Double Deck External Floating Roof Tank

Types of external floating roof consist of.

Double deck external floating roof tank.

Single deck pontoon type figure 1 4 double deck figure 1 5 special buoy and radially reinforced roofs floating roof tank will be further discussed in details in later chapter. The structural form of external floating roof is similar to internal floating roof both of them have a steel tray form floating cabin form single deck floating roof or double deck floating roof even external floating roof with aluminum alloy sandwich structure. The sketches shown illustrate the above single deck and double deck floating roof with the critical components for these structures. External floating roofis where the roof floats on the product in an open tank and the roof is open to atmosphere.

It consists of an open topped cylindrical steel shell equipped with a roof that floats on the surface of the stored liquid. The two preferred configurations for external floating roofs are the double deck and the low single deck with 30 minimum pontoon area. Double deck pontoon roofs which are designed with concentric annular pontoons with radial bulkheads in each pontoon section. The low single deck is the more efficient of the two for 30 to 170 foot diameter tanks.