Final answer:
The question seeks the minimum cover requirement in inches for underground gas piping to protect it from external damage. The exact value can vary based on building codes and standards, and cannot be provided without specific context.
Step-by-step explanation:
The question pertains to the protective measures for underground gas piping to prevent external damage. In construction and engineering, certain standards and codes specify the minimum requirements for the safe installation of underground infrastructure. However, without the specific code or standard in context (like the International Fuel Gas Code, local building codes, or regulations relevant to the jurisdiction the student is asking about), it is not possible to provide the exact requirement in inches for the cover above the piping.
It's generally acknowledged that gas piping should have adequate cover to protect from external damage, which could be from vehicles, construction work, or other such risks. Typical installation practices involve sufficient cover to guard against potential damage.