AbstractLithium‐ion battery (LIB) energy storage systems play a significant role in the current energy storage transition. Globally, codes and standards are quickly incorporating a framework for safe design, siting, installation, commissioning, and decommissioning of battery energy storage systems (BESS). Full‐scale fire testing provides essential understanding of thermal runaway, fire, and explosion hazards associated with LIBs and BESSs. Engineers must then interpret that data to inform the site‐specific design, but there are cell, module, unit, and installation‐level data to decipher. Understanding the testing data and their limitations is critical for the design and operation of BESSs. Real‐life examples of where engineers misunderstood or misapplied test data will be presented to help bridge the knowledge gaps between stakeholders, industry, and engineers.