1.1 ,This guide is intended to provide the reader with a knowledge of construction examination procedures and current technologies that can be used to give an owner or operator of an aboveground storage tank (AST) in petroleum service, relevant information on the hydraulic integrity of a new, repaired, or reconstructed tank bottom prior to return to service. This guide does not pertain to horizontal ASTs, manufacture of tanks using UL 142, or to tanks constructed of concrete or other non-ferrous materials.