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UL 9540A Test Method

Testing the fire safety hazards associated with propagating thermal runaway within battery systems.

Battery energy storage system inside building

Overview of the UL 9540A test method

We developed the UL 9540A, Test Method for Evaluating Thermal Runaway Fire Propagation in Battery Energy Storage Systems, to help manufacturers have a means of proving compliance to the new regulations. Leveraging our long practice of developing standards with vast experience in similar industries, we worked with regulators to understand concerns and deliver a viable test method to accelerate adoption of innovative technology.

UL 9540A was developed to address safety concerns identified by the building codes and the fire service in the United States. The current ICC International Fire Code (2018 IFC) allows an individual battery energy storage system (BESS) unit not exceeding 50 kWh and having a maximum quantity of systems totaling 600 kWh of energy per indoor fire area (battery room). The 2018 IFC and the draft NFPA 855 standard for installation of energy storage systems currently limits the individual BESS unit size for UL 9540 listed units to 250 kWh. These BESS units are to be installed with separation distances of 3 feet (1 meter) between units and between units and any wall. The latest IFC and NFPA 855 drafts allow the code official (AHJ) to approve larger individual BESS units, and separation distances less than 3 feet based on large scale fire testing conducted in accordance with the UL 9540A Test Method.

Testing to the UL 9540A standard

  • BESS installation instructions
  • Installation ventilation requirements
  • Effectiveness of fire protection (integral or external)
  • Fire service strategy and tactics

We will work with you to understand your products and develop an individualized test plan that works for your company and meets your needs.

Why UL for UL 9540A testing

We are a leader in battery safety technology. Examples of this leadership are highlighted by the first-ever stationary battery Standard ANSI/CAN UL 1973, the world’s first energy storage system Standard ANSI/CAN UL 9540  as well as recent publication of the UL 9540A Test Method. We offer:

  • Unparalleled availability of UL owned full fire testing facilities will be made available – no need for subcontracting.
  • Full depth of experienced engineering and research teams will be made available to develop insights. We have in-depth knowledge of battery chemistries and fire suppression.
  • Demonstrable track record of success serving organizations and entities such as fire departments as well as electrical and building inspectors.

UL 9540A Test Method Brings Clarity to Insurance and Fire Mitigation Professionals

UL’s new test method for evaluating thermal runaway fire propagation in BESS will bring clarity on the performance of a BESS under a possible thermal event that can occur in the life of the system.

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