What is the maximum distance that horizontal cast iron pipe can be from an approved hanger?

The maximum distance that horizontal cast iron pipe can be from an approved hanger is 18 inches. This guideline is established to ensure that the weight of the pipe is adequately supported, reducing the risk of stress on the joints and preventing sagging that could lead to leaks or pipe failure. Proper support placement is critical not only for maintaining the integrity of the piping system but also for ensuring compliance with plumbing codes and standards. Regular adherence to these guidelines helps to promote safety and longevity in plumbing installations.

Supporting cast iron pipe at intervals greater than 18 inches would not provide adequate structural support, potentially compromising the system's functionality.