Plumbing System Design 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 flashcards as text
Which type of water heater installation requires a dedicated sealed combustion air supply from outside the building?
Answer: Direct vent (Category IV) gas water heaters
Direct vent Category IV appliances draw combustion air from outdoors through a sealed concentric pipe system, eliminating indoor air dependency.
When sizing a grease interceptor for a commercial kitchen, the design capacity is primarily based on which factor?
Answer: The flow rate of fixtures served and a retention time factor
Grease interceptor sizing uses the total fixture flow rate (GPM) multiplied by a retention time, per PDI G101 or local code.
In a storm drainage system design, the 100-year storm event rainfall intensity is used to calculate which parameter?
Answer: The required pipe diameter and roof drain capacity
Roof drain and storm pipe sizing is calculated using the design rainfall intensity (inches/hour) for the local 100-year storm to ensure adequate capacity.
A dual-check backflow preventer is the minimum required protection for which type of cross-connection?
Answer: Residential water softeners and humidifiers
Dual-check assemblies are acceptable for low-hazard applications like residential water softeners and humidifiers that present no health hazard.
The developed length of a gas supply pipe is used in conjunction with which other value to determine minimum pipe diameter from code tables?
Answer: Operating pressure and total BTU demand
Gas pipe sizing tables require both the developed length of piping and the total BTU/hr demand of all connected appliances at the design operating pressure.
What is the primary purpose of an air gap in a plumbing system?
Answer: To provide the highest level of backflow protection by physical separation
An air gap provides complete physical separation between the water outlet and the flood rim of a receptor, making backflow physically impossible.
When designing fixture rough-in locations, what minimum clearance does the IPC require from the centerline of a water closet to an adjacent side wall or obstruction?
Answer: 15 inches
The IPC requires a minimum of 15 inches from the water closet centerline to any side wall, partition, or obstruction.