B3: Residential Irrigation System Flashcards
Why should water conservation be a priority?
Ecological reasons
What are 3 types of irrigation systems?
1) agricultural
2) commercial
3) residential
What are 2 different styles of residential irrigation systems?
Traditional sprinkler
Drip irrigation systems
What are Traditional sprinklers well suited for?
Large areas of grass and plants w/ similar water needs
Water uniformly - 5’ or more in diameter
What type of system is used for specific areas (planters on patios, hanging baskets, etc)
Drip irrigation
What is step one in gaining site information?
Contact AHJ for permits / backflow prevention
What is BC 1 Call?
Call before you dig
What does BC 1 Call provide?
Location / depth of known underground services (hydro, water, telephone, gas / sewer)
What does each square of graph paper represent?
1 square foot of property
What does local climate influence?
How much water is needed to maintain good plant growth
What is evaporation?
It’s water lost from the atmosphere from the soil / soil surface.
What is transpiration?
Is the amount of water used by the plant
What is the combined form of evaporation and transpiration?
Evapotransporation
What is a cool climate
Under 70f (21c) – an average midsummer high
What is a warm climate?
Bn 70f and 90f (21 -32c) - midsummer highs
What is the temp of hot climate?
Over 90f (32C)
What is over 50% humidity called?
Average midsummer relative humidity
What is humidity under 50% considered?
Dry
What is needed for larger agricultural watering needs?
More accurate calculations
How does soil affect type of sprinkler being used?
Type of soil holds a certain amount of water
True or false: the type of soil affects the irrigation schedule
True
What determines the percentage of soil texture?
The sand, silt and clay that makes up soil
What does a Jar Test determine?
The amount of sand, silt and clay soil contains
What is capillary action on soil?
Is the primary force in spreading water horizontally through the soil.
How does sandy or coarse soils affect water absorption?
Water sifts through quickly and has a hard time retaining moisture (requires more frequent watering)
How does clay affect water absorption?
Has a much slower absorption rate - retains water longer = less frequent watering
What is the best type of soil for water absorption / retention?
Loamy
What is a main problem of irrigation to avoid?
Applying water faster than the soil can receive it
Puddling / runoff are signs of what?
Overwatering: wastes water / cause soil erosion
What needs to be determined prior to design work?
Water flow / pressure
What is the min pressure sprinklers need to operate properly?
35 psi (245kPa)
What does GFCI stand for?
Ground fault circuit interrupter
Where should the controller be located?
In as close proximity as possible to the zone valve locations - minimize length of control wire needed bn 2 points
What is the goal when selecting sprinklers?
Select sprinklers that covers the most area with the least amount of sprinklers
What are the 2 basic types of sprinklers?
Fixed spray and rotating
What is a bubbler?
They are fixed spray heads that produce short throw or zero radius water distribution
What are spray sprinklers?
They are required for
smaller landscaped areas
Areas for controlled spray
area with dense tree growth
What type of spray pattern are fixed spray sprinklers?
Part of a circle or arc
What is an advantage of a bubbler
Can irrigate a specific area w/o overthrow onto other plants
What are 2 types of spray sprinklers?
Mounted on risers
Pop up variety
How does a rotating sprinkler work?
Uses flow and pressure to “drive” energy to turn the sprinkler
What are rotating sprinklers use for?
Larger area / shrubs
What is the operating pressure of rotating sprinklers?
25 - 100 psi (175 - 700kPa)
True or False: the distance of throw for a rotating sprinkler head is greater than spray sprinklers.
True
What is the throw distance of a rotating sprinkler?
20ft (6m) min
100 ft (30m) max
What are the discharge rates for a rotating sprinkler?
100gpm (6.3L/s)
What are impact sprinklers? (A little slappy to make daddy happy)
Are a variety of rotating sprinklers that are more common in commercial/ agricultural
What type of sprinklers are appropriate for slopes, tight soils and areas where slower application rates are required?
Rotating sprinklers
What drives the choice bn stream rotors / fixed spray heads?
Economics
What are the advantages of rotating sprinklers?
fewer sprinklers, fewer fittings / less trenching
What are the advantages of spray sprinklers?
can be used with smaller or irregularly shaped areas
What is head to head coverage?
Spray from one head will reach all the heads adjacent to it
True or false: it’s ok to mix spray and rotor sprinklers
False! do not mix
What is it called when the distance bn heads is 50% or half of the diameter of the spray pattern?
50% spacing
What are the 2 main types of sprinkler spacings?
Square and triangle
What is the square pattern sprinkler spacing?
It has equal sides running bn 4 sprinkler locations
Where would square pattern spacing be seen?
In areas that are square themselves or have 90 degree angles
Why is square spacing considered weak?
the diagonal stretch leaves a weak spot at the center
Where is the triangular spacing located?
used in areas that have:
irregular boundaries or boarders that are open to overspray
do not require part circles sprinklers
Why are triangular spacing the better choice?
Less equipment cost, less install time / lower maintenance costs
What happens if there is too much pressure at the head of a sprinkler?
The spray is more like a mist
What is meant by the radius of a sprinkler?
the distance that a nozzle “throws” water
The farther the radius = what GPM?
the higher the flow rate in GPM
What is the ideal nozzle pressure?
bn 25 - 65 psi (172 - 448 kPa)
What is a zone?
is a group of sprinkler heads connected with pipe fed by a single valve
What is a zone valve controlled by?
By the controller / timer
What are the 2 types of zone valves?
Anti-siphon
In - line
What are Anti-siphon zone valves?
Have backflow prevention devices integrated into each individual valve
What is a disadvantage to an anti-siphon zone valve?
they must be installed above ground
6 - 12” above the highest sprinkler
What are in - line valves?
They are installed below ground in valve boxes for out-of-sight operation
Does an in - line valve system have to have a backflow preventer installed?
Yes
What is the most common type of sprinkler zone valve used?
In - line valves
Is a dual check valve in - line testable?
No
What type of pipe is used for residential sprinklers?
3/4 - 1” PVC schedule 40
Class 200 PVC pipe is popular for?
use between zone valves / sprinklers due to its thinner walls / lower burst strength
What is the downside of Polyethylene (PE) pipe?
It has more of a pressure drop due to its fitting that restrict flow (barbed type fittings)
Which wire connects all the valves? ( neutral or hot)
Hot wire
Each sprinklered area needs how many zone valve?
one
PVC piping systems should be designed to keep water flow rates no higher than what?
5 ft/sec (1.5m/sec)
Why is it important to keep 5ft / sec the flow rate?
- keeps pressure lose dt friction to a min.
- ensures adequate pressure to all sprinkler
- minimizes erosion dt excessive velocities
Adding 25% in when calculating friction loss is to allow for?
fittings
Should you allow for extra zones for future alterations in landscapping?
Yes
Controllers should be located close to what?
a 120 VAC wall plug
Where is a common location for a controller?
On a wall inside a garage
If a controller is mounted on an outside wall it should be certified for what?
Outdoor installation
Wires must be ran from the controller to each what?
zone valve
Any cables used must be acceptable for what?
direct earth burial
What is the most common size of wire for residential systems?
18 gauge (#18AWG)
How many volts are needed for zone valves?
24 VAC
What’s a good way to minimize digging?
place multiple pipes in a trench
How deep do trenches need to be?
8 - 12” (200 - 300mm)
What handy tool can be used as a guide for how deep a trench should be?
a shovel
What type of shovel should you use if trenching through an existing lawn?
a square - nosed shovel
remove rectangular pieces of sod approx 2 inches thick
A pipe jetter is used for what?
trenching under a sidewalk
What should be placed at the bottom of a manifold box?
drain rock – helps drain the box / keep it from becoming muddy
What are swing joints good for?
allows 3 directional mvmt
allows vertical mvmt in case of traffic on top
What length of Funny pipe is suggested?
1 - 4’
Are swing joints / sprinklers connected before or after flushing?
Installed after flushing
How should the wires be connection be made?
By a waterproof twist on connector
How can debris be removed from valves?
Taking off its bonnet and flushing it
When flushing the system, which sprinkler head should be left off?
the furthest head of a pipe run – allows for debris to be pushed out
How does one determine the base irrigation schedule?
By determining the weekly evapo-transpiratition rate for the area
When should watering take place?
Early in the morning - pressure is greatest , reduces water evaporation
Why is watering at night not ideal?
the lawn is more likely to become diseased when wet for long durations
What does calcium and magnesium create?
Hard water
What happens to the nozzle head if the water is hard?
becomes partially plugged
When winterizing, water valves should be placed in what position?
in the half open position
