Conclusions

The fire growth characteristics for the Li-ion batteries and the FM Global standard commodities that were evaluated exhibited similar fire development leading to the estimated time of first sprinkler operation.

Commodity containing densely packed Li-ion batteries and minimal plastics (i.e., cylindrical and polymer cells) exhibited a delay in the battery involvement. For the Li-ion batteries used in this project, significant involvement was observed within five minutes after ignition.

Commodity containing a significant quantity of loosely packed plastics (i.e., CUP and power tool packs) exhibited a rapid increase in the released energy due to plastics involvement early in the fire development. Battery involvement was not observable due to the contribution from the plastics.

The CUP commodity exhibited a fire hazard leading to initial sprinkler operation that was similar or greater than the Li-ion battery products tested. Therefore, the CUP commodity was chosen as a suitable surrogate for Li-ion batteries in a bulk packed rack storage test scenario, provided the fire protection system suppresses the fire prior to the time of significant Li-ion battery involvement.

Without full-scale sprinklered testing experience with Li-ion batteries, protection system performance must preclude Li-ion battery involvement.