D2 WATER DISTRIBUTION EXAM TEST QUESTIONS WITH
CORRECT ANSWERS RATED A+ ASSURED SUCCESS
The minimum pressure at ground level at all points in the
distribution system under all flow conditions must be
20 psi
What is the water velocity limit for normal operations
About 5ft/s
1 psi = ? Ft head
2.31
1 ft head = ? Psi
0.433
What are some factors that make a difference in the type of
pipe used?
Water Hammer, External Pressures, Corrosion Resistance, C-
Value, Compatibility with existing materials, economy, local
conditions, state/ local regulations, weather, earthquakes, fire
protection, sunlight
1
Page
,What are the 2 types of service pipes?
Transmission Pipe & Distribution Mains
Transmission Mains
From source to distribution (ductile iron material most
common)
Distribution Mains
From distribution to customer (cast-iron most common)
What are some types of ductile iron pipe joints?
Flanged, mechanical, push-on, ball and socket, restrained
What type of joints are often used in exposed locations such as
treatment plants and pumping station?
Flanged (Pipe installation is to be rigid and pipe must be
restrained from movement
What type of joint has special bells fitted with rubber gaskets?
Mechanical Joint
2
Page
, What type of joint is the most popular type for main installation
because they are inexpensive and easy to install?
Push-on Joints
What type of valves are start/stop valves?
Gate valves
What type of valves are the most common, cheaper and easier
to control?
Butterfly valves
What type of valves flows in only one direction?
Check Valve
Which type of valves should not be used for throttling flow for
prolonged periods because vibration of gates will eventually
wear and damage valve?
Gate and Butterfly
3
Page
CORRECT ANSWERS RATED A+ ASSURED SUCCESS
The minimum pressure at ground level at all points in the
distribution system under all flow conditions must be
20 psi
What is the water velocity limit for normal operations
About 5ft/s
1 psi = ? Ft head
2.31
1 ft head = ? Psi
0.433
What are some factors that make a difference in the type of
pipe used?
Water Hammer, External Pressures, Corrosion Resistance, C-
Value, Compatibility with existing materials, economy, local
conditions, state/ local regulations, weather, earthquakes, fire
protection, sunlight
1
Page
,What are the 2 types of service pipes?
Transmission Pipe & Distribution Mains
Transmission Mains
From source to distribution (ductile iron material most
common)
Distribution Mains
From distribution to customer (cast-iron most common)
What are some types of ductile iron pipe joints?
Flanged, mechanical, push-on, ball and socket, restrained
What type of joints are often used in exposed locations such as
treatment plants and pumping station?
Flanged (Pipe installation is to be rigid and pipe must be
restrained from movement
What type of joint has special bells fitted with rubber gaskets?
Mechanical Joint
2
Page
, What type of joint is the most popular type for main installation
because they are inexpensive and easy to install?
Push-on Joints
What type of valves are start/stop valves?
Gate valves
What type of valves are the most common, cheaper and easier
to control?
Butterfly valves
What type of valves flows in only one direction?
Check Valve
Which type of valves should not be used for throttling flow for
prolonged periods because vibration of gates will eventually
wear and damage valve?
Gate and Butterfly
3
Page
