NEIEP Mechanics Practice Exam

From what point should the plumb line be suspended when plumbing the jack hole?

1. At the middle of the hoistway

2. As near as possible to the top of the hoistway

3. At the bottom of the hoistway

4. Anywhere convenient along the side

The correct answer is: As near as possible to the top of the hoistway

When plumbing the jack hole, it is essential to suspend the plumb line as near as possible to the top of the hoistway. This positioning allows for the most accurate vertical reference when determining the alignment of the jack hole, which is crucial in the installation and operation of an elevator or similar systems. Suspending the plumb line at the top ensures that any measurement taken is long enough to avoid minor discrepancies that may arise from any obstructions or irregularities at lower levels. It effectively utilizes gravity to provide a straight vertical line, which serves as a reliable reference for ensuring that the jack is properly aligned. Accurate plumbing at this height minimizes the potential for misalignment that could affect the structure's overall integrity and performance. The other locations, such as the middle or bottom of the hoistway, would not provide the same level of accuracy, as they may be influenced by factors that the top positioning would negate. In addition, suspending the line anywhere convenient along the side could lead to misalignment due to potential variances in the structure of the hoistway itself. Thus, the correct approach is to suspend the plumb line as near as possible to the top for the best results.