Evaluation of Accidental Oil Spills from Bunker Tanks

Current Status

Panel Activity Summary: Ad Hoc Panel #11 was formed in October 2000 to study the bunker tank issue from the vessel design perspective and consider potential bunker tank/spill performance standards. The Panel developed a performance-based methodology for evaluating the oil outflow from bunker tanks as the basis for a possible alternative standard to a prescriptive "double hull" standard for bunker tanks. The methodology was submitted to IMO (DE 46/INF.4) for consideration in December 2002 by Panel member INTERTANKO, which has NGO status at IMO.

The Panel's planned work then called for an assessment of relative capital and operating costs associated with alternate tank configurations (of several ship types) utilizing the methodology developed. These costs were to be used to provide a sense of the cost-benefits of the configurations examined. However following the Prestige casualty (November 2002), EU initiatives and IMO proposals for prescriptive fuel tank double hull requirements indicated it was unlikely that economic impacts would influence the deliberations at IMO. As a result, the Panel elected not to carry out this work until there was some indication that economic factors would be considered at IMO.

Latest Developments at IMO: At the recently held 48th session of IMO’s Ship Design and Equipment Sub-Committee (DE 48, February 2005) an agreement was reached on a new draft MARPOL regulation for the protection of fuel tanks. The draft regulation allows two options: either a prescriptive double hull requirement or an alternative probabilistic oil outflow requirement (see DE 48/WP.2 for details). It is worth noting that much of the Panel's initial technical input to DE 46 (via Panel member INTERTANKO) has been incorporated into the alternative probabilistic oil outflow option in the draft regulation. This draft regulation will be considered for approval at the 53rd session of the Marine Environment Protection Committee (MEPC 53) in July 2005, and if later adopted as currently drafted, be applicable to all ships ordered after August 2007, or delivered after August 2010.

IMO Activity

Summary from DE 46 (March 2003)

Ad Hoc Panel's Interim Report to DE 46: An Ad Hoc Panel Interim Report Evaluation of Accidental Oil Spills from Bunker Tanks (DE 46/INF.4) was submitted to DE 46. The Interim Report was submitted as an information paper by Panel member INTERTANKO, which has NGO status at IMO, on behalf of SNAME. The Panel has taken a rational approach to the problem and concluded that a performance based standard for bunker tank outflow, rather than mandatory "double hulling" of bunker tanks, is preferred. This interim report/information paper does not take a position which is consistent with SNAME's role as a technical body presenting objective technical findings.

DE 46 Background Information: Although Protection of Fuel Tanks was not actually on the agenda for DE 46, an IACS paper Carriage of emulsified oil and other high density oil (BLG 7/INF.6) contained provisions for the protection of fuel tanks and was referred to DE 46 for consideration under the Any Other Business agenda item. As a result, it was considered important for the Ad Hoc Panel to submit an interim report on its work to DE 46.

Netherlands Paper: The Netherlands submitted a paper Protection of fuel tanks against collision and stranding (DE 46/29) to DE 46. This paper asked that Protection of Fuel Tanks be put on the agenda for DE 47 and also proposed a new MARPOL 13H regulation containing fuel tank double bottom, double hull and tank size limit requirements.

Outcome at DE 46: Although the 3 papers were introduced in plenary at DE 46, there was not any substantial discussion on their contents. It was agreed to include Protection of Fuel Tanks on the agenda for DE 47 with a target completion date of 2005, and that document DE 46/29 together with documents DE 46/INF.4 and BLG 7/INF.6 would be further considered at DE 47.

Summary from MEPC 49 (July 2003)

Norway submitted a paper Protection of fuel tanks (MEPC 49/16/6) to MEPC 49. This paper proposed double hulls in way of fuel tanks similar to the cargo oil double hull requirements in MARPOL regulation 13F, and that heavy fuel oil should be carried in fuel tanks protected by double hulls regardless of fuel tank capacity. In addition it proposed to move the target completion date to 2004. After some discussion, MEPC 49 sent the paper to DE 47 for detailed consideration and left the target completion date 2005.

Summary from DE 47 (March 2004)

Outcome at DE 47: The Sub-Committee considered the issue and the two basic proposals: a probabilistic oil outflow approach and a prescriptive double hull approach. The Sub-Committee then established a Correspondence Group, coordinated by Germany, to develop a draft MARPOL regulation on the protection of fuel tanks while considering the following items: its application to new ships only; its impact on smaller ships; use of tank capacity as a criterion; application to heavy fuel oil; and use of probabilistic outflow method.

Summary from DE 48 (February 2005)

Outcome at DE 48: The Sub-Committee considered the report of the Correspondence Group, which contained a draft MARPOL regulation allowing two options for the protection of fuel tanks: a prescriptive double hull requirement or an alternative probabilistic oil outflow requirement. The Sub-Committee then established a Working Group to finalize the work and subsequently agreed on a new draft MARPOL regulation, for submission to MEPC 53 (July 2005) for action as appropriate. The draft regulation applies to all ships with an aggregate fuel capacity of 600 cubic meters and greater; fuel is defined as any oil used as fuel for the propulsion and auxiliary machinery of the ship; small tanks less than 30 cubic meters are excluded; there is a maximum individual tank size limit of 2,500 cubic meters; an important new factor for minimum oil outflow from bottom damage to tanks bounding the bottom shell was added to the alternative probabilistic oil outflow option. See DE 48/WP.2 for details.

Working Group Activities

• WG1 - Historical Bunker Oil Spill Data
• WG2 - Forecast Future Bunker Oil Spill Data
• WG3 - Develop Bunker Oil Outflow Calculation Methodology
• WG4 - Review Current Ship Designs & Operational Considerations and Develop New Designs
         +  Tankers
         +  Bulk Carriers
         +  Containerships/RO-ROs
         +  Passenger Vessels
• WG5 - Perform Bunker Oil Outflow Calculations for WG4 Designs
• WG6 - Assess Cost of Alternative Bunker Tank Arrangements

Kick-Off Meeting Held on March 24, 2001

The Panel Kick-Off Meeting was held March 24, 2001, at Coast Guard Headquarters in Washington, DC.

Agenda for the meeting:
1. Introduction of members (Haskell)
2. Statement of Work (Haskell)
3. Overview of SNAME Ad Hoc Panel Structure (Cojeen)
4. Presentation of current regulatory requirements for protecting bunker tanks, and overview of recent proposals to IMO and U.S. Congress (Person)
5. Discussion of bunker spill statistics (Michel)
6. Overview of recent studies on spills from bunker tanks (Michel/Person)
7. Review-actual double hull bunker tank design on RoRo (Boylston)
8. Identify issues to be addressed
9. Discuss approach for assessing each key issue and types of designs to be evaluated
10. Establish division of work load
11. Timeline for completing tasks
12. Date for next (final) meeting

Minutes of the meeting:

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