1). Desing And Manutacture: API 6D, ANSI B16.34, BS1868 2). Face to face/End to end: ANSI B16.10 3). Flange dimensions: ANSI B16.5 4). Butt welding dimension: ANSI B16.25 5). Pressure temperature lating: ANSI B16.34 6). Inspection and test: API 598 API 6D