A BS flange is a type of flange that conforms to the standards set by the British Standards Institution (BSI), which is recognized by the abbreviation BS. BS flanges are widely used in the United Kingdom and other regions that adopt British standards for piping systems. These flanges are designed to ensure compatibility, safety, and reliability in various industrial applications, including oil and gas, chemical, water treatment, and power generation.
Main Standards
BS 4504: It specifies design, dimensions, materials, and testing requirements for circular flanges in piping systems, valves, and fittings. It covers nominal pressure ranges from PN 2.5 to PN 40 and nominal sizes up to DN 4000.
BS 10:1962: It contains flange dimensions and pressure ratings, with flange sizes ranging from small size 3 to large size 48, and pressure ratings from 150 psi to 2500 psi.
BS 3293:1960: Deals with the dimensions and tolerances of welding neck and slip-on flanges with pressure classes of 150 lb - 600 lb, as well as ring joint facings.
Dimension Specifications
Nominal Size: Ranges from DN10 to DN2000 or even DN4000 in some cases, following the stipulation of ISO 6708.
Pressure Rating: Usually PN 2.5, PN 6, PN 10, PN 16, PN 25, PN 40, in line with ISO 7268.
Flange Face Types: Include flat face (FF), raised face (RF), and ring type joint (RTJ).
Marking Requirements: Flanges are marked with BS number, code number, PN, DN, material designation, manufacturer's name or trademark, cast number or melt identification, and thread identification, like BS 4504/111/B – PN16 - DN400 - B4 – xxx – 12345.
Carbon Steel: Such as ASTM A105, SS400, SF440 RST37.2, S235JRG2, P250GH, C22.8. They have good strength and weldability, suitable for general pipeline connection applications.
Stainless Steel: Such as ASTM A182 F304, F304L, F316, F316L, 316Ti. Austenitic stainless steels like these have excellent corrosion resistance and heat resistance. Besides, duplex stainless steel UNS S31803 and super duplex stainless steel UNS S32750 are also used.
Alloy Steel: Such as ASTM A182 Gr.F1, F11, F22, F5, F9, F91. Alloy steels have good high-temperature strength, creep resistance and oxidation resistance, which are suitable for high-temperature and high-pressure environments.
1. Oil and Gas Industry
BS flanges connect pipes and equipment in oil & gas exploration, extraction, transportation, and refining processes.
2. Chemical Industry
Used in chemical plants for connecting pipes carrying various chemicals, ensuring safe and efficient transfer.
3. Power Generation
Applied in power plants' steam, water, and fuel pipelines, maintaining system integrity under high conditions.
4. Water Treatment Industry
Used in water treatment and distribution systems, as well as sewage treatment for pipe connections.
5. Marine and Shipbuilding
Employed in ship piping systems, withstanding harsh marine environment and dynamic forces.
6. Pharmaceutical Industry
BS flanges are used in pharmaceutical manufacturing to maintain production process integrity and hygiene.
EN
