Union

A union is a multi-piece mechanical piping joint that allows two line sections to be disconnected without rotating a long adjoining pipe run. Its components assemble and separate in a controlled manner, but the generic identity does not establish the exact end construction, seat form, or sealing arrangement. Thread form, material, coating, and operating limits likewise cannot be inferred from the name. Selection should define the actual joint construction, both end sizes and arrangements, sealing interface or element, material compatibility, wrench clearance, and maintenance access, with safe isolation and depressurization before disassembly.