Safe Storage of Lithium-Ion Batteries: Best Practices for Facility Managers

2/5/2024

Early in 2024, the International Code Council published its International Fire Code (IFC) 2024. That code, like the International Building Code (IBC) 2024 and the National Fire Protection Association (NFPA) 855, provides updated guidelines for the safe storage of lithium-ion batteries. But unfortunately, these updated guidelines – although helpful – do not fully address all the questions facility managers may have.  

Below is an overview of what the current codes cover and do not cover, and what facility managers should do to protect tenants, buildings, and communities while the industry awaits more comprehensive updates.  

Codes and questions 

The current codes and standards focus far more on energy storage systems (ESS) than indoor battery storage applications. As defined by the NFPA, an ESS is an assembly of devices capable of storing energy to supply electrical energy for future use. Indoor battery storage, on the other hand, simply refers to areas where lithium-ion and other batteries are housed for future use or disposal and does not include manufacturing or testing facilities. 

Only the most recent codes from the NFPA, IBC, and IFC include additional requirements for ESS and indoor storage applications, but not to the level of specificity facility managers require.  For example, NFPA 855 and IFC offer design criteria for sprinkler density for up to 600 KWH of electrochemical ESS within a fire area for segregated groups not exceeding 50kWh. But 600 KWH is much smaller than the large-scale applications that are becoming increasingly common.  Furthermore, none of the codes define maximum allowed quantities (MAQ) and sprinkler densities for indoor storage applications when batteries exceed a certain state of charge.  

The same problem arises in separation requirements. The guidelines suggest three-foot separations between each battery group for a given ESS, but again these separations are based on a MAQ for ESS and not for indoor storage applications.  

Furthermore, the codes do not address variations from standards in testing. Some battery types and arrangements represent less of a fire hazard than others. Indeed, some manufacturers claim that their lithium-ion chemistries, along with their monitoring systems, greatly reduce the potential for thermal runaway, which is an uncontrollable self-heating state. Other variables, such as state of charge, cell capacity, types of packaging, and storage height, differ from one application to another. It therefore is unrealistic to classify all storage arrangements in the same way.   

Best practices to follow 

In the absence of comprehensive, detailed guidelines for indoor storage of lithium-ion batteries, facility managers and building owners can take steps to reduce the risk of fire. One option is to follow guidelines from insurance underwriters. These tend to be more comprehensive and stricter than the NFPA, IBC, and IFC codes and standards but still, these guidelines apply to very specific battery types and arrangements.  

Testing is arguably the most important step, however, especially in situations where the variables don’t align with code standards. The NFPA, IBC, and IFC all mandate large-scale testing, but, as mentioned earlier, variables differ from facility to facility. Furthermore, there are exceptions to the large-scale testing standards, such as unit testing, that may be considered sufficient if the manufacturer can demonstrate a certain degree of cell-to-cell propagation resistance. For these reasons, even if one test yields a perfect result, one cannot assume that the perfect result will be replicated at another facility with a slightly different application. Therefore, facility managers should ask each prospective tenant whether the manufacturer has conducted testing and analysis for the specific, intended storage arrangement.  

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The manufacturer should have conducted testing and analysis to determine maximum allowable quantities and separation requirements for the facility’s sprinkler density or fire-extinguishing system. Alternatively, the manufacturer could recommend a fire suppression system based on their testing that the tenant or landlord could install. Manufacturers should also report the results of hazard mitigation analysis and evaluations of deflagration potential involving the off gassing of flammable gases during a thermal runaway. Only with such information can the facility manager, the building owner, and the authority having jurisdiction (AHJ) confidently decide whether the tenant is taking sufficient safety measures. 

It’s important to note that most AHJs in the United States have not yet adopted the latest codes; that will likely take a few years. Nevertheless, AHJs will want to know how a facility is ensuring safety. Consequently, whatever information the tenant shares with the facility manager and owner should also be shared with the AHJ as early during the leasing negotiations as possible. This will help ensure that any buildouts or installations are well positioned to meet not only current local codes, but also future ones, and it will speed up permitting processes when approvals are necessary.   

Facility managers should not assume that a proposed design is safe because it is not fully addressed in the latest codes or even with an underwriter’s standard document. As stated earlier, most applications for the indoor storage of lithium-ion batteries greatly differ from one another.  In addition, battery and EV manufacturers are investing heavily in R&D, so the variations and energy densities are likely to further increase in the coming years. Thus, it is critical for facility managers and owners to require tenants to provide testing data for specific, proposed applications. Such a requirement may delay lease signings and approvals, but it will keep tenants, buildings, and local communities safe.    

Nickolas Patsios, PE, is Associate Partner at Syska Hennessy Group.