Journeyman Plumbers Exam Isometric Analysis and Math 2

Question 1

On an isometric drawing, a pipe running parallel to the right front edge of the cube is drawn at what angle from horizontal?

Accepted Answer

30 degrees

Answer

In isometric drawing, the three primary axes are drawn at 30 degrees above horizontal (left and right) and vertical.

Question 2

A plumber needs to offset around a beam using 45-degree elbows. The diagonal (travel) distance is 18 inches. What is the set (offset) distance?

Accepted Answer

12.73 inches

Answer

For a 45-degree offset, the set equals the travel multiplied by 0.707, so 18 × 0.707 ≈ 12.73 inches.

Question 3

What is the constant used to calculate the travel of a 60-degree offset?

Accepted Answer

1.155

Answer

The travel constant for a 60-degree offset is 1.155, meaning travel = set × 1.155.

Question 4

In an isometric plumbing diagram, what does a line drawn vertically represent?

Accepted Answer

A pipe running plumb (vertical)

Answer

In isometric drawing conventions, vertical lines represent pipes that run plumb (true vertical).

Question 5

A drain pipe drops 1/4 inch per foot over a run of 32 feet. What is the total drop?

Accepted Answer

8 inches

Answer

Total drop = 32 feet × 0.25 inches/foot = 8 inches.

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