Specification for the design and manufacture of site built@ vertical@ cylindrical@ flat-bottomed@ above ground@ welded@ steel tanks for the storage of liquids at ambient temperature and above
This document specifies the requirements for the materials@ design@ fabrication@ erection@ testing and inspection of site built@ vertical@ cylindrical@ flat bottomed@ above ground@ welded@ steel tanks for the storage of liquids at ambient temperatures and above@ and the technical agreements that need to be reached (see Annex A). This document does not apply to tanks where the product is refrigerated to maintain it as a liquid at atmospheric pressure (see EN 14620 part 1 to 5). This document is concerned with the structural integrity of the basic tank structure and does not provide requirements for considering process design@ operational issues@ safety and firefighting facilities@ in-service inspection@ maintenance or repair. These aspects are covered in detail in other Codes of Practice (see Annex B). This document applies to closed-top tanks@ with and without internal floating roofs (see Annex C) and open-top tanks@ with and without floating roofs (see Annexes D and E). It does not apply to 'lift-type' gas holders. This document applies to storage tanks with the following characteristics: a) design pressure less than 60 mbar1 and design internal negative pressure not lower than 6@0 mbar (see 5.1 for pressure limitations); b) design metal temperature not lower than -40 ??and not higher than +300 ??(see 5.2.2); c) maximum design liquid level not higher than the top of the cylindrical shell. The limits of application of this document terminate at the following locations: ?? face of the first flange in a bolted flange connection; ?? first threaded joint on the pipe or coupling outside of the tank shell@ roof or bottom; and ?? first circumferential joint in a pipe not having a flange connection. This document is applicable to storage tanks where@ irrespective of the material strength used@ the maximum allowable stress does not exceed 260 N/mm2. In addition to the definitive requirements@ this document also states that the items detailed in Annex A have to be documented. For compliance with this document@ both the definitive requirements and those required in Clause 4 are meant to be satisfied.