Gas piping shall not penetrate building foundation walls at any point ______ ______.

Gas piping is typically categorized based on where it is located in relation to the foundation walls of a building. The correct answer focuses on the importance of preventing gas piping from penetrating building foundation walls below grade.

When gas piping penetrates below grade, it poses significant safety risks. This area is often subjected to moisture and potential flooding, which increases the risk of corrosion and leak formation in the piping. Such leaks could lead to hazardous situations involving gas buildup, which is particularly dangerous in a confined or enclosed environment. By avoiding penetration below grade, the risk associated with these factors is significantly minimized, enhancing both safety and the integrity of the gas delivery system.

In contrast, other locations such as above grade, next to grade, or in the attic do not carry the same level of risk. Above grade typically refers to areas that are more accessible and less likely to suffer from the conditions that affect piping below the ground level. Therefore, coding and best practices for gas piping prioritize the safety and structural integrity of systems to ensure they operate without presenting hazardous conditions.