API Std 650 cylindrical welded storage tanks secondary seal

Requirements for prefabrication of bottom plate of large vertical API Std 650 cylindrical welded storage tanks:
1. The diameter of tank bottom should be enlarged by 0.1% ~ 0.15% according to the design diameter.
2. The minimum dimension of edge plate along the radius direction of tank bottom shall not be less than 700mm.
3. The distance between any adjacent welds of the base plate shall not be less than 300 mm.

The API Std 650 cylindrical welded 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.

Upon completion of construction, provide Purchaser with copies of Field Erected API Std 650 cylindrical welded storage tanks Storage Tank Datasheets in accordance with Appendix L of API 650, which reflects the as-built conditions, certifying that the tank conforms with the requirements of this specification.

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Our steel products are widely used in petroleum and natural gas, chemical industry, shipbuilding, automobile manufacturing, power generation, mining, and other industries. The products API Std 650 cylindrical welded storage tanks are sold in more than 20 provinces, cities and all over the world. The company has strong technical force, complete production equipment, advanced production technology, perfect testing methods, and high-quality products.