New NYC Department of Buildings Rules Set Comprehensive Standards for Energy Storage Systems
The New York City Department of Buildings (DOB) has finalized two significant new rules regulating the design, installation, operation, and decommissioning of energy storage systems (ESS) throughout the city. These rules, effective October 26, 2025, mark the first time the DOB has directly addressed indoor ESS installations and expand regulatory oversight beyond existing FDNY requirements.
The new rules are codified at Section 101-19 and Section 3616-07 of Title 1 of the Rules of the City of New York (RCNY). Together, they establish a uniform permitting framework aligned with national safety standards while incorporating city-specific modifications tailored to New York City's dense urban environment.
Section 101-19: Comprehensive Regulatory Framework for ESS
The newly adopted Section 101-19 sets forth DOB’s requirements for the safe design, filing, construction, commissioning, operation, maintenance, decommissioning, and registration of ESS. It applies to:
- Indoor ESS installations exceeding threshold capacities defined in the modified version of NFPA 855.
- Outdoor ESS installations that exceed FDNY capacity thresholds.
- All ESS installed at one- and two-family dwellings, regardless of size.
Key components of Section 101-19 include:
- Mandatory peer review of most site-specific ESS installations by New York State-licensed engineers with fire protection experience.
- Submission of technical design documents, zoning analyses, and flood-resistant construction evidence.
- A two-step DOB acceptance process, including issuance of a Conditional Acceptance Letter before permit approval and a Final Acceptance Letter following certification.
- Prohibition on operation until DOB issues either a Letter of Completion or a new Certificate of Occupancy, where applicable.
- Required registration of all new ESS prior to operation, with existing systems subject to a registration deadline of October 2028.
Section 101-19 also requires that most installations incorporate an Energy Storage Management System (ESMS) when triggered by the Fire Code or FDNY rules. The ESMS must monitor system performance and maintain parameters within manufacturer specifications.
Section 3616-07: NYC Adoption of Modified NFPA 855 Standard
The companion rule, Section 3616-07, formally adopts a NYC-modified version of the National Fire Protection Association (NFPA) 855 – Standard for the Installation of Stationary Energy Storage Systems. This Modified NFPA 855 standard lowers capacity thresholds that trigger compliance, imposes stricter siting and fire safety requirements, and reflects alignment with current and forthcoming FDNY Fire Code updates.
Notable provisions include:
- Adoption of capacity thresholds as low as 1 kilowatt-hour (kWh) for lithium-ion systems, substantially below the national NFPA 855 standard.
- Mandatory use of UL 9540 and UL 9540A standards for safety certification and thermal runaway fire testing, respectively.
- Prohibition on below-grade ESS installations or those within flood-prone areas, unless specifically approved.
- Additional safety requirements for indoor installations, including fire separation, sprinkler protection under NFPA 15, and restricted access to dedicated ESS rooms.
For residential applications at one- and two-family homes, the Modified NFPA 855 provides detailed limits on ESS siting and cumulative capacity. For example, installations are limited to 80 kWh per lot, with further restrictions on garage and exterior mounting locations. Certain systems are exempt from site-specific peer review if they have obtained an FDNY Certificate of Approval and otherwise comply with DOB standards.
Implications for Developers, Building Owners, and Installers
FDNY and DOB have been leaders in guiding regulations, ensuring safe ESS installation and operation. The new rules present their first foray into indoor storage, opening up significant additional ESS opportunities. These new DOB rules provide a permitting and safety framework for energy storage systems in New York City. They offer clarity for developers and building owners integrating ESS in support of decarbonization goals (and legal mandates), while aligning with broader city and state efforts to electrify buildings and support renewable energy adoption.
Stakeholders planning to install new ESS or retrofit existing systems should consult with experienced engineers and permitting professionals to ensure compliance with both DOB and FDNY requirements. The DOB’s adoption of national safety standards, modified for local conditions, creates a clear regulatory pathway but imposes significant documentation, certification, and safety obligations.
For More Information
If you have questions on permitting ESS, contact Jenna Rackerby, Daniel Spitzer, Charles Malcomb, Alicia Legland, or a member of our Renewable Energy Practice. The full text of the adopted rules is available here:
Disclaimer: This client alert is a form of attorney advertising. Hodgson Russ LLP provides this information as a service to its clients and other readers for educational purposes only. Nothing in this client alert should be construed as, or relied upon, as legal advice or as creating a lawyer-client relationship.