Fittings

Fittings are components used in piping systems to connect sections of pipe or tubing, adapt to different sizes, change flow direction, or terminate a line. They are selected based on the material, pressure and temperature ratings, threading or solvent-welding requirements, and the intended fluid. Common functions include joining pipes (couplings and unions), altering direction (elbows and bends), reducing or enlarging diameter (reducers), branching flow (tees and crosses), and sealing ends (caps and plugs). Flanges and adapters enable mechanical connections or conversions between different standards.

Fittings are made from metals such as copper, brass, steel, stainless steel, and ductile iron, as well as plastics such as PVC, CPVC, PE, and ABS. Material choice depends on the fluid compatibility, corrosion resistance, mechanical strength, and code requirements. Threads (such as NPT or BSP) and mechanical joints (sweat soldering, brazing, crimping, or welding) determine the joining method. Sealing is achieved with threads, gaskets, o-rings, or solvent cement, depending on the type.

In plumbing and industrial systems, fittings must comply with applicable standards and codes (for example, ISO, ASTM, ANSI, or DIN) and be rated for the system pressure and temperature. Proper selection also considers longevity, ease of installation, and maintenance needs.

Fittings are manufactured by casting, forging, stamping, extrusion, or molding, depending on the material. Standard diameters and threading exist to enable interoperability across manufacturers and regions.