API standard 650 storage tanks design internal pressure

According to the structure type of floating roof, floating roof API standard 650 storage tanks can be divided into internal floating roof tank and external floating roof storage tank. The internal floating roof tank is a floating roof tank with tank roof. The top is the combination of dome roof and floating roof, the external is dome roof, and the internal is floating roof. There is no vault on the top of the External floating roof tank, only a top plate floating with the storage liquid. The common feature of the inner floating roof tank and the outer floating roof tank is that both of them can reduce the evaporation loss of the storage liquid.

The API standard 650 storage tanks stiffener ring and backing strip (if used) are primary components, and they shall comply with the requirements of API 620 storage steel tank Q.2.1. The stiffener rings may be fabricated from plate using an intermittent weld on alternating sides between the web and the flange.
Except for aluminum or stainless steel tanks, all fillet welds shall consist of a minimum of two passes. The ends of the fillet welds shall be 2 in. from the rat hole (see Figure Q-1), and these welds shall be deposited by starting 2 in. from the rat hole and welding away from the rat hole. An acceptable alternative to the detail that includes stopping fillet welds 2 in. short of the rat hole would be to weld continuously through the rat hole from one side of the stiffener to the opposite side. All craters in fillet welds shall be repaired by back welding.

The API 650 tank Standard has the built in flexibility to be used in building tanks to store a wide variety of products while ensuring the structural stability of the API standard 650 storage tanks tank.