What is the minimum cover that should be maintained over all underground metallic piping?

The minimum cover that should be maintained over all underground metallic piping is indeed 12 inches. This standard is in place to protect the integrity of the piping and prevent damage from surface activities and natural elements. Maintaining this cover depth reduces the risk of accidental impacts, such as from vehicles or excavation activities, which could compromise the piping and lead to hazardous leaks.

Additionally, proper cover helps prevent corrosion by minimizing exposure to moisture and other environmental factors. It ensures that the pipes remain insulated from temperature fluctuations that could affect the materials. This depth is also aligned with regulations and best practices for safety in handling and installing underground pipelines, which highlight the importance of sufficient cover for long-term durability and safety compliance.

In contrast, lesser depths, such as 6 inches, may not provide adequate protection, and greater depths, such as 18 or 24 inches, may be unnecessarily excessive for typical installations and could pose additional challenges in terms of installation and retrieval during maintenance or repairs. Hence, 12 inches is recognized as the standard and practical depth for sufficient protection of underground metallic piping.