20. (1) Save as otherwise provided in this section, this Chapter shall not apply to- (a) any weight or measure which, being subject to verification and stamping under the law as in force immediately before the commencement of this Ordinance, is in use at such commencement; (b) any cast iron, brass, bullion or carat weight or any beam scale, except those prescribed by rules made in this behalf; (c) length measures (not being measuring tapes) ordinarily used in retail trade for measuring textile or timber; (d) capacity measures which are ordinarily used in retail trade for measuring kerosene, milk or portable liquors. (2) Where any officer of the Government charged with the duty of implementing the law relating to weights and measures has any reason to believe that the model of any weight or measure referred to in sub section (1) requires a test by the authorised person, he may obtain one such weight or measure from the market and forward it to the authorised person for test, the fees for which shall be payable by the Government. (3) Every person shall, before making or manufacturing any weight or measure to which this Chapter applies, submit for approval to the authorised person, such number of models, drawings and other information relating to such weight or measure as may be specified by the authorised person: Provided that in relation to any weight or measure which has already been made or manufactured, or which is in the process of being made or manufactured, models of such weight or measure shall be submitted to the authorised person from out of the weights or measures which have already been, or are in the process of being, made or manufactured: Provided further that in the case of a weight or measure the model whereof cannot be submitted, whether by reason of its nature or otherwise, it shall be sufficient if the drawings and other specified information about the weight or measure is submitted to the authorised person and thereupon the authorised person shall test the models of such weight or measure at the place where it is made or manufactured or at such other place as may be specified by the Government. (4) The authorised person may levy and collect from the maker of manufacturer such fees for the testing of any model, submitted under this section for approval, as may be fixed by the Government. (5) The authorised person shall test the models submitted to him with a view to- (a) ascertaining whether such models conform to the standards established by or under this Ordinance; (b) finding out the ability of such models to maintain accuracy over periods of sustained use; and (c) determining the performance of such models under such varied conditions as may be specified by the ¹[Director-General]. (6) The authorised person may, if he is satisfied after considering the report that the aforesaid model is in conformity with the provisions of this Ordinance or any rule made thereunder and is likely to maintain accuracy over periods of sustained use and to render accurate service under varied conditions, issue a certificate of approval in respect of that model. (7) Every certificate of approval of a model may either be published in the official Gazette or in such other manner as the Government may direct. (8) The authorised person may, if he is satisfied that the product made or manufactured in accordance with the model which was approved by him has failed to render the expected performance or to conform to the standards established by or under this Ordinance, revoke the certificate of approval issued by him under sub section (6): Provided that no such revocation shall be made except after giving the maker or manufacturer of such weight or measure a reasonable opportunity of being heard: Provided further that where the authorised person is satisfied that as a result of the alteration made by the maker or manufacturer in the model of the weight or measure, such model has become fit for approval, he may vacate the order of revocation of the certificate of approval issued by him. (9) If for any reason any material of the approved model of a weight or measure becomes non available in Bangladesh, the manufacturer may continue the manufacture of such weight or measure with such substitute materials as may be, in his opinion, most suitable for the manufacture of such weight or measure, but where the manufacturer does so, he shall send such substitute materials to the authorised person for test. (10) If the authorised person is of opinion that the substitute material referred to in sub section (9) is not suitable and that there is available in Bangladesh any other material which is more suitable, the authorised person shall intimate his findings to the manufacturer, and thereupon the manufacturer shall not manufacture the weight or measure with any material other than the material recommended by the authorised person, until the material which was originally approved by the authorised person becomes available in Bangladesh: Provided that where, in the opinion of the authorised person, the substitute material referred to in sub section (9) is not suitable and no other suitable material is also available in Bangladesh, the approval in relation to the model shall stand suspended until a suitable material becomes available in Bangladesh. (11) Where the model of any weight or measure has been approved, the models of different denominations of such weight or measure shall not require any approval if such denominations are manufactured in accordance with the principles according to which, and the materials with which, the approved model has been manufactured.