The Battery Revolution
Michael O'Brian Code Savvy Consultants
Each day, news stories highlight the accelerating shift toward lithium-ion battery technology in many aspects of our life. While much attention has focused on converting gasoline-powered vehicles to electric vehicles (EVs), the battery revolution extends far beyond transportation. It’s transforming how we power our homes, maintain our lawns, and operate tools such as chainsaws and handheld equipment.
Increasingly, communities are turning their attention to energy storage—both at the residential and utility level—as part of a broader strategy to manage electrical demand and integrate renewable energy. Energy Storage Systems (ESS) are rapidly evolving, available in many configurations depending on design, capacity, and chemistry.
The International Code Council (ICC) defines Energy Storage Systems (ESS) as “one or more devices, assembled together, capable of storing energy in order to supply electrical energy at a future time.” This broad definition encompasses various technologies capable of storing energy, not just batteries.
When focusing on battery-based ESS, it's important to understand that, like EV battery packs, ESS systems often contain hundreds—or even thousands—of individual cells. These cells may be cylindrical, prismatic, or pouch-type, depending on the manufacturer, and are arranged in configurations that meet specific design and safety testing criteria.
The rapidly changing ESS landscape has prompted significant updates in building and fire codes related to system design, installation, and third-party listings. In the US, chief among these is NFPA 855: Standard for the Installation of Stationary Energy Storage Systems, originally published in 2020. A 2023 revision followed, and the 2026 edition is anticipated after the NFPA Technical Committee meeting in June 2025.
The Canadian Electrical Code (CE Code) 2024 includes new provisions for energy storage systems (ESS), particularly for residential occupancies. Some key requirements include:
- Location Restrictions: ESS cannot be installed in sleeping areas or rooms that open directly into sleeping areas.
- Fire Safety Measures: A smoke alarm or detector must be installed in the room where the ESS is located and be interconnected with the remainder of the smoke alarms in the dwelling.
- Capacity Limitations: Residential ESS must not exceed 20 kWh per unit.
- Installation Standards: ESS must be approved and installed according to manufacturer instructions.
Additionally, the ANSI/CAN/UL 9540 standard provides safety guidelines for ESS, ensuring compatibility with national electrical and fire codes. If you're looking for specific installation details, you may need to check provincial electrical codes or local regulations.
The growth in ESS technology — driven by innovations in chemistry and form factor — is exciting, but it also presents permitting and compliance challenges for authorities having jurisdiction. Relying on the latest codes and standards ensures that safety remains paramount in this fast-evolving space.
Requirements for ESS systems rated over 1 kWh are covered within the scope of binational (Canada & US) Standard ANSI/CAN/UL 9540, which evaluates overall system safety. UL 9540A, fire testing methodology used to evaluate thermal runaway and fire propagation risks.
Energy storage systems are intended for installation and use in accordance with codes and standards in effect depending on the jurisdictional requirements. The National Electrical Code, NFPA 70, the Fire Code, NFPA 1, the National Electrical Safety Code, IEEE C2, the International Fire Code, ICC IFC, the International Residential Code, and the ICC IRC and the Standard for the Installation of Stationary Energy Storage Systems, NFPA 855, in the US, and in Canada, the Canadian Electrical Code, Part I Safety Standard for Electrical Installations, CSA C22.1, the National Building and Fire Codes of Canada, depending on the jurisdictional requirements.
Large-scale fire testing (LSFT) plays a critical role in validating fire and explosion risks associated with ESS installations. Organizations such as CSA Group have published CSA/ANSI C800-2025: Testing protocol for energy storage system reliability and quality assurance program, helping align testing protocols across North America, while UL9540 is working to provide this information in future editions of the standard.
Home-Based ESS
Residential energy storage systems are becoming more common, especially when paired with solar photovoltaic (PV) systems. In other cases, ESS is installed as a standalone backup power source. These installations must comply with the locally adopted residential building codes and residential sections of NFPA 855. Notably, NFPA 855’s upcoming edition consolidates residential requirements into a single chapter for easier reference.
Residential ESS installations are subject to key safety requirements, including placement in non-habitable spaces, protection against impact, proper spacing, and fire protection measures. Variables such as system capacity, chemistry type, and listing status all impact how systems must be installed. For example, manufacturers can use LSFT results to justify reduced spacing between battery units—provided the data demonstrate fire and gas emissions do not cause hazardous propagation.
Interest in residential ESS is accelerating, with some developers exploring integration into traditional appliances like refrigerators and stoves. However, once the battery exceeds 1 kWh, it qualifies as an ESS and must meet applicable codes and be listed for use in habitable areas. Unfortunately, many new products entering the market do not yet meet these minimum safety requirements.
Commercial and Utility-Scale ESS
Commercial and utility-scale ESS can vary widely in size and application—from a small system supporting a server room to grid-scale installations serving entire communities. These systems may be housed in buildings or pre-manufactured enclosures (commonly referred to as “Conex” containers).
High-profile incidents like those at Moss Landing and the Gateway Energy Storage Facility in Otay Mesa, California, have illustrated the difficulty of mitigating building-based ESS fires. These incidents are making many question the large design due to the size of the failure if it occurs. As a result, many designers now prefer modular, enclosure-based ESS due to their improved containment and factory-controlled construction.
Regardless of the setting, critical safety parameters—such as unit separation, chemistry type, and system capacity—must comply with model codes and listing requirements. Certification to UL 9540 and UL 9540A testing help ensure each design’s suitability and fire safety performance.
These systems often include integrated fire suppression, fire detection, gas monitoring, and ventilation features to manage thermal runaway scenarios. The inclusion of such features is often required based on the LSFT results submitted during certification.
The ever-changing chemistry and configurations of ESS technology demand agility in codes and standards. The goal is to apply consistent minimum safety measures that reduce the likelihood and impact of potential incidents.
When ESS installations are provided, the location in a community can vary. Single units may be installed to support a single building, while another location could use 100 units to support the grid in the area. It is vital in both cases that the owner work with the local community as it relates to gaining approval through local zoning and planning as well as fire and building code requirements.
For many code officials, these systems can present large challenges during the plan review process, and submittals which include the necessary documentation is vital. What can separate these systems from other building items, is the complexity of the data submitted which can include the data from the largescale fire testing, as well as multiple reports from various designers and fire protection engineers.
One question that continually rises, the requirements around fire detection on pre-manufactured units. In many cases the system manufacturer installs the needed fire detection devices, panels, wiring, cable, etc, to support the system in a factory, and in some cases the equipment needs to be installed by a locally Licensed contractor. This can lead to some complications and should be established early in the project.
Not All Batteries Are ESS
It’s important to clarify that not all battery-related installations fall under ESS requirements. ESS codes apply only when installations meet the formal definition.
Many communities are seeing battery-related projects that don’t qualify as ESS, including laboratories, manufacturing sites, and retail storage. For example, a university might operate a battery test lab for EV applications, or a drone manufacturer might assemble lithium-ion cells. These types of facilities are not governed by ESS-specific provisions but rather fall under general fire safety codes.
In the US, the 2024 edition of the International Fire Code provides the most comprehensive and up-to-date requirements for batteries in the built environment, even if not yet formally adopted in all jurisdictions. It includes specialized sections addressing mobility devices and lithium-ion storage, and emphasizes fire detection, sprinkler protection, and emergency planning for high-risk battery operations.
In Canada, there are not yet specific requirements in the National Building Code and National Fire Code for large scale energy storage systems. Provincial and local building and fire officials may refer to the ICC and NFPA requirements and it is up to the Authority Having Jurisdiction to specify those requirements.
Conclusion
The continued evolution of energy storage systems presents exciting opportunities for both innovation and public safety. As homes and communities increasingly rely on battery storage—whether for grid resilience, renewable energy integration, or backup power—it’s clear that the role of fire alarm and life safety professionals has never been more important.
The fire alarm industry plays a pivotal role in supporting the safe deployment of ESS across residential, commercial, and utility sectors. From fire detection to emergency response integration, alarm systems are an essential layer of defense. By staying informed, embracing updated codes and standards, and promoting tested and certified technologies, our industry not only safeguards lives and property—it leads the charge into a more resilient and electrified future.
Share this article!