ASTM A678 plates API Std 650 SUG I tanks

There is no dome roof in the top of the vertical external floating roof oil storage tank, only the disc floating roof which can float up and down. The wall plates are connected by butt welding, and the construction is usually carried out by the forward installation method, and the storage capacity is usually more than 10000 cubic meters. Vertical internal floating roof API Std 650 SUG I tanks has both dome roof and internal floating roof. The internal floating roof floats on the liquid surface inside the dome roof oil tank and can float up and down. The storage capacity is usually between 1000 and 10000 cubic meters.

The API Std 650 SUG I 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.

Application scope of API 650 petroleum storage tank:
1. API Std 650 SUG I tanks Working pressure: atmospheric storage tank;
2. API 650 petroleum storage tank working temperature: -30℃～150℃;
3. API 650 petroleum storage tank liquid medium: various oil products, including naphtha, gasoline, diesel, kerosene, crude oil, fuel oil, heavy oil, benzene, xylene, methanol, ethanol;
4. API 650 petroleum storage tank volume: current design considerations generally do not exceed 10,000 cubic meters.