ESS capacity limits based on large-scale fire testing. Explosion protection for electrochemical ESS. Additional criteria for thermal ESS. Revisions to Appendix D to align with the new UL 1973 Alternative Approach for Evaluating Valve Regulated or Vented Lead Acid or Nickel Cadmium Batteries Annex. Clarification of material and Enclosure Tests for smaller ESS. Use of Representative Subassemblies for Testing. External Warning Communication System Criteria. Revisions to address hazardous fluids and liquid coolant system hazards. New Appendix G for Direct Injection Clean Agent Cooling Systems.