7742-88 4851903 00573038 C-81-20 ISO INTERNATIONAL STANDARD 7742 First edition 1988-07-15 INTERNATIONALORGANIZATIONFORSTANDARDIZATION ORGANISATION INTERNATIONALE DE NORMALISATION MEXKAYHAPOAHAAOPIAHM3ALMHNO CTAHAAPTM3ALMM Solid fertilizers - Reduction of samples Matieresfertilisantessolides-Réductiondeséchantillons Referencenumber ISO 7742; 1988 (E) reproduction or networking permitted without license from IHS Not for Resale 7742-88 hOE2500 E06T58h T ISO 7742 : 1988 (E) Foreword Iso (the International Organization for Standardization) is a worldwide federation of national standards bodies (Iso member bodies). The work of preparing International Standards is normally carried out through Iso technical committees. Each member body interested in a subject for which a technical committee has been established has mental and non-governmental, in liaison with Iso, also take part in the work. ISo collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the Iso Council. They are approved in accordance with IsO procedures requiring at least 75 % approval by the member bodies voting. International Standard ISo 7742 was prepared by Technical Committee ISo/TC 134, Fertilizersandsoilconditioners Annex A forms an integral part of this International Standard. Annex B is for infor- mation only. @ International Organization for Standardization, 1988 Printed in Switzerland 7742-88 EObTSh 50E2500 8 INTERNATIONAL STANDARD ISO7742:1988 (E) Solid fertilizers - Reduction of samples Scope curtain, such as is created by allowing the fertilizer to fall on to the apex of a cone distributor. In the case of the cutter type, This International Standard specifies a method suitable for the each increment shall consist of a complete cross-section of the reduction of a sample of a solid fertilizer to a smaller quantity stream. such as may be used for analysis or for further reduction after suitable comminution. All sample dividers shall conform to the following basic re- quirements: By choosing suitable equipment, the method is applicable to the reduction of a sample of any mass above a minimum de- a) The effective opening of the cutter or slot shall be at fined by the size and number of particles. The method can be leastthreetimes,butpreferablyfivetimes,themaximum applied to the division of samples into a number of equally particle size of the fertilizer to be divided. in practice, this representativesub-samples. means a minimum dimension of at least 15 mm. b) The divider shall be constructed and operated in such a Other reduction devices and methods are described in annex A mannerthateveryparticlehasanequalopportunityofbeing but they are not as accurate as the recommended procedure. included in the sub-sample. Provided that all parts of the stream are sampled in due proportion, an unbiased sample This International Standard does not include information on the should be obtained. methods of obtaining the original sample. c)At least 50 to 60 increments shall be taken from the gross sample at each stage of division. 2 Normative references 4.2 Testforbias The following standards contain provisions which, through reference in this text, constitute provisions of this International The sample divider is considered acceptable for a certain type Standard. At the time of publication, the editions indicated of fertilizer only after it has been instalied and has been shown were valid. All standards are subject to revision, and parties to to comply with the test requirements for bias and precision. agreements based on this International Standard are encour- The tests should be based on the particle size distribution of the aged to investigate the possibility of applying the most recent fertilizer(seeISO8397)asthisislikelytobethepropert