API Std 650 carbon steel tank slab foundations

A refrigerated tank may be a single-wall insulated tank or a double-wall tank that consists of an inner tank for storing the refrigerated liquid and an outer tank that encloses an insulation space (which usually has a lower gas pressure) around the inner tank. A double-wall tank is a composite tank, and the outer tank is not required to contain the product of the inner tank. In a double-wall tank, differences in API Standard 620 tank materials, design, and testing exist between the inner and outer tanks.

Test welds of each API 650 tank nozzle and manway reinforcing pad (or each section of multiple piece pad) using dry air and apply a soap solution test in the presence of Purchaser's Inspector before hydro testing the API Std 650 carbon steel tank tank. Tap one inch NPT test hole in each pad or section.

Define the welding sequence of API Std 650 carbon steel tank bottom plate: the welding sequence of metal vertical storage tank shall be carried out according to the procedure required by the welding scheme. Spot welding shall be consistent with the formal welding requirements, and no spot welding shall be carried out for the weld not welded. Back bar should be added to prevent deformation when welding the full length seam of middle plate, butt joint of edge plate and turtle shell joint.