ISO INTERNATIONAL STANDARD 28521 First edition 2009-06-01 Ships and marine technology - Hydraulic oil systems Guidance for grades of cleanliness and flushing Navires et technologie maritimeCircuits d'huile hydrauliques- Guide relatif aux degrés de proprete et de rincage Referencenumber ISO 28521:2009(E) ISO 2009 ISO 28521:2009(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In accepts no liability in this area. Adobe is a trademark of Adobe Systems Incorporated. Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. COPYRIGHTPROTECTEDDOCUMENT ISO 2009 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, IsO's member body in the country of the requester. ISO copyright office Case postale56.CH-1211Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail [email protected] Web www.iso.org Published in Switzerland ii @ ISO 2009 - All rights reserved ISO28521:2009(E) Contents Page Foreword 1 Scope 2 Normative references 3 Symbols.. 4 Recommended pipe cleaning levels... 4.1 Pipe cleaning levels during/after prefabrication 4.2 Surfacetreatment... 4.3 Storage of prefabricated pipes and fittings 5 Level ofcleanliness. 6 Assemblyand installation ofpipe system. 7 Blow-through/pull-through of the system. 8 Descriptionof coupling 8.1 Design phase 8.2 Otherconsiderations.. 9 Leakage test. 10 Filling with oil. 11 Shock testing/pressure testing.. 12 Flushing of yard-installed pipe system. 12.1 Connection 12.2 Special pump units. 12.3 Fiushing filters. 12.4 Flushing oil... 12.5 Flushing times 12.6 Methods for checking the cleanliness level... 12 12.7 Leakage testing... 13 13 Start-up of system.. 13 Annex A (informative)Example of particle counting. 14 Bibliography @ IS0 2009 - All rights reserved ili ISO28521:2009(E) Foreword IsO (the International Organization for Standardization)is a worldwide federation of national standards bodies InternationalElectrotechnicalCommission(lEC)onallmattersofelectrotechnicalstandardization. International Standards are drafted in accordance with the rules given in the ISO/lEC Directives, Part 2. The main task of technical committees is to prepare International Standards. 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. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent SC 3, Piping and machinery. iv ISo 2009-All rights reserved INTERNATIONAL STANDARD ISO28521:2009(E) Ships and marine technology Hydraulic oil systems : Guidance for grades of cleanliness and flushing Scope 1 This International Standard specifies pipe cleaning and cleaning levels of hydraulic oil pipe systems. The cleaning of pipes and components in hydraulic oil pipe systems is essential for the trouble-free operation of hydraulic systems. systems withappurtenant components. The purpose of the cleaning process is to remove installation dirt and to check that the piping and hydraulic system have been adequately cleaned. The cleaning process of a system is considered a "washing through" process when the Reynolds number, Re ≤ 3 000, and a flushing process when Re ≥3 000. The Reynolds number is an indicator of whether a fluid flow is considered laminar or turbulent. This In