Flange Standard

A flange standard lays down the dimensions, surface finish, facing type, marking, material and technical specifications for flanges.

Our company provides various standard flange products.

We provide flange products of various standards such as American standards, European standards, German standards, and Japanese standards. The list of common standards is as follows:

  • ASME/ANSI B16.47 Flange  Class 150-900 Series A – 26″to 60″
  • ASME/ANSI B16.47 Flange  Class 75-900 Series B – 26″to 60″
  • ASME/ANSI B16.5 Flange  Class 150-2500 – 1/2″to 24″
  • DIN FLANGES
  • JIS FLANGES
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ASME/ANSI B16.47 Flange 

ASME B16.47 is an American standard that refers to large-diameter steel flanges. This standard also covers the requirements for flange gaskets, flange bolting, flange joints, etc. The standard covers the design of flanges from NPS 24 to NPS 60. With rating classifications 75, 150, 300, 400, 600, and 900, the standard ASME B16.47 offers pressure-temperature ratings, tolerances, marking, dimensions, and measurements for pipe flanges. ASME B16.47 standard has two series such as Series A and Series B flanges.
ASME B16.47 standard covers pipe flanges in sizes 26” through 60” and in pressure class ratings 75, 150, 300, 400, 600, and 900. Then, ASME B16.47 is further divided into ASME B16.47 Series A and ASME B16.47 Series B flanges for Blinds and Weldnecks.
The designation formerly referred to as MSS SP-44 flanges are now considered ASME B16.47 Series A flanges, while API 605 flanges are now ASME B16.47 Series B flanges. Materials covered in this standard are the same as ASME B16.5 except for nickel alloys. Due to this, they share the same pressure-temperature chart for the selection of flange materials.

ASME/ANSI B16.5 Flange

ASME B16.5 standard covers steel pipe flanges and flanged fittings from NPS ½” through NPS 24” in pressure classes 150 to 2500. This includes pressure ratings, dimensions, tolerances, materials, marking, and testing. ASME B16.5 and ANSI B16.5 only cover sizes up to 24 inches.
Included are:
(1) flanges with rating class designations 150, 300, 400, 600, 900, and 1500 in sizes NPS 1/2 through NPS 24 and flanges with rating class designation 2500 in sizes NPS 1/2 through NPS 12, with requirements given in both metric and U.S. Customary units with a diameter of bolts and flange bolt holes expressed in inch units;
(2) flanged fittings with rating class designation 150 and 300 in sizes NPS 1/2 through NPS 24, with requirements given in both metric and U.S. Customary units with a diameter of bolts and flange bolt holes expressed in inch units;
(3) flanged fittings with rating class designation 400, 600, 900, and 1500 in sizes NPS 1/2 through NPS 24 and flanged fittings with rating class designation 2500 in sizes NPS 1/2 through NPS 12 that are acknowledged in Non-Mandatory Appendix E in which only U.S. Customary units are provided.

B16.5 is limited to flanges and flanged fittings made from cast or forged materials, and blind flanges and certain reducing flanges made from cast, forged, or plate materials. Also included in this Standard are requirements and recommendations regarding flange bolting, flange gaskets, and flange joints.
This Standard is to be used in conjunction with equipment described in other volumes of the ASME B16 Series of Standards as well as with other ASME standards, such as the Boiler and Pressure Vessel Code and the B31 Piping Codes.

Careful application of these B16 Standards will help users to comply with applicable regulations within their jurisdictions while achieving the operational, cost, and safety benefits to be gained from the many industries’ best practices detailed within these volumes.

Intended for manufacturers, owners, employers, users, and others concerned with the specification, buying, maintenance, training, and safe use of valves with pressure equipment, plus all potential governing entities.

Here’s the list of common flange standards presented in a table format for better clarity:

StandardDescription
ANSI/ASME B16.5– Commonly used in the United States.
– Covers dimensions and pressure-temperature ratings for pipe flanges and flanged fittings.
– Includes flange types like Weld Neck, Slip-On, Blind, Socket Weld, and Lap Joint.
ANSI/ASME B16.47– Two sub-standards under ANSI/ASME B16.47.
(Series A and B)– Series A focuses on larger diameter and higher-pressure flanges.
– Series B covers smaller diameter and lower-pressure flanges.
EN 1092-1– Used in Europe and other regions following European standards.
– Provides specifications for steel flanges, including dimensions and facing types.
DIN Standards– German standards for flanges.
– DIN 2501 covers flange dimensions and types.
– DIN 2576 specifies flat flanges with sealing faces.
JIS B2220– Japanese Industrial Standards for steel pipe flanges.
– Includes specifications for flange dimensions and facing types.
BS 10– British Standard for flanges.
– Covers tables of flange dimensions, facing types, and pressure ratings.
ISO 7005– International Organization for Standardization (ISO) standard.
– Provides a series of standards for flanges used globally.
AWWA C207– American Water Works Association standard.
– Specifically for flanges used in water supply systems.
API 6A– American Petroleum Institute standard.
– Focuses on flanges used in the oil and gas industry, particularly for wellhead equipment.
GOST Standards– Russian standards for flanges.
– Govern flange specifications in Russia and some other countries following GOST standards.
AS 2129– Australian Standard for pipe flanges.
– Used in Australia and neighboring regions.
MSS SP-44– Standard Practice developed by the Manufacturers Standardization Society of the Valve and Fittings Industry.
– Focuses on steel pipeline flanges.
BS EN 1759– British Standard for flanges used in the petrochemical industry.
common flange standards

These standards play a crucial role in ensuring the compatibility, reliability, and safety of flanged connections in various industries and regions.

ANSI B16.5 -1996 is the official standard for ANSI Class Pipe Flanges and Flanged Fittings, applied specifically to those made from cast or forged materials, as well as blind flanges and some reducing flanges crafted in the cast, forged, or plate.

ANSI Flanges are manufactured based on standards developed by organizations and ASME Flanges are based on codes and standards for mechanical devices. The ANSI Flanges are designed based on approx. 9500 standards whereas ASME Flanges are manufactured on 600 codes and standards for different mechanical devices.

Flanges to ISO 7005 are internationally standardized. This standard series comprises DIN flanges (PN 2.5; 6; 10; 16; 25 and 40) and ASME flanges. This standard, however, also specifies DN and PN designations for ASME flanges (PN 20; 50; 110; 150; 250, and 420).

B16. 5 is limited to flanges and flanged fittings made from cast or forged materials, and blind flanges and certain reducing flanges made from cast, forged, or plate materials. Also included in this Standard are requirements and recommendations regarding flange bolting, flange gaskets, and flange joints.

The term “B16. 5” or “B16 5” is used interchangeably and refers to the same standard. However, the standard ASME B16 5 (ANSI B16 5) only covers sizes up to 24 inches. For bigger sizes, ASME B16.

The key types of flanges are the welding neck, long welding neck, slip-on, socket weld, lap joint, threaded, and blind flanges. In addition to these standard flanges, some special ones exist, called Weldoflange/Nipoflange and Elboflange, swivel flange, expander/reducer flange, and orifice flanges.