IACS and the Industry discuss corrosion protection of cargo and ballast tanks

As a follow-up action from the Tripartite meeting in Seoul, IACS and the Industry met to assess means of improving the protection from corrosion of the seawater ballast tanks of tankers and bulk carriers and of the cargo tanks of oil tankers.

More specifically, the Industry is assisting IACS with:

- the revision of the IACS Unified Interpretation SC122 on Corrosion Prevention in Seawater Ballast Tanks - verification of compliance with SOLAS Reg.II-1/3-2 and IMO Resolution A.798(19);

- the development of a new IACS Unified Requirement for Corrosion Prevention Systems for Cargo Oil Tanks of Oil Tankers;

- the drafting of IACS Guidelines for inspection, maintenance and repairs of coating in seawater ballast tanks.

IACS is giving high priority to completing the draft guidelines, which would assist its inspectors in making a better assessment of the condition of ships’ coatings. The guidelines would set minimum standards for coating maintenance and for proper coating repairs. The draft guidelines are based on similar guidance issued in 2002 by the Tanker Structure Cooperative Forum (TSCF).

If concluded, the draft Unified Requirement would require that, after a certain date, new oil tankers' cargo tanks should have a corrosion protection system at the bottom (e.g. inner bottom and vertically 0.5 m above inner bottom), the top (e.g. deckhead with complete internal structure, including brackets connecting to longitudinal and transverse bulkheads, vertical plating of surrounding bulkheads with attached structure extending 10% of the tank’s height, but not more than 2 m down from the deck, with an additional 100mm around the vertical brackets) and the upper part of the horizontal stringer. Equivalent corrosion protection means could also be applied such as the use of shop primer together with cathodic protection, good quality stainless steel, etc.

The group also considered recent developments in Japan with regard to a new mild steel with enhanced anti-corrosive properties. The industry has a mixed experience with regard to corrosion in the cargo tanks of oil tankers. It was agreed that before concluding the draft Unified Requirement, IACS member societies should check their own records with regard to corrosion and the rate of corrosion on the cargo tanks of oil tankers. IACS and the Industry would also need to define a goal-based standard for a good coating protection. This would be the benchmark for assessing the equivalency of any other means of corrosion protection.

There seems to be a general agreement that more work should be done with regard to the selection of the proper coating. This would logically involve Class Societies at the newbuilding stage in work such as checking that the paint used is in conformity with the manufacturer's specification, checking the surface preparations and supervising the application of the coating. It was agreed that the Industry would continue to explore these areas.

The meeting was hosted by the Italian Class Society, RINA in Genoa, Italy, and chaired by Mario Dogliani, RINA, Chairman of the IACS General Policy Group (GPG). All IACS Societies except the Russian Register attended the meeting. The Industry was represented by ICS (Secretariat, Union of Greek Shipowners and Japanese Shipowners Association), TSCF, OCIMF, INTERTANKO/INTERCARGO. There were also observers from EMSA, the EU Commission and from the European Shipbuilders Association. INTERTANKO was represented by Stefan Nystrom (SNTG), Johnny Eliasson (SNTG), Federico Beltrami (Premuda) and Dragos Rauta.

Contact: Dragos Rauta