48519030619027004 INTERNATIONAL ISO STANDARD 6708 Secondedition 1995-07-01 Pipework components Definition and selection of DN (nominal size) Composants de réseau de tuyauteries -Définition et sélection des DN (diametrenominal) Referencenumber ISO 6708:1995(E) COPYRIGHT 2ooo International Organization For Standardization Information Handling Services, 2ooo 48519030619028 T40 ISO6708:1995(E) Foreword IsO (the International Organization for Standardization)isaworldwide federation of national standards bodies (IsoO 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 representedonthatcommittee.Internationalorganizations,governmental and non-governmental, in liaison with Iso, alsotake part in thework.isO collaborates closelywith the International Electrotechnical Commission (lEC) 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 6708 was prepared by Technical Committee ISO/TC 5, Ferrous metal pipes and metallic fittings, Subcommittee SC 10, Metallic flanges and their joints. This second edition cancels and replacesthe first edition inclusionofclause3. ISO1995 All rights reserved.Unless otherwise specified,nopartof thispublication maybe reproduced or utilized in any form or by any means, electronic ormechanical, including photocopying and microfilm, without permission in writing from the publisher. International OrganizationforStandardization CasePostale56·CH-1211Geneve20·Switzerland Printed in Switzerland ii CoPYRIGHT 2ooo International OrganizationFor Standardization Information Handling Services, 2oo0 4851903 0619029 987 INTERNATIONAL STANDARD ISO ISO6708:1995(E) Pipework components Definition and selection of DN (nominal size) 1 Scope 3 In those standards which use the DN designation sys- tem, any relationship between DN and component dimen- This International Standard gives the definition of DN sions should be given, e.g. DN/OD or DN/ID. (nominal size) when applied to components of a pipework system, as specified in those standards which use the DN designation system. NOTE 1 Other methods of size designation are also used, 3 DN Series e.g.,products having threaded, compression, solder or The preferred DN values are as follows: (nominal pipe size), OD (outside diameter), ID (inside diam- eter), but these are not defined in this International Stan- dard. DN 10 DN 250 DN 1 500 This International Standard gives a list of preferred DN DN 15 DN 300 DN 1600 values. DN 20 DN 350 DN 1 800 DN 25 DN 400 DN 2 000 2 Definition DN 32 DN 450 DN 2 200 DN 40 DN 500 DN 2 400 2.1 DN: An alphanumeric designation of size for DN 50 DN 600 DN 2 600 components of a pipework system, which is used for DN 60 DN 700 DN 2 800 referencepurposes.ItcomprisesthelettersDNfol- lowed by a dimensionless whole number which is in- DN 65 DN 800 DN 3 000 directly related to the physical size, in millimetres, of DN 80 DN 900 DN 3 200 the bore or outside diameter of the end connections. DN 100 DN1 000 DN 3 400 NOTES DN 125 DN 1 100 DN3600 DN 150 DN 1 200 The number following the letters DN does not represent DN 3800 2 a measurable value and should not be used for calculation DN 200 DN 1 400 DN 4 000 purposesexceptwhere specified intherelevant standard. COPYRIGHT 2ooo International Organization For Standardization Information Handling Services, 2oo0