Founded in 1880 as the American Society of Mechanical Engineers, today ASME International is a non-profit educational and technical organization with more than 120,000 members worldwide.
The aim of ASME is to promote art, science and allied science and the practice of mechanical and multi-disciplinary engineering. ASME has developed several codes and standards to enhance public safety and productivity of Engineers.
ASME Codes and Standards
ASME codes and standards were developed to enhance the public safety and productivity of the engineers.
The ASME standards are the sort of technical guides for the designers, manufacturers and users regarding the usage of the product. Some of these standards are written in few paragraphs, while others may run into multiple pages.
ASME codes set the guidelines for the mechanical engineers to follow to common system of manufacturing not only in US but also in the countries that have adopted ASME standards.
However, the manufacturers, inspectors and installers cannot be forced to use the ASME codes and standards, as they are only the guidelines. They will become compulsory only if they have been included in the contract.
The ASME standards are effective because they have been universally accepted. Their use makes communication between the manufacturers and users faster and more effective.
Further, the customers will get the same product no matter where they purchase from if they are standard products. For example, if you have purchased a Weld Neck flange in Houston, if it is standardized item, no matter where you purchase a Blind flange from, it will fit on the flange purchased in Houston.
A Standard can be defined as a set of technical definitions and guidelines that function as instructions for designers, manufacturers, operators, or users of equipment.
A standard becomes a Code when it has been adopted by one or more governmental bodies and is enforceable by law, or when it has been incorporated into a business contract.
B16.10: Face to Face and End to End Dimensions of Valves
This Standard covers face-to-face and end-to-end dimensions of straightway Valves, and center-to-face and center-to-end dimensions of angle Valves.
Its purpose is to assure installation interchangeability for Valves of a given material, type size, rating class, and end connection.
B16.11: Forged fittings, Socket-Welding and Threaded
This Standard covers ratings, dimensions, dimensional tolerances, marking and material requirements for socket-welding and threaded forged fittings.
These fittings are designated as Class 2000, 3000, and 6000 for threaded end fittings and Class 3000, 6000, and 9000 for socket-weld end fittings.
B16.20: Metallic gaskets for pipe flanges: Ring-Joint, Spiral-wound, and Jacketed
This Standard covers materials, dimensions, dimensional tolerances, and markings for metal ring-joint gaskets, spiral-wound gaskets, and metal-jacketed gaskets.
These gaskets are dimensionally suitable for use with flanges described in reference flange standards ASME B16.5, ASME B16.47, API Specification 6A, and ISO 10423.
This Standard covers spiral-wound metal gaskets and metal-jacketed gaskets for use with raised-face and flat-face flanges.
B16.21: Nonmetallic Flat gaskets for pipe flanges
This Standard covers types, sizes, materials, dimensions, dimensional tolerances, and markings for nonmetallic flat gaskets. These gaskets are dimensionally suitable for use with flanges described in the referenced flange standards.
B16.25: Buttwelding Ends
This Standard covers the preparation of buttwelding ends of piping components to be joined into a piping system by welding. It includes requirements for welding bevels, for external and internal shaping of heavy-wall components, and for preparation of internal ends (including dimensions and dimensional tolerances). Coverage includes preparation for joints with the following: no backing rings; split or noncontinuous backing rings; solid or continuous backing rings; consumable insert rings; gas tungsten arc welding (GTAW) of the root pass.
B16.34: Valves Flanged, Threaded and Welding End
This standard applies to new construction and covers pressure-temperature ratings, dimensions, dimensional tolerances, materials, nondestructive examination requirements, testing, and marking for cast, forged, and fabricated flanged, threaded, and welding end and wafer or flangeless Valves of steel, nickel-base alloys, and other alloys shown in Table 1.
Wafer or flangeless Valves, bolted or through-bolt types, that are installed between flanges or against a flange are treated as flanged-end Valves. Alternative rules for NPS 2.1/2 and smaller Valves are given in Mandatory Appendix V.
B16.36: Orifice Flanges
This Standard covers flanges (similar to those covered in ASME B16.5) that have orifice pressure differential connections.
Coverage is limited to the following: (a) Welding Neck flanges Classes 300, 400, 600, 900, 1500, and 2500 (b) slip-on and threaded Class 300.
B16.47: Large diameter Steel Flanges: NPS 26 through NPS 60 metric/inch standard
This Standard covers pressure-temperature ratings, materials, dimensions, dimensional tolerances, marking, and testing for pipe flanges in sizes NPS 26 through NPS 60 and in ratings Classes 75, 150, 0300, 400, 600, and 900. Flanges may be cast, forged, or plate (for blind flanges only) materials, as listed in Table 1A. Requirements and recommendations regarding bolting and gaskets are also included.
Note: ASME has incorporated most of the MSS-SP44 specification into B16.47 Series A and most of the API 605 Specification into B16.47 series B. They have also added Blinds to these two specs. You may note that these specs include only Weld Necks and Blinds.
For other flanges over NPS 24 you must refer to either Industry Standard (which are not automatically covered by ASME) or Boiler Code Flanges. If you need help deciding which flange best suits your application feel free to contact me.
B16.48: Line Blanks
This Standard covers pressure-temperature ratings, materials, dimensions, dimensional tolerances, marking, and testing for operating line blanks in sizes NPS 1/2 through NPS 24 for installation between ASME B16.5 flanges in the 150, 300, 600, 900, 1500, and 2500 Pressure Classes. The dimensions are suitable for blanks made of materials listed in Table 1.
B16.49: Factory-made, Wrought Steel, Buttwelding Induction Bends for Transportation and Distribution systems
This Standard covers design, material, manufacturing, testing, marking, and inspection requirements for factory-made pipeline bends of carbon steel materials having controlled chemistry and mechanical properties, produced by the induction bending process, with or without tangents.
This standard covers induction bends for transportation and distribution piping applications (e.g., ASME B31.4, B31.8, and B31.11). Process and power piping have differing requirements and materials that may not be appropriate for the restrictions and examinations described herein, and therefore are not included in this Standard.
B16.5: Pipe Flanges and flanged fittings: NPS 1/2 through 24
This Standard covers pressure-temperature ratings, materials, dimensions, dimensional tolerances, marking, testing, and methods of designating openings for pipe flanges and flanged fittings.
Included are: flanges with rating class designations 150, 300, 400, 600, 900, 1500, and 2500 in sizes NPS 1/2 through NPS 24, with requirements given in both metric and U.S.
Customary units with diameter of bolts and flange bolt holes expressed in inch units; 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 diameter of bolts and flange bolt holes expressed in inch units; and flanged fittings with rating class designation 400, 600, 900, 1500, and 2500 in sizes NPS 1/2 through NPS 24 that are acknowledged in Annex G in which only U.S. Customary units are provided.
This Standard 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.
B16.9: Factory-made Wrought Buttwelding fittings
This Standard covers overall dimensions, dimensional tolerances, ratings, testing, and markings for wrought carbon and alloy steel factory-made buttwelding fittings of NPS 1/2 through 48. It covers fittings of any producible wall thickness. This standard does not cover low pressure corrosion resistant buttwelding fittings. See MSS SP-43, Wrought Stainless Steel Butt-Welding Fittings.
B1.20.1: Pipe threads, general purpose, inch
This American National Standard covers dimensions and gaging of pipe threads for general purpose applications.B1.20.1 is a revision and redesignation of ANSI B2.1-1968.
B1.20.2M: Pipe threads, 60 deg. general purpose (metric)
ASME B.1.20.2M-2006; Pipe Threads, 60 deg, General Purpose (Metric) Standard is a metric conversion of the widely accepted ASME B1.20.1-1983; Pipe Threads, General Purpose (Inch) Standard NPT Taper Pipe Threads. The ASME B1 Standards Committee prepared this metric translation in order to encourage global use and acceptance of the NPT Pipe Thread. For ease of use, product threads and gauging are contained in the Standard. There are no changes to the thread or gage designs.
B36.10M: Welded and Seamless wrought steel pipe
This standard covers the standardization of dimensions of welded and seamless wrought steel pipe for high or low temperatures and pressures. The word pipe is used as distinguished from tube to apply to tubular products of dimensions commonly used for pipeline and piping systems. Pipe NPS 12 (DN 300) and smaller have outside diameters numerically larger than corresponding sizes. In contrast, the outside diameters of tubes are numerically identical to the size number for all sizes.
B36.19M: Stainless Steel pipe
This Standard covers the standardization of dimensions of welded and seamless wrought stainless steel pipe. The word pipe is used as distinguished from tube to apply to tubular products of dimensions commonly used for pipeline and piping systems. Pipe dimensions of sizes 12 and smaller have outside diameters numerically larger than the corresponding size. In contrast, the outside diameters of tubes are numerically identical to the size number for all sizes. The wall thicknesses for sizes 14 through 22 inclusive of Schedule 10S, for size 12 schedule 40S, and for sizes 10 and 12 of schedule 80S are not the same as those of ANSI/ASME B36.10. The suffix “S” in the Schedule Number is used to differentiate B36.19M pipe from B36.10M pipe. ANSI/ASME B36.10 includes other pipe thicknesses which are also commercially available with stainless steel material.