Pipeline Flange
A pipeline flange is a forged or machined ring bolted to a mating flange to join pipes, valves, pumps and other equipment, allowing the joint to be assembled and dismantled for inspection and maintenance. Common types include weld neck, slip-on, socket weld, threaded, lap joint and blind flanges. The joint seals by compressing a gasket between facings such as raised face (RF), flat face (FF) or ring type joint (RTJ). Dimensions and pressure-temperature ratings are standardized in ASME B16.5 for NPS 1/2 to NPS 24 and ASME B16.47 for larger sizes, with pressure classes 150, 300, 600, 900, 1500 and 2500; wellhead flanges follow API 6A and European flanges EN 1092-1. Selection parameters include nominal size, pressure class, facing, bore matched to pipe schedule, material grade (for example ASTM A105, A182 or A350) and service temperature.
Examples
- Class 600 RF weld neck flange on a process line
- RTJ flange on a high-pressure gas pipeline
- Blind flange closing a line end for hydrotesting