At its 25th meeting (November 2014) the General Conference on Weights and Measures (CGPM) adopted a Resolution on the future revision of the International System of Units.
In the "New SI" four of the SI base units – namely the kilogram, the ampere, the kelvin and the mole – will be redefined in terms of constants; the new definitions will be based on fixed numerical values of the Planck constant (h), the elementary charge (e), the Boltzmann constant (kB), and the Avogadro constant (NA), respectively.
Further, the definitions of all seven base units of the SI will also be uniformly expressed using the explicit-constant formulation, and specific mises en pratique will be drawn up to explain the realization of the definitions of each of the base units in a practical way. It was desided that despite this progress the data produced till now do not yet appear to be
sufficiently robust for the CGPM to adopt the revised SI at its 25th
meeting
The CGPM encourages the continued effort by the CIPM, together with its Consultative Committees, the NMIs, the BIPM, and other organizations such as the International Organization of Legal Metrology (OIML), to complete all work necessary for the CGPM at its 26th meeting (2018) to adopt a resolution that would replace the current SI with the revised SI, provided the amount of data, their uncertainties, and level of consistency are deemed satisfactory.
An important date to note is the closing date for the publication of new data to be considered by the CODATA Task Group on Fundamental Constants for the special adjustment of the fundamental constants in preparation for the redefinition. New results for inclusion in this adjustment must be accepted for publication by 1 July 2017.
A roadmap for the redifinition of units is available here
Source: www.bipm.org
In the "New SI" four of the SI base units – namely the kilogram, the ampere, the kelvin and the mole – will be redefined in terms of constants; the new definitions will be based on fixed numerical values of the Planck constant (h), the elementary charge (e), the Boltzmann constant (kB), and the Avogadro constant (NA), respectively.
Further, the definitions of all seven base units of the SI will also be uniformly expressed using the explicit-constant formulation, and specific mises en pratique will be drawn up to explain the realization of the definitions of each of the base units in a practical way. It was desided that despite this progress the data produced till now do not yet appear to be
sufficiently robust for the CGPM to adopt the revised SI at its 25th
meeting The CGPM encourages the continued effort by the CIPM, together with its Consultative Committees, the NMIs, the BIPM, and other organizations such as the International Organization of Legal Metrology (OIML), to complete all work necessary for the CGPM at its 26th meeting (2018) to adopt a resolution that would replace the current SI with the revised SI, provided the amount of data, their uncertainties, and level of consistency are deemed satisfactory.
An important date to note is the closing date for the publication of new data to be considered by the CODATA Task Group on Fundamental Constants for the special adjustment of the fundamental constants in preparation for the redefinition. New results for inclusion in this adjustment must be accepted for publication by 1 July 2017.
A roadmap for the redifinition of units is available here
Source: www.bipm.org
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