For a successful internal inspection of a vessel, what must be removed at every level?

For a successful internal inspection of a vessel, it is essential to remove manway inspection trays at every level. These trays are specifically designed to allow access to the interior of the vessel while providing a means to support personnel and equipment during inspections. They typically catch any debris or material that may fall during the inspection process.

By ensuring that manway inspection trays are removed, inspectors can gain clear access to all areas of the vessel, allowing for a thorough examination of the interior surfaces, welds, and any potential defects. This is crucial for maintaining safety standards and ensuring the structural integrity of the vessel.

While inspection valves, breather valves, and access panels are important components for operational purposes, they do not provide the same level of direct access to the vessel's interior as manway inspection trays do. Thus, their removal may not facilitate the inspection process as effectively.