What must separate the tank and the hold down pad when installing a bottom hold down pad?

The requirement for an adequate bedding of backfill material between the tank and the hold down pad is essential to ensure proper support and stability during operation. This bedding helps to distribute the weight of the tank evenly and mitigates any potential stress points that could lead to structural failure or damage to the tank. In addition, using backfill material can assist in accommodating any minor settling or shifting that may occur over time, thereby maintaining the integrity of the installation.

Concrete slabs, insulation layers, or steel frames may have their own purposes in specific applications, but they are not necessary for ensuring that the tank is optimally supported by the hold down pad. The primary function of the bedding is to provide a suitable foundation that conforms to the tank shape and characteristics, which directly impacts the safety and functionality of the underground storage system.