in industry for some time, you will run into a few hydraulic systems
Micro Spray Sprinklers:
Are similar to spray heads except * their throw is considerably less -(approximately 3-6 feet) and * they have very low flow rates - sometimes expressed in GPH (gallons per hour) * because of their low volume - controlling the pressure will help prevent the spray turning to fine mist/causing an evaporation problem
Evapostranspiration (ET) based controllers:
Are state-of-the art technology * Regulate the water scheduling based on - local ET rates that are programmed into (or acquired) by the controller * This allows for precise watering to replenish water that is lost through evaporation & transpiration ( water the plant actually uses) * Due to modern technology, advanced controllers with capability of some central control units are now affordable to the average homeowner note to self: Good for water restrictions, so if you get water on days your restricted you could get a ticket. But if you have this you can get an exemption/not get a ticket
Globe Valves:
Are used as control valves in * Manual/automatic irrigation systems * While they can be of angle or straight-thru configuration - the angle design offers less friction loss - the manual globe valves utilizes a rubber disc seat resulting in minimal wear under heavy use * It also allows for a precise shut-off - without leakage * Most remote control valves are - configured on the globe valve design Example: Electric globe valve (straight-thru)
Spray heads: In some parts of the country, Copper risers- (although more expensive)
Are used because they tarnish/blend with the landscape
PVC: The wall thickness increases
As the size of the pipe increases
Controllers:
Automated irrigation systems are very important when it comes to water conservation * With current technological advances - controllers have expanded from * very simple mechanical devices to * very sophisticated central control units that operate numerous satellite units in the field which are used for - large city projects - parks - athletic fields - golf courses etc * Wireless automatic systems are emerging & * computer irrigation controller interface hardware/software solutions are becoming the standard
The Hybrid Solid State Controllers:
Available in many models/are extremely popular * These controllers which includes some of the ET-based controllers have all the modern - circuit boards - LCD readouts/buttons * However, incorporate these features with a conventional type selector wheel for ease of programming * This controller is the Best choice for most homeowners Example: Rain bird LCD readouts and has wifi capabilities very neat
The actual head pressure should not:
Be much higher than the optimum head pressure or pressure range stated by the manufacturer.
Galvanized pipe:
Before plastic came into its own, some early sprinkler systems were constructed with this steel pipe * Although very strong/acceptable in its time, there were several disadvantages - corrosion over time would close up the inside diameter of the pipe - as the systems aged, the flow decreased until there was insufficient water to operate the system - the outside would, rust/deteriorate, eventually leaving holes/cracks in the pipe - installation/repairs were difficult, time consuming/costly Example: galvanized risers for sprinklers starting to rust
There are several types of rotary heads available:
Both in pop-up and above ground configurations, * the latter being mounted on risers to water large areas of shrubs/ground cover.
Spray heads: Poly risers can break easier-
But the repair is quick/inexpensive.
Backsiphonage:
Caused by a negative or sub-atmospheric pressure * On a sprinkler system, when the pressure on the supply side drops due to an event, - such as a break in the city main, it can cause water to be sucked (or siphoned) back into the potable water supply - The fire department can also induce this situation by pumping large volumes of water, - thus creating a backsiphonage (negative pressure)
Type L :
Copper with medium wall
Type M:
Copper with thinnest wall
Integrated emitters- Selection is:
Dependent on factors such as: * plant material * soil type and * slope The tighter the soils, such as - clay, will allow the water to spread out farther, so greater spacing between emitters is acceptable - sand, will absorb water quicker/would require closer spacing
Don't get precipitation rate inches/hour confused with:
Flow rate
Rotary heads: Gear driven heads- Unlike spray heads you have to match the precipitation rates yourself by selecting appropriate nozzle sizes.
For instance, - if you select a 6 GPM nozzle for the full (360 degree) heads, - your selection for the half (180 degree) heads will need near 3 GPM nozzle - quarter (90 degree) heads will need near 1.5 GPM nozzle Most manufacturers, the nozzle radii will vary considerably between the full, half/quarter nozzles. Provided there is sufficient pressure, a larger stream of water will carry farther than a smaller stream of water. Also, the spacing of heads in the design is - based on the head with the shortest throw so all heads will have head-to-head spacing. The dependability/its quiet operation make the " " one of the most popular heads for large turf/shrub areas. Some units (producing large GPM) have the control valve located in the head. These " valve-in-head" models are usually located on very large projects such as golf courses.
Average operating pressure for rotary heads:
Generally range from 25 to 90 PSI The radius throw ranges from about - 20 feet - to well over 100 feet in the larger, high GPM units Typically installed on * Athletic fields * Parks and * Golf courses The gallons per minute vary from - One or - Two to - Around 90 GPM
Schedule PVC:
Has a higher pressure rating than Class PVC in the smaller sizes * Schedule 40 has the same physical dimensions as that of steel pipe * Schedules 40 and 80 are most common * The wall thickness increases as the - schedule number increases * Because of schedule 40's higher pressure ratings (over class pvc pipe) - in the smaller sizes (up to 1 1/2") - irrigators sometime prefer schedule 40 pipe on the main line - where there is constant water pressure
Rotary heads: Gear driven heads-
Have a slower, constant rotation that is achieved by water passing through a series of gears within the head. -Like impact heads, both pop-up and -riser mounted versions are available * the pop-up models have retraction springs -which seat the head when the water is shut off Diffusion is generally achieved by adjusting a small screw (in the top of the head) down into the stream of water - most units come with a nozzle tree which offers an assortment of nozzles with varying GPM's
Schematics of a gate valve:
How it works→
Designation on each strand of PVC pipe:
Identifies the * type * grade and * hydrostatic design stress For example: PVC 1220 denotes the following: PVC pipe, type 1, grade 2, 2000 PSI hydrostatic design stress
The advantages of using Rotary heads:
Include: * fewer heads * fewer fittings * less pipe * less trenching * reduced labor cost and * quicker installations
Advantages of Drip irrigation:
Include: * minimal weed growth * healthier plant growth * water saving * no unsightly sprinkler heads
Both adjustable and fixed pressure regulators are available:
Installing a " " up-line from all of your control valves would lower the pressure for all the sprinklers in a given irrigation system * An in-line " " , installed right after a control valve, would be the right choice - if only you want to lower the pressure on one zone, such as a drip zone note to self: the adjustable pressure regulators are not common. However, the fixed pressure regulators are more common to see Example: Inline pressure regulator for irrigation and sprinkler systems
Quick-Coupler Valves:
Is a constantly pressurized valve * Set vertically in the ground to provide supplemental water - usually to a remote area * It may have a vinyl or metal cover * A spring-loaded disc keeps the valve shut - while not in operation * To operate, a coupler key (sometimes called a quick coupler key) - is manually inserted/turned one quarter revolution * The coupler key may have a sprinkler (generally a rotor head) or - a hose bib attachment * Typically used on large irrigation systems - such as parks/athletic fields where maintenance personnel are available to utilize them * Be careful to avoid unwanted - cross-connection since parks & athletic fields are very likely to be using reclaimed water
Valves: Gate valves-
Is a straight-thru valve - typically used as a main turn off for the irrigation system * because of its design - very little friction loss is encountered * not intended for frequent use - as in the case of a zone (or section) valve * Regular use will create wear on - the metal to metal seat/eventually leak
Bubblers and Drip Irrigation: A Bubbler: flood bubbler-
Is a type of sprinkler head designed to irrigate level/defined shrub beds - it is mounted on a riser and - puts out a very small-umbrella-shaped adjustable flow of water - output is usually +/− 0.5 to 4 GPM
Backflow:
Is an unwanted reversal of the flow of water in a piping system -which can potentially allow non-potable water to pollute or contaminate the potable water supply * To insure clean drinking water, - the use of proper backflow prevention is imperative in industrial, as well as in residential environments * When installing a " " device - caution must be used in order to prevent any debris or contaminants entering the potable water
Rotary heads: A ball-driven head-
Is another type of rotary head seen in the field - it is not as popular as both the impact or gear driven heads. - rotation is achieved by a steel ball which is set into a circular motion by water passing through the head. - as it hits the drive arm, rotation occurs
Class Pipe:
Is categorized by its working pressure. * You won't actually see the word class on the pipe, you will see for example: wp2psi, this means 200 psi * It is also known as SDR pipe - (Standard Dimension Ratio) * The wall thickness of this pipe is based on - the ratio of the pipe diameter to the wall thickness * The pressure rating is uniform throughout - the various sizes For example: PVC pipe rated at 200 PSI has that same rating whether it is 3/4", 1" and so forth * Standard pressure classes include 125, 160, 200, and 315
Hydrostatic design stress:
Is measured as the -estimated maximum tensile stress in the pipe wall - while subjected to constant internal static water pressure, without failing
PVC: Type 1, Grade 1
Is more resistant to chemicals * Irrigation systems are only concerned with - the flow of water
PVC: Grade 2
Is most commonly used for irrigation systems - because the hydrostatic design stress is one of the highest at 2000 PSI
Bubblers/drip irrigation: Drip Irrigation-
Is the slow application of water to the - specific root zone area of the plant material using very low pressure - because the flow is low , its usually expressed in gallons per hour (GPH) as opposed to gallons per minute (GPM) - average flow rates range from approximately 0.5 to 2 GPH, but can be substantially higher example: point emitter
Bubbler Advantages:
Its ability to * irrigate a defined area without overthrow and * minimize evaporation Since gravity dictates the flow of the water, care is needed in creating a level shrub bed To minimize run-off and erosion -the beds must have confined borders to retain the water example: bubbler with/without cap with adjustable screw on top
Three types of copper are available:
K, L, and M * Type K - has the heaviest wall thickness/is the most common of the 3 used in irrigation * Type L - has a medium wall thickness * Type M - has the thinnest wall Types K and L are available in -coils and - rigid lengths Type M is only available in -rigid lengths note to self: type K you lose more friction
Polyethylene (PE) pipe:
Known as (poly pipe) * Is more flexible than PVC piping - however, it has less strength -Is designed for lower water pressures * Barbed insert fittings or compression fittings - are used for connections - stainless steel clamps are required for some of the older poly pipe * The SDR " " normally used in irrigation systems - has a uniform ID (inside diameter), - unlike PVC which has a controlled OD (outside diameter * " " is very common in drip irrigation applications - since it is UV resistant, above ground placement is acceptable * Types I, II, III and IV are available - with type I being the most suitable for drip systems due to its more flexible characteristic
Copper pipe:
Like galvanized, was used in the installation of earlier irrigation systems * It was strong/costly like galvanized - however, more flexible/resistant to the elements * Although, not used in the complete installation process now - it is still a mainstay component feeding the water from the city main to the meter, house & backflow device, depending on city codes. Example: not really use for irrigation any more
Drip Irrigation can be at the * surface (above ground) * subsurface (underground approximately 2-6")
Many landscapers cover surface drip irrigation with mulch - this is aesthetically more pleasing to the home owner - this protective barrier minimizes * evaporation * holds in moisture and * controls the soil temperature
Wind sensors:
Measure wind velocity and * shut the system down if wind conditions are too high, usually preset velocity * This eliminates water waste/liability issues of -wet sidewalks/streets from water spray that is distorted from heavy wind
Drip irrigation delivers the water at a very slow rate right to the plant's root system with
Minimal effects of * wind * run-off or * evaporation It is one of the most efficient irrigation methods
PVC is smoother than Copper:
More friction loss going through copper than with PVC - even if the diameter is the same, because it is more rigid/rough inside copper
Pipe/Fittings: PVC Pipe (poly vinyl chloride)-
Most commonly distributed in 20' lengths - is the industry standard and - mainstay for the majority of all irrigation systems today * Its advantages include - high strength - light weight - chemical resistance and - longevity * It is Not UV resistant - so any exposed pipe above ground (for extended period) should be covered * Most PVC pipe buried for years in normal soil conditions -appear practically new when examined * Although very durable - PVC pipe can easily crack when dropped on a hard surface - or in bundles where it is dropped/the pipe impacts with surrounding pipe * Although rigid - will bow/bend to make installation easy * PVC pipe dates back to the 1940's - however, widespread irrigation usage wasn't until years later
Backpressure:
Occurs when the pressure in the sprinkler system-(or downstream side) becomes greater than the supply side - gravity or a pump (installed down-line of the water supply) can create this " " situation (exceeds positive pressure)
Soil moisture sensors:
Offer a more direct approach to water scheduling. * The sensor initiates a watering cycle when it senses a predetermined moisture level that reflects the stress level on the plant material * " " are more common on large commercial or institutional projects. * Placement is very important. * If the sensor is placed where the landscape is getting a different amount (more or less) of water than the remainder of the landscape, - the " " sensor may trigger the system to over or under water landscape Example: wireless moisture sensor
Drain Valves: (both manual/automatic) Used to protect irrigation components against freeze damage Automatic drain valve-
On an " " type " " * Pressure applied (when the system is on) forces a steel ball (or plunger) to - seat and seals off the outlet * When the system is turned off - water automatically drains out of the line * Since gravity will determine the direction of the water - drain valves should be installed at the lowest elevation in the system * To allow the water to drain properly - a small basin filled with gravel or drain piping should accompany the drain valve
Remote Control Valve (RCV):
Regulate (on command from the controller) The on/off mode of the water from the main line to the sprinkler heads * These are referred to as - electrical valves - hydraulic valves - automatic control valves - section valves _ circuit valves or - zone valves
Excessive pressure at the head may:
Result in a pattern distortion/wasted water (through evaporation) due to a "misting or fogging" effect at the head. This adverse effect can be corrected by the use of a pressure regulator or By using pressure compensating heads -which provide for a constant discharge pressure at each head regardless of the inlet pressure Pressure compensating nozzles allow for greater uniformity within a zone. Example: too much pressure at the head causing misting/or fogging effects
Valves: Ball valves-
Serves the same purpose; as a gate valve -it is preferred since it not metal * Intended as a main turn off valve * Not for frequent use
Using schedule PVC in irrigation systems has:
Several limitations * First, the pressure ratings are not uniform - throughout all pipe sizes * Furthermore, the pressure ratings decrease as the pipe size increases * Only in the 1 1/2" and smaller sizes (on schedule 40) do the pressure ratings exceed that of class pvc pipe * Schedule 80 has a higher pressure rating - than Class PVC pipe up to 4" piping
Spray heads: For best uniformity, you should zone sprinklers with the same radii together- (ie. 10' heads with 10' heads/15' heads with 15' heads etc)
Spray heads generally are used in small to medium-size turf/shrub areas. They are great for areas enclosed by borders & where the landscaping would hinder the use of larger rotary heads.
Depending on the manufacturer, matched precipitation can be achieved by mixing various arcs/or radii on the same watering zone:
Sprinkler heads with varying radii, that are mixed on the same watering zone, should be Spaced with like radii in order to maintain the uniform distribution of water/consistent head spacing within that zone. Unless the manufacturer offers matched precipitation within the arc/radii, mixing heads with varying radii on the same zone should be avoided
Sensors:
Technology today using sensing devices which, when used in conjunction with a controller or central control computer - have improved watering schedules and saved water Example: wireless rain/freeze sensor
Some of the features of modern controllers:
That help conserve water include: * Multiple programs which provide -more uniformed water scheduling between shrubs & turf area water requirements * Multiple start times which help - prevent or control run-off by providing several shorter run times - as opposed to one long run time in an area where the application rate may far exceed the infiltration rate due to - over-sized sprinkler nozzles, soil type and or slope * Rain, freeze, wind/soil moisture sensor compatibility -which greatly reduce water waste/liability issues (with frozen walks/streets) * The water budgeting feature also called - seasonal adjust feature * Provides a very quick/workable method to save water * It allows for an increase or decrease in run time by percentage. For example: If you had station #1 programmed with 10 minutes, placing the water budget feature at 90% would change station #1 from 10 minutes of watering to 9 minutes (90% of 10 minutes). * It will, in turn, change all the stations to 90% of their run time * This is one of the most practical ways that a homeowner, with limited education from the irrigator contractor, can practice water conservation/save water/money ET-based capability which is state-of-the-art when confronting water conservation issues.
Spray heads: The risers are made of rigid pvc or other more flexible plastics such as poly-
The Advantage of a more rigid riser is * that it is harder to break off The Disadvantage is that when it breaks * it usually breaks the fitting below the riser -resulting in a more timely/expensive repair If you are using a rigid riser, measure the riser below the head. Cut off risers work for almost any required height adjustment. example in pic of rigid riser on left side and poly cut off riser on right side
Remember, placement of all sensors is critical for maximum efficiency:
The aforementioned sensors can be used by themselves or in conjunction with each other for maximum efficiency * Some manufacturers offer weather stations that encompass - rain - wind, and - freeze sensors in one unit * when installed/maintained by a seasoned irrigation professional - these devices can drastically increase irrigation performance in respect to - saving water - having healthier plants and - minimizing labor costs add pic later
There are many choices in irrigation controllers to choose from with each having its advantages & disadvantages.
The general categories include: * hydraulic * mechanical and * the solid state (which includes hybrids)
Note: The inside of pipes varies on its smoothness & has a C-Factor rating:
The higher the C Factor, the smoother the inside of the pipe. For example * PVC pipe has a C-Factor of 150 - whereas * Copper pipe has a C-Factor of 140 * As pipe ages the C-Factor decreases - as the inside surface gets rougher * The rougher the inside surface - the more friction loss is encountered
Most sprinkler head manufacturers will convey a minimum head pressure ( in order for the head to operate efficiently), an operating pressure range/or an optimum head pressure for a specific model head:
The nozzle discharge rate/radius can vary significantly depending on the pressure to that head. For example, the following samples of several different nozzle selections show the various discharge rates (in GPM)/radii when the pressure to the base of the head varies: Sample Nozzle Performance ------Pressure---Radius---GPM ----------PSI------------------ Rain Bird --15-----9-------0.45- 2' Quarter--20----10------0.53- MPR Nozzle-25----11------0.60- -----------30----12------0.65- ************************************* Toro Fixed--20----13------1.37- 15' Half MPR-30----15------1.65- Nozzle------40----16------2.02- ------------50----16------2.14- ************************************** Irritrol 17' Full-20---14------2.90- Pro Van ------30---16------3.60- Nozzle-------40---17------4.10- -------------50---17------4.60-
Earlier spray heads were made of brass/came in stationary (non pop-up)/pop-up models:
The pop-up models utilized gravity to seat the head. As plastics improved, the brass heads (although still available) took a back seat to technology. The brass pop-up could not clear higher grass. Gravity was no match for the newer spring-loaded plastic heads. Installation of brass pop-ups had to be more precise. If slightly canted or if grass or debris were lodged under the nozzle, the head would not seat. Example: half circle brass pop-up spray head
Rotary heads: While most of these heads have a higher GPM than spray heads-
The precipitation rate is generally lower (1/4" to 2" per hour) Because of the larger area they have to cover Ideal applications for rotary heads include - large open areas - clay soils that accept water at a slower rate & - slopes where run off is a problem
It is important never to mix different types of sprinklers on the same zone (or section):
The reason for this is that different sprinkler types have varying precipitation rates
Sprinkler Heads:
There are several factors in determining which sprinkler heads to use for different areas. * The size/shape of the area to be irrigated * The type of landscaping- -trees -shrubs -turf and or -groundcover *Climate * Slope and * Soil type are all factors to consider
Stationary shrub spray is another type of spray head commonly used in today's landscapes:
These heads utilize the same spray design but don't pop up. Instead- They use a shrub adapter/are mounted on a riser in the shrub beds. The preferable installation is slightly above ground level -so they spray directly to the plant roots Sometimes, they are installed higher -to clear the present shrubs in order to reach desired distance to more shrubs The heads should be located * against the walls or * higher borders in order to prevent damage from foot traffic or injuries to people. Toro stationary 15' spray shrub/adapter mounted on riser
Drip irrigation has many superior features to that of conventional spray/rotary systems, It does have its drawbacks-
These include: * because the flow is low -sometimes a more sophisticated controller (with longer running times) is needed to set up a proper watering schedule * for subsurface drip irrigation (or surface drip covered with mulch) - there is no obvious indication when an emitter is not working. - for the homeowner or irrigation contractor, checking each plant for ample water is difficult and timely - most frequently, the first indication of a problem is a dead plant * damage from an -edger, mower or workers is very common * because of the small orifices, - emitters can clog easily * from a marketing standpoint - many homeowners still want to be able to physically see the water in order to have confidence in the quality/workmanship by the contractor
Freeze sensors:
These sensors Also known as weather sensors turn the automatic watering system off - when freezing temperatures threaten freezing plants or crops * This also prevents possible hazards and liability issues associated with ice forming on streets or sidewalks * " " can, in some cases, be used to turn on the water to cool plants when extreme heat is present
Atmospheric Vacuum breaker (AVB):
This backflow prevention device incorporates a floating disc - which when pressurized, rinses/seals off the air inlet. - with the absence of pressure from upstream - the disc falls/creates a vent opening(or air gap) which prevents backsiphonage - this device must be installed vertically/a minimum of 6" above the highest head (in its stationary position) or outlet in the system - this also allows ease of inspection/service - it does not protect against backpressure * An " " cannot be subjected to more than 12 hours of constant pressure in a 24 hour period * Doing so will allow the disc to become jammed, or frozen, disabling the device * There cannot be any shut off valves downstream of the " " * A separate " " must be installed on the discharge side of each control valve, - between the valve/all emission devices * It is approved for health hazard situations if installed correctly picture of installation→
Pressure Vacuum breaker (PVB):
This backflow prevention device incorporates a spring-loaded check valve - which closes off when the water pressure from upstream stops - an air relief valve opens at low pressures & stops any backsiphonage - the " " must be installed vertically and a minimum of 12" above the highest head (in its stationary position) or outlet * As with AVB, it stops backsiphonage, but not backpressure * It is designed to handle constant pressure * It is approved for health hazard applications where there is no threat of backpressure * There are 2 shut-off valves * The " " has 2 test cocks for testing the device picture of installation→
Reduced Pressure Principle Device (RP)
This backflow prevention device is * Approved for health hazard conditions * Protects against backsiphonage and back pressure * Offers the most protection of any mechanical backflow device * This device uses a pressure differential relief valve - in between 2 spring-loaded check valves * 2 shut-off valves are present * It must be installed horizontally with a minimum of 12" above grade in a location that cannot be submerged * It can handle constant pressure and * It is required when fertilizer injectors are being used Example: Installation minimum of 12" above grade
Double Check Assembly (DCA): OR Double Check Valve Assembly (DCVA)
This backflow prevention device utilizes 2 spring-loaded check valve assemblies to protect against backsiphonage/backpressure * Depending on local codes, it can be installed -horizontally or vertically and - above or beneath the ground * Below ground installation should include - a y-strainer on the inlet side of the unit and - allow for adequate drainage - and room for inspection/servicing * As with the PVB, it has - 2 shut-off valves * It can handle constant pressure and * Is approved for non-health hazard application only * This unit has - 4 test cocks to test the check valves Picture of installation→
Spray Heads:
Throw a uniform sheet of water in a * Fixed or * Adjustable pattern Water is distributed very quickly with the average application from approximately 1 to 3 inches per hour. Minimum operating pressure is usually between 15 and 30 PSI with the spray distance varying between 4' and 20' feet " " usually have matched precipitation within the arcs which allows you to install various arc nozzles (ie, quarter, half, full, etc.) on the same zone and maintain matched precipitation rates. Example: 20' throw spray heads
One way to monitor drip irrigation systems:
To run a surface emitter at the end of a zone - so you can physically see if water is flowing through the pipe - in addition, you can monitor the flow through the meter or - a flow meter and - check moisture (by hand) near each emitter in question Example: flow meter
Flow Meters:
Track the flow rates/velocity during run times. * Using a " " can help an irrigation professional manage -water cost by giving the total water used during a cycle - It can also be programmed to shut the system off if it detects a break in the line - thus saving water until the repair is made
Mechanical controllers:
Typically larger than most solid state controllers they are - reliable - simple to understand and - not as temperamental to electrical surges or outages associated with more sophisticated solid state controllers * Because of water conservation concerns on the increase - the lack of scheduling capability in mechanical controllers is a large draw-back
Rotary Heads:
Use the energy of the water to rotate the sprinkler, distributing water (in single or multiple streams) Over a large turf or Shrub area * Are generally used for larger landscaped areas These include- - larger residential sites - commercial landscapes - golf courses - parks and - athletic fields where tight landscaping does not hinder their longer radius of throw.
Rotary head types: Impact heads-
Utilize a driver arm (mounted on the side) to create rotation - the force of the water knocks the arm outward while attached spring pulls it back - with the water in motion, this pendulum action creates an impact on the head which results in the rotation of the head - 2 flanges below the nozzle enable adjustment of the desired arc. - diffusion of the spray and - angle of the trajectory are achieved by a) lowering a flange into the water path or by b) turning a diffusion screw (on selected models) into a stream of water. plastic/brass models are available in both pop-up and riser mounted configurations. They are commonly used with a quick coupler valve at larger parks/athletic fields.
Hydraulic controllers:
Utilize water to activate the valves * Although not as common now,they were very popular before the electrical solenoid valves came onto the market * Unlike solid state controllers,they are not as sensitive to power surges * Some of the drawbacks include - more time-consuming installations - leaks in the tubing - clogged lines due to debris and - freeze damage add pic later
Filters:
When designing an irrigation system, remember to consider a filter system - especially if you have any drip lines - the drip emitters have very small orifices and clog easily over time without a filtering system - Check with local distributors on specific types ( screen/disc filters) and - models available with specifications to meet your project needs Example: screen/disc filter for drip irrigation
Pressure Regulator:
Where pressure is too high for optimum system operation - a " " needs to be installed * Excessive pressure at the sprinkler heads can - create a misting/or fogging effect resulting in lost water through increased evaporation * In addition, drip irrigation needs to operate at low pressures Example: " " hooked to an irrigation sprinkler system
Cross connection:
Where there is a " " , there is the chance to pollute or contaminate (the latter being the more severe) -the drinking (or potable) water supply. * A " " is any actual or potential connection between a potable water supply/any source (sprinkler system etc) that have the possibility - to introduce polluted or contaminated water back into the potable water that is supplying it * Any one of many elements - fertilizers -chemicals- -bacteria etc can be introduced into the potable water supply, creating a very dangerous situation This phenomenon is a result of either - backsiphonage or - backpressure
The plastic pop-up spray head is the most common:
With pop-up heights ranging from 2 to 12 inches with 3 to 4 inches being most popular. * Most of these heads are- "spring loaded", which means the water pressure pops the head up/a retraction spring seats the head when the water flow is shut off. It should be installed ground level or slightly lower & several inches from any hardscape (walks, drives, etc.) that require edging. Installing the head too high or too close to the hardscape could result in head damage from a mower or edger. It could create a health hazard for pedestrian traffic/or promote vandalism. Installing too low results in poor performance as the pop-up is unable to clear the lawn/water properly. Example Toro 4" pop up spray head
There is an abundance of: Electric Valves on the market:
With various combinations of features; ie * brass * plastic * flow control * internal/external bleeds * thread * slip or barbed outlet, etc They are "normally closed" which means that -the valve is in the closed position if there is no power being sent by the controller example: " " valve →
MP Rotator pop up head being adjusted:
adjusting the radius/arc
Type K :
copper with thickest wall
12 ft (Q) quarter circle spray pattern for pop up
head nozzle
15 ft (F) full circle spray pattern for pop up
head nozzle
15 ft fixed (H) half circle spray pattern for pop up
head nozzle
17 ft (A) adjustable spray pattern for pop up
head nozzle 25° to 360° arc
Electric Angle globe valve:
less friction loss
Drip irrigation: Point emitters-
offer water to a specific plant by connecting into the lateral piping near a specific plant * they are available in - single and - multiple emitter units * small micro tubing is used to carry water from the pressure compensating type -single and - multi-emitter units directly to various plants in the immediate area * Water flow is delivered drop by drop at the base of the individual plant
Rotary heads Cutaway of the inside of a
rotary pop up sprinkler
Drip irrigation: Flush valve
to flush debris from the line
Spray heads: End strip pattern nozzle (EST) 15'
up close see markings
Drip irrigation: Air Relief Valve
used to eliminate any vacuum that could result in debris or contaminants being sucked into the piping system
