ISO 23226:2020

INTERNATIONAL ISO
STANDARD 23226
First edition
2020-11
Corrosion of metals and alloys —
Guidelines for the corrosion testing
of metals and alloys exposed in deep-
sea water
Corrosion des métaux et alliages — Lignes directrices pour les essais
de corrosion des métaux et alliages exposés en eau profonde
Reference number
©
ISO 2020
© ISO 2020
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ii © ISO 2020 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Selection of test site . 2
5 Assembly and components . 2
5.1 Assembly . 2
5.2 Test rack . 4
5.3 Other parts and equipment . 4
5.3.1 Equipment for environmental monitoring . 4
5.3.2 Release system . 4
5.3.3 Surface water location unit . 4
5.3.4 Under water location unit . 4
5.3.5 Buoys . 4
5.3.6 Connecting accessories . 5
5.3.7 Tension rope . 5
5.3.8 Batteries . 5
5.3.9 Anchor system . 5
6 Specimens . 5
6.1 Preparation of specimens . 5
6.2 Mount of specimens . 6
6.3 Packaging and transportation of specimens . 7
7 Testing procedure . 8
8 Evaluation of specimens . 8
9 Test report . 9
Bibliography .11
Foreword
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This document was prepared by Technical Committee ISO/TC 156, Corrosion of metals and alloys.
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iv © ISO 2020 – All rights reserved

Introduction
With the developments of the offshore oil and gas industry, the activities of exploration and production
of oil and gas have been extended into deep sea. Many subsea equipment and systems for oil/gas
production have been deployed in deep-sea water. There are also some instruments placed in the
subsea for environmental observation and scientific exploration. Corrosion is a crucial problem for
these valuable installations because it seriously affects the performance, reliability and safety of these
equipment and systems.
This document gives guidance on the corrosion testing of metals and alloys exposed in deep-sea water.
The testing can be conducted based on the specified conditions and procedures, and meaningful
comparisons may be made for different tests.
INTERNATIONAL STANDARD ISO 23226:2020(E)
Corrosion of metals and alloys — Guidelines for the
corrosion testing of metals and alloys exposed in deep-
sea water
1 Scope
This document gives guidelines for the corrosion testing of metals and alloys exposed in deep-sea
water, including the selection of the test site, components and assembly of the test system, specimen
preparation, testing procedure, evaluation after the retrieval from exposure sites and test report.
This document is applicable to the general corrosion exposure testing of metals and alloys as well as
localized corrosion tests such as stress corrosion cracking (SCC) testing, galvanic corrosion testing and
crevice corrosion testing of specimens exposed in deep-sea water.
Testing with exposure in deep sea of other materials such as composites and elastomers can also be
carried out with reference to these guidelines, but the evaluation of these materials after the retrieval
is different from that of metals and alloys.
This document does not include the performance testing of sacrificial anodes for cathodic protection in
the field of deep sea, which can be conducted using specified testing cells and equipment in the deep-
sea exposure. However, this guidance can also provide useful information as reference for conducting
performance testing of sacrificial anodes in deep-sea water.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 8044, Corrosion of metals and alloys — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8044 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
deep-sea water
sea water zone with a depth generally ranging from 200 meters to thousands of meters
Note 1 to entry: Deep-sea water has a corrosive environment with parameters such as temperature, salinity,
dissolved oxygen content, microorganism and biofouling that are quite different from those in surface sea water.
3.2
test site
location where corrosion tests exposed in deep sea are performed
3.3
service environment
environment for which the corrosion data is required
3.4
test rack
structure within which the specimens or modules of specimens are housed
4 Selection of test site
The selection of test site is very important for corrosion tests exposed in deep-sea water because the
environment can vary considerably at different test sites.
The selected test site should be suitable for conducting the testing. Generally, the test site should be
selected with consideration of the following requirements.
a) The environmental parameters of the test site should be representative of the service environment.
b) The seabed at the test site should be generally flat without protruding rocks or deep traps, and the
slope should be smaller than 3 %. The sediment at the seabed should be stable.
c) The test site should be in an open area, where sea water can flow freely without being blocked in a
valley or a basin.
d) The test site should be in a place where the assembly will not be damaged by shipping, trawling or
other foreseeable activities. Also, the as-set assembly at the test site should not affect the safety of
foreseeable activities such as shipping and trawling.
e) The test site should be selected in consideration of relevant rules and regulations. The risks of
environmental impact and safety should be assessed prior to any activity is undertaken.
5 Assembly and components
5.1 Assembly
5.1.1 The assembly should have at least the following functions:
a) carrying the specimens reliably during the test in deep sea;
b) gathering the key environmental parameters related to corrosion at the test site;
c) locating the assembly in deep sea;
d) retrieving the assembly at the end of testing.
5.1.2 The assembly is mainly composed of the following parts:
a) buoy(s);
b) tension rope;
c) test rack(s);
d) release system;
e) environmental parameter collection and storage unit;
f) surface water location unit and under water location unit;
g) anchor system.
2 © ISO 2020 – All rights reserved

5.1.3 The typical assembly of test system is shown in Figure 1. There may be a single test rack in the
assembly. Alternatively, there may be several test racks deployed at different elevations on the assembly.
This assembly with multiple test racks is longer and more complicated than the assembly with only one
test rack.
Key
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