Category
Piping & Fittings
Subcategory
Components
Applicable standards
6
Issuing bodies
5
Description
Steel pipe flange — weld neck, slip-on, socket weld, threaded, lap joint, blind.
Applicable Standards (6)
ASME — 2 standards
ASME B16.5
Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24
Flange dimensions, ratings, materials and tolerances for NPS 1/2–24, Class 150–2500.
Key requirements (8)
- Pipe flanges & flanged fittings for NPS 1/2 to 24.
- Pressure classes: 150, 300, 400, 600, 900, 1500, 2500.
- Class 150 CS: 285 psig at 100 °F, 200 psig at 400 °F.
- Class 300 CS: 740 psig at 100 °F, 555 psig at 700 °F.
- Flange types: weld neck, slip-on, socket weld, threaded, lap joint, blind.
- Facing types: raised face (RF), ring-type joint (RTJ), flat face (FF).
- Bore matching: weld neck bore selected to match pipe schedule.
- Hydrotest: per pressure class temperature/pressure rating chart.
ASME B16.47
Large Diameter Steel Flanges: NPS 26 through NPS 60
Series A (formerly MSS SP-44) and Series B (formerly API 605) large-diameter flanges.
Key requirements (6)
- Large-diameter steel flanges — NPS 26 through 60.
- Series A (MSS SP-44 lineage, heavier) or Series B (API 605, lighter).
- Pressure classes 150, 300, 400, 600, 900.
- Used for pipelines, large vessels, atmospheric tanks.
- Hydrotest: per pressure class rating chart.
- Bolting per ASTM A193 / A194; Series A typically larger studs than Series B.
MSS — 1 standard
MSS SP-44
Steel Pipeline Flanges
Large-diameter pipeline flanges; merged into ASME B16.47 Series A.
EN/CEN — 1 standard
EN 1092-1
Flanges and their joints — Circular flanges, PN designated — Part 1: Steel flanges
European steel flange dimensions (PN system).
BIS — 1 standard
IS 6392
Steel Pipe Flanges
Indian steel flange standard.
DIN — 1 standard
DIN 2501 (legacy)
Flanges; mating dimensions
Legacy German flange standard, still seen on older drawings.