What is the minimum size of the port that must be provided in the top of the tank?

The minimum size of the port that must be provided in the top of the tank is specified as 12 inches. This requirement is in place to ensure sufficient accessibility for inspection, maintenance, and potential repair activities. A larger port size allows better entry and egress for personnel and equipment, thereby enhancing safety and functionality.

Additionally, a 12-inch port can accommodate various tools and equipment needed for effective tank management, reducing the risk of accidents or inefficiencies during any work performed. While smaller port sizes might seem feasible, they can limit the capacity for necessary maintenance tasks, potentially increasing risks associated with tank management. Thus, the requirement for a 12-inch port reflects best practices in tank design and worker safety.