ASPE CPD Study Questions AH with complete solutions.

ASPE CPD Study Questions AH with complete solutions. Front - correct answer. Back What is the specific weight of water? - correct answer. 62.4 lbs per cubic foot What happens in a storm and sanitary system after it passes the water test? - correct 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? - correct 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? - correct 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? - correct 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? - correct 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? - correct 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? - correct 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? - correct 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? - correct 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? - correct 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? - correct answer. 2 FUs, sump pumps, ejectors, air conditioning equipment, water cooled, equipment, etc What minimum slopes are required for building drains and why? - correct 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? - correct answer. 1/2 full to 3/4 full max under uniform flow conditions What is a house (building) drain? - correct 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? - correct answer. 45 degrees Does an interior drainage stack that offsets 45 degrees or less from the vertical require a change in size? - correct answer. No. Any more than a 45 degree offset requires sizing the offset as a house drain. What is a branch interval? - correct answer. A building story or a distance between two branch connections greater than 8 feet apart. Describe the procedure for sizing interior drainage stacks. - correct 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? - correct answer. 7/24 of the total cross sectional area of the stack. Where should and shouldn’t you connect branch connections to stack offsets? - correct 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? - correct 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? - correct answer. 45 degrees When does terminal velocity occur in a drainage stack? - correct answer. It is achieved at approximately 10 - 15 fps and this velocity is achieved within 10 - 15 feet of fall from the point of entry. A drainage stack should never be designed for a capacity greater than what and why? - correct answer. One-thrid full, because the pressure fluctuations in the system could greatly exceed the maximum 1 in water column criterion and lose their seal by siphonage blowout What is one positive and one negative of a tee-wye fitting? - correct answer. The long radius tee-wye fitting gives the water a greater downward component than a sanitary tee, but also has a greater probability of siphoning the traps How are horizontal branch connections to the stack made? - correct answer. With a sanitary tee (a short radius tee-wye, vertical position only) or with a long radius tee-wye (vertical or horizontal position). (The tee-wye is also called a combination wye and one-eighth bend) What is the difference between soil stacks and waste stacks? - correct answer. Soil stacks collect wastes that contain fecal matter, and waste stacks collect wastes that do not contain fecal matter (lavatories, sinks, etc) What is a vent stack? - correct answer. A vent stack prevents the development of excessive pressures in the lower regions of the drainage stack by relieving the air that is rapidly carried down the drainage stack. It does not include vertical fixture drains and branch vents that do not pass through more than two stories before being connected to the soil or waste stack or vent stack. What is a general term for any vertical line of soil or waste piping that collects water and wastes from fixture drains and horizontal branch drains from two or more floors of a building? - correct answer. A Stack. Properties of uniform flow apply to branches of what length and longer? - correct answer. 5 feet Special wastes, tank overflows, tank emptying lines, releif valve discharges, etc. should discharge where and why? - correct answer. Through an air break to an appropriate receptacle (floor drain or other) to prevent overpressurization of the drainage system. High temperature wastes should be cooled to what temperature before discharging into the drainage system? - correct answer. 140F When interior drainage piping developed length reaches 100 feet, what should happen and why? - correct answer. 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? - correct answer. 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? - correct answer. 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? - correct answer. 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? - correct answer. 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? - correct answer. The same as the rate of flow discharged at the fixture outlet. For interior drainage systems, the minimum fixture drain size is what? - correct answer. 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? - correct answer. 0.0145 The designer must know what as related to the sewer, water, and gas inverts and locations? - correct answer. 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? - correct answer. 2 fps, 4 fps, 3 fps. Dont forget to limit the length of runs for 1-1/2 and 2” 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? - correct answer. 0.707 and 1.414 The hydraulic mean depth of flow or hydraulic radius is what ratio and what value? - correct answer. 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 “rate of flow” expressed? - correct answer. Cross sectional area of flow times the average velocity. What formula determines the velocity of uniform flow in sloping drains? - correct answer. The Manning Formula Flow in piping and open channels is caused by what? - correct answer. 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? - correct answer. 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? - correct answer. From simultaneous use factors given in a table. What are recommended minimum medical gas riser sizes? - correct answer. Oxygen: 3/4” Medical air: 3/4” Nitrous Oxide: 3/4” Nitrogen: 1” Vacuum: 1” What are minimum medical gas pipe sizes? - correct answer. 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? - correct answer. 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? - correct answer. 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? - correct answer. 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? - correct answer. 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? - correct answer. 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? - correct answer. 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? - correct answer. 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? - correct answer. 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? - correct answer. 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? - correct answer. Name of the gas or vacuum system, room or areas served, a caution to not close or open the valve except in an emergency