Master Plumber Exam Plumbing System Design & Sizing 5

Question 1

Under IPC, what is the maximum number of fixture units permitted on a 3-inch horizontal branch drain at 1/4-inch per foot slope?

Accepted Answer

20 DFU

Answer

Per IPC Table 710.1(1), a 3-inch horizontal branch at 1/4-inch per foot slope has a maximum capacity of 20 drainage fixture units.

Question 2

What is the minimum trap-to-vent distance for a 1.5-inch fixture drain per IPC?

Accepted Answer

3.5 feet

Answer

IPC Table 909.1 specifies a maximum 3.5-foot distance from the trap weir to the vent connection for a 1.5-inch pipe.

Question 3

In a high-rise building, which system is used to prevent positive pressure surges in the drainage stack from blowing trap seals?

Accepted Answer

Sovent or aerator/deaerator fittings

Answer

Sovent single-stack systems use aerator and deaerator fittings to manage air entrainment and pressure differentials, preventing both siphonage and positive pressure blow-out.

Question 4

When sizing a thermal expansion tank for a closed water heating system, which factor is most critical?

Accepted Answer

The system volume, temperature rise, and incoming cold water pressure

Answer

Expansion tank sizing requires knowing the system water volume, the temperature differential, and the cold water supply pressure to calculate the volume of expansion.

Question 5

A sewage ejector pump system is required when fixtures are located how relative to the building drain?

Accepted Answer

Below the level of the public sewer or building drain

Answer

Fixtures located below the elevation of the building sewer or public sewer cannot drain by gravity and require a sewage ejector or lift station.

Master Plumber Exam Practice Test

Master Plumber Exam Practice Test

Master Plumber Exam Plumbing System Design & Sizing 5