Vertical cross-linked Polyethylene pipe shall be supported separately at intervals not to exceed _______________.

Vertical cross-linked Polyethylene (PEX) pipe is designed to be supported in a way that minimizes movement and stress on the joints and fittings. The requirement for support intervals is established by plumbing codes to ensure the integrity and performance of the piping system.

In this case, the correct answer is that vertical cross-linked PEX pipe must be supported separately at intervals not to exceed 48 inches. This specific distance is crucial because it helps to prevent sagging and potential damage caused by the weight of the water and the pipe itself over long spans. Proper support is necessary to ensure that the PEX pipe maintains its shape and functionality, reducing the likelihood of leaks or failures in the system.

The other options reflect distances that exceed the recommended maximum support interval, which could lead to insufficient support for the pipe. By adhering to the 48-inch guideline, plumbers ensure compliance with the Omaha Plumbing Code, leading to safer and more reliable installations. Additionally, it reflects industry best practices for plumbing installations to ensure longevity and reduce maintenance issues over time.