Design & Engineering Standards

7/14/2017: Update to Policy Letter 01-12, design criteria for natural gas fuel systems

Submitted by Timothy Meyers, Systems Engineering Division

On July 12, 2017, the Office of Design and Engineering Standards (CG-ENG) issued Change 1 to Policy Letter 01-12, Equivalency Determination – Design Criteria for Natural Gas Fuel Systems, which uses the International Code of Safety for Ships Using Gases or Other Low-Flashpoint Fuels (IGF Code), as a basis for allowing the installation of liquefied natural gas (LNG) fuel systems on U.S.-flag vessels.

The use of natural gas as a shipboard propulsion fuel is a leading alternative to traditional oil fuels for meeting domestic and international air emission requirements. However, since LNG is relatively new as a marine fuel in the U.S., there are no federal regulations to address the safe design of shipboard LNG-fueled systems.

Policy Letter 01-12 was first issued in April of 2012, to provide a streamlined approach for establishing equivalency under the Code of Federal Regulations, using Interim Guidelines published by IMO during development of the IGF Code as a baseline standard.

The IGF Code became effective Jan. 1, 2017, and provides substantive improvements over the earlier Interim Guidelines, including: revised terminology for clarity in fuel containment system design; a well-defined approach for considering alternatives; clarification on risk assessment requirements; new options for protective tank locations; and an expanded section on LNG fuel bunkering.

The improvements adopted by the IGF Code reflect a better understanding of the rapidly evolving nature of new fuel technologies, and continued reliance on what is now an outdated standard is no longer warranted. Therefore, this policy letter update uses the IGF Code as a baseline standard for vessels using LNG fuel as an alternative to those fuel systems covered by current domestic regulations.

This blog is not a replacement or substitute for the formal posting of regulations and updates or existing processes for receiving formal feedback of the same. Links provided on this blog will direct the reader to official source documents, such as the Federal Register, Homeport and the Code of Federal Regulations. These documents remain the official source for regulatory information published by the Coast Guard.

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