Valves and Hydrants

Question 1

Identify the different types of valves used in a distribution system:

Answer 1

• Gate Valve
• Butterfly Valve
• Globe Valve
• Plug Valve
• Ball Valve
• Diaphragm
• Air Valve
• Check Valve
• Needle Valve
• Pressure Reducing Valve (PRV) - regulates flow to keep range of pressure - if it fails, you’ll see an increase in pressure

Question 2

Describe the operation and use of a GATE VALVE:

Answer 2

For isolation in distribution system. Little resistance to flow, but some.

Isolate for repair, (main) may need key for extension….what?

Question 3

Describe the operation and use of a BUTTERFLY VALVE:

Answer 3

Isolation. Horizontal/Vertical spindle.

For larger mains

Cheaper

Question 4

Explain how to determine if a valve is open or closed

Answer 4

Consult a ““valve record card” to see how many turns is open/closed

Or listen to it (aquaphone)

Or feel vibrations

Question 5

Explains what happens if a valve is closed too fast:

Answer 5

“Water Hammer”
Initially high pressure, then will spread, could be a block or two away.
Then increases and decreases pressure until it is absorbed by the system
Causes leaks

Question 6

Explain why water mains are tapped under pressure,

Answer 6

“Wet Tapping” - dry tapping is when there is no water in it
No dirty water complaints
Can stay in service for consumer

Question 7

Describe the locations or angles recommended for tapping a water main

Answer 7

10 & 2
45 degrees above the horizontal
3 & 9 o’clock for plastic
NEVER AT MIDNIGHT - to prevent accumulation in pipe and better chance of hitting it when digging for main

Question 8

List the procedural steps involve in tapping a water main under pressure using a tapping machine

Answer 8

• Clean Pipe
• Set up machine on saddle
• Slide into correct position
• tighten chains
• ready to drill & tap (one movement)

“second movement - setting up the corporation stop

Question 9

Sketch drawing from main to customer’s meter

Answer 9

Draw:
Water Main
Corporation Stop
Gooseneck
Curb Stop Valve
Curb Stop Valve Box (Vault)

Question 10

What is a thrust block?

Identify locations where thrust blocks and tie rods (bolts) should be used

Answer 10

A thrust block is a concrete pipe restraint that prevents the mainline from moving by transferring pipe loads (mainly due to pressure thrust) to a wider load-bearing surface. Usually, thrust blocks are provided for buried pipelines at fittings requiring branching or direction change.
_/

At the thrust point, goes out angular to undisturbed soil

Keeps joint together, its a device to hold valve/pipes in place as water changes direction

Question 11

List the items of information to be recorded on a valve record card

Answer 11

Manufacturer
Location
Diameter
# of turns open/close
depth
Any maintenance/issues

Question 12

Explain the difference between dry and wet barrel fire hydrants

Answer 12

Dry - In freezing places like WI
dry barrel because close valve and water will drain (goes dry after use)
Problem: Prone to break

Wet - Put out more water, always charged, more sturdy, bigger diameter, used in warm climates

Question 13

List and describe the function of the basic elements of a fire hydrant:

Answer 13

Bonnet (the semi-circle on top)
Stem - allows water in/closes water access via operating nut
Breakable coupling - in case it gets hit by car

Question 14

How often should valves/hydrants be operated?

Answer 14

2-5 years recommended

DNR will ask for valve exercise program

Question 15

What is the pressure standard for:

A. Minimum Fire Flow
B. Minimum Static
C. Maximum Static

Answer 15

A. Dynamic Pressure - At least 20 psi
B. 35 psi
C. 100 psi

Question 16

Discuss the methods used to locate valves and mains

Answer 16

-Maps & Records
-Magnetic Locator
-Pipe locator
-geophone (amplifies sounds in the ground)
-Aquaphone (amplifies sound of water maybe??)
Some sort of needles

Question 17

Explain the use and importance of records in locating valves or hydrants

Answer 17

So you can find them later