ASPE CPD MAIN TIPS ANSWERS AND QUESTIONS
SET A+
✔✔When interior drainage piping developed length reaches 100 feet, what should
happen and why? - ✔✔A vent to atmosphere should be provided. It should run
independently through the roof, this is to prevent the rapid fouling of the pipe due to the
growth of slime and fungi in the absence of air circulation.
✔✔The sizing for indirect wastes is the same as direct-waste connections with what
exception? - ✔✔Due to the low velocities usually present in indirect wastes, stoppages
are more prevalent, and cleanouts should be provided at every possible location.
✔✔For an indirect waste, the discharge outlet should be what? - ✔✔A minimum of 1.5
times the indirect pipe size above the flood level of the receptacle.
✔✔How can the fixture unit flow rate be calculated? - ✔✔By dividing the total discharge
flow in gallons per minute of a single fixture divided by 7.5 gal/ft^3
✔✔What factors do FUs account for? - ✔✔Application in conjunction with the probability
of simultaneous use of fixtures.
✔✔For interior drainage systems, the rate of flow in a fixture drain should be what? -
✔✔The same as the rate of flow discharged at the fixture outlet.
✔✔For interior drainage systems, the minimum fixture drain size is what? - ✔✔The
minimum size of the fixture trap (often given in a table)
✔✔What is the recommended value of n, the coefficient of roughness, for storm drains
of all sizes? - ✔✔0.0145
✔✔The designer must know what as related to the sewer, water, and gas inverts and
locations? - ✔✔The actual elevation of all of the floors of the building.
,✔✔What is the minimum velocity of flow to achieve scouring action in piping? For
keeping grease in suspension in greasy wastes? For suspension in Storm Sewers? -
✔✔2 fps, 4 fps, 3 fps. Dont forget to limit the length of runs for 1-1/2 and 2‚Äù pipe to
maintain scouring action.
✔✔What is the conversion for uniform flow velocity and capacity in sloping pipe going
from from 1/4 in/ft slope to 1/8 in/ft? 1/2 in/ft? - ✔✔0.707 and 1.414
✔✔The hydraulic mean depth of flow or hydraulic radius is what ratio and what value? -
✔✔The ratio of the cross sectional area of flow to the wetted perimeter of pipe surface,
expressed as D/4 where D is diameter in feet. It is the same ratio for full and half flow.
✔✔How is the quantity ‚Äúrate of flow‚Äù expressed? - ✔✔Cross sectional area of flow
times the average velocity.
✔✔What formula determines the velocity of uniform flow in sloping drains? - ✔✔The
Manning Formula
✔✔Flow in piping and open channels is caused by what? - ✔✔The gravitational force
induced by the slope of the drain and the height of water in that drain.
✔✔How is maximum pressure drop calculated for a medical gas system? - ✔✔Identify
the maximum pressure drop allowed for the specific gas system, divide it by equivalent
length, and multiply by 100.
✔✔In medical gas piping, how is diversity calculated? - ✔✔From simultaneous use
factors given in a table.
✔✔What are recommended minimum medical gas riser sizes? - ✔✔Oxygen: 3/4‚Äù
Medical air: 3/4” Nitrous Oxide: 3/4” Nitrogen: 1” Vacuum: 1”
✔✔What are minimum medical gas pipe sizes? - ✔✔Med gas mains and branches:
1/2” Vacuum mains and branches: 3/4” Drops to individual outlets/inlets: 1/2”
Piping to alarm panels: 1/4”
✔✔Where should medical gas piping be labeled? - ✔✔Every 20 feet, once in each
room, at each side of every wall penetration, and at each floor level, and with the
appropriate color.
✔✔What joints are prohibited in medical gas systems? - ✔✔Flared or compression type,
straight thread connections, clamp/gasket style couplings, pipe crimping tools, all joints
that do not provide the mechanical, thermal, and sealing integrity of a brazed joint.
,✔✔What type of piping material is used for vacuum or WAGD medical gas? -
✔✔Seamless, hard-drawn type K, L or M copper tube or stainless steel tube. For level 3
vacuum systems, schedule 40 wall pvc plastic may be used.
✔✔What type of piping material is used for medical air or gases? - ✔✔Hard drawn
seamless type K or L copper tube, cleaned and capped for medical services (ASTM
B819)
✔✔For gas piping, how is probable peak demand calculated? - ✔✔Identify the number
of outlets for the system, identify the outlet/room flow rate for each specific gas,
determine the simultaneous use factor/diversity percentage
✔✔What are the requirements for medical/surgical vacuum outlets? - ✔✔Med/surg
vacuum outlets should draw 85 LPM (3 standard cfm) without reducing the vacuum
pressure below 12 in Hg at any adjacent outlet
✔✔What is the delivery required for oxygen and medical air outlets serving critical
areas? - ✔✔170 liters per minute (6 standard cfm) for a minimum of three seconds
✔✔What is the delivery rate, pressure drop, and static pressure for support outlets? -
✔✔140 liters per minute (5 standard cfm, or scfm) delivery, pressure drop of no more
than 5 psi, and a static pressure of 160-185 psig
✔✔What is the pressure, delivery rate, pressure drop, and static pressure for oxygen,
nitrous oxide, medical air and carbon dioxide outlets? - ✔✔50 psig pressure, 100 liters
per minute (3.5 standard cfm, or scfm) delivery, pressure drop of no more than 5 psi,
and a static pressure of 50-55 psig
✔✔What shall medical gas valve identification include? - ✔✔Name of the gas or
vacuum system, room or areas served, a caution to not close or open the valve except
in an emergency
✔✔What is a WAGD system? - ✔✔Waste anaesthetic gas disposal system includes oil-
les/inert vacuum producers, and is required at each anesthetizing location. It is violet
colored and gas specific. The minimum flow/Hg is determined by patient equipment
requirements
✔✔What are the three levels and their ramifications in terms of potential patient risk if a
medical gas system fails? - ✔✔Level 1: Places patients in imminent danger of morbidity
or mortality Level 2: Places patients at manageable risk for morbidity or mortality Level
3: Terminates procedures but would not place patients at risk of morbidity or mortality
✔✔What is the definition of medical gases and can you name the 8 major gases? -
✔✔Gases that are used as part of a healthcare procedure other than for normal body
, functions. 1) Oxygen, 2) Medical Air 3) Nitrous Oxide 4) Carbon dioxide 5) Nitrogen 6)
Instrument Air 7) Vacuum and 8) WAGD
✔✔What two methods of gas sizing may be used? - ✔✔1) The longest length method
sizes the main from the meter to the farthest gas user (stay constant along the
maximum horizontal length). The same maximum length can be used for branches. 2)
The branch length method sizes the branches (not the main) based on their individual
actual lengths from the meter.
✔✔What five factors are involved in the sizing of gas systems? - ✔✔1) Allowable
pressure drop from meter to farthest outlet 2) Demand (load) in (ft^3/h) 3) Actual length
of run (see NFPA 54 National Fuel Gas Code for gas sizing tables) 4) Specific gravity of
gas 5) Diversity factor (or factor of usage) if allowed by code
✔✔What is the testing procedure for the gas piping? - ✔✔The entire system should be
subjected to an air test for 10 min at a pressure that is twice the working pressure
without showing any loss of pressure.
✔✔What design considerations are there for gas piping within a building? - ✔✔All risers
should be valved, and drips should be located at all low points in the building and at the
base of all risers. Connections from the mains should be from the top or side whenever
possible, if impossible, a connection can me made from the bottom with either a drip or
a pitch down to the main in the branch piping. Each piece of equipment should have a
shutoff valve.
✔✔What range should the total pressure drop fall within from the gas meter to the
farthest outlet? - ✔✔0.2 to 0.5 in wc, never exceeding 10 percent of the available gas
pressure.
✔✔Describe the gas line coming into the building: - ✔✔It must have a minimum cover of
2 ft or greater, a curb valve should be installed at the tap off of the main, and a shutoff
valve should be installed within 2 ft of the point of entry into the building. The point of
entry into the building should be 10 feet away from any stairway.
✔✔Before commencing design of the system, the engineer should contact the local
utility company to determine what? - ✔✔Their rules and regulations, the point at which
the utility company’s work ends and the contractors work begins, BTU value and
pressure of gas supplied, any special requirements
✔✔What is a special consideration for burying steel piping? - ✔✔Protect it with a
corrosion-resistant material (bitumastic paint, etc.)
✔✔What is the preferred material for gas piping, and when and what other materials
can be used? - ✔✔Black steel is preferred, brass and copper can be used when the gas
is not corrosive, stainless steel and corrugated stainless steel may also be used.
SET A+
✔✔When interior drainage piping developed length reaches 100 feet, what should
happen and why? - ✔✔A vent to atmosphere should be provided. It should run
independently through the roof, this is to prevent the rapid fouling of the pipe due to the
growth of slime and fungi in the absence of air circulation.
✔✔The sizing for indirect wastes is the same as direct-waste connections with what
exception? - ✔✔Due to the low velocities usually present in indirect wastes, stoppages
are more prevalent, and cleanouts should be provided at every possible location.
✔✔For an indirect waste, the discharge outlet should be what? - ✔✔A minimum of 1.5
times the indirect pipe size above the flood level of the receptacle.
✔✔How can the fixture unit flow rate be calculated? - ✔✔By dividing the total discharge
flow in gallons per minute of a single fixture divided by 7.5 gal/ft^3
✔✔What factors do FUs account for? - ✔✔Application in conjunction with the probability
of simultaneous use of fixtures.
✔✔For interior drainage systems, the rate of flow in a fixture drain should be what? -
✔✔The same as the rate of flow discharged at the fixture outlet.
✔✔For interior drainage systems, the minimum fixture drain size is what? - ✔✔The
minimum size of the fixture trap (often given in a table)
✔✔What is the recommended value of n, the coefficient of roughness, for storm drains
of all sizes? - ✔✔0.0145
✔✔The designer must know what as related to the sewer, water, and gas inverts and
locations? - ✔✔The actual elevation of all of the floors of the building.
,✔✔What is the minimum velocity of flow to achieve scouring action in piping? For
keeping grease in suspension in greasy wastes? For suspension in Storm Sewers? -
✔✔2 fps, 4 fps, 3 fps. Dont forget to limit the length of runs for 1-1/2 and 2‚Äù pipe to
maintain scouring action.
✔✔What is the conversion for uniform flow velocity and capacity in sloping pipe going
from from 1/4 in/ft slope to 1/8 in/ft? 1/2 in/ft? - ✔✔0.707 and 1.414
✔✔The hydraulic mean depth of flow or hydraulic radius is what ratio and what value? -
✔✔The ratio of the cross sectional area of flow to the wetted perimeter of pipe surface,
expressed as D/4 where D is diameter in feet. It is the same ratio for full and half flow.
✔✔How is the quantity ‚Äúrate of flow‚Äù expressed? - ✔✔Cross sectional area of flow
times the average velocity.
✔✔What formula determines the velocity of uniform flow in sloping drains? - ✔✔The
Manning Formula
✔✔Flow in piping and open channels is caused by what? - ✔✔The gravitational force
induced by the slope of the drain and the height of water in that drain.
✔✔How is maximum pressure drop calculated for a medical gas system? - ✔✔Identify
the maximum pressure drop allowed for the specific gas system, divide it by equivalent
length, and multiply by 100.
✔✔In medical gas piping, how is diversity calculated? - ✔✔From simultaneous use
factors given in a table.
✔✔What are recommended minimum medical gas riser sizes? - ✔✔Oxygen: 3/4‚Äù
Medical air: 3/4” Nitrous Oxide: 3/4” Nitrogen: 1” Vacuum: 1”
✔✔What are minimum medical gas pipe sizes? - ✔✔Med gas mains and branches:
1/2” Vacuum mains and branches: 3/4” Drops to individual outlets/inlets: 1/2”
Piping to alarm panels: 1/4”
✔✔Where should medical gas piping be labeled? - ✔✔Every 20 feet, once in each
room, at each side of every wall penetration, and at each floor level, and with the
appropriate color.
✔✔What joints are prohibited in medical gas systems? - ✔✔Flared or compression type,
straight thread connections, clamp/gasket style couplings, pipe crimping tools, all joints
that do not provide the mechanical, thermal, and sealing integrity of a brazed joint.
,✔✔What type of piping material is used for vacuum or WAGD medical gas? -
✔✔Seamless, hard-drawn type K, L or M copper tube or stainless steel tube. For level 3
vacuum systems, schedule 40 wall pvc plastic may be used.
✔✔What type of piping material is used for medical air or gases? - ✔✔Hard drawn
seamless type K or L copper tube, cleaned and capped for medical services (ASTM
B819)
✔✔For gas piping, how is probable peak demand calculated? - ✔✔Identify the number
of outlets for the system, identify the outlet/room flow rate for each specific gas,
determine the simultaneous use factor/diversity percentage
✔✔What are the requirements for medical/surgical vacuum outlets? - ✔✔Med/surg
vacuum outlets should draw 85 LPM (3 standard cfm) without reducing the vacuum
pressure below 12 in Hg at any adjacent outlet
✔✔What is the delivery required for oxygen and medical air outlets serving critical
areas? - ✔✔170 liters per minute (6 standard cfm) for a minimum of three seconds
✔✔What is the delivery rate, pressure drop, and static pressure for support outlets? -
✔✔140 liters per minute (5 standard cfm, or scfm) delivery, pressure drop of no more
than 5 psi, and a static pressure of 160-185 psig
✔✔What is the pressure, delivery rate, pressure drop, and static pressure for oxygen,
nitrous oxide, medical air and carbon dioxide outlets? - ✔✔50 psig pressure, 100 liters
per minute (3.5 standard cfm, or scfm) delivery, pressure drop of no more than 5 psi,
and a static pressure of 50-55 psig
✔✔What shall medical gas valve identification include? - ✔✔Name of the gas or
vacuum system, room or areas served, a caution to not close or open the valve except
in an emergency
✔✔What is a WAGD system? - ✔✔Waste anaesthetic gas disposal system includes oil-
les/inert vacuum producers, and is required at each anesthetizing location. It is violet
colored and gas specific. The minimum flow/Hg is determined by patient equipment
requirements
✔✔What are the three levels and their ramifications in terms of potential patient risk if a
medical gas system fails? - ✔✔Level 1: Places patients in imminent danger of morbidity
or mortality Level 2: Places patients at manageable risk for morbidity or mortality Level
3: Terminates procedures but would not place patients at risk of morbidity or mortality
✔✔What is the definition of medical gases and can you name the 8 major gases? -
✔✔Gases that are used as part of a healthcare procedure other than for normal body
, functions. 1) Oxygen, 2) Medical Air 3) Nitrous Oxide 4) Carbon dioxide 5) Nitrogen 6)
Instrument Air 7) Vacuum and 8) WAGD
✔✔What two methods of gas sizing may be used? - ✔✔1) The longest length method
sizes the main from the meter to the farthest gas user (stay constant along the
maximum horizontal length). The same maximum length can be used for branches. 2)
The branch length method sizes the branches (not the main) based on their individual
actual lengths from the meter.
✔✔What five factors are involved in the sizing of gas systems? - ✔✔1) Allowable
pressure drop from meter to farthest outlet 2) Demand (load) in (ft^3/h) 3) Actual length
of run (see NFPA 54 National Fuel Gas Code for gas sizing tables) 4) Specific gravity of
gas 5) Diversity factor (or factor of usage) if allowed by code
✔✔What is the testing procedure for the gas piping? - ✔✔The entire system should be
subjected to an air test for 10 min at a pressure that is twice the working pressure
without showing any loss of pressure.
✔✔What design considerations are there for gas piping within a building? - ✔✔All risers
should be valved, and drips should be located at all low points in the building and at the
base of all risers. Connections from the mains should be from the top or side whenever
possible, if impossible, a connection can me made from the bottom with either a drip or
a pitch down to the main in the branch piping. Each piece of equipment should have a
shutoff valve.
✔✔What range should the total pressure drop fall within from the gas meter to the
farthest outlet? - ✔✔0.2 to 0.5 in wc, never exceeding 10 percent of the available gas
pressure.
✔✔Describe the gas line coming into the building: - ✔✔It must have a minimum cover of
2 ft or greater, a curb valve should be installed at the tap off of the main, and a shutoff
valve should be installed within 2 ft of the point of entry into the building. The point of
entry into the building should be 10 feet away from any stairway.
✔✔Before commencing design of the system, the engineer should contact the local
utility company to determine what? - ✔✔Their rules and regulations, the point at which
the utility company’s work ends and the contractors work begins, BTU value and
pressure of gas supplied, any special requirements
✔✔What is a special consideration for burying steel piping? - ✔✔Protect it with a
corrosion-resistant material (bitumastic paint, etc.)
✔✔What is the preferred material for gas piping, and when and what other materials
can be used? - ✔✔Black steel is preferred, brass and copper can be used when the gas
is not corrosive, stainless steel and corrugated stainless steel may also be used.
