| Standard | Region | Key Difference | |----------|--------|----------------| | | Europe / International | Site-built, flat-bottomed, ambient temp, low pressure. | | API 650 | USA / Global | Similar scope but different design rules, inspection, and annexes. | | BS 2654 | UK (withdrawn) | Predecessor to EN 14015. | | EN 1993-4-2 | Eurocode | Part of Eurocode for tanks – complements EN 14015. | | DIN 4119 | Germany | Old German standard – largely replaced. |