SPE CPD TEST PREP QUESTIONS WITH
SOLUTIONS LATEST UPDATE 2025
GRADED A+
◉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.
SOLUTIONS LATEST UPDATE 2025
GRADED A+
◉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.
