ASPE CPD EXAM 350 QUESTIONS & CORRECT
ANSWERS LATEST 2025
Front - ANSWER-Back
What is the specific weight of water? - ANSWER-62.4 lbs per cubic foot
What happens in a storm and sanitary system after it passes the water test? -
ANSWER-A smoke pressure test is recommended with a smoke pressure of 1 in
wc to prove the system gas tight.
Is an air test acceptable for a storm and sanitary system? - ANSWER-Yes, if a
water test is not possible, at a pressure of 5 psi, are tests are impractical and
costly
What are the testing procedures for the storm and sanitary system? - ANSWER-A
water test upon completion of the rough piping and prior to concealment of 10 ft
wc minimum (except the topmost 10 feet of pipe), not to exceed 100 ft wc. If
system is higher than 100 feet, test plugs must be installed to facilitate testing,
rarely are more than 7 stories tested at one time. A peppermint oil test may also
be done with 2 oz of peppermint oil and 10 qt boiling water, and searching for
peppermint smell at leaks, however it is difficult to pinpoint the leak by this
method
The maximum length from the vent connection to any future drain outlet is
required by code, why, how long is the distance (listed in the book), and what’s
,the exception? - ANSWER-To prevent a dead end where slime, sludge and fungi
can grow, 2 feet, unless the piping must be extended to an accessible location for
a cleanout
A sanitary tee may be used in the vertical but what may not be used in the vertical
and why? - ANSWER-A double sanitary tee because the possibility of flow
crossover and excessive pressures when one branch is discharging and the other
isn’t are possible
What are the slopes of pipe inside the building that correspond to 2 fps velocity? -
ANSWER-1/4 in per foot for 3 in and smaller 1/8 in per foot for larger pipe all
elbows, taps, tees etc are tapped at a pitch of 1/4” per foot
Where should cleanouts be provided? - ANSWER-1) Inside or outside the building
at the point of exit (use a wye branch) 2) at every change in direction greater than
45 degrees 3) every 50 feet for piping 4” and less, and 100 ft for larger piping 4)
underground piping larger than 10 in should be provided with manholes at every
change in direction and every 150 feet 5) at the base of all stacks 6) as required by
code
What size cleanouts are provided in piping? - ANSWER-Piping up to 4 inches, the
cleanout is the same size as the pipe. Piping greater than 4 inches, 4 inch
cleanouts are adequate.
What should be installed in the house drain if there is a danger of backflow of
sewage into the building? Whats the difference? - ANSWER-A backwater valve or
a combination BWV with manually operated gate valve. The BWV does not
interfere with the airflow throughout the system, and the gate valve is
recommended where there is a history of backflow as a positive means of
protection.
,Branch connections to the house drain should be made where and why? -
ANSWER-At the upper portion of the pipe (above the 1/2 - 2/3 full mark) because:
1) there is a lower chance of stoppages in the branch 2) there is less flow
interference at the point of connection 3) When there is no flow in the branch,
the full area of the pipe is available to relieve pneumatic pressure fluctuations in
the house drain
How many fixture units are equivalent to 1 gpm continuous or semicontinuous
flow and what are examples of these types of flow? - ANSWER-2 FUs, sump
pumps, ejectors, air conditioning equipment, water cooled, equipment, etc
What minimum slopes are required for building drains and why? - ANSWER-3 in
pipe and smaller: 1/4 in/ft 4-6 in pipe: 1/8 in/ft 8 in pipe and larger: 1/16 in/ft to
maintain 2 fps scouring action if low flow fixtures are present, 1/4 in/ft for all is a
good idea
House drains are designed to flow how full? - ANSWER-1/2 full to 3/4 full max
under uniform flow conditions
What is a house (building) drain? - ANSWER-The lowest piping of a gravity
drainage system that receives the discharge from soil, waste, and other drainage
pipes inside the building that extends a short distance from the building and
conveys the drainage to the building sewer
What is the measurement from horizontal that separates horizontal and vertical
drainage stacks? - ANSWER-45 degrees
, Does an interior drainage stack that offsets 45 degrees or less from the vertical
require a change in size? - ANSWER-No. Any more than a 45 degree offset
requires sizing the offset as a house drain.
What is a branch interval? - ANSWER-A building story or a distance between two
branch connections greater than 8 feet apart.
Describe the procedure for sizing interior drainage stacks. - ANSWER-1) First size
the horizontal branches connecting to the stack 2) Determine the minimum size
that will accept each branch at one branch interval 3) Total all fixture units
connected to the stack, and determine the size. The minimum size must be at
least equal to the largest diameter required at the base. You may reduce in size at
upper branch intervals, but never by more than 1/2 the largest size.
What is the total recommended maximum permissible flow in a stack? - ANSWER-
7/24 of the total cross sectional area of the stack.
Where should and shouldn’t you connect branch connections to stack offsets? -
ANSWER-Not to the horizontal offset to the stack if at all possible, unless its at
least 10 pipe diameters downstream, and ideally 2 feet above the offset or 2 feet
below to avoid pressure fluctuations.
What can minimize hydraulic jump? - ANSWER-Increasing the slope of the
horizontal drain. Connecting to a horizontal drain that is larger than the stack.
Any offset of the stack greater than what can cause hydraulic jump? - ANSWER-45
degrees
ANSWERS LATEST 2025
Front - ANSWER-Back
What is the specific weight of water? - ANSWER-62.4 lbs per cubic foot
What happens in a storm and sanitary system after it passes the water test? -
ANSWER-A smoke pressure test is recommended with a smoke pressure of 1 in
wc to prove the system gas tight.
Is an air test acceptable for a storm and sanitary system? - ANSWER-Yes, if a
water test is not possible, at a pressure of 5 psi, are tests are impractical and
costly
What are the testing procedures for the storm and sanitary system? - ANSWER-A
water test upon completion of the rough piping and prior to concealment of 10 ft
wc minimum (except the topmost 10 feet of pipe), not to exceed 100 ft wc. If
system is higher than 100 feet, test plugs must be installed to facilitate testing,
rarely are more than 7 stories tested at one time. A peppermint oil test may also
be done with 2 oz of peppermint oil and 10 qt boiling water, and searching for
peppermint smell at leaks, however it is difficult to pinpoint the leak by this
method
The maximum length from the vent connection to any future drain outlet is
required by code, why, how long is the distance (listed in the book), and what’s
,the exception? - ANSWER-To prevent a dead end where slime, sludge and fungi
can grow, 2 feet, unless the piping must be extended to an accessible location for
a cleanout
A sanitary tee may be used in the vertical but what may not be used in the vertical
and why? - ANSWER-A double sanitary tee because the possibility of flow
crossover and excessive pressures when one branch is discharging and the other
isn’t are possible
What are the slopes of pipe inside the building that correspond to 2 fps velocity? -
ANSWER-1/4 in per foot for 3 in and smaller 1/8 in per foot for larger pipe all
elbows, taps, tees etc are tapped at a pitch of 1/4” per foot
Where should cleanouts be provided? - ANSWER-1) Inside or outside the building
at the point of exit (use a wye branch) 2) at every change in direction greater than
45 degrees 3) every 50 feet for piping 4” and less, and 100 ft for larger piping 4)
underground piping larger than 10 in should be provided with manholes at every
change in direction and every 150 feet 5) at the base of all stacks 6) as required by
code
What size cleanouts are provided in piping? - ANSWER-Piping up to 4 inches, the
cleanout is the same size as the pipe. Piping greater than 4 inches, 4 inch
cleanouts are adequate.
What should be installed in the house drain if there is a danger of backflow of
sewage into the building? Whats the difference? - ANSWER-A backwater valve or
a combination BWV with manually operated gate valve. The BWV does not
interfere with the airflow throughout the system, and the gate valve is
recommended where there is a history of backflow as a positive means of
protection.
,Branch connections to the house drain should be made where and why? -
ANSWER-At the upper portion of the pipe (above the 1/2 - 2/3 full mark) because:
1) there is a lower chance of stoppages in the branch 2) there is less flow
interference at the point of connection 3) When there is no flow in the branch,
the full area of the pipe is available to relieve pneumatic pressure fluctuations in
the house drain
How many fixture units are equivalent to 1 gpm continuous or semicontinuous
flow and what are examples of these types of flow? - ANSWER-2 FUs, sump
pumps, ejectors, air conditioning equipment, water cooled, equipment, etc
What minimum slopes are required for building drains and why? - ANSWER-3 in
pipe and smaller: 1/4 in/ft 4-6 in pipe: 1/8 in/ft 8 in pipe and larger: 1/16 in/ft to
maintain 2 fps scouring action if low flow fixtures are present, 1/4 in/ft for all is a
good idea
House drains are designed to flow how full? - ANSWER-1/2 full to 3/4 full max
under uniform flow conditions
What is a house (building) drain? - ANSWER-The lowest piping of a gravity
drainage system that receives the discharge from soil, waste, and other drainage
pipes inside the building that extends a short distance from the building and
conveys the drainage to the building sewer
What is the measurement from horizontal that separates horizontal and vertical
drainage stacks? - ANSWER-45 degrees
, Does an interior drainage stack that offsets 45 degrees or less from the vertical
require a change in size? - ANSWER-No. Any more than a 45 degree offset
requires sizing the offset as a house drain.
What is a branch interval? - ANSWER-A building story or a distance between two
branch connections greater than 8 feet apart.
Describe the procedure for sizing interior drainage stacks. - ANSWER-1) First size
the horizontal branches connecting to the stack 2) Determine the minimum size
that will accept each branch at one branch interval 3) Total all fixture units
connected to the stack, and determine the size. The minimum size must be at
least equal to the largest diameter required at the base. You may reduce in size at
upper branch intervals, but never by more than 1/2 the largest size.
What is the total recommended maximum permissible flow in a stack? - ANSWER-
7/24 of the total cross sectional area of the stack.
Where should and shouldn’t you connect branch connections to stack offsets? -
ANSWER-Not to the horizontal offset to the stack if at all possible, unless its at
least 10 pipe diameters downstream, and ideally 2 feet above the offset or 2 feet
below to avoid pressure fluctuations.
What can minimize hydraulic jump? - ANSWER-Increasing the slope of the
horizontal drain. Connecting to a horizontal drain that is larger than the stack.
Any offset of the stack greater than what can cause hydraulic jump? - ANSWER-45
degrees
