Exam practice test for Texas Irrigator License
Gear rotor model B
Spray with X nozzle
Spray with Y nozzle
Spray with Z nozzle
1" valve model Q
Backflow device
Mainline pipe
Laterals pipe
House service pipe
Sleeves
City main pipe
City meter
Controller
Legend
To convert psi to feet
Multiply by 2.31
To convert feet to psi
Multiply by 0.433 psi
Precipitation Rate Formula
GPM (Full Circle Head) X 96.3
-------------- = PR
Head Spacing X Row Spacing (Divide)
,Precipitation Rate for Drip
GPH (one emitter) X 231
------------ = PR
Head Spacing (inches) X Row Spacing (inches)
Runtime Formula
I x 60
RT ----=Runtime
PR
Calculating Drip Flow Zone
Total Linear feet of drip /emitter spacing x GPH of emitter/ 60 = GPM for that zone
Or DMDMD
Slope formula
Rise
S = -----------
Run
Triangular Head Spacing
Multiply spacing by .866 to get row spacing
Efficiency of System
Example if 50% efficiency with 1.12 Precipitation rate
Divide 1.12 by .50 to get 2.3/PR
Design Pressure
DP = = Recommended head pressure + total losses
Actual Head Pressure
AHP == Static Pressure - Total losses
D - DIVIDE
THE FIRST STEP TELLS YOU HOW MAY ROWS.....DIVIDE THE WIDTH BY EMITTER SPACING IN FEET (EX;
18" = 1.5 FEET) ALWAYS ADD 1
M -MULTIPLY
THIS STEP TELLS YOU HOW MANY TOTAL FEET...MULTIPLY THE TOTAL ROWS BY THE LENGTH
, D - DIVIDE
THIS STEP TELLS YOU HOW MANY TOTAL EMITTERS..DIVIDE THE TOTAL LENGTH BY THE EMITTER
SPACING IN FEET
M -MULTIPLY
THIS STEP TELLS YOU HOW MANY TOTAL GALLONS PER HOUR..MULTIPLY THE TOTAL EMITTERS BY
THE GPH GIVEN FOR EACH EMITTER
D - DIVIDE
THIS LAST STEP TELLS YOU HOW MANY GALLONS PER MINUTE...DIVIDE THE TOTAL GPH BY 60 TO
CONVERT IT TO MINUTES
Double check Assembly Backflow Preventer is suitable for?
Back pressure,back siphonage,but its not suitable for high hazard applications.
Reduced Pressure Principle Backflow Preventer is suitable for?
Back pressure,back siphonage,and is good for high hazard applications.
Backflow
. . Back pressure is the irrigation side and backsiphonage is the city side. All backflow devices work for
backsiphonage and only the double check and RP work for back pressure. Study what causes
backsiphonage and back pressure. You have to know how to install each backflow device including air
gap.
Which device can stop backsiphonage?
Pvb,DCA,RP,and AVB
Which device can stop backpressure?
DCA and RP
Which device can handle constant pressure?
RP,DCA,and Pvb
The approved backflow devices for non-health hazards include:
All devices (AVB,PVB,DCA,
and RP)
Which device,or devices,are approved when there is chemical applied by aspiration,injection,or
emission?
RP
If there is an on-site sewage facility on site, which backflow is approved?
RP
Gear rotor model B
Spray with X nozzle
Spray with Y nozzle
Spray with Z nozzle
1" valve model Q
Backflow device
Mainline pipe
Laterals pipe
House service pipe
Sleeves
City main pipe
City meter
Controller
Legend
To convert psi to feet
Multiply by 2.31
To convert feet to psi
Multiply by 0.433 psi
Precipitation Rate Formula
GPM (Full Circle Head) X 96.3
-------------- = PR
Head Spacing X Row Spacing (Divide)
,Precipitation Rate for Drip
GPH (one emitter) X 231
------------ = PR
Head Spacing (inches) X Row Spacing (inches)
Runtime Formula
I x 60
RT ----=Runtime
PR
Calculating Drip Flow Zone
Total Linear feet of drip /emitter spacing x GPH of emitter/ 60 = GPM for that zone
Or DMDMD
Slope formula
Rise
S = -----------
Run
Triangular Head Spacing
Multiply spacing by .866 to get row spacing
Efficiency of System
Example if 50% efficiency with 1.12 Precipitation rate
Divide 1.12 by .50 to get 2.3/PR
Design Pressure
DP = = Recommended head pressure + total losses
Actual Head Pressure
AHP == Static Pressure - Total losses
D - DIVIDE
THE FIRST STEP TELLS YOU HOW MAY ROWS.....DIVIDE THE WIDTH BY EMITTER SPACING IN FEET (EX;
18" = 1.5 FEET) ALWAYS ADD 1
M -MULTIPLY
THIS STEP TELLS YOU HOW MANY TOTAL FEET...MULTIPLY THE TOTAL ROWS BY THE LENGTH
, D - DIVIDE
THIS STEP TELLS YOU HOW MANY TOTAL EMITTERS..DIVIDE THE TOTAL LENGTH BY THE EMITTER
SPACING IN FEET
M -MULTIPLY
THIS STEP TELLS YOU HOW MANY TOTAL GALLONS PER HOUR..MULTIPLY THE TOTAL EMITTERS BY
THE GPH GIVEN FOR EACH EMITTER
D - DIVIDE
THIS LAST STEP TELLS YOU HOW MANY GALLONS PER MINUTE...DIVIDE THE TOTAL GPH BY 60 TO
CONVERT IT TO MINUTES
Double check Assembly Backflow Preventer is suitable for?
Back pressure,back siphonage,but its not suitable for high hazard applications.
Reduced Pressure Principle Backflow Preventer is suitable for?
Back pressure,back siphonage,and is good for high hazard applications.
Backflow
. . Back pressure is the irrigation side and backsiphonage is the city side. All backflow devices work for
backsiphonage and only the double check and RP work for back pressure. Study what causes
backsiphonage and back pressure. You have to know how to install each backflow device including air
gap.
Which device can stop backsiphonage?
Pvb,DCA,RP,and AVB
Which device can stop backpressure?
DCA and RP
Which device can handle constant pressure?
RP,DCA,and Pvb
The approved backflow devices for non-health hazards include:
All devices (AVB,PVB,DCA,
and RP)
Which device,or devices,are approved when there is chemical applied by aspiration,injection,or
emission?
RP
If there is an on-site sewage facility on site, which backflow is approved?
RP
