ISO INTERNATIONAL STANDARD 4021 Second edition 1992-11-15 Hydraulic fluid power --- Particulate contamination analysis --- Extraction of fluid samples from lines of an operating system Transmissions hydrauliques - Analyse de ta pollution par particules - Prelevement des échantillons de fluide dans les circuits en fonctionnement Reference number ISO 4021:1992(E) IHS Not for Resale ted without license from IHS ISO 4021:1992(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 the right to be represented on that committee. International organizations, govern- 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 national Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard IsO 4021 was prepared by Technical Committee ISO/TC 131, Fluid power systenms, Sub-Committee SC 8, Product testing and contamination control. This second edition cancels replaces the first edition pue (ISO 4021:1977), which has been technically revised. Annex A of this International Standard is for information only. @ 1SO1992 All rights reserved, 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 Case Postale 56 C-1211 Geneve 20 · Switzerland Printed in Switzerland ii Not for Resale without license from IHS ISO 4021:1992(E) Introduction In hydraulic fluid power systems, power is transmitted and controlled through a fluid under pressure within an enclosed circuit. This fluid is both a lubricant and a power-transmitting medium. Reliable system performance requires control of the fluid medium Qualitative and quantitative determination of particulate contamination in the fluid medium requires precision in obtaining the sample and de- termining the nature and extent of contamination. The most representative sample is obtained using a sampler installed in a main flowline where the fluid is flowing in a turbulent manner. if such a sampler is unavailable, then fluid samples may be extracted from thesystemreservoir. This International Standard describes procedures for obtaining both dy- namic and static sampies from an operating system ili izairstandardizaion ted without license from IHS Not for Resale