Firefighter Practice Exam

What is the outside diameter of a booster line with an internal diameter of 1 inch and a wall thickness of 0.25 inches?

1. 1.25 inches

2. 1.5 inches

3. 2 inches

4. 1.75 inches

The correct answer is: 1.25 inches

To determine the outside diameter of the booster line, the wall thickness must be taken into consideration. The internal diameter is given as 1 inch, and with a wall thickness of 0.25 inches on each side of the pipe, the calculation for the outside diameter involves adding the wall thickness to both sides of the internal diameter. The formula for the outside diameter calculates as follows: 1. Start with the internal diameter: 1 inch. 2. Add the wall thickness to both sides: 0.25 inches on one side plus 0.25 inches on the other side gives a total addition of 0.5 inches. 3. Therefore, the outside diameter is 1 inch (internal) + 0.5 inches (total wall thickness) = 1.5 inches. Thus, the correct outside diameter of the booster line is indeed 1.5 inches, confirming that this is a logical and mathematical application of how to determine the outside diameter from the internal diameter and wall thickness.