June 2020 announcements from two BESS providers offer paths to address NFPA 855

While S2 Solar primarily focuses on commercial and regulatory strategies and insights for successful procurement and deployment of assets, this blog deviates from that path to discuss the more technical topic of battery product safety, specifically highlighting recent announcements from two companies, out of recognition that addressing and mitigating risk by taking fire and life safety into consideration is vital for financeable projects, the long-term success of the industry, and the transformation of the grid.

Battery storage integrators and asset owners now have two new commercial and industrial (C&I) product options to assist in successful permitting and safe operation with maximized site energy density, as battery storage system providers Powin Energy Corporation and solar inverter manufacturer Sungrow (through a joint venture with Samsung SDI) each announced a big milestone in June by passing product safety test UL 9540A, Test Method for Evaluating Thermal Runaway Fire Propagation in Battery Energy Storage Systems.

Thermal runaway reaction is an unwanted chemical reaction caused by excess heat (whether beginning internally or externally), and the major cause of fires and explosions involving today’s Li-ion batteries, which continue to burn until they run out of fuel. UL 9540A Test Method was developed to address such safety concerns from the cell- to system-level as identified by the building codes and the fire service, particularly in response to the National Fire Protection Association (NFPA) criteria for NFPA 855, Standard for the Installation of Stationary Energy Storage Systems and NFPA 70, National Electric Code. NFPA 855 was released in September 2019 and is a collection of criteria for the fire protection of energy storage system (ESS) installations. The standard provides requirements based on the technology used in ESS, the setting where the technology is being installed, the size and separation of ESS installations, and the fire suppression and control systems that are in place.

Currently, the individual battery energy storage system (BESS) unit size for UL 9540-listed units is limited to 250kWh. These stationary BESS units are to be installed with separation distances of 3 feet (92 cm) between units and between units and any wall. The latest ICC International Fire Code (2018 IFC) and NFPA 855 allow the code official (the AHJ) to approve larger individual BESS units, and separation distances less than 3 feet based on large scale fire testing conducted in accordance with the UL 9540A Test Method.

Putting into Context

A code or standard is written (e.g. NFPA 855), then a Nationally Recognized Testing Laboratory (NRTL) can test a product to the standard and certify product conformance to the test (e.g. UL 9540A). While it’s just one certification in a long list of applicable codes and standards (from CSA, IEC, IFC, IEEE, NFPA, UL, etc.) and fire safety best practices (e.g. early detection, first-responder education, etc.), many in our industry, including Powin Energy VP, Danny Lu, contend UL 9540A Test Method is likely to become the internationally-recognized benchmark for fire safety. Powin and Sungrow join battery manufacturer Samsung SDI as the only three companies currently compliant; however, additional stationary energy storage system manufacturers and integrators are thought to be in the process of proving compliance with the standard.

Paraphrasing Andy Colthorpe at Energy Storage News (Solar Media Ltd.), from the downstream industry perspective, having UL 9540A in the US means that NFPA 855 can be waived by the AHJ and batteries do not require additional fire-proofing barriers and fire-retardant materials to be added to the module design in order to be considered safe for installation and utilization.

Sungrow’s compliant C&I energy storage system is “ST556kWh-250UD while Powin Energy’s “Stack 225” system (no public specification sheet) is primarily aimed at 2-hour duration storage applications.

Thank you for your interest in the latest news around battery storage product and installation safety! We hope you found this to be helpful and that you’ll spend a few minutes reviewing other entries and insights on our Blog page. To dig-in further on this topic and discuss specific behind-the-meter and across-the-meter battery storage strategies for your organization, please Contact Ben.