What is an important feature of the manhole assembly in fuel tank installations?

The manhole assembly in fuel tank installations is designed to provide flexibility to prevent stress on the underground storage tank (UST). This flexibility is crucial because it allows for the natural movement of soil and surrounding materials, which can occur due to a variety of factors such as changes in temperature, moisture, or seismic activity. By incorporating flexibility, the manhole assembly mitigates the risk of damaging the tank or its fittings, ensuring the longevity and integrity of the UST system.

Flexibility in the design also supports the ability to access the tank for maintenance or inspection without compromising the overall structural stability of the installation. This feature is essential to maintaining the functionality and safety of the fuel storage system.