In what scenario must additional protection for underground piping be provided?

The requirement for additional protection for underground piping relates primarily to the depth at which the piping is installed. When underground piping is buried at a depth of less than 18 inches, there is a heightened risk of damage from surface activities, such as excavation or impacts from vehicles. This shallow installation increases the likelihood of accidental strikes or pressures that could compromise the integrity of the piping. Therefore, additional protective measures, such as increased burial depth, protective barriers, or warning tapes, become essential to ensure the safe and secure operation of the underground system.

The consideration of depth is critical because codes and regulations often stipulate minimum cover requirements to safeguard against physical stresses and environmental factors. In contrast, options like proximity to electric lines, susceptibility to extreme weather, or specific usage types (like liquid delivery) might involve other safety concerns but do not necessarily dictate the same level of need for protective measures solely based on depth. Thus, the depth of burial serves as a clear and specific criterion for requiring additional protection for underground piping.