Preservation of Void Spaces |
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Tue Aug 7, 2007 11:30 am |
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RINA is concerned that the "Performance Standard for Protective Coatings for Void Spaces on Bulk Carriers and Oil Tankers", as currently drafted in Annex 3 to DE50/27, conflicts with existing statutory requirements for the inspection and maintenance of spaces which are critical to the structural integrity of current and future Bulk Carriers and Oil Tankers. In consultation with the IMO Naval Architecture Group, RINA has therefore submitted a paper commenting on the draft MSC resolution and suggesting amendments to the scope of the standard.
The paper is published on the Maritime Safety Committee page. |
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Fri Aug 3, 2007 8:36 am |
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The following additional comments have been gathered from SNAME members by the SNAME T&R Steering Committee:
(1) Because these bulkhead stools are considered critical and thus have specific inspection requirements, there must be a means to access those spaces in order to conduct the proper inspections. However, even if the vessel has no access hatch designed into the structure, access can be
made through cuts via a cutting torch where the designer has deemed it is safe to cut through. Once inspections are made, the hole can be welded shut again and recoated. Naval vessels currently incorporate a similar type of design feature. In order to allow for the removal of large equipment from deeper decks, specific areas of the deck and
bulkheads are designed to be cut away for temporary through access. Thus, it is not definitive what the term "access" would be for those spaces.
(2) In reviewing IMO Resolution A.866(20), GUIDANCE TO SHIPS' CREWS AND
TERMINAL PERSONNEL FOR BULK CARRIER INSPECTIONS, there is significant concerns brought to the ship's crew about the likely location of cracks
and other damage that can occur within the bulk cargo inner shell, and specifically the transverse bulkhead structure (Figures 13 and 14). The presence of these cracks can allow moisture and venting to take place into the previously "totally enclosed spaces" causing corrosion and breakdown of the structures.
While point (1) might seem to justify the exceptions that the MSC is currently against, my basis for this comment is to highlight the need to clarify the type of access that would be necessary to accomplish the proper inspections. A tank void or other inaccessible space can be coated and then welded shut provided that the welded area does not affect the ship's structure.
In the event of a breach via a crack or damage from loading or offloading, the space that is exposed will still have the protective
coating to protect from corrosion damage until repairs can be affected. |
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