Massachusetts 3rd Class Engineer Test 2025 – 400 Free Practice Questions to Pass the Exam

To determine the ligament efficiency of a boiler with specified tube hole dimensions, you can use the formula for ligament efficiency, which is a measure of the effective area of the tubes compared to the overall area of the boiler. Essentially, ligament efficiency assesses how much of the available cross-sectional area is actually occupied by the tubes, with the remaining space being the "ligament" areas of the material between the tubes.

Given a tube diameter of 3 inches and a pitch (the center-to-center distance between the tubes) of 5.25 inches, you input these values into the appropriate formula for calculating the ligament efficiency. The calculation involves determining the area occupied by the tubes versus the total area available due to the pitch.

Using the given dimensions, one can compute:

1. The area of one tube hole.

2. The total area that would encompass all the tubes given the pitch.

3. The ratio of the area occupied by the tubes to the total area, which gives the ligament efficiency as a percentage.

This methodology leads to the conclusion that the calculated ligament efficiency for the given dimensions is approximately 42.85%, which corresponds to the correct answer in this scenario.

Such an understanding is crucial for engineers and operators, as it allows for the assessment