- Lifesaving & Fire Safety

Design guidance for commercial vessels using Lithium-Ion batteries for propulsion or electrical systems

Submitted by Lt. Kevin Ralson, Systems Engineering Division

After a multi-year effort, the Office of Design and Engineering Standards (CG-ENG) issued CG-ENG Policy Letter No. 02-19, “Design Guidance for Lithium-Ion Battery Installations Onboard Commercial Vessels,” to improve the plan approval process for commercial vessel propulsion or electrical systems powered by installed Lithium-ion (Li-ion) batteries.

The policy does not apply to the carriage of Li-ion batteries as cargo or portable devices with Li-ion batteries that are not permanently installed on the vessel.

There is increased interest in Li-ion batteries and other new types of stored energy technology onboard U.S. flag inspected vessels. Unique safety concerns are associated with these technologies and the plan review process can be lengthy due to system complexities and the lack of published regulations or marine standards on the topic. CG-ENG-Policy Letter No. 02-19 establishes design guidance for commercial vessels using Li-ion batteries within the existing regulatory framework.

This document was drafted in collaboration with the Marine Safety Center in order to provide consistent guidance to designers of vessel electrical systems, and for Coast Guard personnel reviewing those designs. The purpose of this guidance is to provide an acceptable method for using Li-ion battery technology that will result in a streamlined and consistent plan approval process. Other design concepts will be reviewed by the Marine Safety Center in collaboration with CG-ENG on a case-by-case basis.

The policy incorporates ASTM F3353-19, “Standard Guide for Shipboard Use of Lithium-Ion Batteries.” The standard provides an equivalent level of safety to the existing regulations in 46 CFR Subchapter J for Li-ion batteries and gives guidance on testing requirements, operating environment, fire safety, battery system design, and maintenance.

The Marine Safety Center and the Officer in Charge of Marine Inspection may still determine that other design criteria or certain restrictions must be applied based on the vessel’s risk assessment.

Questions about this policy may be directed to the Systems Engineering Division at 202-372-1372 or emailed to Kevin.L.Ralson@uscg.mil.

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.