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June 28, 2023

ULSE Publishes Third Edition of UL 9540, Energy Storage Systems and Equipment

Energy Storage System in alpine setting with solar panels in background

Third edition includes numerous revisions to keep pace with rapidly advancing technology

On June 28, 2023, UL Standards & Engagement published the third edition of ANSI/CAN/UL 9540, Energy Storage Systems and Equipment. As with other standards for new and rapidly advancing technology, the technical committee reviewed numerous proposed revisions aimed at addressing new research and other information to help assure safe operation of energy storage systems, which receive and store energy in some form so that the ESS can provide electrical energy to loads or to the local/area electric power system when needed. 

The new edition contains various revisions, such as:

  • Addition of AC and DC ESS concepts
  • Clarification of capacity and separation limits of ESS subject to UL 9540A testing to align with the national fire code (NFPA 855)
  • Addition of explosion control requirements to align with the codes
  • Addition of external warning communication system criteria that gives an advance notification to operators of a potential safety issue with the ESS
  • Additional comprehensive criteria for thermal ESS including tests to address the unique hazards associated with these systems
  • Additional testing requirements for mechanical ESS
  • Addition of requirements for clean agent direct injection coolant system
  • Addition of requirements for remote software updates
  • Addition of requirements to address noise levels for ESS
  • Addition of requirements to address hazardous fluids and liquid coolant system hazards

UL Standards & Engagement recognizes the work of TC 9540 members along with the many nonvoting stakeholders who submitted and/or commented upon proposed revisions. 

Our standards are developed through a consensus-based process, which integrates scientific and testing expertise with input from our TC members and stakeholders. TC members represent a variety of interests, including industry, academia, government, retail, and manufacturing. If you are involved in the design, construction, sale, or operation of ESS, and you would like to help improve safety in your industry, please take a moment to learn how you can get involved.