Chapter 4 Water Distribution Systems

Question 1

Four basic components of water supply systems

Answer 1

1. water supply source
2. water treatment facilities
3. mechanism for forcing water through the system
4. a system of piping to transport the water through the community

Question 2

average daily consumption

Answer 2

the average of the total amount of water used daily in water distribution system over one year

Question 3

maximum daily consumption

Answer 3

to maximum total amount of water that was used during any 24 hour interval within a three-year period

Question 4

peak hourly consumption

Answer 4

the maximum amount of water used in any one hour interval over the course of a day

Question 5

the maximum daily consumption is normally about…

Answer 5

1.5 average daily consumption

Question 6

what are the two basic categories of water supply sources

Answer 6

surface water

groundwater

Question 7

which is the more commonly used source of water

Answer 7

surface water

Question 8

what is the purpose of man-made water impoundments

Answer 8

they can be filled, and left to let many appeared his filter out naturally

Question 9

4 characteristics of surface water

Answer 9

softer water
more suspended solids and color
more bacterial contamination
depleted more rapidly, low rainfall

Question 10

two types of ground waters and may be used for domestic systems

Answer 10

wells

Springs

Question 11

characteristics of groundwater supplies

Answer 11

heart of water
clearer
less bacteria
less quickly affected by periods of drought

Question 12

two processes of water treatment

Answer 12

adding elements that improve water quality

removing contaminants

Question 13

two additives that are added to water

Answer 13

fluoride

oxygen

Question 14

where the four processes that remove contaminants from water during water treatment

Answer 14

1. sedimentation- particles fall on water
2. filtration- passing water through a set of filters
3. coagulation- chemical that causes solid particles to bond together and form larger particles, which can be filtered out
4. chemical treatment- adding subtracting chemicals to make the water healthy ( oxygen and fluoride)

Question 15

are the three means of moving water

Answer 15

gravity
direct pumping
combination

Question 16

was the most common method of moving water through a water distribution system

Answer 16

combination systems, using elements of both direct pumping and gravity systems, water towers serve as backup pressure sources when system demand is high

Question 17

for the three common designs for water supply system piping arrangements

Answer 17

tree system- Central primary supply pipe that feeds branch distribution lines, mostly from one direction
circle, or belt system- found in small jurisdictions/ private systems… they form a loop serves the consumer’s own system normally have a directional flow haven of her break correction can be reversed
grid systems- in loop system of pipes connected at standard intervals providing reliable multidirectional flow, most reliable type of water distribution

Question 18

primary feeders

Answer 18

largest pipes, or mains, in the system convey large quantity of water to various points

Question 19

secondary feeders

Answer 19

network of intermediate sized pipes reinforce the grid with various loops off primary feeder system. Aid in the concentration of the required flow at any point

Question 20

distributors

Answer 20

smaller main serving individual fire hydrants and blocks of consumers throughout the system

Question 21

from a fire protection standpoint one of the grid systems primary advantages is…

Answer 21

hydrants can receive water from two directions, greatly reducing the amount of friction loss in the system

Question 22

what are some characteristics of well designed grid systems

Answer 22

• two or more primary feeders run by separate routes from the supply source to the community’s high risk industrial districts
• secondary feeders are arranged… Far possible to give two directions of supply at any point

Question 23

What are the sizes of pipes in a grid system

Answer 23

primary feeders 8-72”
secondary feeders 6-36”
distributors 4-20, can be as small as 2

Question 24

American Water Works Association currently recommends a minimum diameter of___ for any new pipe installation

Answer 24

8”

Question 25

what is one of the most important factors in the water supply system

Answer 25

the ability to operate valves promptly during the emergency of equipment breakdown

Question 26

how do you know if an OS&Y valve is open or closed

Answer 26

the threaded portion of the stem is out of the yoke when the valve is open…. inside when closed

Question 27

where the two mechanisms used in controlled valves of water distribution system

Answer 27

gate mechanisms

butterfly mechanisms

Question 28

standard hydrant usually are equipped with a ___ valve opening, and a ___ connection to water main

Answer 28

5” valve opening

6” connection to water main

Question 29

where the three reasons private water systems usually exist

Answer 29

1. water solely for fire protection
2. water for sanitary purposes, consumption, and fire protection
3. water for fire protection and manufacturing processes

Question 30

firefighters should be alert for what type of leaks when hydrant is in use

Answer 30

1. at the main valve when the valve is closed
2. at the drain valve when the main valve is opened but the outlets are capped
3. In the water mains near the hydrant