FREE Journeyman Plumbers Pipe Sizing and Calculations Questions and Answers

Question 1

A plumbing system requires a flow rate of 15 GPM and the maximum allowable velocity is 8 feet per second (fps).
What is the minimum nominal pipe size required for this application, assuming standard copper tubing (Type L)?

Accepted Answer

1 1/4 inch

Answer

1 inch

Answer

1 1/2 inch

Answer

2 inch

Question 2

Which of the following factors has the LEAST direct impact on calculating the pressure drop in a domestic hot water recirculation line?

Accepted Answer

Water heater BTU rating

Answer

Pipe material and condition

Answer

Length of the pipe run

Answer

Number and type of fittings

Question 3

A plumber is designing a drainage system for a building. The total fixture unit (FU) count for a horizontal branch drain is 40 FU. According to typical plumbing codes (e.g., UPC or IPC), what is the minimum diameter required for this branch drain if it's installed at a 1/4 inch per foot slope?

Accepted Answer

3 inch

Answer

2 inch

Answer

2 1/2 inch

Answer

4 inch

Question 4

When sizing a water distribution system, what is the primary purpose of accounting for 'equivalent length' of fittings?

Accepted Answer

To convert fitting losses into an equivalent length of straight pipe for friction loss calculations.

Answer

To determine the actual physical length of the pipe run.

Answer

To calculate the total static pressure in the system.

Answer

To ensure the correct type of pipe joint is used for each fitting.

Question 5

A water service pipe needs to supply a building with a peak demand of 25 GPM. The available municipal water pressure is 60 PSI at the property line. Assuming a total equivalent length of 150 feet for the service line, what minimum nominal pipe size (Type K copper) would be most appropriate to maintain at least 20 PSI residual pressure at the building entrance, considering typical friction loss charts?

Accepted Answer

1 1/4 inch

Answer

3/4 inch

Answer

1 inch

Answer

1 1/2 inch

Question 6

When sizing vent piping for a plumbing system, which of the following is NOT a primary consideration?

Accepted Answer

The potable water supply pressure

Answer

Total developed length of the vent pipe

Answer

Number of fixture units being vented

Answer

Diameter of the drainage pipe it serves

A plumbing system requires a flow rate of 15 GPM and the maximum allowable velocity is 8 feet per second (fps).What is the minimum nominal pipe size required for this application, assuming standard copper tubing (Type L)?

A plumbing system requires a flow rate of 15 GPM and the maximum allowable velocity is 8 feet per second (fps).
What is the minimum nominal pipe size required for this application, assuming standard copper tubing (Type L)?