What is the typical extension requirement for a bottom hold-down pad beyond the tank side?

The typical extension requirement for a bottom hold-down pad beyond the tank side is 18 inches. This dimension is important because it allows for adequate support of the tank and ensures stability, especially when considering soil movement or external loads that might affect the integrity of the installation.

The primary purpose of this extension is to provide a solid foundation that can distribute the weight and forces exerted on the tank, preventing shifting or settling that could lead to leaks or structural failure. An 18-inch extension is considered a balance between providing enough support while allowing for practical installation concerns, including material availability and excavation space.

In applying this requirement, the design considers factors such as local soil conditions and the tank's dimensions, ensuring compliance with safety regulations and industry standards for underground storage tanks.