UL 9540

UL 9540 is the safety standard for energy storage systems and equipment, and UL 9540A is the test method that measures how fire propagates between battery cells, modules, and units.

UL 9540 certifies the complete system: batteries, power conversion, and controls as installed. UL 9540A does not pass or fail a product; it produces the thermal runaway test data that fire codes and local authorities use to set spacing, ventilation, and suppression requirements. Both are routinely required for permitting a battery energy storage system in the United States.

Also called: UL 9540A