API Std 650 ground supported flat-bottom tanks spectral acceleration coefficients

Welding inspection of bottom plate of API Std 650 ground supported flat-bottom tanks, vertical oil tank: During the fabrication and installation of API Std 650 ground supported flat-bottom tanks, the bottom edge plate is welded first. According to the requirements of the technical standard, penetrant inspection is required for the weld of edge plate at the bottom of API Std 650 ground supported flat-bottom tanks, that is, penetrant testing is required for each weld bead priming, filling and capping. In the process of testing, if any defect is found, it shall be repaired immediately. After the repair, the surface coloring penetrant test shall be conducted again until the test result is qualified.

All API Std 650 ground supported flat-bottom tanks fillet welds shall consist of a minimum of two passes. The ends of the fillet welds shall be 2 in. from the rat hole, 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 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 outer layer of API 650 tank is glass fiber reinforced plastic layer with a thickness of more than 2.5mm, which API Std 650 ground supported flat-bottom tanks has strong corrosion resistance and electric corrosion resistance. Special process technology is used between the two layers to make the gap reach 0.1 mm, so as to eliminate the existence of potential safety hazard from the root.