The American National Standard developed and published by the Manufacturers Standardization Society (MSS) of the Valve and Fittings Industry, Inc., MSS SP-44, which was last revised in 2016, has been reissued. The current edition is ANSI/MSS SP-44-2016 (Reissue 2017): Steel Pipeline Flanges.
Pipeline creation and maintenance makes use of heavy demands and distinctive components and processes. The line pipe is uniquely characterized by high-strength, cold worked, thin-wall of the carbon steel grade, which necessitates special considerations for the welding end of the flanges. This concern was present as far back of the establishment of this standard around fifty years ago, after MSS had received continued requests for steel pipe flanges for pipeline use, particularly in sizes larger than those covered by ASME B16.5.
The ANSI/MSS SP-44-2016 (Reissue 2017) standard practice covers pressure-temperature ratings, materials, dimensions, tolerances, marking, and testing for steel pipeline flanges. In accordance with the document, the welding neck type flanges are to be forged steel, while the blind flanges can be made from either forged steel or steel plate.
The pipe sizes covered by the standard, designated as the dimensionless nominal pipe size (NPS), are NPS 12 to NPS 60, in two number intervals, with dimensional and tolerance guidelines for NPS 10 and smaller being provided by reference to ASME B16.5. Please note that international standards make use of the nominal diameter “DN” system, and the corresponding values of these are listed in the document. ANSI/MSS SP-44-2016 (Reissue 2017) addresses flanges of Class, 150, 300, 400, 600, or 900.
The 2016 revision of the ANSI/MSS SP-44-2016 standard was major, and its updates included:
- Defined chemistry limits (added a Table 1 and removed external references).
- Clarified the “lot” definition.
- Made impact testing at -50 °F mandatory for grades over F42.
- Added requirement for hardness testing.
- Clarified allowable heat treatment methods.
- Changed marking requirements.
- Added tolerances for raised face height and bolt hole diameter.
- Added requirements for Manufacturing Procedure Specification and Inspection and Test Plans.
- Added Figure 4 to illustrate test locations and orientation.
- Removed ring gasket dimensions and referenced ASME B16.20A.
- Added Supplementary Requirements SR1 through SR16.
- Updated and renumbered the reference annex.
To correct publication processing related errata, the 2017 reissue, ANSI/MSS SP-44-2016 (Reissue 2017), replaces the 2016 version of the standard. A separate errata sheet was also issued in September 2017 for insertion into the original 2016 edition.
ANSI/MSS SP-44-2016 (Reissue 2017): Steel Pipeline Flanges is available on the ANSI Webstore.