This report summarizes fire tests conducted to determine fire protection guidance for warehouse storage of cartoned Li-ion batteries. The main methodology for this project consisted of a two prong approach to analyze the fire hazard of Li-ion batteries in cartons: (1) a comparison of free burn flammability characteristics of a large-format polymer pouch Li-ion battery to FM Global standard commodities and previously tested small-format Li-ion batteries in a rack storage array1,2 and (2) a large-scale fire test to assess the performance of ceiling-level sprinkler protection on cartoned large-format polymer pouch Li-ion batteries. The goal of the experimental approach was to maximize the application of the successful large-scale fire test result.

Additional tasks of this project involved (3) assessing the impact of internal ignition within a pallet load of batteries versus the external ignition typically used in large-scale fire testing; and (4) assessing the effectiveness of sprinkler water at suppressing a fire at a later stage of battery involvement than could be achieved in the large-scale test. These tasks reinforce the sprinkler protection guidance resulting from the successful large-scale fire test. All data, test descriptions, data analysis, and figures in this report were provided by FM Global. Exponent has relied on the FM Global testing report entitled, “Development of Protection Recommendations for Li-ion Battery Bulk Storage: Sprinklered Fire Test,” as a basis for this report.

This project was conducted in partnership with the Property Insurance Research Group (PIRG) and was in collaboration with the Fire Protection Research Foundation (FPRF). The previous two phases of the project included a use and hazard assessment report4 (Phase I) and a series of reduced-commodity fire tests comparing the flammability characteristics of common Li-ion batteries/products to FM Global standard commodities (Phase II).1,2 These tests showed that bulk storage of small-format (2.6 Ah) Li-ion batteries exhibit similar fire growth leading to first sprinkler operation as other more common cartoned commodities. Further, it was determined that the time required for involvement of the Li-ion batteries in a fully developed fire is approximately five minutes. These conclusions provided the basis for sprinkler protection recommendations for small-format Li-ion batteries in bulk storage, with the goal of suppressing the fire before the anticipated time of involvement of Li-ion batteries.