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BACKFLOW PREVENTION GENERAL INFORMATION WITH
VERIFIED QUESTIONS AND ANSWERS
Which backflow device is recommended for low hazard applications - ANSWERS-Atmospheric vacuum breaker, pressure vacuum breaker, double check assembly Which backflow device can be installed below grade ground level? - ANSWERS-Double check assembly valve Which backflow device can be under constant pressure - ANSWERS-Pressure vacuum breaker, double check assembly valve, reduce pressure principle Which backflow devices is acceptable to use when there is a possibility of back pressure - ANSWERS- Double check assembly valve, reduce pressure principle Which backflow device is recommended to prevent back siphonage - ANSWERS-Atmospheric vacuum breaker, pressure vacuum breaker, double check assembly valve Atmospheric vacuum breaker is not suitable for - ANSWERS-Back pressure Irrigation system with any kind of injection device associated with it would be termed as - ANSWERS- Health hazard
Which backflow device is required to be used with pumps - ANSWERS-Which ever one is required by state or local codes The mechanical prevention of reverse flow, or back siphonage, of non-potable water from an irrigation system into public water system is called - ANSWERS-Backflow prevention Any pressure, regulated of its source, against the outlet side of a backflow prevention device, which exceeds the supply pressure against the inlet side of the device is - ANSWERS-Back pressure Which backflow device is most recommended for systems with fertilizer injection - ANSWERS-Reduce pressure principal Which statement is correct - ANSWERS-The pressure vacuum breaker, unlike the atmospheric vacuum breaker, will operate satisfactorily under constant pressure Backflow in the water distribution system can be caused by - ANSWERS-Back pressure and back siphonage Hey pressure vacuum breaker can be installed with a - ANSWERS-Control valve immediately downstream Backflow prevention assembly is on high hazard systems should be repaired - ANSWERS-When the field test results show failure The control valve downstream a backflow device may result in - ANSWERS-Constant pressure Where are the shut off valve is located on an AVB - ANSWERS-There are no shut off valve's How many test cocks are on a DCA - ANSWERS-Four What will happen if it AVB is installed in the wrong direction - ANSWERS-Water will escape through the top portion of the device
With most rotary heads, if you would adjust the Ark down for instance , from 360 to 180, the precipitation rate - ANSWERS-Increases Which most rotary heads, if you adjust the Ark down, the discharge rate - ANSWERS-Remains the same Rotary heads precipitate water more rapidly than any other type of heads - ANSWERS-false Irrigation heads should be selected - ANSWERS-To apply water equal to or slightly below the infiltration rate of the soil Frequent watering will result in - ANSWERS-A shallow root system Which is not ideal for dissolving surface fertilizer - ANSWERS-Subsurface drip What is essential to prevent emitters from clogging - ANSWERS-Filters Why is it never acceptable to run drip lines and sprayheads on the same zone valve - ANSWERS-Because their precipitation rates vary The licensed irrigator should base his design on - ANSWERS-Average night time windspeed Which piping of a sprinkler system will be under constant pressure - ANSWERS-Mainline A gate valve will have - ANSWERS-less pressure loss than a globe valve of equal size Schedule 40 fittings can be solvent welded to - ANSWERS-Schedule 40 pipe, class pipe, schedule 80 pipe Portable water is - ANSWERS-Suitable for human consumption
Which of the following statements about the C value is correct - ANSWERS-The lower the C value the greater the friction loss The main design factor that affects the effectiveness of a sprinkler system is - ANSWERS-Precipitation rate Conventional sprayheads discharge a pattern that is usually blank in shape - ANSWERS-Circular Which would be affected most adversely by wind - ANSWERS-Stretched head spacing A well-designed rotary system can be just as a patient as a well-designed system with spray heads - ANSWERS-True Which of the following is resistant to UV light - ANSWERS-Polyethylene tubing Electric valves are classified as - ANSWERS-Normally closed valves The wire to a valve should be pulled fairly tight to prevent the wire from moving in the ditch - ANSWERS- false Which wire is larger - ANSWERS-Smaller than number, larger the wire Multi conductor wire such as 18-6 has - ANSWERS-Five circuit wires and one common Master valves are used to prevent velocities above 7 ft./s - ANSWERS-False Any connection made to a portable water supply - ANSWERS-Cross connection What are has higher infiltration rates in - ANSWERS-Course Sandy solis
Which is the designated type of copper tubing - ANSWERS-K L M Which of the following would have the smallest inside diameter - ANSWERS-1" type K copper tube If the proposed pipe size for your irrigation system is 1" then, then the sleeves for the pipe needs to be at least - ANSWERS-Inch and a half PVC 2210 has a design burst strength of - ANSWERS-1000 psi class 315 pipe has a working pressure rating - ANSWERS-315 psi A safe critical velocity for the water in PVC pipe is - ANSWERS-5 ft./s Oversize in pipe results in - ANSWERS-More expense Looping a main supply line in a sprinkler system can - ANSWERS-Lower pressure to the circuits, allow you to use more pipe for the main supply line The main factor used to determine how to size down lateral line piping is - ANSWERS-Velocity If I systems head spacing is 15 foot then the row spacing should be blank for triangular spaceing - ANSWERS- 13 What will happen if a gear driven rotary head is installed at an angle - ANSWERS-The spray pattern will be distorted and he will have poor distribution the water What happens if the rotation of a rotary head is too fast - ANSWERS-The radius decrease
Changing out the size of the nozzle on the rotary head will also change - ANSWERS-GPM of the head, radius of throw An increase in head pressure will - ANSWERS-Increase flow rate When is a door not a door - ANSWERS-When it's a jar As the average wind speed increases - ANSWERS-The heads spacing should be decreased If you double the flow of water through your piping, the pressure will be - ANSWERS-Four times greater What are the three types of copper - ANSWERS-Type K heaviest, Type L medium, Type M thinnest 6 GPM = up to what pipe size - ANSWERS-1/2" 10 GPM = what pipe size - ANSWERS-3/4" 1" pipe size = what GPM - ANSWERS-17 GPM 1 1/4" pipe size = what GPM - ANSWERS-26 GPM Where is the precipitation rate of a spray had the greatest - ANSWERS-Closest to the head The weight of in 1 foot tall column of water consisting of 12 cubic inches is - ANSWERS-.433 LBS Rise divided into run equals - ANSWERS-Slope
