Appendix 2 – Immersion Test
Clasification Society 2024 - Version 9.40
Statutory Documents - IMO Publications and Documents - Resolutions - Maritime Safety Committee - Resolution MSC.288(87) – Performance Standard for Protective Coatings for Cargo Oil Tanks of Crude Oil Tankers – (Adopted on 14 May 2010) - Annex – Performance Standard for Protective Coatings for Cargo Oil Tanks of Crude Oil Tankers - Annex 1 – Test Procedures for Coating Qualification for Cargo Oil Tanks of Crude Oil Tankers - Appendix 2 – Immersion Test

Appendix 2 – Immersion Test

Parent topic: Annex 1 – Test Procedures for Coating Qualification for Cargo Oil Tanks of Crude Oil Tankers

1 Test condition

 The immersion testfootnote is developed to simulate the conditions in a crude oil tank in loaded condition.

  • .1 The exposure time is 180 days.

  • .2 The test liquid should be made as per item 6 in the Standard.

  • .3 The test liquid should be added to a container with an inside flat bottom until a column of the test liquid of height of 400 mm is reached, resulting in an aqueous phase of 20 mm. Any other alternative test set-up, using an identical test liquid, which will also result in the immersion of the test panel in 20 mm of the aqueous phase, is also accepted. This can be achieved by using, for instance, inert marbles.

  • .4 The temperature of the test liquid should be 60 ± 2°C and should be uniform and maintained constant with recognized methods such as water or oil bath or air circulation oven capable of keeping the immersion liquid within the required temperature range.

  • .5 Test panels shall be positioned vertically and fully immersed during the test.

  • .6 Testing shall be carried out using duplicate panels.

  • .7 Inert spacers which do not cover the test area shall be used to separate test panels.

  • .8 The size of each test panel is 150 mm x 100 mm x 3 mm.

  • .9 The panels shall be treated according to the Performance Standard table 1, 1.2 and the coating system applied according to table 1, 1.4 and 1.5.

  • .10 The zinc silicate shop primer, when used, shall be weathered for at least 2 months and cleaned by low pressure fresh water washing. The exact method of shop primer preparation before being over coated shall be reported, and the judgement issued for that specific system. The reverse side, and edges, of the test piece shall be coated appropriately, in order not to influence the test results.

  • .11 After the full immersion test period is completed the panels shall be removed from the test liquid and wiped with dry clean cloth before evaluation of the panels.

  • .12 Evaluation of the test panels shall be done within 24 h after completion of the test.

2 Test results

  2.1 Prior to testing, the following measured data of each coating composing the coating system, including the zinc silicate shop primer when used under the coating system, shall be reported:

  • .1 infrared (IR) identification of the base and hardener components of the coating;

  • .2 specific gravity of the base and hardener components of the paint;footnote and

  • .3 mean dry film thickness (DFT) (by using a template).footnote

  2.2 After testing, the following measured data shall be reported: blisters and rust.footnote

3 Acceptance criteria

  3.1 The test results based on section 2 shall satisfy the following criteria, the poorest performing of the duplicate test panels shall be used in the report:

Item Acceptance criteria for epoxy-based systems Acceptance criteria for alternative systems
Blisters on panel No blisters No blisters
Rust on panel Ri 0 (0%) Ri 0 (0%)

  3.2 When evaluating test panels, blistering or rusting within 5 mm of the panel edge should be ignored.

4 Test report

 The test report shall include the following information:

  • .1 coating manufacturers' name and manufacturing site;footnote

  • .2 dates of test;

  • .3 product name/identification of each coat and, where applicable, zinc silicate shop primer;

  • .4 batch numbers of each component of each product;

  • .5 details of surface preparation of steel panels, before shop primer application, and treatment of the shop primer before over coating where relevant and at a minimum including the following:

    • .5.1 surface treatment, or treatment of weathered shop primer, and any other important information on treatment influencing the performance; and

    • .5.2 water soluble salt level measured on the steel prior to application of the shop primer;footnote

  • .6 details of coating system, including the following:

    • .6.1 zinc silicate shop primer if relevant, its secondary surface pre-treatment and condition under which applied, weathering period;

    • .6.2 number of coats, including the shop primer, and thickness of each;

    • .6.3 mean dry film thickness (DFT) prior to testing;footnote

    • .6.4 thinner if used; footnote

    • .6.5 humidity ; footnote

    • .6.6 air temperature; footnote and

    • .6.7 steel temperature; footnote

  • .7 test results according to section 2; and

  • .8 results according to section 3.

Copyright 2022 Clasifications Register Group Limited, International Maritime Organization, International Labour Organization or Maritime and Coastguard Agency. All rights reserved. Clasifications Register Group Limited, its affiliates and subsidiaries and their respective officers, employees or agents are, individually and collectively, referred to in this clause as 'Clasifications Register'. Clasifications Register assumes no responsibility and shall not be liable to any person for any loss, damage or expense caused by reliance on the information or advice in this document or howsoever provided, unless that person has signed a contract with the relevant Clasifications Register entity for the provision of this information or advice and in that case any responsibility or liability is exclusively on the terms and conditions set out in that contract.