2014 in Review: Sean Bond, ABS

The challenges of adopting LNG as bunker are multiple but not insurmountable, says Sean Bond, director of Global Gas Solutions at classification society ABS. One of the primary issues is that the regulatory framework is not yet finalized. 

“However, because the present requirements of both class and flag are largely based on the IMO’s interim guidelines, we can assist clients in applying our latest criteria so that projects can move forward with agreement from the flag and to the client’s satisfaction,” he says.

Notations that define the relevant class requirements are spelled out in the ABS Guide for Propulsion and Auxiliary Systems for Gas Fuelled Ships and are used largely in the traditional way. However there are elements of LNG fuelled designs that are not traditional for fuel concepts, such as boil off gas handling equipment, and the guide’s specific notations in that regard help to tie the requirements to the right components. 

ABS has a long pedigree in supporting owners as they evaluate the use of LNG as fuel, undertaking Approvals in Principle and completing numerous LNG-ready evaluations. ABS has been at the forefront of the application of LNG propulsion to conventional cargo ships and is providing classification services for two LNG-powered containership newbuilding projects, as well as for a series of LNG fuelled OSVs and ethane/ethylene carriers.

Already in the construction phase are two LNG-powered containerships for TOTE of the U.S., while still in the design phase is a project to class two small containerships for GNS/Nordic Hamburg of Germany, which will operate in the European Emissions Control Areas. 

“Our involvement on both projects has been to provide conventional classification services as well as additional assistance to the vessel designers on specific LNG as fuel issues, such as risk and safety assessments, rule requirements and the direction of the regulatory framework. In addition, ABS is providing classification services to a conversion project for TOTE on two ORCA class trailer ships and a pilot project for converting a Staten Island ferry to LNG propulsion.”

These projects have demonstrated the variability of the requirements from the designer’s and owner’s perspective, such as the types of fuel systems and propulsion components, and has highlighted the impact on the design of the vessel. They have also assisted in understanding the possible implications associated with making a vessel LNG ready.

ABS has now published the Guide for LNG Fuel Ready Vessels, to support members and clients preparing newbuildings for future conversion to gas propulsion. The guide formalizes the process for shipowners who wish to plan for conversion to LNG fuel at a future date, providing a detailed review.

The guide includes a basic level for concept design approval and optional levels for general design approval for installed equipment, which constitutes a complete design review and survey of a system that is installed on the LNG Ready ship. 

The first two levels result in a descriptive note in the ABS Record listing the parts of the system that have been reviewed. The third level results in an LNG Ready class notation for the parts of the system that have been installed. Obtaining the class notation requires that the fuel system also be in full compliance with the ABS Guide to Gas Fuelled Ships.

For ships voyaging to the U.S., there may be further design considerations. “The main guidance in terms of requirements in the United States is consideration of the U.S. Coast Guard’s Policy Letter of 2012,” says Bond. “This establishes the design criteria for natural gas fuel systems considered by the Coast Guard to have at least an equivalent level of safety to that of other conventional fuel systems including their differences and similarities to the IMO interim Guidelines. 

“Other US-related issues could include the requirements of specific port requirements where the ship will operate, which may require decisions affecting the vessel itself. There will be additional requirements to consider if the ship is built to operate under the terms of the Jones Act.”

As was highlighted by the publication of Bunkering of Liquefied Natural Gas-fuelled Marine Vessels in North America, by ABS, bunkering regulations in the US and Canada vary from state to state, so owners need to understand the local implications. 

Under ABS notations, there are a number of requirements intended to address the risks associated with LNG such as the use of secondary barriers or high tank reliability to address specific cryogenic and explosive atmosphere risks. “In addition, for the most part we see double walled piping being specified in the engine room to separate potential leaks from the machinery space,” says Bond. 

LNG tanks have the potential to BLEVE. A boiling liquid expanding vapor explosion (BLEVE) is an explosion caused by the rupture of a vessel containing a pressurized liquid above its boiling point. “In a shipboard application the primary risk that needs to be managed is long exposure of the fuel tanks to fire, so that they do not collapse under the impact of the heat, releasing fuel as vapor that could explode. 

“If tanks are located inside the hull a fire can effectively be smothered by injecting inert gas or just closing the air supply. If tanks are provided above deck a spray system needs to be provided to cool down the tanks in case of a fire.

“It should be remembered that many safety identification studies have already been completed by class societies, operators and ship designers and much of the technology for LNG as fuel is not new. It has been developed and used on LNG carriers over decades on hundreds of ships and is being transferred to conventional tonnage where there is a smaller amount of design history. Just as important therefore is that owners and operators provide adequate training to ensure that their crew understand the potential risks.”

Bond is optimistic about the future of LNG. It is a fuel of the present as well as a fuel of the future, he says. “The numbers of LNG-fuelled conventional cargo ships are still small but they are growing and there is more interest from owners who wish to explore this and governments that want to promote it. More ports are building bunkering infrastructure and more suppliers are examining the business case for providing LNG for marine applications. 

“We are now at a point where the impediments and obstacles are being removed and we might see an acceleration in the number of projects moving from the drawing board to reality. Further, for shipowners who are building vessels for future conversion to LNG fuel, the ABS Guide to LNG Fuel Ready vessels is a powerful tool that helps owners specify work to be done in the construction phase and when they are ready to convert. This enables them to request conversion tenders at a later date without having to approach the newbuilding yard or appoint a separate designer to prepare a tender package.”