Open top API standard 650 unanchored flat-bottom tank

API standard 650 unanchored flat-bottom tank, floating roof tank is composed of vertical cylindrical tank wall and floating roof, which is floating on the surface of liquid storage. The volume of floating roof storage tank is generally large, and its bottom plate is arched edge plate. The difference between floating roof tank and other types of storage tank is that there is a floating top cover floating on the surface of liquid storage, and the top cover floats up and down with the rise and fall of liquid storage.

API 620 crude oil tank piping materials made according to ASTM A333 and A350 may be used at API standard 650 unanchored flat-bottom tank design metal temperatures no lower than the impact test temperature required by the ASTM specification for the applicable material grade without additional impact tests. For temperatures below those allowed by the ASTM specification, the following paragraph shall apply.

Upon completion of API standard 650 unanchored flat-bottom tank construction, provide Purchase with a Vendor's Certification that the tank conforms to the requirements of API 650 and to the additional requirements as specified.