In response to the new and evolving hazard for the fire service, the International Association of Fire Fighters partnered with UL Solutions and UL Fire Safety Research Institute to conduct a series of large-scale tests sponsored by the U.S. Department of Energy. The test series was designed to characterize the challenges for fire fighters responding to fires involving residential energy storage systems with a focus on developing size-up and tactical considerations to support the fire service in navigating the modern fireground.