Commission Directive (EU) 2019/1258 of 23 July 2019 amending, for the purpose of its adaptation to technical progress, the Annex to Council Directive 80/181/EEC as regards the definitions of SI base units (Text with EEA relevance.)

Amendment

Article 1

The Annex to Directive 80/181/EEC is amended in accordance with the Annex to this Directive.

Transposition

Article 2

1.   Member States shall adopt and publish, by 13 May 2020 at the latest, the laws, regulations and administrative provisions necessary to comply with this Directive. They shall forthwith communicate to the Commission the text of those provisions. They shall apply those provisions from 13 June 2020. When Member States adopt those provisions, they shall contain a reference to this Directive or be accompanied by such a reference on the occasion of their official publication. Member States shall determine how such reference is to be made. 2.   Member States shall communicate to the Commission the text of the main provisions of national law which they adopt in the field covered by this Directive.

Entry into force

Article 3

This Directive shall enter into force on the twentieth day following that of its publication in the Official Journal of the European Union . This Directive is addressed to the Member States.

ANNEXSupplementary provisions

ANNEX In the Annex, Chapter I, Section 1.1 is replaced by the following: ‘1.1.    SI base units Quantity Unit Name Symbol Time second s Length metre m Mass kilogram kg Electric current ampere A Thermodynamic temperature kelvin K Amount of substance mole mol Luminous intensity candela cd Definitions of SI base units:   Unit of time The second, symbol s, is the SI unit of time. It is defined by taking the fixed numerical value of the caesium frequency Δ ν Cs , the unperturbed ground-state hyperfine transition frequency of the caesium 133 atom, to be 9 192 631 770 when expressed in the unit Hz, which is equal to s – 1 .   Unit of length The metre, symbol m, is the SI unit of length. It is defined by taking the fixed numerical value of the speed of light in vacuum c to be 299 792 458 when expressed in the unit m/s, where the second is defined in terms of Δ ν Cs .   Unit of mass The kilogram, symbol kg, is the SI unit of mass. It is defined by taking the fixed numerical value of the Planck constant h to be 6,626 070 15 × 10 – 34 when expressed in the unit J s, which is equal to kg m 2 s – 1 , where the metre and the second are defined in terms of c and Δ ν Cs .   Unit of electric current The ampere, symbol A, is the SI unit of electric current. It is defined by taking the fixed numerical value of the elementary charge e to be 1,602 176 634 × 10 – 19 when expressed in the unit C, which is equal to A s, where the second is defined in terms of Δ ν Cs .   Unit of thermodynamic temperature The kelvin, symbol K, is the SI unit of thermodynamic temperature. It is defined by taking the fixed numerical value of the Boltzmann constant k to be 1,380 649 × 10 – 23 when expressed in the unit J K – 1 , which is equal to kg m 2 s – 2 K – 1 , where the kilogram, metre and second are defined in terms of h , c and Δ ν Cs .   Unit of amount of substance The mole, symbol mol, is the SI unit of amount of substance. One mole contains exactly 6,022 140 76 × 10 23 elementary entities. This number is the fixed numerical value of the Avogadro constant, N A, when expressed in the unit mol – 1 and is called the Avogadro number. The amount of substance, symbol n , of a system is a measure of the number of specified elementary entities. An elementary entity may be an atom, a molecule, an ion, an electron, any other particle or specified group of particles.   Unit of luminous intensity The candela, symbol cd, is the SI unit of luminous intensity in a given direction. It is defined by taking the fixed numerical value of the luminous efficacy of monochromatic radiation of frequency 540 × 10 12 Hz, K cd , to be 683 when expressed in the unit lm W – 1 , which is equal to cd sr W – 1 , or cd sr kg – 1 m – 2 s 3 , where the kilogram, metre and second are defined in terms of h , c and Δ ν Cs . 1.1.1.    Special name and symbol of the SI derived unit of temperature for expressing Celsius temperature Quantity Unit Name Symbol Celsius temperature degree Celsius °C Celsius temperature t is defined as the difference t = T – T 0 between the two thermodynamic temperatures T and T 0 where T 0   = 273,15 K. An interval or difference of temperature may be expressed either in kelvins or in degrees Celsius. The unit “degree Celsius” is equal to the unit “kelvin”.’