API Std 650 aboveground steel oil storage tanks tank joints

Considering the large workload of allocation and transportion for our steel materials, we have built special shipping department, and make it independent form transportation department. The transportation department is in charge of transporting steel materials from our mill and warehouse to the port, and our shipping department is in charge of the shipping matters. So that our whole shipping efficiency is improved, and shorten time for customers to receive goods.

API Std 650 aboveground steel oil storage tanks, 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.

The API Std 650 aboveground steel oil 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.