What is the required distance the top of the fill cap should be below the manhole lid?

The required distance from the top of the fill cap to the manhole lid is correctly noted as 4-6 inches. This specification is important for several reasons related to safety and functionality.

First, maintaining this distance helps to ensure that the fill cap is adequately protected from contaminants and debris that might accumulate around the manhole lid. If the fill cap were too high, it could be more susceptible to exposure from rainfall, spills, or surface contaminants, resulting in potential contamination of the stored fuel. Additionally, the specified distance allows for sufficient air ventilation above the fill cap, which is crucial for safe operation during the filling process and helps prevent pressure buildup within the tank.

Furthermore, adhering to this measurement is often a requirement outlined in both industry standards and regulations governing UST installations, which aim to promote safety and environmental protection.

Therefore, understanding the rationale behind this requirement is essential for anyone involved in UST installation and maintenance, as it contributes to effective risk management and environmental safeguarding.