Journeyman Plumbers Isometric Analysis and Math Questions and Answers

Question 1

A plumber needs to install a 45-degree offset.
The horizontal distance between the centerlines of the two parallel pipes, known as the 'set', is 20 inches.
What is the center-to-center length of the 'travel' piece of pipe?

Accepted Answer

28 1/4 inches

Answer

20 inches

Answer

34 5/8 inches

Answer

24 1/2 inches

Question 2

A horizontal drainage line that is 48 feet long must be installed with a uniform grade of 1/8 inch per foot. What is the total fall of the pipe from its starting point to its end point?

Accepted Answer

6 inches

Answer

4 inches

Answer

8 inches

Answer

12 inches

Question 3

When fabricating a rolling offset, a pipe must shift 15 inches horizontally (run) and 20 inches vertically (rise). What is the 'true offset' of this configuration?

Accepted Answer

25 inches

Answer

35 inches

Answer

28 inches

Answer

22 inches

Question 4

In pipe measurement, the dimension that must be subtracted from a center-to-center measurement to determine the exact cut length of the pipe is known as:

Accepted Answer

Fitting allowance

Answer

Developed length

Answer

Travel

Answer

Throw

Question 5

Which of the following is the correct mathematical constant used to calculate the 'travel' piece when the 'set' of a 60-degree offset is known?

Accepted Answer

1.155

Answer

1.414

Answer

2.613

Answer

1.732

Question 6

An isometric drawing shows a vertical drain pipe rising from the floor. The line then turns to run horizontally toward the back and to the left. Which combination of fittings would be required to make this change of direction?

Accepted Answer

One 90-degree elbow and one 45-degree elbow

Answer

One 45-degree elbow

Answer

Two 90-degree elbows

Answer

One tee and one 45-degree elbow