Simplified design requirements for API Std 650 flat-bottom tanks

In this project a cylindrical tank 75 ft in diameter is designed for an internal pressure of 0.5 lbf/in.2 gauge in the vapor space. The plate material is ASTM A131 Grade B steel for thicknesses of 1/2 in. and less.
The top course of the butt-welded cylindrical sidewall is 1/4 in. thick. The tank API Std 650 flat-bottom tanks roof is a conical shape with a 2:12 slope and a 1/4 in. thickness with single full-fillet welded lap joints. The maximum design liquid level is 6 in. below the plane of juncture of the roof and sidewall.

Structural features of API 650 double-layer oil tank: steel glass fiber reinforced plastic double-layer structure, special processing method is adopted between the API Std 650 flat-bottom tanks internal steel shell and glass fiber reinforced plastic layer, so that a gap of 0.1 mm is created between the internal and external layers. Even if the API 650 oil storage tank leaks, it can ensure that the contained dangerous substances only flow in the gap, and will not immediately overflow the external environment.

Strictly control the welding groove forming of API Std 650 flat-bottom tanks: in order to ensure the geometric dimension of assembly and good welding of welding seam, before hoisting and laying, the edge of all metal vertical storage tank plate shall be polished by grinder, and the flatness of plate shall be ensured according to the design requirements. Strictly control the size of API Std 650 flat-bottom tanks weld assembly: measures must be taken to strictly control the assembly size of metal vertical tank bottom plate during assembly.