ASME B16.11 Forged Fittings, Socket-Welding & Threaded
HISTORY - (FOREWORD ASME B16.11-2005)
The Sectional Committee on the Standardization of Pipe Flanges and Fittings, B16, organized in 1920 under the procedure of the American Standards Association (ASA) appointed a subgroup of Subcommittee 3 (now Subcommittee F) to initiate the standardization of welding fittings in May 1937. The first meeting of this group was held later that month, and at its meeting in December 1938, in New York, it was agreed to undertake the standardization of dimensions of socket-welding fittings and to refer this project to a new drafting subgroup. One of the most important dimensions of this type of fitting requiring standardization was considered to be the dimension from the centerline of the fitting to the bottom of the socket, since from the standpoint of the designing engineer, this dimension governs the location of adjacent pipe with reference to the entire piping layout. Another important item for consideration was the welding fillet dimensions.
The drafting subgroup held meetings in Chicago, Detroit, and New York in March 1939, and May and October 1940, respectively, and at the last named meeting, the completed draft of the proposed standard was discussed, and further revisions were suggested. When applied to the September 1940 draft, these changes produced the May 1941 draft, which was prepared for distribution to industry for criticism and comment.
This distribution resulted in a number of helpful comments. The members of the subgroup agreed by mail that many of the changes suggested should be incorporated in the revised draft (December 1941). Progress on the approval of the standard was delayed by the war, after which, a few more changes were added to make the proposal acceptable to all concerned. The revised draft (April 1946) was then submitted to the members of the sectional committee for letter ballot vote.
Following the approval of the sectional committee, the proposed standard was next approved by the sponsor bodies and presented to the ASA with recommendation for approval as an American Standard. This designation was given on December 9, 1946.
In 1960, it was agreed that the standard needed a complete revision and simultaneously that it should be expanded to cover threaded fittings and plugs, then covered by MSS SP-49 and SP-50. A Task Force worked diligently for four years before arriving at a draft that it felt was acceptable. They also found that ratings were outdated and eliminated the 4000-lb classes of threaded fittings, assigned pressure-temperature ratings for a number of materials, and converted the socket-weld fitting ratings to 3000 and 6000 lb. Following approval by the Sectional Committee and Sponsors, ASA approval was granted on January 28, 1966.
Following designation changes of ASA to ANSI and Sectional Committee to Standards Committee, Subcommittee 6 began consideration of changes in 1969. Early in 1972, changes in the pressure class designations, materials, and clarification of wording were agreed upon and submitted for approval. This approach was granted on June 20, 1973.
The work of development of the 1980 edition of B16.11 began in 1975 when the committee began consideration of comments and proposals for change that were received.
The development procedure was arduous in that a number of ballots were taken which elicited many additional comments and counter proposals. The major changes included an expanded scope for better definition, requirements for conformance marking, a nonmandatory annex with provisions for proof or burst testing, and the inclusion of metric equivalents. Following approval by the Standards Committee and Co-Secretariat, final approval by ANSI was granted on October 6, 1980.
In 1982, American National Standards Committee B16 was reorganized as an ASME Committee operating under procedures accredited by ANSI. The 1991 edition of the standard, re-titled "Forged Fittings, Socket-Welding and Threaded," incorporated forging material listed in Table 1 of ASME B16.34-1988, including Group 3 material that was not previously covered in B16.11. The 1991 edition established U.S. Customary units as the standard. Other clarifying and editorial revisionswere made in order to improve the text. Following approval by the Standards Committee and ASME, final approval by ANSI was granted on March 4, 1991.