4. (1) The units of weights and measures to be used throughout Bangladesh shall be units known as system international (SI) units. (2) For the purpose of sub section (1), the international system of units as recommended by the General Conference on Weights and Measures, and such additional units as may be recommended by the International Organisation of Legal Metrology shall be the units of the metric system or international system. (3) The base units shall be as under- (a) kilogram- (i) the base unit of mass shall be the kilogram; (ii) the “kilogram” is the unit of mass; it is equal to the mass of the international prototype of the kilogram; (b) metre- (i) the base unit of length shall be the metre; ¹[(ii) the “metre” is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second;] (c) second- (i) the base unit of time shall be a second; (ii) a “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; (d) ampere- (i) the base unit of electric current shall be the ampere; (ii) the “ampere” is that constant current which, if maintained in two straight paralled 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 ├ù10 7┬¼ newton per metre of length; (e) kelvin- (i) the base unit of thermodynamic temperature shall be the kelvin; (ii) the “kelvin” is the fraction 1/273.16 of the thermodynamic temperature of the triple point of water; Note- (i) The unit kelvin and its symbol k will be used to express on interval or a difference of temperature: (ii) In addition to the thermodynamic temperature (symbol t) expressed in kelvins use is also made of Celsius temperature (symbol t) defined by the equation t=T=To where To-273.15 k by definition. The Celsius temperature is in general expressed in “degrees Celsius” (symbol o C). The unit “degree Celsius” is thus equal to the unit “kelvin” and an interval or a difference of Celsius temperature may also be expressed in degrees Celsius: (f) candela- (i) the base unit of lumirous intensity shall be the candela; (ii) the “candela” is the luminous intensity in the perpendicular direction, of a surface of 1/600 000 square metre of a black body at the temperature of freezing platinum under a pressure of 101 325 newtons per square metre; (g) mole- (i) the base unit of amount of substance shall be the mole; (ii) the “mole” is the amount of substance of system which contains as many elementary entities as there are atoms in 0.012 kilogram of carbon 12. Note.- When the mole is used, the elementary entities shall be specified and may be atoms, molecules, ions, electrons, other particle, or specified groups of such particles.

5. (1) The Government may, by notification in the official Gazette, from time to time, vary, alter or adjust the base units of weights and measures and may, in relation to such units, specify such supplementary, derived, or other units or standard symbols or definitions as the General Conference on Weights and Measures or the International Organisation of Legal Metrology may recommend. Explanation.- For the purpose of this sub-section, “derived unit” shall mean a unit which is derived from the base or supplementary units or both. (2) The Government may specify such multiples and sub-multiples of, and physical constants and ratios of co-efficients in relation to such units of weight or measure as the General Conference on Weights and Measures or the International Organization of Legal Metrology may recommend. (3) The Government may, by notification in the official Gazette, declare, for such period as it may consider necessary, such special units of weight or measure as the General Conference on Weights and Measures or the International Organisation of Legal Metrology may recommend.

6. (1) The Government shall cause to be prepared a national prototype of the kilogram and shall cause the same to be certified in terms of the international prototype of kilogram and shall deposit the same in such place and in such condition as it may think fit. (2) The Government shall cause to be prepared a national prototype of the metre and shall cause the same to be certified by the International Bureau of Weights and Measures and shall deposit the same at such place and in such custody as it may think fit. (3) The other national prototypes of weights and measures shall also be kept at such place and in such custody as may be specified by the authorised person who shall cause them to be verified and certified before they are deposited and at intervals of not more than ten years thereafter.

7. The Government may, by notification in the official Gazette, declare the magnitude and denomination of such units of measure as it deems fit to be the secondary units of measure under this Ordinance: Provided that every such secondary unit except that of time shall be an integral positive or negative power of ten of the relevant primary unit.

8. (1) The units of weights and measures referred to in sections 4 and 6 and the secondary units of measures declared under section 7 shall be the standard of weights and measures. (2) The weight at any place of the primary unit of mass referred to in sub section (3) (a) of section 4 shall be the standard unit of weight at that place. (3) No weight, measure or numeral, other than the standard weight, measure or numeral, shall be a standard weight, measure or numeral. (4) No weight or measure shall be made or manufactured unless it conforms to the standards of weight or measure established by or under this Ordinance: Provided that the Government may permit the making or manufacturing of any weight or measure which does not conform to the standards established by or under this Ordinance, if such weight or measure is made or manufactured exclusively for the purpose of export and is made or manufactured under such conditions and restrictions as may be laid down by the Government. (5) No weight, measure or other goods shall bear thereon any inscription or indication of weight, measure or number except in accordance with the standard unit of such weight measure or numeration established by or under this Ordinance: Provided that in relation to any weight, measure or other goods which are exported, inscription or indication thereon of any weight, measure or number may also be made in accordance with any other system of weight, measure or numeration if such inscription or indication is demanded by the person to whom the export is to be made.

9. (1) The value expressed in terms of any unit of weight or measure other than the standard unit of weight or measure may be converted into the value expressed in terms of the appropriate standard of measure at the rate specified in the Schedule. (2) All references in any enactment or in any notification, rule or order made under any enactment for the time being in force, or in any contract, deed or other instrument to a value expressed in terms of any unit of weight, measure or numeration other than that of a standard unit of weight, measure or numeration shall be construed as references to that value expressed in terms of standard units of weight, measure or numeration, as the case may be, converted at the rates specified in the Schedule. (3) The Government may, by notification in the official Gazette, specify the rates at which the value expressed in terms of any weight or measure other than those referred to in sub section (1) may be converted into the value expressed in terms of the standard of weights and measures. (4) Where in any transaction the value expressed in terms of any weight or measure is required to be converted into the value expressed in terms of the standard of measure under this section, the calculation, for the purposes of such transaction, shall be made in such manner as may be prescribed.

10. (1) The Government shall cause to be prepared as many sets of such standards of measure specified in sub section (1) of section 8 or multiples or sub multiples thereof, to be called reference standards, as it may consider expedient and shall cause the measure of each such set to be authenticated as having been ascertained from the primary units of measure. (2) The reference standards shall be kept in such place and in such condition as may be specified by the authorised person.

11. (1) For the purpose of verifying the correctness of the working standards, the Government may cause to be prepared as many sets of standard weights and standard measures, to be called secondary standards, as it may consider expedient and shall cause each such set to be authenticated as having been verified with the reference standards. (2) The Secondary standards shall be kept in such places and in such conditions as may be specified by the authorised person who shall cause them to be verified with the reference standards at least once in every five years and marked with the date of such verification.

12. (1) For the purpose of verifying the correctness of commercial weights and measures, the Government may cause to be prepared as many sets of standard weights and measures, to be called working standards, as it may consider expedient and shall cause each such set to be authenticated as having been verified with the secondary standards: Working Standards Provided that the working standards in respect of bullion and precious stones shall be verified with the reference standards. (2) The working standards shall be kept in such place and in such condition as may be specified by the authorised persons who shall cause them to be verified with the secondary standards or reference standards, as the case may be, at such intervals and in such manner as may be specified by him and to be marked with the date of such verification. (3) A working standard which has not been verified at any interval specified therefore shall not, after the expiry of the day closing the interval, be used until it has been verified and marked with the date of verification.

13. (1) For the purpose of verifying the correctness of the weighing instruments and measuring instruments used in trade or commerce, the Government may cause to be prepared as many sets of standard weighing instruments and standard measuring instruments as it may consider expedient and the correctness of such instrument shall be verified, and the date of such verification shall be marked, in such manner as may be specified by the authorised person. (2) The standard weighing instruments and standard measuring instruments shall be kept at all places where the secondary standards or working standards are kept.