Distribution System Facilities

Question 1

True or False? The solvent weld on plastic pipe consists of a solvent that causes both pieces of pipe to be cemented together.

Answer 1

True

Question 2

True or false? Any plumbing fixture or faucet below the hydraulic grade line will be exposed to negative pressure.

Answer 2

False. Any plumbing fixture or faucet ABOVE the hydraulic grade line

Question 3

Are large variations in pressure desirable in distribution systems?

Answer 3

No

Question 4

True or false? All air must be removed before pressure testing a pipe

Answer 4

True

Question 5

True or false? Selecting an appropriate type of shoring to support the walls of a trench depends largely on soil conditions in the area.

Answer 5

True

Question 6

True or false? Lack of shoring or shoring failure are the major causes of underground construction deaths.

Answer 6

True

Question 7

How many valves should be used at pipe crosses and how many at tees?

a) 2 valves should be used at pipe crosses and 3 at tees
b) 3 valves should be used at pipe crosses and 2 at tees

Answer 7

3 valves should be used at pipe crosses and 2 at tees

Question 8

True or false? Electronic meters are moderately accurate and head loss is high.

Answer 8

False. Electronic meters are HIGHLY accurate and THERE IS NO head loss.

Question 9

True or false? In the excavation of a trench for water lines, all concrete and asphalt debris from the cut paving must be used to refill the trench

Answer 9

False. It must be REMOVED b/c debris CANNOT be used to refill the trench.

Question 10

Will water flowing in a pipe or conduit gain or lose pressure due to pipe friction loss?

Answer 10

Lose

Question 11

Why should dead-end water mains in distribution systems be avoided?

a. To prevent the development of taste and odors
b. to minimize the number of fire hydrants required in the system
c. to avoid backflow and backsiphonage conditions
d. To create efficient procedures for reading water meters

Answer 11

To prevent the development of tastes and odors

Question 12

What is the main application of gate valves in a water distribution system?

a. To isolate the sections of mains to permit emergency repairs in the system
b. To regulate flow rates in the system
c. To prevent damage from water hammer in the system
d. To control water pressures in the system

Answer 12

to isolate sections of mains to permit emergency repairs in the system

Question 13

Why should excessive water velocities be avoided when filling pipes for pressure and leakage tests?

a. To prevent erosion corrosion of the pipes
b. to prevent cavitation on futons and valves due to flowing water
c. to prevent pipe movements, which could cause leaks
d. To prevent damage from water hammer

Answer 13

To prevent pipe movements, which could cause leaks

Question 14

How is outside of stew pipe usually protected if it is exposed above ground?

a. chemical treatment
b. plastic
c. paint
d. electrical control

Answer 14

Paint

Question 15

What is the primary function of a water meter ?

a. to measure and display the amount of water passing through it
b. to measure and display system pressures
c. to collect information regarding system flows
d. to record electrical usage during peak hours

Answer 15

to measure and display the amount of water passing through it

Question 16

Why should a check valve be provided on the discharge side of each pump?

a. To divert flows to storage facilities
b. to check flows for compliance with quality standards
c. To prevent backflow
d. To meter flows being pumped

Answer 16

To prevent backflow

Question 17

Why are hydraulic shores frequently used?

a. Appropriate for all soil conditions
b. Ease of installation and removal
c. unbeatable strength
d. Can be left in place for long periods of time

Answer 17

ease of installation and removal

Question 18

What problem can occur when air pockets form in pipelines?

a. supersaturated oxygen conditions
b. Excessive pressures in the system
c. Increased resistance to flow or complete stoppages of the water flow
d. Concentrations of toxic gases

Answer 18

Increased resistance to flow or complete stoppages of the water flow

Question 19

Where are reduced pressure (RP) devices installed in the water distribution system?

a. At services where dangerous materials are present or where a backflow situation is likely
b. in Mains between storage tanks and the distribution system
c. in mains between clear wells and storage tanks
d. At services between the main and the consumers premises

Answer 19

At services where dangerous materials are present or where a backflow situation is likely

Question 20

What type of water meter is best when water flow fluctuates widely ?

a. Compound meter
b. Venturi meter
c. Orifice plate meter
d. Nutating-disc meter

Answer 20

Compound meter

Question 21

What is the service pipe in a distribution system?

a. The pipeline delivering water from the service storage to the main
b. The pipeline serving service stations
c. The pipeline extending from the water main to the building served
d. The pipeline transmitting water from the treatment plant to service storage

Answer 21

The pipeline extending from the water main to the building served

Question 22

What is sheeting as used in trench shoring?

a. The solid material used to keep the interior of the pipe clean during installation
b. The solid material used to prevent groundwater infiltration into the trench
c. The solid material placed on the bottom of the trench to soak up groundwater infiltration
d. The solid material placed directly against the sides of the trench

Answer 22

The solid material placed directly against the sides of the trench

Question 23

What is bedding as used in pipe installation?

a. The material wrapped around mains to control corrosion
b. The material used under joints to stop leakage
c. The material placed in the bottom of a trench to support the pipe
d. The material used to insulate the pipes to prevent freezing

Answer 23

The material placed in the bottom of a trench to support the pipe

Question 24

What is the purpose of backflow prevention valves in the water distribution system?

a. To isolate the system for repairs
b. To provide backup for other system valves
c. To stop the flow of an unapproved and possibly contaminated supply into the domestic water system
d. To prevent the loss of water through leaks

Answer 24

To stop the flow of an unapproved and possibly contaminated supply into the domestic water system

Question 25

Under what conditions must trenches less than 4 feet in depth be shored ? a. When short shoring is available b. When there is water standing in the bottom of the trench c. When examination indicates hazardous ground movement may be expected d. When new operators are working in the trench

Answer 25

When examination indicates hazardous ground movement may be expected

Question 26

What safety precautions must be taken during the installation of pipe? 1. Leaking joints must be repaired or adjusted 2. Children should be discouraged from playing near the job 3. Barricades should be put up on the curb side of the trench to limit accidental access by pedestrians 4. All operators must wear gloves, hard hats, and steel toed shoes 5. Easily visible construction signs, guards, lighting, and flaggers should be provided where needed for the protection of the public

Answer 26

2. Children should be discouraged from playing near the job 3. Barricades should be put up on the curb side of the trench to limit accidental access by pedestrians. 4. All operators must wear gloves, hard hats, and steel-toe shoes 5. Easily visible construction signs, guards, torches, and flaggers should be provided where needed for the protection of the public

Question 27

How can air get into the water in a distribution system? 1. Through the electrical power system 2. Through packing glands 3. Through pumps 4. Through leaky joints 5. Through bubbler-type irrigation systems

Answer 27

2. packing glands 3. pumps 4. leaky joints

Question 28

Which types of waste water facilities are often subject to local and state health department guidelines on minimum separation distances from water mains ? 1. Sanitary sewer lines 2. Cesspools 3. Septic tanks 4. wastewater leach fields 5. Seepage pits

Answer 28

1. Sanitary sewer lines 2. cesspools 3. septic tanks 4. Wastewater leach fields 5. Seepage pits

Question 29

Which threats can be kept out of covered reservoirs by covering vents, drains, and overflow outlets with a fine mesh screen? 1. Vandals 2. Birds 3. Small animals 4. Snakes 5. Insects

Answer 29

2. Birds 3. Small animals 4. Snakes 5. Insects

Question 30

Why must pipe protection be provided? 1. To control corrosion 2. To prevent leakage 3. To prevent rupture 4. To prevent collapse 5. To control flows

Answer 30

1. control corrosion 2. prevent leakage 3. prevent rupture 4. prevent collapse

Question 31

Which items are important considerations when selecting a type of pipe for a specific installation? 1. Cost of the installation and the pipe 2. Water pressures and external pressures the pipe must withstand 3. Corrosive conditions of the soil and water 4. Record keeping requirements for the pipe material 5. Administrative costs for pipe testing

Answer 31

1. Cost of the installation and the pipe 2. Water pressures and external pressures the pipe must withstand 3. Corrosive conditions of the soil and water

Question 32

Under which conditions are thrust blocks used to anchor pipes and fittings to keep them from moving or being pulled apart? 1. Change in demand for corrosion control 2. Change in water quality 3. Change in direction of the pipe 4. Sudden stoppage of flow 5. Sudden increase in velocity

Answer 32

3. Change in direction of the pipe 4. Sudden stoppage of flow 5. Sudden increase in velocity

Question 33

What could be the source of supply for a water distribution system? 1. Well 2. Treatment plant clear well 3. Lakes 4. Rivers 5. Purchased water connection

Answer 33

1. Well 2. Treatment plant clear well 5. Purchased water connection

Question 34

What benefits can distribution storage provide? 1. Chlorinated water may be held in covered distribution reservoirs to provide an extended contact time for effective disinfection 2. Power costs can be reduced by pumping only during off peak hours 3. Reservoirs may serve as sand traps to allow the settling of sand and suspended solids in the water 4. Water from various sources can be blended together in the reservoir to provide water of consistent and acceptable quality to the consumers 5. Uncovered reservoirs increase protection against surface contamination

Answer 34

1. Chlorinated water may be held in covered distribution reservoirs to provide extended contact time for effective disinfection. 2. Power costs can be reduced by pumping only during off-peak hours. 3. Reservoirs may serve as sand traps to allow settling of sand and suspended solids in water. 4. Water from various sources can be blended together in reservoir to provide water of consistent and acceptable quality to consumers.

Question 35

What are the disadvantages of concrete pipe ? 1. Is durable 2. Is heavy 3. May be hard to tap 4. May deteriorate in aggressive (corrosive) soils 5. Needs special fittings

Answer 35

2. Is heavy 3. May be hard to tap 4. May deteriorate in aggressive (corrosive) soils 5. Needs special fittings

Question 36

What kinds of existing and predictable hazards may be identified during inspections by a competent person at excavations and the adjacent areas ? 1. Protective system failures 2. Hazardous conditions such as hazardous wastes 3. Potential cave-ins 4. Hazardous atmosphere 5. Investigative reporters

Answer 36

1. Protective system failures 2. Hazardous conditions such as hazardous wastes 3. Potential cave-ins 4. Hazardous atmospheres

Question 37

Which items should be considered when selecting a water meter? 1. Availability of spare parts 2. Ability to meet required capacity with minimum head loss 3. Durability 4. Ability to accurately measure and register anticipated flow levels 5. Ease of repair

Answer 37

1. Availability of spare parts 2. ability to meet required capacity with minimum head loss 3. Durability 4. Ability to accurately measure and register anticipated flow levels 5. Ease of repair

Question 38

Which topics are typically included in shoring regulations? 1. Access to construction work area 2. Soil conditions and trench location 3. Sloping excavation walls 4. Operator safety 5. Pedestrian safety

Answer 38

1. Access to construction work area 2. Soil conditions and trench location 3. Sloping excavation walls 4. Operator safety 5. Pedestrian safety

Question 39

What are the various types of pipe fittings used for in distribution systems? 1. Tap the line for pipe extensions 2. change flow direction 3. Stop flow 4. Reduce the pipe size 5. Connect pipes of different sizes

Answer 39

1. Tap the line for pipe extensions 2. change flow direction 3. stop flow 4. reduce the pipe size 5. connect pipes of different sizes

Question 40

What are the limitations of compound water meters? 1. Not suited for locations with widely varying flows where accurate low flow measurements is needed 2. Large and cumbersome 3. Expensive 4. Accuracy drops during the changeover from low to high and high to low flows 5. Loss of head from friction is higher than in high flow meters

Answer 40

2. Large and cumbersome 3. Expensive 4. Accuracy drops during the changeover from low to high and high to low flows 5. Loss of head from friction is higher than in high-flow meters

Question 41

What are the basic requirements of pipes for water distribution systems? 1. Maximum corrosion resistance 2. Support of bio films 3. Durability 4. No adverse effect on water quality 5. Adequate strength

Answer 41

1. maximum corrosion resistance 3. durability 4. no adverse effect on water quality 5. adequate strength

Question 42

Which strategic points in a distribution system are water meter locations? 1. Reservoirs outlets 2. Pumping stations 3. Connections to other utility systems 4. Each customers service 5. Main supply lines

Answer 42

1. reservoir outlets 2. pumping stations 3. connections to other utility systems 4. each customer's service 5. main supply lines

Question 43

What causes water hammer in a pipeline? 1. Turning pumps on or off 2. Pounding to hard on a pipe with a hammer 3. Stagnant or slowly flowing water in the pipeline 4. Operating valve too rapidly 5. Too much air in surge chamber

Answer 43

1. Turning pumps on or off | 4. Operating valves too rapidly

Question 44

What are the purposes of valves in a distribution system? 1. Prevent backflow 2. Provide air release and vacuum relief 3. Reduce pressure 4. Regulate the flow of water 5. Blow off or drain water from parts of the system

Answer 44

1. prevent backflow 2. provide air release and vacuum relief 3. reduce pressure 4. regulate flow of water 5. blow off or drain water from parts of the system

Question 45

Which factors influence the need for shoring and shoring requirements ? 1. Nearby activities that could cause vibrations 2. Depth of the trench 3. Soil conditions 4. Type of soil 5. Width of the trench

Answer 45

1. nearby activities that could cause vibrations 2. depth of the trench 3. soil conditions 4. type of soil 5. width of the trench