FM Approved Lithium-Ion Battery Off-Gas Detector works to prevent thermal runaway and mitigate fire hazards

Publish Date • 28 February 2025

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FM Approvals recently completed the testing and certification of Nexceris’ Lithium-Ion Battery Off-Gas Detector – Li-ion Tamer (LT-SEN-M). The Nexceris detector successfully met the requirements of FM Approvals Standard 6540 for Lithium-Ion Battery Off-Gas Detection.

Functionally, the FM Approved Nexceris Li-ion Tamer senses the presence of a rising concentration of battery electrolyte solvent vapor due to the off gassing of lithium-ion batteries. Since this rising concentration occurs in the initial stages of a failing lithium-ion battery, early detection enables the shutdown of the failing battery before it reaches the dangerous thermal runaway stage. LT-SEN-M has been tested and certified to perform as expected under demanding circumstances.

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Fig 1 – Nexceris' Li-ion Tamer is designed to provide control at the earliest possible indication of lithium-ion battery failure, before thermal runaway and any potential fire hazards occur

Often, when thermal runaway is not controlled, the result is a fire that may be challenging to extinguish. Avoiding the potential property loss and business interruption that would come with this type of fire is critical to the operations of all facilities, but particularly important in ‘always on’ facilities like data centers.

FM Property Loss Prevention Data Sheet 5-33 for Lithium-Ion Battery Energy Storage Systems includes loss prevention recommendations that cite the use of FM Approved equipment, such as Nexceris’ Li-ion Tamer, to mitigate hazards associated with this type of equipment.

FM Approvals Standard 6540 states the testing and certification requirements for rate of rise gas detection instruments used in the detection of off gases from lithium-ion batteries generated in the first stage of a failing lithium-ion battery prior to thermal runaway. Some of the performance tests included in FM 6540 are:

  • Sensitivity test – to determine the minimum rate of change of off gases from lithium-ion batteries to initiate an alarm.
  • Verification of rate of rise test – to determine whether the detector alarms based on a rate or change.
  • Repeatability test – to determine whether the detector alarms are repeatable over time.
  • Functional test – to determine whether the equipment complies with relevant functional tests of ANSI/FM/UL 26990-1.
  • Durability test – to determine whether the equipment is reliable over a variety of environmental stresses.
  • Detector without field calibration – to assess the reliability of the detectors that do not require routine field calibration throughout their intended lifespan.

According to Nexceris, Li-ion Tamer comprises on-board detection algorithms making them sensitive to off-gassing compounds. These monitoring systems are regularly installed directly in battery racks and help protect property from lithium-ion battery incidents with the ability to control and address any situation at the earliest possible indication of failure.

During the testing process, the FM Approvals technical teams worked through several challenges to complete the independent, third-party evaluation of this product. FM Approvals’ objective testing of property loss prevention products identifies which ones meet globally recognized standards. In a world full of risk and uncertainty, an FM Approvals certification instills confidence that tested and certified products will protect facilities under the most demanding circumstances.

For over 135 years, the presence of our certification mark indicates a product has been through rigorous, objective testing and successfully completed the relevant standard requirements If your organization is in search of FM Approved products, go to the Approval Guide and view all our listings that include product information, engineering data, and technical information for the more than 60,000 FM Approved products.

If your organization manufactures property loss prevention products, begin the FM Approvals certification process by applying for certification online or contacting Patrick Byrne (FM Approvals, Operations Vice President, Group Manager – Electrical Systems) at patrick.byrne@fmapprovals.com.