Which of the following is NOT a factor in determining tank excavation depth?

When determining the excavation depth for a tank installation, various factors must be taken into account, such as tank diameter, amount of dirt, and slope and length of piping. The thickness of the backfill, while it does influence the overall site preparation and stability once the tank is installed, does not directly impact the excavation depth necessary for placing the tank itself.

The diameter of the tank is crucial because it informs the size of the excavation required to accommodate the tank securely. The amount of dirt present refers to the material that may need to be removed or adjusted to create the appropriate excavation space. Additionally, the slope and length of the piping can affect how the tank is positioned and the depth needed to ensure proper drainage and functionality of the system.

In contrast, while backfill thickness is important for ensuring the tank is correctly supported after installation, it does not serve as a determining factor in how deep the excavation must be made prior to the tank installation.