API Std 650 SUG III tanks isolation valves

The thickness of the API Std 650 SUG III tanks annular bottom plates shall be in accordance with Table Q-4 (for steel or aluminum, as applicable). The thicknesses shown are minimums. The ring of annual plates shall have a circular outside circumference, but it may have a regular polygonal shape inside the tank shell with the number of sides equal to the number of annular plates. These pieces shall be butt-welded in accordance with Q.7.1.1, Item b. The plates of the first shell course shall be attached to the annular bottom plates by a weld as required by API 620 oil tank 5.9.5 except when a full-penetration weld is used or required (see Q.7.1.1). Butt-welds in annular plates shall be not closer than 12 in. from any vertical weld.

This specification, in conjunction with API 650 Standard, prescribes minimum standards for the API Std 650 SUG III tanks design, supply fabrication, erection, and testing of field erected welded steel storage tanks complete with accessories as specified herein and as shown on attached datasheets and/or drawings.

In order to ensure the safety of the vertical storage tank, API Std 650 SUG III tanks, the supplier should inspect the tank carefully before delivery. The failure of the tank body is mainly due to the weld and crack of the product. The inspection of API Std 650 SUG III tanks, vertical storage tank weld and microcrack is mainly to inspect the appearance forming quality of weld. The inspection contents include weld leg height, undercut, welding deformation, weld bead, arc pit, weld straightness, etc., as well as the internal quality of weld, such as slag inclusion, porosity, incomplete penetration, crack, incomplete fusion, etc.