API Spec 12F pdf download Specification for Shop Welded Tanks for Storage of Production Liquids 5.15 Shell Attachment The tank deck shall be attached to the tank shell, if the deck if flanged, by a double-welded butt joint with completepenetration, or by a double-welded, ful-flet lap joint, or , if the deck is not flanged, by ful-fillet welds, both inside...