The Units of Measurement Regulations 2009

Further amendments of the 1986 Regulations

4.—(1) The 1986 Regulations are further amended as follows.

(2) In Schedule 1—

(a) in paragraph 1—

(i) at the end of the entry beginning “The kelvin” insert “This definition refers to water having the isotopic composition defined by the following amount-of-substance ratios: 0.00015576 mole of ²H per mole of ¹H, 0.0003799 mole of ¹⁷O per mole of ¹⁶O and 0.0020052 mole of ¹⁸O per mole of ¹⁶O.”; and

(ii) in the italic heading “Special name and symbol of the SI unit of temperature for expressing Celsius temperature”, for “SI unit” substitute “SI derived unit”;

(b) in paragraph 2—

(i) for the italic heading “Other SI units” substitute “SI derived units”;

(ii) omit sub-paragraph (1);

(iii) for sub-paragraph (2) substitute—

“(2) General rule for SI derived units

Units derived coherently from SI base units are given as algebraic expressions in the form of products of powers of the SI base units with a numerical factor equal to 1.”;and

(iv) for sub-paragraph (3) substitute the table and the notes set out in the Schedule.