Plumbing System Design & Sizing Flashcards
7 cards from real Master Plumber Exam 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 System Design & Sizing flashcards as text
Which of the following best describes the 'critical path' in a water distribution system design?
Answer: The longest or most restrictive path from source to the most remote fixture
The critical path is the route with the greatest friction loss, used to size piping so the most remote or demanding fixture receives adequate pressure.
A combination waste and vent system (CW&V) is permitted by IPC for which types of fixtures?
Answer: Floor drains, sinks, and lavatories in specific configurations
IPC Section 912 permits CW&V for floor drains, sinks, and lavatories where the system is designed with oversized horizontal drains acting as both drain and vent.
What minimum residual pressure must be maintained at a flush valve water closet during peak demand per IPC?
Answer: 25 psi
Flush valve water closets require a minimum residual pressure of 25 psi to operate properly, per IPC Table 604.3.
When calculating the total demand in WSFU (water supply fixture units) for a system, what accounts for demand diversity?
Answer: Using the probability curve that converts WSFU to gallons per minute
Hunter's probability curve converts total WSFU to an estimated peak GPM, inherently accounting for the fact that not all fixtures operate simultaneously.
An isometric drawing of a plumbing system is used primarily for what purpose?
Answer: Depicting a three-dimensional view of piping layout without true perspective
An isometric diagram presents pipe runs in three dimensions on a 2D drawing, making it easier to visualize connections, slopes, and spatial relationships.
Which sizing standard is used for gas piping design to ensure adequate BTU delivery to all appliances?
Answer: Longest-length method or branch-length method per NFPA 54/IPC
NFPA 54 and IPC gas piping provisions use the longest-length or branch-length method to ensure pressure drop does not reduce BTU delivery below appliance requirements.
What is the purpose of a 'check valve' in a plumbing system design?
Answer: To allow flow in one direction only and prevent backflow
A check valve permits flow in only one direction, preventing backflow that could contaminate supply water or damage equipment.