Floating-roof tank

ISO 10628-2 (groups 1-2, vessels, tanks and columns) / PIP PIC001

Drawn as

A flat-bottomed tank with an open top and a horizontal deck floating inside below the rim, often with a rolling ladder drawn diagonally from the rim to the deck.

Meaning

External floating-roof tank (API 650 Annex C) for crude and volatile products: the roof rides on the liquid to cut vapour losses. Becomes storage-tank.

Variants

Internal floating roofs are drawn inside a cone or dome roof
The roof drain (articulated) is drawn as a pipe from the deck to the shell