Development of International Standards
Through its participation in the development of legal metrology standards NIST works to consider the interest of all stakeholders to avoid conflicts with related hydrogen standards developed by national and international standards and codes developing organizations.
Currently, there are two international legal metrology standards which address commercial hydrogen measurement.
"Dynamic Measuring Devices and Systems for Cryogenic Liquids" (1998)
R 81 Status: NIST OWM is Secretariat for the International Organization of Legal Metrology (OIML) Recommendation 81 (R 81) and has responsibility for initiating work and ensuring that the standard progresses according to practices established by OIML. The Committee on International Legal Metrology approved a project to revise the 1998 version of R 81 to include: (1) new ISO and IEC Standards as recommended in OIML D 11 (2004), (2) new developments in hydrogen measurements, (3) revise density equations, and (4) any other remaining relevant standards and national documents.
A first committee draft (1 CD) of R 81 "Dynamic Measuring Devices and Systems for Cryogenic Liquids" is under development. The 1 CD is scheduled for distribution in February 2013 to national stakeholders and Technical Committee 8/Subcommittee 6 for their review and comments.
"Compressed Gaseous Fuel Measuring Systems for Vehicles" (2007)
R 139 Status: In December 2012, the Secretariat (the Netherlands) for International Organization of Legal Metrology (OIML) Recommendation 139 (R 139) "Compressed Gaseous Fuel Measuring Systems for Vehicles" distributed the second committee draft (2CD) of the international standard for comment and vote of Technical Committee 8/Subcommittee 7 (TC 8/SC 7) for Project 4 by its March 2013 deadline. The document is the OIML model regulation for equipment used to deliver compressed gases (natural gas, hydrogen, biogas, etc.) as fuel into motor and fuel cell vehicles, small boats, and aircraft.
The 2CD of R 139 includes parts (1) metrological and technical requirements and (2) metrological controls and performance tests which will be combined. The last part to be completed is part 3, the test report. Part 3 will be developed after the TC 8/SC 7 reaches a consensus on parts 1 and 2.
The 2CD of OIML R 139 is a revision of the first committee draft (February 2012) and a compilation of comments the Secretariat received in May, August, and December 2012 as well as points the International Working Group (IWG) agreed on at the IWG November 2012 meeting in Delft, the Netherlands.
On January 23, 2013, NIST OWM distributed the 2CD of OIML R 139-1 and -2 to the OIML R 139 U.S. National Working Group (USNWG) for comment to develop a U.S. position and vote by the March 2013 deadline. USNWG comments should be submitted to NIST OWM by March 13, 2013.
For copies of the latest published drafts of R 81 or R 139, click here: http://www.oiml.org.
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