UL Solutions, a global company for applied safety science, has announced enhancements to the testing methods for battery energy storage systems (BESS).
The new testing methods will address industry innovations, including test methods for non-lithium-ion battery chemistries, such as sodium-ion batteries, considering the development of battery technology and addressing fire risk mitigation.
The changes in UL Solutions test methods showcase updates found in the fifth edition of ANSI/CAN/UL 9540A, the Standard Test Method for Evaluating Thermal Runaway Fire Propagation in Battery Energy Storage Systems, the American and Canadian national standard for addressing thermal runaway propagation for energy storage systems. The fifth edition was published by UL Standards & Engagement after collaboration with the energy storage industry, regulatory authorities and others serving on the standard’s technical committee.
ANSI/CAN/UL 9540A provides a standardized test method to determine a battery technology’s susceptibility to thermal runaway, a chemical reaction causing a battery to increase in temperature and pressure rapidly and leading to safety issues like fire and explosions. The test method also evaluates fire and explosion hazards due to thermal runaway, such as the ejection of hot particles.
After testing, a report provides data used to determine the necessary fire and explosion protection required for tested BESS installations. The data from this test method helps strengthen practical and effective safety measures within the industry.
The data from the report is also used for demonstrating compliance with codes and installation standards, which address public and first responder safety and property protection. These include NFPA 855, Standard for the Installation of Stationary Energy Storage Systems, and fire codes, including the International Fire Code, the International Residential Code and NFPA 1, Fire Code.
The fifth edition standard includes clearer criteria for cell-to-cell propagation, high-temperature test methods for various battery chemistries and testing protocols for emerging applications such as rooftop and open-garage BESS installations.
While ANSI/CAN/UL 9540A focuses specifically on the test method, the related UL standard, UL 9540, the Standard for Energy Storage Systems and Equipment, provides comprehensive product safety criteria and the basis for UL certification of the complete BESS itself. This includes its battery cells, modules and racks, and power conversion, battery management, energy management, communication and safety systems. The coordinated application of UL 9540A and UL 9540 and adherence to relevant installation codes help support the safe deployment of BESS.
UL Solutions is also developing large-scale fire testing (LSFT) methodologies. In collaboration with the NFPA Technical Committee, a task group is working to enhance guidance and consensus-based standards for LSFT. UL 9540A is the only consensus standard referenced in NFPA 855 for LSFT in the U.S. and Canada.
