Which of the following is a disadvantage of Rising Stem Gate Valves?

The selected answer indicates that rising stem gate valves are easily sabotaged, which isn't a recognized disadvantage of these types of valves in standard practice. Instead, it’s important to understand the characteristics and operational context of rising stem gate valves.

Rising stem gate valves are designed to provide a tight seal and are known for their excellent flow characteristics when fully opened, which allows for maximum flow. However, one of the practical disadvantages is that they do require vertical space for the rising stem to operate; therefore, they do not require less headroom but rather require more, as the stem rises above the valve as it opens and closes.

Additionally, maintenance aspects of such valves can be more complex due to their construction, potentially making them difficult to maintain when looking at long-term operation. The stem and associated parts may require replacement or repair, especially in environments subject to corrosion or frequent operation.

Understanding these nuances highlights the more typical disadvantages associated with rising stem gate valves, focusing on the necessity for maintenance and space rather than issues of sabotage or flow capacity.