Journeyman Plumbers Exam Isometric Analysis and Math 3

Question 1

What is the approximate center-to-center measurement when two 1.5-inch 90-degree elbows are connected with a nipple and the take-out of each elbow is 1.125 inches?

Accepted Answer

The sum of the two take-outs subtracted from the overall face-to-face dimension

Answer

Center-to-center = face-to-face overall dimension minus both elbow take-outs.

Question 2

When drawing a 3D pipe system in isometric view, pipes going into and out of the page (north-south) are drawn along which axis?

Accepted Answer

The left-leaning 30-degree axis

Answer

The left-leaning 30-degree axis on an isometric drawing represents the north-south (depth) direction.

Question 3

A rolling offset requires calculating both the horizontal offset and the vertical rise. If the horizontal set is 9 inches and the vertical rise is 12 inches, what is the diagonal set?

Accepted Answer

15 inches

Answer

Diagonal set = √(9² + 12²) = √(81 + 144) = √225 = 15 inches using the Pythagorean theorem.

Question 4

If a 4-inch drain pipe must maintain 1/8-inch-per-foot slope over 24 feet, what is the elevation change from inlet to outlet?

Accepted Answer

3 inches

Answer

Total drop = 24 feet × 0.125 inches/foot = 3 inches.

Question 5

What fitting constant (take-out) is used when calculating the cut length of pipe for a standard 90-degree elbow?

Accepted Answer

The take-out varies by pipe size and elbow type

Answer

Take-out (fitting allowance) varies by pipe diameter and elbow type and must be looked up in a fittings table.

Journeyman Plumbers Exam Practice Test

Journeyman Plumbers Exam Practice Test

Journeyman Plumbers Exam Isometric Analysis and Math 3