INTERNATIONAL OIML D 2 DOCUMENT Consolidated Edition 2007 (E) Legal units of measurement Unités de mesure légales ORGANISATION INTERNATIONALE DE MÉTROLOGIE LÉGALE INTERNATIONAL ORGANIZATION OIML D 2 Consolidated Edition 2007 (E) OF LEGAL METROLOGY OIML D 2: 2007 (E) Contents Foreword .................................................................................................................................................................................... 3 Introduction ............................................................................................................................................................................... 4 1 General provisions ................................................................................................................................................................. 4 2 SI units ................................................................................................................................................................................... 5 3 Decimal multiples and sub-multiples of the coherent SI units ......................................................................................... 10 4 Other units ........................................................................................................................................................................... 11 Annex A Units of measurement and denominations which may be used temporarily up to a date which remains to be fixed by national regulations, but which shall not be introduced where they are not in use ............................................................................. 13 Annex B Units of measurement and denominations whose use must be discontinued as soon as possible where they are currently in use and which shall not be introduced where they are not in use ....................................................................................................................................... 14 Bibliography ............................................................................................................................................................................. 15 2 OIML D 2: 2007 (E) Foreword he International Organization of Legal Metrology International Recommendations, Documents, Guides and (OIML) is a worldwide, intergovernmental organiza- Basic Publications are published in English (E) and Ttion whose primary aim is to harmonize the translated into French (F) and are subject to periodic regulations and metrological controls applied by the national revision. metrological services, or related organizations, of its Member States. Additionally, the OIML publishes or participates in the publication of Vocabularies (OIML V) and periodically The main categories of OIML publications are: commissions legal metrology experts to write Expert • International Recommendations (OIML R), which are Reports (OIML E). Expert Reports are intended to provide model regulations that establish the metrological information and advice, and are written solely from the characteristics required of certain measuring instruments viewpoint of their author, without the involvement of a and which specify methods and equipment for checking Technical Committee or Subcommittee, nor that of the their conformity. OIML Member States shall implement CIML. Thus, they do not necessarily represent the views of these Recommendations to the greatest possible extent; the OIML. • International Documents (OIML D), which are This publication - reference OIML D 2, Consolidated Edition informative in nature and which are intended to 2007 (E) - was developed by the OIML Technical Committee harmonize and improve work in the field of legal TC 2 Units of measurement. The previous Edition (1999) was metrology; approved by the International Committee of Legal Metrology • International Guides (OIML G), which are also in 1996 and harmonized in line with the 7th edition of the informative in nature and which are intended to give International System of Units (1998, BIPM). This 2007 guidelines for the application of certain requirements to Edition consolidates the 1999 Edition (which was found to legal metrology; and contain a number of printing errors), Amendment 1 (2004) • International Basic Publications (OIML B), which and Amendment 2 (2007). As a result, this Edition is in line define the operating rules of the various OIML structures with the 8th edition of the International System of Units and systems. (2006, BIPM). OIML Draft Recommendations, Documents and Guides are OIML Publications may be downloaded from the OIML web developed by Technical Committees or Subcommittees site in the form of PDF files. Additional information on which comprise representatives from the Member States. OIML Publications may be obtained from the Organization’s Certain international and regional institutions also headquarters: participate on a consultation basis. Cooperative agreements have been established between the OIML and certain Bureau International de Métrologie Légale institutions, such as ISO and the IEC, with the objective of 11, rue Turgot - 75009 Paris - France avoiding contradictory requirements. Consequently, manu- Telephone: 33 (0)1 48 78 12 82 facturers and users of measuring instruments, test Fax: 33 (0)1 42 82 17 27 laboratories, etc. may simultaneously apply OIML publica- E-mail: [email protected] tions and those of other institutions. Internet: www.oiml.org 3 OIML D 2: 2007 (E) Legal units of measurement Introduction 4 Other units List of units which continue to be used for practical The purpose of this International Document is to reasons (although outside the scope of the Interna- facilitate the drafting of national regulations relating tional System of Units), but most of which are to legal units of measurement. recognized by the CIPM. This list is not standardized internationally, but it is desirable to consider it as This International Document is drawn up according to restrictive in order to facilitate the extension of the the following principles: International System of Units. 1 The International System of Units (SI), adopted by the General Conference of Weights and Measures (CGPM), is used as the basis for national regulations concerning legal units of measurement. Annex A Annex A lists those units of measurement and de- 2 As a general rule, units other than SI units should be nominations which may be used temporarily up to a eliminated; however, for practical reasons it is date which remains to be fixed by national regula- sometimes necessary to extensively use other units tions, but which shall not be introduced where they as legal units of measurement (e.g. the kilowatt hour are not in use. (kW · h)). 3 Those definitions in this International Document which have been provided or ratified by the CGPM have been reproduced exactly. (See subclauses 2.2.1, Annex B 2.2.6, 2.3.1, 2.3.5, 2.3.10, 2.3.11, 2.4.1, 2.5.1, 2.5.2, Annex B lists those units of measurement and de- 2.5.3, 2.5.5, 2.5.7, 2.5.8, 2.5.9, 2.6.1, 2.7.2 and 2.7.4). nominations whose use must be discontinued as soon as possible where they are currently in use and which For the requirements of legal metrology, other shall not be introduced where they are not in use. definitions are given here in their most usually accepted form. The lists in the Annexes must be completed in accord- ance with the needs or customs of each country. This International Document is divided into the fol- lowing clauses: 1 General provisions 1 General provisions Classification and fields of use of legal units of measurement. 1.1 The legal units of measurement are: 2 SI units 1.1.1 The SI units named and defined in clauses 2 and 3. Catalogue of the SI units. The list of derived units may be supplemented or reduced as required. 1.1.2 The other units named and defined in clause 4. 1.1.3 The compound units formed by combining the 3 Decimal multiples and sub-multiples of the units in subclauses 1.1.1 and 1.1.2. coherent SI units Catalogue of SI prefixes. Rules for the formation of 1.2 The units of measurement mentioned in the decimal multiples and sub-multiples of the coherent Annexes may be used up to dates which are to be fixed SI units by means of the SI prefixes. by national or regional regulations. 4 OIML D 2: 2007 (E) 1.3 The obligation to use the legal units of measure- 2.1.3 The names and symbols of the base units are ment refers to: respectively: • measuring instruments used; • results of measurements carried out; Defined in • indications of quantities which are expressed in subclause units of measurement, For length metre m 2.2.1 in the economic field, in the spheres of public health For mass kilogram kg 2.3.1 and safety, in education, in standardization as well as For time second s 2.2.6 in operations of an administrative character. For electric current ampere A 2.5.1 For thermodynamic 1.4 This Document shall not affect the use of units, temperature kelvin K 2.4.1 other than those it renders obligatory, which are laid down in international conventions or agreements For amount of between governments in the fields of navigation by substance mole mol 2.6.1 sea, air traffic and rail transport. For luminous intensity candela cd 2.7.2 1.5 A legal unit of measurement may be expressed 2.1.4 The derived units are expressed algebraically in only: terms of base units by means of the mathematical • either by its legal name or by its legal symbol speci- symbols of multiplication and division. Certain derived fied in this Document, units have been assigned