Stationary storage battery systems having an electrolyte capacity of more than 100 gal (378.5 L) in sprinklered buildings or 50 gal (189.3 L) in unsprinklered buildings for flooded lead-acid, nickel-cadmium, and valve-regulated lead-acid (VRLA) batteries used for facility standby power, emergency power, or uninterrupted power supplies shall be in accordance with Section 52.2 and Table 52.2.1.
Table 52.2.1 Battery Requirements
| Requirement | Nonrecombinant Batteries | Recombinant Batteries | |
|---|---|---|---|
| Flooded Lead-Acid | Flooded Nickel-Cadmium (Ni-Cd) | Valve-Regulated Lead-Acid (VRLA) | |
| Safety caps | Venting caps | Venting caps | Self-resealing flame-arresting caps |
| Thermal runaway management | Not required | Not required | Required |
| Spill control | Required | Required | Not required |
| Neutralization | Required | Required | Required |
| Ventilation | Required | Required | Required |
| Signage | Required | Required | Required |
| Seismic control | Required | Required | Required |
| Fire detection | Required | Required | Required |
Batteries shall be provided with safety venting caps per 52.2.2.1.1 and 52.2.2.1.2.
Vented lead-acid and nickel-cadmium shall be provided with safety venting caps.
VRLA shall be equipped with self-resealing flame-arresting safety vents.
Battery systems shall be permitted in the same room as the equipment that they support.
Battery systems shall be housed in a noncombustible, locked cabinet or other enclosure to prevent access by unauthorized personnel unless located in a separate equipment room accessible only to authorized personnel.
In other than assembly, educational, detention, and correction facilities; health care, ambulatory health care, and day care centers; and residential board and care and residential occupancies, battery systems shall be located in a room separated from other portions of the building by a minimum of a 1-hour fire barrier.
In assembly, educational, detention and correction facilities; health care, ambulatory health care, and day care centers; and, residential board and care and residential occupancies, battery systems shall be located in a room separated from other portions of the building by a minimum of a 2-hour fire barrier.
Rooms, buildings, or areas containing free-flowing liquid electrolyte in individual vessels having a capacity of more than 55 gal (208 L) or multiple vessels having an aggregate capacity exceeding 1000 gal (3785 L) shall be provided with spill control to prevent the flow of liquids to adjoining areas.
VRLA batteries with immobilized electrolyte shall not require spill control.
An approved method to neutralize spilled electrolyte shall be provided.
For VRLA batteries, the method shall be capable of neutralizing a spill from the largest battery to a pH between 7.0 and 9.0.
For flooded lead-acid, flooded nickel-cadmium, and VRLA batteries, ventilation shall be provided for rooms and cabinets in accordance with the mechanical code and one of the following:
- The ventilation system shall be designed to limit the maximum concentration of hydrogen to 1.0 percent of the total volume of the room during the worst-case event of simultaneous "boost" charging of all the batteries, in accordance with nationally recognized standards.
- Continuous ventilation shall be provided at a rate of not less than 1 ft3/min/ft2 (5.1 L/sec/m2) of floor area of the room or cabinet.
The battery environment shall be controlled or analyzed to maintain temperature in a safe operating range for the specific battery technology used.
Doors or accesses into the following shall be provided with approved signs:
- Battery storage buildings
- Rooms containing stationary storage battery systems
- Other areas containing stationary storage battery systems
For rooms that contain VRLA batteries, the signs required by 52.2.2.8.1 shall state the following:
This room contains:
- Stationary storage battery systems
- Energized electrical circuits
For rooms that contain flooded lead-acid or flooded Ni-Cd batteries, the signs required by 52.2.2.8.1 shall state the following:
This room contains:
- Stationary storage battery systems
- Energized electrical circuits
- Corrosive battery electrolyte
Battery cabinets shall be provided with exterior labels that identify the manufacturer and model number of the system and electrical rating (i.e., voltage and current) of the contained battery system.
Signs shall be provided within battery cabinets to indicate the relevant electrical, chemical, and fire hazard.
Battery systems shall be seismically braced in accordance with the building code.
Normally unoccupied, stand-alone telecommunications structures with a gross floor area of less than 1,500 ft2 (140 m2) shall not be required to have the detection as indicated in 52.2.2.10.
Energy storage systems having a capacity greater than the quantities listed in Table 52.3.1 shall be in accordance with Section 52.3 and where used as a legally required emergency or standby power system, shall also comply with 11.7.3.
| Type | Capacitya |
|---|---|
| Lithium batteries, all types | 20 KWh (18.0 Mega joules) |
| Sodium batteries, all types | 20 KWh (18.0 Mega joules)c |
| Flow batteriesb | 20 KWh (18.0 Mega joules) |
| Other battery technologies | 10 KWh (10.8 Mega joules) |
| Capacitors | 70 KWh (25.2 Mega joules) |
Notes:
aFor batteries and capacitors rated in Amp-Hours, KWh should equal rated voltage times amp-hour rating divided by 1000.
bIncludes vanadium, zinc-bromine, polysulfide-bromide, and other flowing electrolyte-type technologies.
cOr 70 KWh (25.2 Mega joules) for sodium-ion technologies.
Stationary storage battery systems shall be located and constructed in accordance with this section.
Stationary storage battery systems shall be housed in a noncombustible, locked cabinet or other enclosure to prevent access by unauthorized personnel unless located in a separate equipment room accessible only to authorized personnel.
Stationary storage battery systems shall not be located in areas where the floor is located more than 75 ft (22,860 mm) above the lowest level of fire department vehicle access, or where the floor level is more than 30 ft (9144 mm) below the finished floor of the lowest level of exit discharge, unless otherwise permitted by 52.3.2.1.2.
Installations on noncombustible rooftops of buildings exceeding 75 ft (22,860 mm) in height that do not obstruct fire department rooftop operations shall be permitted when approved by the AHJ.
Rooms containing stationary storage battery systems shall be located in high-hazard occupancies, or shall be separated from other areas of the building as stated in 52.3.2.1.3.1 and 52.3.2.1.3.2. Stationary storage battery systems shall be allowed to be in the same room with the equipment they support.
In other than assembly, educational, detention, and correction facilities; health care, ambulatory health care, and day care centers; and residential board and care and residential occupancies, stationary storage battery systems shall be located in a room separated from other portions of the building by a minimum of a 1-hour fire barrier.
In assembly, educational, detention, and correction facilities; health care, ambulatory health care, and day care centers; and residential board and care and residential occupancies, stationary storage battery systems shall be located in a room separated from other portions of the building by a minimum of a 2-hour fire barrier.
Stationary storage battery systems located outdoors shall comply with this paragraph, in addition to all applicable requirements of Section 52.3.
Installations in outdoor enclosures or containers that are occupied for servicing, testing, maintenance, and other functions shall be treated as stationary storage battery system rooms.
Battery arrays in noncombustible containers shall not be required to be spaced 3 ft (914 mm) from the container walls.
Stationary storage battery systems located outdoors shall be separated by a minimum 5 ft (1524 mm) from the following:
- Lot lines
- Public ways
- Buildings
- Stored combustible materials
- Hazardous materials
- High-piled stock
- Other exposure hazards
The AHJ shall be permitted to authorize smaller separation distances if large-scale fire and fault condition testing conducted or witnessed and reported by an approved testing laboratory is provided showing that a fire involving the system will not adversely impact occupant egress from adjacent buildings, or adversely impact adjacent stored materials or structures.
Stationary storage battery systems located outdoors shall be separated from any means of egress as required by the AHJ to ensure safe egress under fire conditions, but in no case less than 10 ft (3048 mm).
Outdoor areas in which stationary storage battery systems are located shall be secured against unauthorized entry in an approved manner.
Fire areas within buildings containing stationary storage battery systems exceeding the maximum allowable quantities in Table 52.3.2.2.1 shall comply with all applicable ordinary-hazard and high-hazard requirements as identified in 6.2.2 of NFPA 101 and the building code.
| Type | Maximum Allowable Quantitiesa | Hazard Classification |
|---|---|---|
| Lithium batteries, all types | 600 KWh | High hazardc |
| Sodium batteries, all types | 600 KWh | High hazardc |
| Flow batteriesb | 600 KWh | High hazardc |
| Other battery technologies | 1200 KWh | High hazardc |
Notes:
aFor batteries rated in amp-hours, KWh should equal rated voltage times amp-hour rating divided by 1000.
bIncludes vanadium, zinc-bromine, polysulfide-bromide, and other flowing electrolyte-type technologies.
cCan be permitted to be ordinary hazard classification if approved by the AHJ based on (1) a hazard mitigation analysis conducted in accordance with 52.3.2.4 and (2) large-scale fire and fault condition testing conducted or witnessed and reported by an approved testing laboratory that shows that a fire involving the stationary storage battery system is contained within the room for a duration equal to the fire resistance rating of the room separation required in 52.3.2.1.3.1 or 52.3.2.1.3.2, as applicable.
Where approved by the AHJ, areas containing stationary storage battery systems that exceed the amounts in Table 52.3.2.2.1 shall be permitted to be treated as a ordinary-hazard and not a high-hazard classification based on a hazardous mitigation analysis in accordance with 52.3.2.4 and large-scale fire and fault condition testing conducted or witnessed and reported by an approved testing laboratory.
Where areas within buildings contain a combination of energy system technologies, the total aggregate quantities shall be determined based on the sum of percentages of each type divided by the maximum allowable quantity of each type. If the sum of the percentages exceeds 100 percent, the area shall be treated as a high-hazard classification in accordance with Table 52.3.2.2.1.
Battery arrays shall comply with 52.3.2.3.2 and 52.3.2.3.3 unless otherwise permitted by 52.3.2.3.4 or 52.3.2.3.5.
Storage batteries, prepackaged stationary storage battery systems, and pre-engineered stationary storage battery systems shall be segregated into arrays not exceeding 50 KWh (180 Mega joules) each.
Listed pre-engineered stationary storage battery systems and prepackaged stationary storage battery systems shall not exceed 250 KWh (900 Mega joules) each.
The AHJ shall be permitted to approve listed pre-engineered and prepackaged battery arrays with larger capacities or smaller battery array spacing if large-scale fire and fault condition testing conducted or witnessed and reported by an approved testing laboratory is provided showing that a fire involving one array will not propagate to an adjacent array, and be contained within the room for a duration equal to the fire resistance rating of the room separation required by 52.3.2.1.3.
A failure mode and effects analysis (FMEA) or other approved hazard mitigation analysis shall be provided to the AHJ when any of the following conditions are present:
- Battery technologies not specifically identified in Table 52.3.1 are provided.
- More than one stationary storage battery technology is provided in a room or indoor area where there is a potential for adverse interaction between technologies.
- When allowed as a basis for increasing maximum allowable quantities as specified in Table 52.3.2.2.1.
The analysis shall evaluate the consequences of the following failure modes, and others deemed necessary by the AHJ. Only single failure modes shall be considered for each mode:
- Thermal runaway condition in a single module or array
- Failure of a battery management system
- Failure of a required ventilation system
- Voltage surges on the primary electric supply
- Short circuits on the load side of the stationary battery storage system
- Failure of the smoke detection, fire suppression, or gas detection system
The AHJ shall be permitted to approve the hazardous mitigation analysis provided the consequences of the FMEA demonstrate the following:
- Fires or explosions will be contained within unoccupied stationary storage battery system rooms for the minimum duration of the fire resistance rated specified in 52.3.2.1.3.1 or 52.3.2.1.3.2, as applicable
- Fires and explosions in stationary storage battery system cabinets in occupied work centers allow occupants to safely evacuate
- Toxic and highly toxic gases released during charging, discharging, and normal operation shall not exceed the permissible exposure limit (PEL)
- Toxic and highly toxic gases released during fires and other fault conditions shall not reach concentrations in access of IDLH level in the building or adjacent means of egress routes during the time deemed necessary to evacuate from that area
- Flammable gases released from batteries during charging, discharging, and normal operation shall not exceed 25 percent of the lower flammable limit (LFL)
Construction, equipment, and systems that are required for the stationary storage battery system to comply with the hazardous mitigation analysis shall be installed, maintained, and tested in accordance with nationally recognized standards and specified design parameters.
Storage batteries shall be listed in accordance with UL 1973, Standard for Batteries for Use in Light Electric Rail (LER) Applications and Stationary Applications. Prepackaged and pre-engineered stationary storage battery systems shall be listed in accordance with UL 9540, Outline of Investigation for Energy Storage Systems and Equipment.
Prepackaged and pre-engineered stationary storage battery systems shall be installed in accordance with their listing and the manufacturer's instructions.
The storage battery environment shall be controlled to maintain temperatures and conditions within the battery manufacturer's specifications.
An approved battery management system shall be provided for battery technologies for monitoring and balancing cell voltages, currents, and temperatures within the manufacturer's specifications. The system shall transmit an alarm signal to an approved location if potentially hazardous temperatures or other conditions including short circuits, overvoltage (i.e., overcharge) or under voltage (i.e., over discharge) are detected.
Battery chargers shall be compatible with the battery manufacturer's electrical ratings and charging specifications. Battery chargers shall be listed in accordance with the UL 1564, Standard for Industrial Battery Chargers, or provided as part of a listed pre-engineered or prepackaged stationary storage battery system.
Vehicle impact protection shall be provided where stationary storage battery systems are subject to impact by motor vehicles.
Combustible materials not related to the stationary storage battery system shall not be stored in battery rooms, cabinets, or enclosures.
Combustible materials in occupied work centers shall comply with Section 10.18 and shall not be stored within 3 ft (915 mm) of battery cabinets.
New signage installations shall require the following items:
- Hazard identification markings in accordance with NFPA 704.
- "This room contains energized battery systems," or the equivalent.
- Identification of the type(s) of batteries present
- AUTHORIZED PERSONNEL ONLY
- Technology-specific markings, if required in 52.3.2.11
Existing stationary storage battery systems shall be permitted to include the signage required at the time it was installed.
Battery cabinets shall be provided with exterior labels that identify the manufacturer and model number of the system and electrical rating (i.e., voltage and current) of the contained battery system.
Signs shall be provided within battery cabinets to indicate the relevant electrical, chemical, and fire hazard.
Fire command centers in buildings containing stationary storage battery systems shall include signage or readily available documentation that describes the location of stationary storage battery systems, the types of batteries present, operating voltages, and location of electrical disconnects.
Battery systems shall be seismically braced in accordance with the building code.
Vented batteries shall be provided with flame-arresting safety caps.
Different types of batteries shall not be installed in the same room or cabinet if there is a potential for unsafe interaction between them, as determined by the AHJ.
Rooms containing stationary storage battery systems shall be protected by an automatic sprinkler system installed in accordance with Section 13.3.
An approved automatic smoke detection system shall be installed in rooms containing stationary battery storage systems in accordance with NFPA 72 and the required automatic smoke detection system shall be supervised by an approved central, proprietary, or remote station service or a local alarm that will give an audible signal at a constantly attended location.
Where required by 52.3.2.11, ventilation shall be provided for rooms and cabinets in accordance with the mechanical code and one of the following:
- The ventilation system shall be designed to limit the maximum concentration of flammable gas to 25 percent of the lower flammable limit (LFL) of the total volume of the room during the worst-case event of simultaneous "boost" charging of all the batteries, in accordance with nationally recognized standards.
- Mechanical ventilation shall be provided at a rate of not less than 1 ft3/min/ft2 (5.1 L/sec/m2) of floor area of the room or cabinet. The ventilation can be either continuous, or activated by a gas detection system in accordance with 52.3.2.8.2.
Where required by 52.3.2.8(2), rooms containing stationary storage battery systems shall be protected by an approved continuous gas detection system.
The gas detection system shall be designed to activate when the level of flammable gas exceeds 25 percent of the lower flammable limit (LFL)
Activation of the gas detection system shall result in activation of the mechanical ventilation system, which shall remain on until the flammable gas detected is less than 25 percent of the LFL.
The gas detection system shall include a minimum two hours of standby power.
Failure of the gas detection system shall annunciate a trouble signal at an approved central, proprietary, or remote station service, or when approved at a constantly attended onsite location.
Where required by 52.3.2.11, approved methods and materials shall be provided for the control and neutralization of spills of electrolyte or other hazardous materials in rooms containing stationary storage batteries as follows:
- For batteries with free-flowing electrolyte, the method and materials shall be capable of neutralizing a spill of the total capacity from the largest cell or block to a pH between 5.0 and 9.0.
- For batteries with immobilized electrolyte, the method and materials shall be capable of neutralizing a spill of 3.0 percent of the capacity of the largest cell or block in the room to a pH between 5.0 and 9.0.
Stationary storage battery systems shall comply with 52.3.2 through 52.3.2.10 and this section, as applicable.
Stationary storage battery systems utilizing lithium batteries shall be provided with thermal runaway protection in accordance with 52.3.2.10.
Stationary storage battery systems utilizing sodium batteries shall comply with the following:
- Ventilation shall be provided in accordance with 52.3.2.8.
- Spill control and neutralization shall be in accordance with 52.3.2.9.
- Thermal runaway protection shall be provided for in accordance with 52.3.2.10.
- A hazard mitigation analysis shall be provided for systems that utilize sodium sulfur batteries, or other sulfur-type battery systems that operate above ambient temperatures.
- The signage required in 52.3.2.6.5 shall include, where applicable, "Water Reactive Hazard — Apply No Water."
Stationary storage battery systems utilizing flow batteries shall comply with the following:
Stationary storage battery systems utilizing battery technologies other than those described in 52.3.2.11.1 through 52.3.2.11.1 shall comply with the following:
- Ventilation shall be provided in accordance with 52.3.2.8 where flammable, toxic or highly toxic gases could be present during charging, discharging, and normal system use.
- Spill control and neutralization shall be in accordance with 52.3.2.9 where the batteries contain electrolytes that could be released from the batteries.
- Thermal runaway protection shall be provided in accordance with 52.3.2.10.
- The signage required in 52.3.2.6.5 shall also identify any potential hazards associated with the batteries.
Stationary capacitor energy storage systems having capacities greater than those described in Table 52.3.1 shall comply with 52.3.3.
Stationary capacitor energy storage systems shall be located and constructed as required for stationary storage battery system in accordance with 52.3.2.1 through 52.3.2.1.4.3.
Fire areas within buildings containing capacitor energy storage systems exceeding 600 KWh (2160 mJ) shall comply with all applicable ordinary-hazard and high-hazard requirements as identified in 6.2.2 of NFPA 101 and the building code.
Capacitors shall be listed in accordance with UL 1973, Standard for Batteries for Use in Light Electric Rail (LER) Applications and Stationary Applications. Prepackaged and pre-engineered capacitor energy systems shall be listed in accordance with UL 9540, Outline of Investigation for Energy Storage System and Equipment.
The environment surrounding the capacitors shall be controlled to maintain temperatures and conditions within the manufacturer's specifications.
Capacitor chargers shall be compatible with the capacitor manufacturer's electrical ratings and charging specifications, and shall be listed in accordance with the UL 1564, Standard for Industrial Battery Chargers, or provided as part of a listed pre-engineered or prepackaged capacitor energy storage system.
Combustible materials not related to the capacitor energy storage system shall not be stored in capacitor rooms, cabinets, or enclosures.
Combustible materials in occupied work centers shall comply with Section 10.18 and shall not be stored within 3 ft (915 mm) of capacitor cabinets.
Where the capacitor energy storage system disconnecting means is not within sight of the main service disconnect, placards or directories shall be installed at the locations of the main service disconnect to indicate the location of all capacitor energy storage system disconnecting means in accordance with NFPA 70.
Capacitor cabinets shall be provided with exterior labels that identify the manufacturer and model number of the system and electrical rating (i.e., voltage and current) of the contained battery system.
Signs shall be provided within capacitor cabinets to indicate the relevant electrical, chemical, and fire hazard.