When installing piping and hoses, what must be considered for external piping installed underground?

Answer: C — minimum of 18 inches of cover

When it comes to external piping installed underground, the consideration of a minimum of 18 inches of cover is essential for ensuring safety and functionality. This requirement is in place to protect the piping from physical damage that may occur due to soil movement, vehicle traffic, or other external forces. The depth of 18 inches also helps mitigate the risk of freezing in colder climates, which can impact the integrity of the piping and the flow of compressed natural gas. Adequate cover is a critical aspect of underground installations, as it ensures compliance with safety regulations and helps to prolong the lifespan of the piping system by shielding it from hazards that could lead to leaks or other failures.