What is the minimum working pressure rating for water service pipe or tubing installed underground and outside of a structure?

The minimum working pressure rating for water service pipe or tubing that is installed underground and outside of a structure is specified as 160 PSI. This standard is established to ensure the integrity and durability of the piping system under various environmental conditions, which can include soil pressure and water table effects, while also taking into account potential temperature variations and the possibility of water hammer.

A rating of 160 PSI is essential because it allows the system to withstand both normal usage pressures and unexpected surges that may occur during operation. Choosing a pipe or tubing with an insufficient pressure rating could result in failure due to the cracking or bursting of the material, leading to leaks, water damage, and a significant increase in repair costs. Therefore, 160 PSI is not only a guideline set forth by plumbing codes, but it is also a necessary standard to ensure the long-term effectiveness and safety of underground water service installations.