API standard 650 tanks bottoms

The thickness of the API standard 650 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 standard applies only to API 650 tank API standard 650 tanks whose entire bottom is uniformly supported and to API 650 tank in non-refrigerated service that have a maximum design temperature of 93°C (200 °F) or less.

In order to prevent the deformation of the bottom of metal vertical storage tank, API standard 650 tanks during welding, the number of welders should be reasonably distributed. When welding metal vertical API standard 650 tanks, personnel and welding position shall be reasonably allocated according to the actual situation of welding personnel, and random welding is not allowed.