NFPA 855 & Energy Storage

The rise of battery storage systems has increased significantly as solar photovoltaic and other systems seek a way to capture power during peaks to use at other times.  In turn there have been a fire safety concerns that then led NFPA to generate the new standard, 855.  The National Fire Protection Association has released the new Standard 855 which governs the installation, commissioning, operation, maintenance and decommissioning of energy storage systems.  This includes traditional stationary battery systems used by data centers and utilities. 

The standard aims to cover the fire safety needs of specific battery storage systems, such as Lithium-Ion.  These batteries have raised concerns about runaway temperature increases that lead to explosions and thus were banned from being stowed in checked bags of airplanes.  Additionally, cases have come up where overcharging of Li-Ion batteries has led to fires in warehouses and other locations.

The standard is new, meaning that it isn’t an update from a previous version.  Really it was developed from NFPA 1, chapter 52, but includes much more robust language that covers all variations of chemical energy (battery) storage as well as mechanical energy, including pumped hydro, thermal energy storage, flywheel, and more.  Although it is new, it is expected to be adopted during the next revision of the International Building and Fire Codes which will eventually be used by the individual state building codes and thereby a requirement for all new construction.  The requirements in 855 will impact the design, construction, installation, operation and maintenance of the energy storage system, which may lead to extra costs of each going forward. 

Chapter 4 describes the major issue and general requirements.  The chapter requires, under certain conditions, a hazard mitigation analysis that covers the following failure modes: thermal runaway (single module or array); management system failure; ventilation/exhaust system failure; voltage surges; short circuits (on the load side); and smoke/fire/suppression system failure. 

Capacitors used for power factor correction, filtering, and reactive power were removed from the scope to exclude the capacitors used in traditional utility applications, but not for data centers. 

Separation is required for certain capacities, currently set at 600 kWh of operation.  Fire barriers are required for the rooms energy storage systems are in, although fire suppression requirements reveal a gap of how to properly protect the spaces with sprinklers or alternate suppression systems – more is likely to be developed on this as the standard is updated. 

A couple of other details: Annex B shows examples of specific fire hazards with a wide variety of battery types, including Li-Ion; Annex C has fire-fighting considerations; Annex F contains a brief history on battery systems. 

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