ISO INTERNATIONAL STANDARD 11923 First edition 1997-02-01 Water quality -- Determination of suspended solids by filtration through glass-fibre filters Qualite de I'eau Dosage des matieres en suspension par filtration sur filtre enfibres deverre This material is reproduced from Iso documents under International Organization for Standardization (IsO) Copyright License number IHS/IcC/1996. Not for resale. No part of these Iso documents may be reproduced in any form, electronic retrieval system or otherwise, except written consent of Iso (Case postale 56, 1211 Geneva 20, Switzerland, Fax +41 22 734 10 79), IHs or the Iso Licensor's members. Reference number ISO 11923:1997(E) Copyright International Organization for Standardization No reproduction or networking permitted without license from IHS Not for Resale @ISO ISO 11923:1997(E) Foreword Iso (the International Organization for Standardization) is a worldwide federation of national standards bodies (sO member bodies). The work of preparing nternational 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 the right to be represented on that committee. International organizations, governmental and non-governmental, in 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 11923 was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 2, Physical, chemical and biochemical methods. Annexes A and B of this International Standard are for information only @ISO1997 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. InternationalOrganizationforStandardization Case postale 56.CH-1211Geneve20·Switzerland Internet [email protected] X.400 C=ch; a=400net; p=iso; O=isocs; S=central Printed in Switzerland ii or Standardizatior ed without license from IHS Not for Resale INTERNATIONAL STANDARD @ISO ISO 11923:1997(E) Water quality - Determination of suspended solids by filtration through glass-fibre filters 1 Scope This International Standard describes a method for the determination of suspended solids in raw waters, waste waters and effluents by filtration through giass-fibre filters. The lower limit of the determination is approximately 2 mg/i. No upper limit has been established. NOTE 1 Water samples are not always stable, which means that the content of suspended solids depends on storage time, means of transportation, pH value and other factors. Results obtained with unstable samples need to be interpreted with caution. Floating oil and other immiscible organic liquids will interfere (see annex B). NOTE 2 The result of the determination depends to some extent on the type of filter used, see 5.2. It is therefore necessary that the type of filter be specified. NOTE 3 The size distribution of particles in different water samples can vary widely. Therefore there is no correlation between results obtained with filters of different pore diameter, and no conversion factor can be given for the conversion of results obtained with one type of filter to another. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard.At the time of publication,the editions indicated were valid.All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO