ISO INTERNATIONAL STANDARD 12473 Second edition 2017-10 General principles of cathodic protection in seawater Principes généraux de la protection cathodique en eau de mer Accessed by UNSW - LIBRARY on 05 Nov 2017 (Document currency not guaranteed when printed) Reference number ISO 12473:2017(E) [so @IS02017 IS0 12473:2017(E) Accessed by UNSW - LIBRARY on 05 Nov COPYRIGHT PROTECTEDDOCUMENT IS0 2017, Published in Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form writtenpermission.Permission canberequestedfromeitherIsOattheaddressbelow orIso'smemberbodyinthecountryof the requester. ISO copyright office Ch. de Blandonnet 8 . CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 [email protected] www.iso.org i @ IS0 2017 - All rights reserved IS0 12473:2017(E) Contents Page Foreword ..V 1 Scope .1 2 Normative references 3 Terms, definitions, abbreviations and symbols 4 Application of cathodic protection in seawater 4.1 General. ..5 4.2 Galvanic anode method 4.3 Impressed current method. 6 4.4 Hybrid systems. 5 Determination of level of cathodic protection 5.1 Measurement of protection level 9 5.2 Reference electrodes .9 5.3 Potentials of reference electrodes ..9 5.4 Verification of reference electrodes ..9 5.5 Potential measurement ..10 6 Cathodic protection potential criteria ..10 6.1 General ..10 6.2 Carbon-manganese and low alloy steels. ..10 6.3 Other metallic materials .13 6.3.1 General. 6.3.2 Stainless steels. ..13 6.3.3 Nickel alloys. ..14 6.3.4 Aluminium alloys .14 6.3.5 Copper alloys. .14 7 Design considerations .14 7.1 Introduction .14 7.2 Technical and operating data ..15 7.2.1 Design life. .. 15 7.2.2 Materials of construction .15 7.3 Surfaces to be protected .15 7.4 Protective coatings .15 7.5 Availability of electrical power .16 7.6 Weight limitations. ..16 7.7 Adjacent structures. ..16 7.8 Installation considerations. .16 7.9 Current demand. 16 Effect of environmental factors on current demand .16 8 8.1 Introduction .16 8.2 Dissolved oxygen ..17 8.3 Sea currents ..17 8.4 Calcareous deposits ..17 8.5 Temperature ..18 8.6 Salinity. .18 8.7 pH .18 8.8 Marine fouling ..18 8.9 Effect of depth. 8.10 Seasonal variations and storms .. 19 9 Secondary effects of cathodic protection ..19 9.1 General. ..19 9.2 Alkalinity .19 9.3 Environmentally-assisted cracking .19 @ IS0 2017 - All rights reserved ii