Chapter 14 Flashcards
Water Supply
What are the 2 basic water supply systems in North America?
- Public
2. Private
What are public water supply systems?
a function of local government or state authorized water district
What are private water supply systems?
provide water to municipality, region, or single property
What are some water supply sources?
lakes, reservoirs, ponds, rivers, streams, wells, springs
What are processing or treatment facilities?
purification or desalination plants
What means are used to move the water?
water pumps
Storage tanks, control valves, piping systems, and hydrants are all…
water distribution and storage systems
What are the main components of public and private water supply systems?
- water supply
- processing or treatment facilities
- means of moving water
- water distribution/storage systems
Why is ocean water not good supply source?
220 times saltier than fresh water and contains impurities
How does one determine how much water a community needs?
based off of history of consumption and estimates of anticipated needs
How can a water system be considered as “adequate”?
it must contain enough water for fire protection needs and domestic requirement
Prior to entering the distribution system, what does water have to pass through first?
water treatment or processing facilities
What are the 3 methods for moving water through the systems?
- Gravity
- Direct pumping
- Combination
What is the gravity system?
supply system that relies entirely on the force of gravity to create pressure and cause water to flow through the system
What is elevation pressure?
The difference in the height of the water source and the point of use
Gravity pressure is only adequate if the primary water source is
located more than a 100 feet higher than highest point
True gravity systems are mainly supplied from what water source?
alpine lake or mountain reservoir
What is a direct pumping system?
water supply system supplied directly by a system of pumps rather than elevated storage tanks
Where are most direct pumping systems found?
agricultural and industrial settings
What is a main disadvantage of direct pumping systems?
total dependence on pumps and on electricity
What is a combination system?
water supply system that is combination of both gravity and direct pumping systems.
What is the most common type of municipal water supply systems?
Combination
What is a cistern?
an underground storage tank collecting rain water that is available to fire protection
What do water distribution systems consist of?
- pipes
- storage tanks
- control valves
- hydrants
What is a water main?
a principal pipe in a system of pipes for conveying water, especially one installed underground
What is a primary feeder?
Large arterial pipes ranging from 16-72 inches
What is a secondary feeder?
Intermediate pipes ranging from 12-14 inches
Large pipes and ___________ interconnect to create a grid
secondary feeders
What is a distributor?
Small water mains ranging from 6-8 inches
What serves individual fire hydrants, commercial, and residential consumers?
Distributors
To ensure efficient water supply____________ should run from the source of supply to the high risk and industrial districts of the community along separate routes
two or more primary feeders
What is a big advantage of the grid system?
high demand in one area does not deplete water flow in other areas
What is the minimum size of pipe used in residential subdivisions?
8 inch
What range of water do gravity tanks hold?
5,000-over a million gallons
What are the 2 types of valves?
- Isolation
2. Control
What are isolation valves?
they are used to isolate sections for maintenance and repair
i.e. replacing hydrants, or to make new connections
What are the maximum spacing lengths for valves?
500 feet
800 feet in high value districts
What is a gate valve?
control valve with a solid plate operated by a handle and screw mechanism. Rotating the handle moves the plate into or out of the waterway
What is a butterfly valve?
Control valve that uses a flat circular plate in a pipe that rotates 90 degrees across the cross section of the pipe to control the flow of water
How often should isolation valves be tested?
once a year
Isolation valves are primarily located where?
on or adjacent to streets, sidewalks, and alleys or below ground
Valves and hydrants are opened by rotating the stem….
counterclockwise
What is an indicating valve?
shows whether the gate valve is open, closed, or partially closed
What are two common indicating valves?
- Post Indicator Valve (PIV)
2. Outside Stem and Yoke Valve (OS & Y)
What is a PIV?
type of valve used to control underground water mains that provide a visual means indicating “open” or “shut” position
What is a OS&Y?
a type of control valve for a sprinkler system in which the position of the center screw indicates whether the valve is open or closed
What is typically located between public water and private water distribution systems?
Control valves
What is a flow-meter?
determines the quantity of water that the facility is using for billing purposes
What is backflow preventer?
prohibits any water from flowing back into the public water system
Fire hydrants should not be spaced more than______ apart?
300 feet in high value districts
What does a dead end hydrant mean?
can only receive water from only one direction
What does a circulating hydrant mean?
located on a secondary feeder or distributor main receiving water from two directions
What does circulating feed mean?
fire hydrant that receives water from two or more directions
What is a loop system?
water main arranged in a complete circuit so that water will be supplied to a given point from more than one direction
Failures or reduction in water supply or pressure can result from…
- Damaged hydrant valves
- Broken water mains
- Frozen pipes or hydrants
What are the two main types of fire hydrants used in North America?
- Dry Barrel
2. Wet Barrel
What is a dry barrel hydrant?
has its operating valve located at the base of foot of the hydrant rather than in the barrel of the hydrant. There is no water in the barrel of the hydrant when it is not in use
What is a wet barrel hydrant?
has water all the way up to the discharge valve outlets. This type of valve is only used in areas with no danger of freezing weather conditions
What is the pumper outlet nozzle?
fire hydrant outlet that is 4 inches in diameter or larger
What is the steamer connection?
Large diameter outlet of 4.5 inches at a hydrant or at the base of an elevated water storage container
