CSA G40.21 grade 300WT plates API standard 650 ground supported flat-bottom tanks

Welders participating in the construction of API standard 650 ground supported flat-bottom tanks must pass the examination and perform welding within the validity period of the qualified items. Special operators such as on-site maintenance electricians, cranes, and shelf workers must hold job certificates. All oil pipelines need to use arc welding for bottoming and electric welding to ensure the welding quality. Oil tanks and process pipelines must be tested for non-destructive flaws in accordance with the flaw detection ratios and methods required by the design and acceptance specifications. The flaw detectors must be certified.

All welded seams in the API standard 650 ground supported flat-bottom tanks bottom, and complete penetration and complete fusion sidewall-to-bottom welds, shall be inspected by means of a vacuum box test as described in Q.8.2.1. Sidewall-to-bottom welds not having complete penetration and complete fusion shall be inspected by means of either a vacuum box test of the inside weld as described in API 620 specification Q.8.2.1, or where approved by the Purchaser, a direct pressure solution film test as described in Q.8.2.2.

API 650 sets minimum requirements for the design, material, construction, and testing for aboveground, open and closed-top, cylindrical API standard 650 ground supported flat-bottom tanks steel storage tanks in different capacities and sizes, roughly equating to the pressure of the atmosphere (not greater than the weight of the roof plates).