NFPA Journal

Research is underway to fill some of the knowledge gaps related to energy storage systems (ESS). This spring, NFPA’s research arm, the Fire Protection Research Foundation (FPRF), launched a project studying the effectiveness of various suppression systems in fire tests involving large lithium ion ESS. Researchers hope the results establish minimum requirements for effective sprinkler system design and density to protect lithium ion ESS, currently the dominant type of battery used around the world.

The importance of the project became clear last November when a 1-megawatt lithium ion battery in Belgium caught fire, sending white smoke plumes high in the air, despite the system being fully equipped with fire suppression. Video from the event shows flames leaping from the box as the suppression system fails to control it.

Another FPRF project, also launched this spring, is a two-year effort to help the fire service develop standard operating guidelines for responding to lithium ion battery emergencies. Using data gathered through a literature review and from fire testing, researchers hope to build an ESS fire simulator that replicates common ESS fire scenarios. The simulator will then be field tested with fire departments to evaluate the effectiveness of different firefighting tactics with the hope of ultimately using what is learned to develop standard operating guidelines. The initial simulator could eventually also be replicated, allowing for fire departments across the country to use it in live ESS training.

There have been gains on other fronts as well. In 2017, UL conducted extensive fire testing on a dreaded battery phenomenon called thermal runaway, where heat from a fire or damaged battery cell causes a chemical reaction inside the cell, further increasing the temperature and leading to more chemical reactions that cascade from cell to cell. The research led to UL 9540a, Standard Test Method for Evaluating Thermal Runaway Fire Propagation in Battery Energy Storage Systems. The standard test methods will allow fire engineers to more accurately test ESS in a number of configurations—such as different battery quantities, sizes, chemistries, spacing and more—to find out what might happen in a worst-case scenario where one or more batteries goes into thermal runaway. As more experiments of this sort are conducted, code officials will have a better idea of the potential risks of various ESS scenarios and can adapt NFPA 855 accordingly.

For more information visit the ESS webpage.

JESSE ROMAN is associate editor for NFPA Journal.