1980L0181 — EN — 21.12.1979 — 000.001 — 1
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►B COUNCIL DIRECTIVE
of 20December 1979
on the approximation of the laws of the Member States relating to units of measurement and on
the repeal of Directive 71/354/EEC
(80/181/EEC)
(OJ L 39, 15.2.1980, p. 40)
Corrected by:
►C1Corrigendum, OJ L 296, 15.10.1981, p. 52 (80/181)
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COUNCIL DIRECTIVE
of 20December 1979
on the approximation of the laws of the Member States relating to
units of measurement and on the repeal of Directive 71/354/EEC
(80/181/EEC)
THE COUNCIL OF THE EUROPEAN COMMUNITIES,
Having regard to the Treaty establishing the European Economic
Community, and in particluar Article 100 thereof,
Having regard to Council Directive 71/354/EEC of 18 October 1971 on
the approximation of the laws of the Member States relating to units ofmeasurement(
1), as last amended by Council Directive 76/770/EEC (2),
Having regard to the proposal from the Commission(3),
Having regard to the opinion of the European Parliament(4),
Having regard to the opinion of the Economic and Social Committee(5),
Whereas units of measurement are essential in the use of all measuring
instruments, to express measurements or any indication of quantity;whereas units of measurement are used in most fields of human activity;whereas it is necessary to ensure the greatest possible clarity in theiruse; whereas it is therefore necessary to make rules for their use withinthe Community for economic, public health, public safety or adminis-trative purposes;
Whereas, however, there exist international conventions or agreements
in the field of international transport which bind the Community or theMember States; whereas these conventions or agreements have to berespected;
Whereas the laws which regulate the use of units of measurement in the
Member States differ from one Member State to another and as a resulthinder trade; whereas, in these circumstances, it is necessary to harmo-nize laws, regulations and administrative provisions in order to over-come such obstacles;
Whereas units of measurement are the subject of international resolu-
tions adopted by the General Conference of Weights and Measures(CGPM) set up by the Metre Convention signed in Paris on 20 May1875, to which all the Member States adhere; whereas the ‘InternationalSystem of Units'(SI) was drawn up as a result of these resolutions;
Whereas the Council on 18 October 1971 adopted Directive 71/
354/EEC on the approximation of the laws of the Member States inorder to eliminate obstacles to trade by adopting the internationalsystem of units at Community level; whereas Directive 71/354/EEC wasamended by the Act of Accession and by Directive 76/770/EEC;
Whereas these Community provisions have not overcome all the
obstacles in this field; whereas Directive 76/770/EEC provides for thereview before 31 December 1979 of the situation regarding units ofmeasurement, names and symbols listed in Chapter D of the Annexthereto; whereas it has also proved necessary to review the situationregarding certain other units of measurement;
Whereas it is necessary, in order to avoid serious difficulties, to provide
for a transitional period during which units of measurement which arenot compatible with the international system can be phased out; whereasit is nevertheless essential to allow the Member States wishing to do so
(1) OJ No L 243, 29. 10. 1971, p. 29.
(2) OJ No L 262, 27. 9. 1976, p. 204.
(3) OJ No C 81, 28. 3. 1979, p. 6.
(4) OJ No C 127, 21. 5. 1979, p. 80.
(5) Opinion delivered on 24/25 October 1979 (not yet published in the Offi-
cial Journal).
1980L0181 — EN — 21.12.1979 — 000.001 — 3
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to bring into force as quickly as possible, on their territory, the provi-sions of Chapter I of the Annex; whereas it is therefore necessary tolimit the duration of this transitional period at Community level while,at the same time, leaving the Member States free to curtail that period;
Whereas, during the transitional period, it is essential, particularly in
order to protect the consumer, to maintain a clear position on the use ofunits of measurement in trade between the Member States; whereas theobligation on the Member States to allow use of supplementary indica-tions on products and equipment imported from other Member Statesduring this transitional period seems to serve this purpose well;
Whereas the systematic adoption of a solution of this kind for all
measuring instruments, including medical instruments, is however notnecessarily desirable; whereas the Member States should therefore beable to require that, on their territory, measuring instruments bearindications of quantity in a single legal unit of measurement;
Whereas this Directive does not affect the continued manufacture of
products already on the market; whereas it does, however, affect theplacing on the market and use of products and equipment bearingindications of quantity in units of measurement which are no longerlegal units of measurement, when such products and equipment arenecessary to supplement or replace components or parts of such prod-ucts, equipment and instruments already on the market; whereas it istherefore necessary for Member States to authorize the placing on themarket and the use of such products and equipment to complete andreplace components, even when they bear indications of quantity inunits of measurement which are no longer legal units of measurement,so that products, equipment or instruments already on the market maycontinue to be used;
Whereas the International Organization for Standardization (ISO) on 1
March 1974 adopted an international standard on the representation ofSI and other units for use in systems with limited sets of characters;whereas it is advisable for the Community to adopt the solutions whichhave already been approved on a wider international level by ISOStandard 2955 of 1 March 1974;
Whereas Community provisions relating to units of measurement are to
be found in several Community texts; whereas the question of units ofmeasurement is so important that it is essential that reference may bemade to a single Community text; whereas this Directive therebyconsolidates all the Community provisions on the subject and repealsDirective 71/354/EEC,
HAS ADOPTED THIS DIRECTIVE:
Article 1
The legal units of measurement within the meaning of this Directive
which must be used for expressing quantities shall be:
(a) those listed in Chapter I of the Annex;
(b) those listed in Chapter II of the Annex, until a date to be fixed by
the Member States; this date may not be later than 31 December1985;
(c) those listed in Chapter III of the Annex only in those Member
States where they were authorized on 21 April 1973 and until a dateto be fixed by those Member States; this date may not be later thana date to be set by the Council before 31 December 1989 on thebasis of Article 100 of the Treaty.
Article 2
(a) The obligations arising under Article 1 relate to measuring instru-
ments used, measurements made and indications of quantityexpressed in units of measurement, for economic, public health,public safety or administrative purposes.
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(b) This Directive shall not affect the use in the field of air and sea
transport and rail traffic of units, other than those made compulsoryby the Directive, which have been laid down in internationalconventions or agreements binding the Community or the MemberStates.
Article 3
1. For the purposes of this Directive ‘supplementary indication'means
one or more indications of quantity expressed in units of measurementnot contained in Chapter I of the Annex accompanying an indication ofquantity expressed in a unit contained in that Chapter.
2. The use of supplementary indications shall be authorized until 31
December 1989.
3. However, Member States may require that measuring instruments
bear indications of quantity in a single legal unit of measurement.
4. The indication expressed in a unit of measurement listed in
Chapter I shall predominate. In particular, the indications expressed inunits of measurement not listed in Chapter I shall be expressed incharacters no larger than those of the corresponding indication in unitslisted in Chapter I.
5. The use of supplementary indications may be extended after 31
December 1989.
Article 4
The use of units of measurement which are not or are no longer legal
shall be authorized for:
— products and equipment already on the market and/or in service on
the date on which this Directive is adopted,
— components and parts of products and of equipment necessary to
supplement or replace components or parts of the above productsand equipment.
However, the use of legal units of measurement may be required for the
indicators of measuring instruments.
Article 5
International standard ISO 2955 of 1 March 1974, ‘Information
processing — Representations of SI and other units for use in systemswith limited character sets'shall apply in the field covered by paragraph1 thereof.
Article 6
Directive 71/354/EEC shall be repealed on 1 October 1981.However, by way of derogation from Directive 71/354/EEC, Member
States shall authorize or continue to allow on the terms specified inArticle 1 of this Directive the use of the following units of measurementafter 31 December 1979:
millimetre of mercury (Chapter II)
poise (Chapter II)stokes (Chapter II)yard (Chapter III)square yard (Chapter III)therm (Chapter III).
Article 7
(a) Member States shall adopt and publish before 1 July 1981 the laws,
regulations and administrative provisions necessary to comply withthis Directive and shall inform the Commission thereof.
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They shall apply these provisions from 1 October 1981.
(b) As from the date of notification of this Directive, Member States
shall also ensure that the Commission is informed, in sufficient timeto enable it to submit its comments, of any draft laws, regulations oradministrative provisions which they intend to adopt in the fieldcovered by this Directive.
Article 8
This Directive is addressed to the Member States.
1980L0181 — EN — 21.12.1979 — 000.001 — 6
Unit
Quantity
Name Symbol▼C1
ANNEX
CHAPTER I
LEGAL UNITS OF MEASUREMENT REFERRED TO IN ARTICLE 1 (a)1. SI UNITS AND THEIR DECIMAL MULTIPLES AND SUBMULTI-
PLES
1.1.SI base units
Length metre m
Mass kilogram kg
Time second s
Electric current ampere A
Thermodynamic
temperaturekelvin K
Amount of substance mole mol
Luminous intensity candela cd
Definitions of SI base units:
Unit of lengthThe metre is the length equal to 1 650 763 ·73wavelengths in
vacuum of the radiation corresponding to the transition between thelevels 2p
10and 5d5of the krypton-86 atom.
(Eleventh CGPM (1960), resolution 6).
Unit of mass
The kilogram is the unit of mass; it is equal to the mass of the
international prototype of the kilogram.
(Third CGPM (1901), page 70 of the conference report).
Unit of time
The second is the duration of 9 192 631 770periods of the radiation
corresponding to the transition between the two hyperfine levels ofthe ground state of the caesium-133 atom.
(Thirteenth CGPM (1967), resolution 1).
Unit of electric current
The ampere is that constant current, which if maintained in two
straight parallel conductors of infinite length, of negligible circularcross-section, and placed one metre apart in vacuum, wouldproduce between those conductors a force equal t o2×1 0
−7newton
per metre of length.
(CIPM (1946), resolution 2, approved by the ninth CGPM (1948)).
Unit of thermodynamic temperature
The kelvin, unit of thermodynamic temperature, is the fraction
1/273 ·16 of the thermodynamic temperature of the triple point of
water.
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Unit
Quantity
Name Symbol
Unit
Quantity
Name Symbol(Thirteenth CGPM (1967), resolution 4).
Unit of amount of substance
(1) The mole is the amount of substance of a system which
contains as many elementary entities as there are atoms in0·012 kilogram of carbon 12.
(2) When the mole is used, the elementary entities must be
specified and may be atoms, molecules, ions, electrons, otherparticles, or specified groups of such particles.
(Fourteenth CGPM (1971), resolution 3).
Unit of luminous intensity
The candela is the luminous intensity, in a given direction, of a
source that emits monochromatic radiation of frequency of 540 ×10
12hertz and that has a radiant intensity in that direction of
(1/683) watt per steradian.
(Sixteenth CGPM (1979), resolution 3).
1.1.1.Special name and symbol of the SI unit of temperature
for expressing Celsius temperature
Celsius
temperaturedegree Celsius °C
Celsius temperature t is defined as the differenc et=T—T0between the two thermodynamic temperatures T and T0where T0= 273 ·15 kelvins. An interval of or difference in
temperature may be expressed either in kelvins or in degreesCelsius. The unit ‘degree Celsius' is equal to the unit‘kelvin'.
1.2.Other SI units
1.2.1.SI supplementary units
Plane angle radian rad
Solid angle steradian sr
(Eleventh CGPM, 1960, resolution 12).
Definitions of SI supplementary units:
Unit of plane angle
The radian is the plane angle between two radii of a circle
which cut off on the circumference an arc equal in length tothe radius.
(International standard ISO 31-I, December 1965).
Unit of solid angle
The steradian is the solid angle which, having its vertex at
the centre of a sphere, cuts off an area on the surface of thesphere equal to that of a square with sides of length equal tothe radius of the sphere.
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Unit Expression
Quantity
Name SymbolIn other SI
unitsIn terms of SI base
or supplementary
units(International standard ISO 31-I, December 1965).
1.2.2.SI derived units
Units derived coherently from SI base units and SI supple-
mentary units are given as algebraic expressions in the formof products of powers of the SI base units and/or SI supple-mentary units with a numerical factor equal to 1.
1.2.3.SI derived units having names and symbols
Frequency hertz Hz s−1
Force newton N m·kg·s−2
Pressure, stress pascal Pa N·m−2m−1·kg·s−2
Energy, work;
quantity of heatjoule J N·mm2·kg·s−2
Power (1), radiant
fluxwatt W J·s−1m2·kg·s−3
Quantity of elec-
tricity, electricchargecoulomb C s·A
Electric potential,
potential difference,electromotive forcevolt V W·A−1m2·kg·s−3·A−1
Electric resistance ohm Ω V·A−1m2·kg·s−3·A−2
Conductance siemens S A·V−1m−2·kg−1·s3·A2
Capacitance farad F C·V−1m−2·kg−1·s4·A2
Magnetic flux weber Wb V·sm2·kg·s−2·A−1
Magnetic flux
densitytesla T Wb·m−2kg·s−2·A−1
Inductance henry H Wb·A−1m2·kg·s−2·A−2
Luminous flux lumen lm cd·sr
Illuminance lux lx lm·m−2m−2·cd·sr
Activity (of a radio-
nuclide)becquerel Bq s−1
Absorbed dose,specific energyimparted, kerma,absorbed dose indexgray Gy J·kg−1m2·s−2
Dose equivalent sievert Sv J·kg−1m2·s−2
(1) Special names for the unit of power: the name volt−ampere (symbol ‘VA')when it is used
to express the apparent power of alternating electric current, and var (symbol ‘var')when itis used to express reactive electric power. The ‘var'is not included in CGPM resolutions.
Units derived from SI base units or supplementary units may be expressed in termsof the units listed in Chapter 1.
In particular, SI derived units may be expressed by the special names and symbols
given in the above table; for example, the SI unit of dynamic viscosity may beexpressed as m
−1·kg·s−1or N ·s·m−2or Pa ·s.
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Factor Prefix Symbol
Unit
Quantity
Name Symbol Value1.3.Prefixes and their symbols used to designate certain decimal
multiples and submultiples
1018 exa E
1015 peta P
1012 tera T
109 giga G
106 mega M
103 kilo k
102 hecto h
101 deca da
10−1 deci d
10−2 centi c
10−3 milli m
10−6 micro µ
10−9 nano n
10−12 pico p
10−15 femto f
10−18 atto a
The names and symbols of the decimal multiples and submultiples
of the unit of mass are formed by attaching prefixes to the word‘gram' and their symbols to the symbol ‘g'.
Where a derived unit is expressed as a fraction, its decimal multi-
ples and submultiples may be designated by attaching a prefix tounits in the numerator or the denominator, or in both these parts.
Compound prefixes, that is to say prefixes formed by the juxtaposi-
tion of several of the above prefixes, may not be used.
1.4.Special authorized names and symbols of decimal multiples and
submultiples of SI units
Volume litre1 o r L 1 1 l=1d m3=1 0−3m3
Mass tonnet 1 t=1M g=1 03kg
Pressure,stress barbar 2 1b a r=1 05Pa
1 The two symbols ‘I'and ‘L' may be used for the litre unit.
(Sixteenth CGPM (1979), resolution 6).
2 Unit listed in the International Bureau of Weights and Measures booklet as
among the units to be permitted temporarily.
Note:The prefixes and their symbols listed in 1.3 may be used in
conjunction with the units and symbols contained in Table1.4.
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Unit
Quantity
Name Symbol Value
Quan-Unit
tityName Symbol Value
Unit
Quantity
Name Symbol Value2. UNITS WHICH ARE DEFINED ON THE BASIS OF SI UNITS BUT
ARE NOT DECIMAL MULTIPLES OR SUBMULTIPLES THEREOF
Plane
anglerevolution* 1 a 1 revolution = 2 πrad
grade* or gon* gon* 1 gon =π
200rad
degree ° 1°=π
180rad
minute of angle /prime1 1/primedbl1=π
10 800rad
second of angle /prime1 1/primedbl1=π
648 000rad
Time minute min 1min = 60 s
hour h 1h=3 6 0 0s
day d 1d=8 6 4 0 0s
1 The character (*) after a unit name or symbol indicates that it does not appear in
the lists drawn up by the CGPM, CIPM o BIPM. This applies to the whole of thisAnnex.
a No international symbol exists.
Note:The prefixes listed in 1.3 may only be used in conjunction with the
names ‘grade' or ‘gon' and the symbol ‘gon'.
3. UNITS DEFINED INDEPENDENTLY OF THE SEVEN SI BASE
UNITS
The unified atomic mass unit is one-twelfth of the mass of an atom of the
nuclide12C.
The electronvolt is the kinetic energy acquired by an electron passing in a
vacuum from one point to another whose potential is one volt higher.
Mass unifed atomic
mass unitu1u ≈16 6 05 6 55×1 0−27kg
Energy electronvolt eV 1eV≈16 0 21 8 92×1 0−19J
The value of these units, expressed in SI units, is not known exactly.
The above values are taken from CODATA Bulletin No 11 of December
1973 of the International Council of Scientific Unions.
Note:The prefixes and their symbols listed in 1.3 may be used in
conjunction with these two units and with their symbols.
4. UNITS AND NAMES OF UNITS PERMITTED IN SPECIALIZED
FIELDS ONLY
Vergency of optical
systemsdioptre* 1 dioptr e=1m−1
Mass of precious
stonesmetriccarat 1 metric cara t=2×
10−4kg
Area of farmlandand building land are a 1a=1 02m2
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Unit
Quantity
Name Symbol Value
Unit
Quantity
Name Symbol ValueMass per unit
length of textileyarns and threadstex* tex* 1t e x=1 0−6kg·m−1
Note:The prefixes listed in 1.3 may be used in conjunction with the
above units. The multiple 102a is, however, called a ‘hectare'.
5. COMPOUND UNITS
Combinations of the units listed in Chapter I form compound units.
CHAPTER II
LEGAL UNITS OF MEASUREMENT REFERRED TO IN ARTICLE 1 (b)
QUANTITIES, NAMES OF UNITS, SYMBOLS AND VALUES
Blood pressure milimetre
of mercury(*)mm Hg(*) 1 mm Hg = 133 ·322 Pa
Plane angleg*1
1g=π
200rad
Activity
(of a radionu-
clide)curie C i 1C i=3 ·7×1 010Bq
Absorbed dose rad rad 2 1 rad = 10−2Gy
Dose equivalent rem* rem* 1 rem = 10−2Sv
Exposure (X
andγrays)röntgen R 1R=2 ·58·10−4C·kg−1
Dynamic
viscositypoise P 1P=1 0−1Pa·s
Kinematic
viscositystokes St 1S t=1 0−4m2·s−1
1 Symbol for ‘grade'.
2 When there is risk of confusion with the symbol for radian, rd may be used as symbol for
rad.
Note:The prefixes and their symbols listed in 1.3 of Chapter I may be used in
conjunction with the units and symbols contained in this section, with theexception of millimetre of mercury and its symbol and the symbol ‘g'.
Until the date indicated in Article 1 (b), the units listed in Chapter II may be
combined with each other or with those in Chapter I to form compound units.
CHAPTER III
LEGAL UNITS OF MEASUREMENT REFERRED TO IN ARTICLE 1 (c)
QUANTITIES, NAMES OF UNITS, SYMBOLS AND APPROXIMATE
VALUES
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Length
inch 1 in = 2 ·5 4×1 0−2m
foot 1 ft = 0 ·3048 m
fathom (1)1 f m = 1 ·829 m
mile 1 mile = 1 609myard 1 yard = 0 ·9144 m
Area
square foot 1 sq ft = 0 ·9 2 9×1 0
-1m2
acre 1 ac = 4 047m2
square yard 1 sq yd = 0 ·8361 m2
Volume
fluid ounce 1 fl oz = 28 ·4 1×1 0−6m3
gill 1 gill = 0 ·1421 × 10−3m3
pint 1 pt = 0 ·5683 × 10−3m3
quart 1 qt = 1 ·1 3 7×1 0−3m3
gallon 1 gal = 4 ·5 4 6×1 0−3m3
Mass
ounce (avoirdupois) 1 oz = 28 ·3 5×1 0−3kg
troy ounce 1 oz tr = 31 ·1 0×1 0−3kg
pound 1 lb = 0 ·4536 kg
Energy
therm 1 therm = 105 ·5 0 6×1 06J
(1) For marine navigation only.
Until the date to be fixed under Article 1 (c), the units listed in Chapter III may
be combined with each other or with those in Chapter I to form compound units.