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Distribution and Storage Flashcards

(74 cards)

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1
Q

Water meters used for domestic residential services.

A
  • Displacement type:
  1. Nutating disc meter
  2. Piston meter
  • Velocity type:
    1. Turbine
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2
Q

Most common residential water meter.

A

Nutating disc meter

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3
Q

Wear in positive displacement meter will cause this.

A

Meter will under-register (record less than actual flow)

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4
Q

Only a decimal fraction of the water flows trough this type of meter.

A

Proportional meter

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5
Q

Meters designed specifically to respond accurately to low flows.

A

Displacement type meters

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6
Q

Installation of meters can minimize or reduce this.

A

Wasteful water use (Installation of meters is the first step in water conservation)

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7
Q

Distribution reservoirs are covered for these reasons.

A
  • Eliminate airborne contamination
  • Reduce loss of chlorine
  • Minimize growth of nuisance algae
  • Prevent vandalism
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8
Q

Function or purpose of distribution system reservoirs

A
  • Provide emergency and fire flow reserves
  • Provide disinfection contact times - Equalize peak flows
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9
Q

Corrosion of ductile iron pipe can be minimized by this.

A
  • The interior of the pipe can be lined with cement - The exterior of the pipe can be covered with polyethylene plastic.
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10
Q

the taste and odor problems of distribution system dead ends can be reduced with this.

A

Routine flushing

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11
Q

This should be provided at all distribution system tees and crosses.

A

Isolation valves

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12
Q

Factors that determine friction loss in distribution system piping.

A
  • Pipe diameter - Interior roughness - Flow rate or velocity - Pipe length - Number and type of fittings
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13
Q

Purpose of the isolation valve on the line to a fire hydrant.

A
  • Backup in the event of failure of the hydrant valve - Allows isolation of the hydrant for repair
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14
Q

Distribution leak detection methods.

A
  • Visual inspection during dry weather periods - Listening with various hydrophone systems - Closing off portions of the system and measuring water flow
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15
Q

Minimum maintenance on distribution system valves.

A

Operated once per year

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16
Q

Trench load on a buried pipe is determined by these factors.

A
  • Trench depth - Trench width
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17
Q

Flow measuring devices in a typical compound meter.

A
  • Velocity (turbine) meter for high flow - Displacement meter low flow
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18
Q

This must be provided at distribution system pipe bends.

A

Thrust restraint at the bend

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19
Q

Typical percent of unaccounted water in a metered distribution system.

A

10 to 20 percent

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20
Q

The minimum size water main to supply a standard fire hydrant.

A

6 inch

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21
Q

This increases the thrust at pipe bends

A

The thrust increases as the angle of the bend becomes more acute: - The thrust on a 45° bend is greater than a 30° bend. - The thrust on a 90° bend is greater than a 45° bend.

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22
Q

This should be done when rocky soil is encountered in a trench.

A

The trench should be over excavated by approximately 6 inches and replaced with a suitable back fill material, such as sand

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23
Q

Water meter designed to accurately register over a wide flow range.

A

Compound meter

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24
Q

Materials banned from use in distribution or plumbing systems.

A

Lead based pipe and solder

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25
Brass plug valve threaded into a tapped water main.
Corporation stop
26
Used to de-water excavations and trenches.
Well point system
27
This can be provided to protect steel tanks and pipes from corrosion.
Cathodic protection
28
Rapid opening and closing of a fire hydrant valve can cause this.
Water hammer
29
Minimum distribution system pressure that should be maintained during fire flow.
20 psi
30
The purpose of distribution system valves.
They enable isolation of small portions of the system for maintenance or repair.
31
Process of making a connection to a water line that is under pressure.
"Live tap" or "wet tap"
32
Distance from bottom of hydrant to 4 inches below the flange that connects the upper hydrant barrel.
Hydrant bury
33
Fire hydrant with a drain opening that allows the barrel to drain when the control valve is closed.
Dry barrel hydrant
34
The function of distribution system booster pumps.
Provide pressure "boost" at higher elevation
35
Recommended accuracy for residential water meter.
+/- 1.5% accuracy
36
Acronyms for pipe used in water distribution systems. - ACP - CCP - DIP - PVC - CIP - GIP
- Asbestos cement pipe - Concrete cylinder pipe - Ductile iron pipe - Polyvinyl chloride - Cast iron pipe - Galvanized iron pipe
37
Used to control the water level in a storage reservoir.
Altitude valve
38
Used to measure hydrant flow
Pitot meter
39
Used to provide electrical continuity to ductile iron pipe water mains.
Metal wedges or straps
40
Most common distribution system valve.
Gate valve
41
Used to replace sections of a distribution system main during repair
"Dresser" style coupling
42
Distribution system piping and pumping can be downsized if this is properly located and designed.
Distribution system storage reservoirs.
43
These conditions can contribute to freezing of water distribution mains.
- Extreme cold weather - Shallow pipe bury - Lack of snow cover - Intermittent or low flow
44
These conditions can result in a reduction in the "C" factor for distribution system water mains, with subsequent increase in friction loss.
Tuberculation (deposits formed by corrosion of iron or steel) or scale deposition
45
Distribution system air and relief valves should be placed here.
At high points
46
Trenchless construction method used to install a water main under a road or railroad.
Jacking
47
Purpose of thrust blocking.
Keep pipe joints from separating
48
Recommended spacing interval for distribution system isolation valves in a residential area.
Every 800 ft
49
Permanent point of known elevation.
Benchmark
50
Substance added to water to produce a protective film on the pipe wall, to minimize corrosion.
Passivator or inhibitor
51
Used for water main repair: - Localized leak - Insert new pipe section
- Localized leak: Split sleeve repair system - Insert pipe section: "Dresser" style couplings
52
Controls the level in a water storage tank when the water surface in below the hydraulic gradient.
Altitude valve
53
Important safeguards for a water distribution system.
- Maintain disinfection residual - Maintain continuous pressure - Implement an active cross connection program - Regularly test for disinfection residual and bacteriological quality.
54
The control valve for a dry barrel hydrant is located here.
In the hydrant head
55
Used to "passivate" or provide a protective protective film on distribution system mains to reduce corrosion.
- Silica compounds - Polyphosphates
56
Steps to perform before a newly installed distribution water main is backfilled.
- Perform pressure or leak test - Flush main - Disinfect - Flush main - Collect bacteriological sample
57
Purpose of a dry barrel hydrant.
Protects the hydrant from freezing
58
Maximum rated flow for a 5/8 x 3/4 inch residential meter.
20 gpm
59
Criteria for selecting hydrant types: - Dry barrel - Wet barrel
- Dry barrel hydrants are used where there is a danger of hydrant freezing. - Wet barrel hydrants are used in warm climates where there is no danger of freezing.
60
Use of distribution system maps: - Plan view. - Section or elevation view.
- Used to determine horizontal dimensions and layout. Example: What is the distance from the curb to a water main in the street. - Used to determine depths and elevations. Example Is a sewer line above or below a water main.
61
Purpose of OS & Y gate valves.
gate valve with open stem and yoke, used when it is important to see at a glance if the valve is open or closed.
62
Used to regulate system pressure that exceeds the recommended maximum water service pressure at 80 psi.
Pressure regulating valve
63
Important requirements for water storage tank overflow piping.
- Should be sized to handle maximum fill rate - Should include a "backwater" valve on the outlet
64
Minimum recommended residual system pressure during hydrant flow testing.
20 psi
65
Purpose or function of altitude valves.
Control the maximum filling level in a distribution system storage tank or reservoir.
66
Advantages-disadvantages of ductile iron.
- Able to withstand extreme internal and external stress loads - Can be used in extreme trench conditions. - One of the heaviest pipe materials - Subject to internal or external corrosion unless steps are taken to provide corrosion protection
67
Advantages-disadvantages of concrete cylinder.
- Available in large diameters - High strength, able to withstand internal and external stresses - Resistant to corrosion unless cement lining is damaged
68
Advantages-disadvantages of asbestos cement.
- Light weight - Corrosion resistant except in very acid soils or low pH water - Easily damaged by rough handling during installation, or by trench rocks
69
Advantages-disadvantages of PVC.
- Light weight , easy to handle and install - Complete corrosion resistance - Not suitable for soils with petroleum residues
70
Valve with lowest friction loss when open.
Gate valve
71
Common joint methods used for distribution system piping.
- Mechanical joint - Flange - Rubber ring "push on" - Bell and spigot, with poured lead - Solvent weld
72
Purpose or function of pipeline air/vacuum relief valve.
- Allow pipeline air to escape - Allow air to enter a pipeline to reduce risk of pipe collapse, in the event of sudden loss of pressure
73
Methods used to clean distribution system mains.
- Hydrant flushing - Water main pigging
74
Causes of drinking water contamination.
- Inadequate water treatment or disinfection - Cross connections - Water main break or repairs
DW Distribution
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