ASME (American Society of Mechanical Engineers) is a non-profit organization that continues to develop and maintains nearly 600 codes and standards in a wide range of disciplines. Some of which includes the Boiler and Pressure Vessel Code (BPVC), Elevators and Escalators (A17 Series), Piping and Pipelines (B31 Series), Bioprocessing Equipment (BPE), Nuclear Facility Applications (NQA), Process Performance Test Codes (PTC), and Valves, Flanges, Fittings and Gaskets (B16).
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The ASME B16 Standardization of Valves Flanges, Fittings and Gaskets Committee, which operates under ASME’s Board on Pressure Technology Codes and Standards is responsible for standards covering valves, flanges, pipe fittings, gaskets and valve actuators for use in pressure services. The B16 Standards Committee currently meets once a year in various locations throughout the United States. The meeting is generally held in March and is open to the general public.
ASME B16 Technical Subcommittees
Membership on the B16 Standards Committee and its Subordinate groups include a variety of representations from the field in various interest classifications. These interest classifications are; Manufacturer, Distributor, Material Manufacturer, Consumer/User, Designer/Constructor, Regulatory, Insurance/Inspection and General Interest. The B16 Technical Subcommittees under the B16 Standards Committee review and maintain the ASME B16 Standards within their respective scopes. The current B16 Subcommittees are as follows:
B16 Materials Technical Committee
B16 Subcommittee B - Threaded Fittings (Except Steel), Flanges, and Flanged Fittings
B16 Subcommittee C - Steel Flanges and Flanged Fittings
B16 Subcommittee F - Steel Threaded and Welding Fittings
B16 Subcommittee G - Gaskets for Flanged Joints
B16 Subcommittee J- Copper and Copper Alloy Flanges, Flanged Fittings, and Solder Joint Fittings
B16 Subcommittee L - Gas Shutoffs and Valves
B16 Subcommittee N - Steel Valves and Face-to-Face and End-to-End Dimensions of Valves
B16 Standards
The following is a list of current ASME B16 Standards. These standards are continuously being reviewed to ensure that they reflect new developments and technical advances such as new designs and materials.
B16.1- Gray Iron Pipe Flanges and Flanged Fittings. This Standard for Classes 25, 125, and 250 Cast Iron Pipe Flanges and Flanged Fittings covers: (a) pressure-temperature ratings, (b) sizes and method of designating openings of reducing fittings, (c) marking, (d) minimum requirements for materials, (e) dimensions and tolerances, (f) bolt, nut, and gasket dimensions and (g) pressure testing.
B16.3- Malleable Iron Threaded Fittings. This Standard covers malleable iron threaded fittings, Classes 150 and 300. It also contains provisions for using steel for caps and couplings in Class 150 for NPS 3/8 and smaller.
B16.4- Gray Iron Threaded Fittings. This Standard for gray iron threaded fittings, Classes 125 and 250 covers: (a) pressure-temperature ratings (b) size and method of designating openings of reducing fittings (c) marking (d) material (e) dimensions and tolerances (f) threading, and (g) coatings.
B16.5 - Pipe Flanges and Flanged Fittings NPS 1/2 through 24. This Standard covers pressure-temperature ratings, materials, dimensions, 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, 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 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, 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.
B16.9- Factory-Made Wrought Steel Buttwelding Fittings. This Standard covers overall dimensions, 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.
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, 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.
B16.12- Cast Iron Threaded Drainage Fittings. This standard covers fittings intended for use in gravity drainage systems subject only to the gravity head of waste liquids at temperatures from ambient to approximately 100 deg. C (212 deg. F).
B16.14- Ferrous Pipe Plugs, Bushings, and Locknuts with Pipe Threads. This Standard for Ferrous Pipe Plugs, Bushings, and Locknuts with Pipe Threads covers: (a) pressure-temperature ratings; (b) size; (c) marking; (d) materials; (e) dimensions and tolerances; (f) threading; and (g) pattern taper.
B16.15- Cast Copper Alloy Threaded Fittings. This Standard covers cast Class 125 and 250 copper alloy threaded pipe fittings with provisions for substituting wrought copper alloys for plugs, bushings, caps, and couplings in small sized sizes. This Standard includes: (a) pressure-temperature ratings (b) size and method of designating openings of reducing pipe fittings (c) marking requirements (d) minimum requirements for casting quality and materials (e) dimensions and tolerances in SI (metric) and U.S. Customary units (f) threading requirements (g) pressure test requirements.
B16.18- Cast Copper Alloy Solder Joint Pressure Fittings. This Standard for cast copper alloy solder joint pressure fittings designed for use with copper water tube, establishes requirements for: (a) Pressure-temperature ratings; (b) Abbreviations for end connections; (c) Sizes and method of designating openings of fittings; (d) Marking; (e) Material; (f) Dimensions and tolerances; and (g) Tests.
B16.20- Metallic Gaskets for Pipe Flanges -Ring-Joint, Spiral-Wound, and Jacketed. B16.20 offers comprehensive solutions applying to materials, dimensions, tolerances and marking. It addresses gaskets that are dimensionally suitable for use with flanges described in reference flange standards ASME B16.5, ASME B16.47, API Specification 6A, and ISO 10423 as well as with other ASME standards, such as the Boiler and Pressure Vessel Code and the B31 Piping Codes. Notable revisions to the 2012 edition include a new chapter on Grooved Metal Gaskets with Covering Layers and updates to material tables.
B16.21- Nonmetallic Flat Gaskets for Pipe Flange. This Standard covers non-metallic flat gaskets. It offers comprehensive solutions applying to materials, dimensions, tolerances and marking.
B16.22- Wrought Copper and Copper Alloy Solder Joint Pressure Fittings. This Standard establishes specifications for wrought copper and wrought copper alloy, solder-joint, seamless fittings, designed for use with seamless copper tube conforming to ASTM B88 (water and general plumbing systems), B280 (air conditioning and refrigeration service), and B819 (medical gas systems), as well as fittings intended to be assembled with soldering materials conforming to ASTM B32, brazing materials conforming to AWS A5.8, or with tapered pipe thread conforming to ASME B1.20.1. This Standard is allied with ASME B16.18, which covers cast copper alloy pressure fittings. It provides requirements for fitting ends suitable for soldering. This Standard covers pressure-temperature ratings, abbreviations for end connections, size and method of designating openings of fittings, marking, material, dimensions and tolerances, and tests.
B16.23- Cast Copper Alloy Solder Joint Drainage Fittings – DWV. This Standard establishes specifications for cast copper alloy solder joint drainage fittings, designed for use in drains, waste, and vent (DWV) systems.
B16.24- Cast Copper Alloy Pipe Flanges and Flanged Fittings Class 25, 125, 250, and 800.
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 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.
B16.26- Cast Copper Alloy Fittings for Flared Copper Tubes. This Standard establishes specifications for cast copper alloy fittings and nuts used with flared seamless copper tube conforming to ASTM B88 (water and general plumbing systems).
B16.29- Wrought Copper and Wrought Copper Alloy Solder Joint Drainage Fittings – DWV. This standard for wrought copper and wrought copper alloy solder-joint drainage fittings, designed for use with copper drainage tube conforming to ASTM B-306, covers description, pitch (slope), abbreviations for end connections, sizes and method of designating openings for reducing fittings, marking, material and dimensions and tolerances.
B16.33- Manually Operated Metallic Gas Valves for Use in Gas Piping Systems up to 125 psig (Sizes ½ through 2). This Standard covers requirements for manually operated metallic valves sizes NPS 1/2 through NPS 2, for outdoor installation as gas shut-off valves at the end of the gas service line and before the gas regulator and meter where the designated gauge pressure of the gas piping system does not exceed 175 psi (12.1 bar) 125. The Standard applies to valves operated in a temperature environment between -20°F and 150°F (-29°C and 66°C).
B16.34- Valves-Flanges, Threaded and Welding End. This Standard applies to new construction. It covers pressure-temperature ratings, dimensions, 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 2½ 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.
B16.38- Large Metallic Valves for Gas Distribution (Manually Operated, NPS 2 ½ (DN 65) to 12 (DN 300), 125 psig (8.6 bar) Maximum. This Standard covers requirements for manually operated metallic valves in nominal sizes 2 ½ (DN 65) through 12 (DN 300) having the inlet and outlet on a common centerline. These valves are intended for controlling the flow of gas from open to fully closed positions, for use in distribution and service lines where the maximum gage pressure does not exceed 125 psig (8.6 bar). Valve seats, seals, and stem packing may be nonmetallic. This Standard sets forth the minimum capabilities, characteristics, and properties that a newly manufactured metallic valve must possess in order to be considered suitable for use in the piping systems indicated above, carrying natural gas, manufactured gas [includes synthetic natural gas (SNG)], and liquefied petroleum gases (distributed as a vapor, with or without the admixture of air) or mixtures thereof.
B16.39- Malleable Iron Threaded Pipe Unions. This Standard covers threaded malleable iron unions, classes 150, 250, and 300.It also contains provisions for using steel for NPS 1/8 unions. This Standard includes requirements for design, pressure-temperature ratings, size, marking, materials, joints and seats, threads, hydrostatic strength, tensile strength, air pressure test, sampling, coatings, and dimensions.
B16.40- Manually Operated Thermoplastic Gas Shutoffs and Valves in Gas Distribution Systems. This Standard covers manually operated thermoplastic valves in nominal valve sizes 1/2 through 12. These valves are intended for use below ground in thermoplastic fuel gas distribution mains and service lines. The maximum operating pressure (MOP) at which such distribution piping systems may be operated is in accordance with the Code of Federal Regulation (CFR) Title 49, Part 192, Transportation of Natural and Other Gas by Pipeline; Minimum Safety Standards, for temperature ranges of -20°F to 140°F (-29°C to 60°C). This Standard sets qualification requirements for each basic valve design as a necessary condition for demonstrating conformance to this Standard. This Standard sets requirements for newly manufactured valves for use in below ground piping systems for fuel gas [includes synthetic natural gas (SNG)], and liquefied petroleum (LP) gases (distributed as a vapor, with or without the admixture of air) or mixtures thereof.
B16.42- Ductile Iron Pipe Flanges and Flanged Fittings. This Standard covers minimum requirements for Class 150 and 300 cast ductile iron pipe flanges and flanged fittings.
B16.44- Manually Operated Metallic Gas Valves for Use in Aboveground Piping Systems up to 5 psi. This Standard applies to new valve construction and covers quarter-turn manually operated metallic valves in sizes NPS 4¼ and tubing sizes 1¼ O.D. These valves are intended for indoor installation as gas shutoff valves when installed in above ground fuel gas piping downstream of the gas meter outlet and upstream of the inlet connection to a gas appliance. The valves covered by this Standard are limited to application temperatures between 32 F and 125 F at pressures not to exceed 5 psig. This Standard does not apply to manually operated gas valves which are an integral part of a gas appliance. Manually operated gas valves intended for application to a particular appliance are covered in the American National Standard for Manually Operated Gas Valves for Appliances, Appliance Connector Valves, and Hose End Valves, ANSI Z21.15/CGA 9.1.
B16.47- Large Diameter Steel Flanges NPS 26 through NPS 60. This Standard covers pressure-temperature ratings, materials, dimensions, tolerances, marking, and testing for pipe flanges in sizes NPS 26 through NPS 60 and in ratings Classes 75, 150, 300, 400, 600, and 900.
B16.48- Line Blanks. This Standard covers pressure-temperature ratings, materials, dimensions, 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.
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.
B16.50- Wrought Copper and Copper Alloy Braze-Joint Pressure Fittings. This Standard establishes requirements for wrought copper and wrought copper alloy braze joint seamless fittings designed for use with seamless copper tube conforming to ASTM Standard Specification, B 88 (Water and General Plumbing Systems), B 280 (Air Conditioning and Refrigeration Service), and B 819 (Medical Gas Systems). This Standard covers joints assembled with brazing materials conforming to ANSI/AWS A5.8. This Standard is allied to ASME standards B16.18 and B16.22. It provides requirements for fitting ends suitable for brazing. This Standard covers: (a) pressure-temperature ratings; (b) abbreviations for end connections; (c) size and method of designating openings of fittings; (d) marking; (e) material; (f) dimensions and tolerances; and (g) testing.
B16.51- Cast and Wrought Copper and Copper Alloy Press-Connect Pressure Fittings. This Standard provides requirements for fittings suitable for press-connect joining and covers size designations, pressure-temperature ratings, terminology, dimensions and tolerances, materials, design qualification, required installation instructions, and markings.