Plumbing Systems Design Flashcards
7 cards from real CPD practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Plumbing Systems Design flashcards as text
When sizing a storm drainage system for a roof drain, which design variable primarily determines the pipe size in the IPC storm drain sizing table?
Answer: Rainfall intensity in inches per hour and drainage area
IPC storm drain sizing tables require the designer to input the local rainfall intensity (in/hr) and the tributary drainage area (sq ft) to determine the required pipe size.
A designer is evaluating pipe materials for a waste drain in a laboratory that handles dilute sulfuric acid. Which material is MOST chemically resistant?
Answer: Borosilicate glass pipe
Borosilicate glass pipe (e.g., Pyrex) is highly resistant to strong acids including sulfuric acid and is the preferred material for laboratory acid waste drainage systems.
Under NFPA 13, which type of sprinkler system is required in areas subject to freezing temperatures?
Answer: Dry pipe system
Dry pipe systems hold pressurized air or nitrogen in the piping rather than water, preventing freezing in cold environments; water enters only when a sprinkler activates.
In a hot water system, what is the recommended maximum circulating water velocity in return piping to minimize erosion-corrosion?
Answer: 2–3 ft/s
ASPE recommends limiting hot water recirculation velocity to 2–3 ft/s to minimize erosion-corrosion, noise, and water hammer in copper recirculation piping.
Which venting method allows a single vent pipe to serve multiple fixtures located on the same floor in a wet-vented horizontal branch?
Answer: Wet vent
A wet vent allows the drain pipe itself to serve as both the drain and the vent for multiple fixtures on the same floor level, reducing the number of separate vent pipes required.
A plumbing designer must size a water service for a 50-unit apartment building. After calculating total fixture units, what is the next step in the Hunter's Curve method?
Answer: Convert fixture units to GPM using the probability demand curve
After summing fixture units, the designer uses Hunter's Curve (probability demand curve) to convert total fixture units to peak probable flow rate in GPM for pipe sizing.
What is the primary code purpose of a registered P-trap compared to an S-trap in a drainage system?
Answer: P-traps resist self-siphonage because they vent at the trap arm; S-traps can self-siphon
P-traps maintain their water seal because the vent at the trap arm equalizes pressure after drainage; S-traps drain vertically and the velocity of water leaving can siphon the trap seal dry.