INTERNATIONAL ISO STANDARD 6293-1 First edition 1996-12-01 Petroleum products -- Determination of saponification number . Part 1: Colour-indicator titration method Produits pétroliers - Détermination de I'indice de saponification - Partie 1: Méthode par titrage avec indicateur colore ISO Reference number ISO 6293-1:1996(E) No reproduction or networking permitted without license from IHS Not for Resale ISO 6293-1:1996(E) Foreword ISO (the International Organization for Standardization) is a worldwide fed- eration of national standards bodies (isO member bodies). The work of 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 voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard ISO 6293-1 was prepared by Technical Committee ISO/TC 28, Petroleum products and lubricants. This first edition cancels and partially replaces the first edition of ISO 6293:1983, which has been technically revised. ISO 6293 consists of the following parts, under the general title Petroleum products - Determination of saponification number: Part 1: Colour-indicator titration method Part 2: Potentiometric titration method @ISO1996 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher International Organization for Standardization CasePostale56CH-1211Geneve20·Switzerland Printed in Switzerland CopyrightIntemational Organization for Standardization No reproduction or networking permited without license from IHS Not for Resale INTERNATIONAL STANDARD ISO ISO 6293-1:1996(E) Petroleum products Determination of saponification number - Part 1: Colour-indicator titration method WARNING -- The use of this International Standard may involve hazardous materials, operations and equipment. This International Standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this international Standard'to establish appropriate safety 1 Scope This part of ISO 6293 specifies a method for the determination, by colour-indicator titration, of the amount of constituents in petroleum products that will saponify under the conditions of the test. Compounds of sulfur, phosphorus, halogens and some other compounds interfere by reacting with the alkali and acids under the test conditions. NOTES 1 The results on used crankcase and turbine oils, and on oils containing the interfering compounds above as additive constituents, should be interpreted with care, bearing in mind the possible higher values obtainable due to these additional reactants 2 The interfering compounds above are contained in extraneous materials including certain organic acids and most nonalkali soaps. The odour of hydrogen sulfide near the end of the back-titration step is an indication of the presence of certain reactive sulfur compounds, but other reactive sulfur compounds, as well as those of chlorine, phosphorus and other interfering materials, give no simple indication during the test. A gravimetric determination of fatty acid content is an alternative procedure for the estimation of such compounds. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part of IsO 6293. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this part of isO 6293 are encouraged to investigate the possibility of applying the most recent editions of the standards indicated