International System of Units (SI) Act

Act 6 of 1984


Mauritius

International System of Units (SI) Act

Act 6 of 1984

  • Commenced on 1 July 1984
  • [This is the version of this document at 30 June 2017.]

1. Short title

This Act may be cited as the International System of Units (SI) Act.

2. Interpretation

In this Act—"Minister" means the Minister to whom responsibility for the subject of industry is assigned;"quantity" means any physical characteristic which may be measured;"SI unit" means a unit of the International System of Units approved by the General Conference on Weights and Measures (CGPM) established under the Metre Convention of 1875;"vessel" has the same meaning as in the Ports Act.

3. Units to be used

(1)Subject to subsection (4), the measurement of any quantity shall be expressed in terms of SI units.
(2)The SI units shall consist of—
(a)base units;
(b)supplementary units; and
(c)derived units.
(3)For the purposes of subsection (2)—
(a)base units—
(i)are units specified in the second column;
(ii)shall be used in respect of the corresponding quantity specified in the first column,
of the First Schedule;
(b)supplementary units—
(i)are units specified in the second column;
(ii)shall be used in respect of the corresponding quantity specified in the first column,
of the Second Schedule;
(c)derived units—
(i)are units which are derived from base units or supplementary units or both;
(ii)
(A)include the units specified in the second column;
(B)shall be used in respect of the corresponding quantity specified in the first column,
of the Third Schedule.
(4)The units specified in the second column of the Fourth Schedule may be used for the measurement of the corresponding quantity specified in the first column of that Schedule.

4. Multiples and sub-multiples

(1)Subject to subsections (2) and (3), the multiples and sub-multiples of the units mentioned in section 3 shall be those specified in the first column of the Fifth Schedule.
(2)The multiples and sub-multiples of the units of mass shall be expressed by using the prefixes and symbols specified in the Fifth Schedule in relation to the word "gram", which is represented by the symbol "g".
(3)
(a)Any multiple or sub-multiple of a unit mentioned in section 3, other than that specified in the Fifth Schedule, shall be expressed in powers of 10 or in terms of a decimal function.
(b)For the purposes of paragraph (a), the decimal sign shall be indicated by a point.

5. Symbols and prefixes

No person shall, in relation to any unit mentioned in section 3, its multiple or sub-multiple, use a symbol or prefix, other than the symbol or prefix specified in the appropriate Schedule.

6. Regulations

The Minister may—
(a)make such regulations as he thinks fit for the purposes of this Act;
(b)by regulations, amend the Schedules.

7. Offences

Any person who fails to comply with this Act or any regulations made under it shall commit an offence and shall, on conviction, be liable to a fine not exceeding 2,000 rupees and to imprisonment for a term not exceeding one year.

8. ***

9. Application of Act

This Act shall not apply to any measurement of quantity
(a)in respect of a vessel for the purposes of any tax, licence, fee or dues;
(b)in sea or air navigation or meteorology.

10. The State

This Act shall bind the State.[S. 10 amended by Act 48 of 1991.]

11. ***

First Schedule (Section 3 (3) (a))

QuantityBase unitSymbolDefinition
lengthmetremThe metre is the distance travelled by light in a vacuum during 1 299 792 458 of a second.
masskilogramkgThe kilogram is the unit of mass; it is equal to the mass of the international prototype of the kilogram.
timesecondsThe second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom.
electric currentampereAThe ampere is that constant current which, if maintained in 2 straight parallel conductors of infinite length, of negligible circular cross-section, and placed one metre apart in vacuum would produce between these conductors a force equal to 2 x 10-7 newton per metre length of conductor.
thermodynamic temperaturekelvinKThe kelvin, unit of thermodynamic temperature, is the fraction 1/273.16 of the thermodynamic temperature of the triple point of water.
luminous intensitycandelacdThe candela is the luminous intensity in a given direction of a source which emits monochromatic radiation of frequency 540 x 1012 hertz and of which the radiant intensity in that direction is 1/683 watt per steradian.
amount of substancemolemolThe mole is the amount of substance of a system which contains as many elementary entities as there are atoms on 0.012 kilogram of carbon-12. When the mole is used, the elementary entities must be specified and may be atoms, molecules, ions, electrons, other particles or specified groups of such particles.

Second Schedule (Section 3 (3) (b))

QuantitySupplementary unitSymbolDefinition
plane angleradianradThe radian is the plane angle between two radii of a circle which cut off on the circumference an arc equal in length to the radius.
solid anglesteradiansrThe steradian is the solid angle which, having its vertex in the centre of a sphere, cuts off an area of the surface of the sphere equal to that of a square with sides of length equal to the radius of the sphere.

Third Schedule (Section 3 (3) (c))

QuantityDerived unitSymbolDefinition in terms of other SI units
frequencyhertzHz1/s
forcenewtonNmkg/s2
pressurepascalPaN/m2
energy, work, quantity of heatjouleJNm
power, energy fluxwattWJ/s
quantity of electricity, electric chargecoulombCAs
electric tension, electric potentialvoltVW/A
electric capacitancefaradFC/V
electric resistanceohmWV/A
conductancesiemensSA/V
magnetic fluxweberWbVs
magnetic flux densityteslaTWb/m2
inductancehenryHWb/A
luminous fluxlumenlmcdsr
illuminanceluxlxcd sr/m2
activity (radioactive)becquerelBq1/s
absorbed dose (of ionising radiation)grayGyJ/kg
dose equivalent (of ionising radiation)sievertSvJ/kg

Fourth Schedule (Section 3 (4))

QuantityName of unitSymbolEquivalent
plane angledegree-o1° = (p/180) rad
 arcminute-'1' = (1/60)°
 arcsecond-"1" = (1/60)'
areahectareha1 ha = 104m2
volumelitreL*1 L = 1 dm3
  *The symbol ℓ is also permitted for litre.
timedayd1 d = 24 h
hourh1 h = 60 min
minutemin1 min = 60 s
velocitykilometre per hourkm/h
flow rate (volume basis)litre per secondL/s
rotational frequencyrevolution per secondr/s
revolution per minuter/min1 r/min = 1 /60 r/s
masstonnet1 t = 103kg
metric caratCM1 CM = 0.2 g
linear density (mass per unit length)textex1 tex = 1 g/km
flow ratetonne per secondt/s
(mass basis)tonne per hourt/h
dynamic viscositypoiseP1 P = 0.1 Pa. s
kinematic viscositystrokeSt1 St = 100 mm2/S
energy, workwatt hourWh1Wh = 3.6 kJ
temperaturedegree Celsius°CThe Celsius temperature (t) is equal to the difference between the thermodynamic temperature T and 273.15 K
electric charge, quantity of electricityampere hourAh1 Ah = 3.6 kC
apparent powervolt ampereVA
reactive powervarvarvar 1 var - 1 VA reactive power
molar volumelitre per moleL/mol 
sound power leveldecibeldBThe sound power level in decibels is equal to 10 times the logarithm to the base 10 of the ratio of the measured power to a reference sound power (1 pW).
concentrationmole per litremol/L 
pressurebarbar1 bar = 100 kPa
 millimetre of mercurymm Hg1 millimetre of Mercury = 133.322 Pa
[Fourth Sch. amended by GN 80 of 1989.]

Fifth Schedule (Section 4)

Multiples and sub-multiplesPrefixSymbol
1018exaE
1015petaP
1012teraT
109gigaG
106megaM
103kilok
102hectoh
101decada
10-1decid
10-2centic
10-3millim
10-6microm
10-9nanon
10-12picop
10-15femtof
10-18attoa

Sixth Schedule (Section 8)

UnitEquivalentSize in appropriate SI unit Expiry period
inch (in)0.025 4m 
foot (ft)12 inches0.304 8m 
yard (yd)3 feet0.914 4m 
mile1760 yards1609.344m 
pouce (French)0.027 070 1m22 years
pied (French)12 pouces (French)0.324 841m 
toise6 pieds (French)1.949 05m 
gaulette (length)10 pieds (French)3.248 41m 
perche2 gaulettes6.496 82m 
Unit of area
square inch (in2)0.000 645 16m2 
square foot (ft2)144 square inches0.092 903 0m2 
square yard (yd2)9 square feet0.836 127m2 
square mile (mile2)2.589 99km2 
pied carré (French)0.105 522m2 
toise carrée36 pieds carrés (French)3.798 78m22 years
perche carrée400 pieds carrés (French)42.208 7m2 
arpent100 perches carrées (French)4 220.87m2 
gaulette (area)10x5 pieds carrés (French)5.276 09m2 
Unit of volume
cubic inch (in3)16.387 1cm3 
cubic foot (ft3) 11 728 cubic inches0.028 316 8m3 
cubic yard (yd3)27 cubic feet0.764 555m3 
UK fluid ounce28.413 1cm3 
UK pint20 UK fluid ounces0.568 261dm31 year
UK quart2 UK pints1.136 52dm3 
UK gallon4 UK quarts4.546 09dm3 
peg46cm3 
topette50cm3 
Unit of volumetric
flow rate    
pouce fontainier0.007833 cubic foot/second21.805cm3/s1 year
Unit of mass
ounce (oz)28.349 5g 
UK (and US) pound (lb)16 ounces0.453 592 37kg 
UK (long) ton2 240 pounds1 016.05kg 
UK (short) ton2 000 pounds907.185kg1 year
UK (and US) ounce troy31.103 5g 
tola10g 
Unit of force
pound force (Ibf)*4.448.22N5 years
kilogram force (kgf)*9.806.65N 
Unit of pressure
pound force per square inch(Ibf/in2 or psi)*6 894.76Pa 
kilogram force per square cm(kgf/cm2)*technical atmosphere98 066.5Pa5 years
Unit of power
metric horse power735.499W5 years
UK horse power745.700W 
*Sizes in appropriate SI units for these units have been calculated assuming a value of 9.806 65m/s2 for the acceleration due to gravity.*Sizes in appropriate SI units for these units have been calculated assuming a value of 9.806 65m/s2 for the acceleration due to gravity.*Sizes in appropriate SI units for these units have been calculated assuming a value of 9.806 65m/s2 for the acceleration due to gravity.*Sizes in appropriate SI units for these units have been calculated assuming a value of 9.806 65m/s2 for the acceleration due to gravity.
[Sixth Sch. amended by GN 80 of 1989.]
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History of this document

30 June 2017 this version
Consolidation
01 July 1984
Commenced