flanges

A flange is a mechanical conduit connection used to join pipes, valves, pumps, and other equipment in a piping system. It creates a removable joint that is bolted together with a gasket to form a leak-tight seal, allowing disassembly for inspection, maintenance, or replacement.

Common flange types by connection include weld neck, slip-on, threaded, socket weld, lap joint, and blind flanges. Reducing flanges connect pipe sections of different diameters. Flange faces vary, including raised, flat, ring-type joint, and tongue-and-groove faces, with gasket materials selected to match the service conditions.

Materials used for flanges range from carbon steel and stainless steel to alloy steels, cast iron, and plastics such as PVC and CPVC. Material choice depends on operating pressure and temperature, corrosion resistance, and the chemical nature of the fluid.

Standards define dimensions, bolt patterns, and pressure ratings. Common classes include 150, 300, and 600 in imperial units, while metric systems use PN ratings. Widely adopted standards include ASME B16.5, ASME B16.47, EN 1092-1, and ISO 7005, which specify geometry, tolerances, and testing requirements for different flange types.

Design considerations encompass flange thickness, bolt circle diameter, number and size of bolts, gasket type, and the selected flange face. Proper installation requires correct gasket seating, alignment, and bolt torque to ensure leak-tight performance and joint integrity.

Flanges are employed across industries such as oil and gas, chemical processing, water treatment, power generation, and HVAC, serving as essential interfaces in fluid-handling systems. Regular inspection and maintenance help detect corrosion, wear, or gasket degradation that could compromise service.