unflanged

Unflanged is an adjective used to describe components or fittings that lack a flange, a projecting rim or lip used for mounting, alignment, or bolted connections. The term is common in engineering and manufacturing contexts, where the presence or absence of a flange changes assembly methods, sealing options, and disassembly ease.

In piping and plumbing, an unflanged end or joint means there is no added flange for bolting to a corresponding partner. Such components are typically joined by welding, threading, compression, or other non-flanged methods. Unflanged pipes may be less convenient to disconnect for maintenance, but they can offer reduced cost, weight, and space requirements compared with flanged assemblies. The choice between flanged and unflanged configurations depends on factors like pressure rating, temperature, accessibility, and the need for serviceability.

In ductwork and ventilation, unflanged connections may rely on slip-fit joints, mechanical couplings, sealants, or sheet-metal screws rather than bolted flange assemblies. These arrangements can simplify installation in tight spaces but may provide different sealing characteristics and serviceability.

In mechanical design, unflanged shafts, hubs, or pulleys lack a flange to locate or locate-and-retain components. Mounting in such cases often uses alternative methods, such as set screws, clamps, keys, or bearing inserts, and may impose different tolerances or alignment considerations.

Overall, unflanged configurations emphasize simplicity, reduced weight, and often lower cost, at the potential expense of ease of disassembly or certain sealing and mounting conveniences provided by flanges. See also flange, flange connection, butt-weld, socket-weld, and clamped joint.