Which of the following must hot water supply lines meet?

The requirement for hot water supply lines to meet specific temperature and pressure ratings is crucial for ensuring the safety, functionality, and longevity of plumbing systems. These ratings are established to prevent damage to the pipes and to minimize the risk of failures that could lead to leaks or burst pipes.

Temperature ratings are particularly important as they help determine the maximum heat that the pipes can handle without compromising their structural integrity. Similarly, pressure ratings ensure that the pipes can withstand the internal pressure generated by the water flow without risk of rupture.

While there are design specifications and insulation requirements that are also important in the context of plumbing, these do not specifically address the physical limits of thermal and hydraulic performance, which are critical to maintaining safe operating conditions. Volume flow tests are useful for determining the efficiency and capacity of the plumbing system but do not directly address the fundamental temperature and pressure constraints needed to protect the integrity of hot water supply lines.