Washington Would Swap Prescriptive Battery Fire Code For NFPA 855 References As The Standard Drops Its 600 kWh Threshold

The Washington State Building Code Council has given a short rationale for amending Sections 1207.1 through 1207.13 of the state fire code: removing prescriptive model code requirements and replacing them with references to NFPA 855, “to increase clarity.”

That rationale sits in WSR 26-10-069, the rulemaking that adopts the 2024 International Fire Code in place of the 2021 edition under Chapter 51-54A WAC. The council has set an intended adoption date of August 28, 2026, with a statewide effective date of May 3, 2027 for all counties and cities.

Section 1207. This is where a state writes down what a battery installation owes: spacing, maximum quantities, fire-resistance ratings, ventilation, signage. Washington proposes taking its own sentences out of thirteen subsections and putting a citation in their place. A new Section 1207.14, together with an amended Section 1107, addresses operation and maintenance of systems carrying an operational permit. WAC 51-54A-0320 separately references NFPA 855 for lithium-ion and lithium metal battery storage.

The deleted number. NFPA 855 removed a threshold in the same cycle. Under the 2023 edition, a Hazard Mitigation Analysis attached to electrochemical storage once maximum stored energy exceeded 600 kWh. The 2026 edition removes that threshold, making the analysis the default for in-scope indoor and outdoor installations. Section 9.3.2 carves out lead-acid and aqueous nickel-based chemistries. For lithium-ion, the analysis attaches at every size.

Three failure cases. The 2026 analysis must model thermal runaway or mechanical failure of a single unit; failure of the energy management or protection system; and failure of thermal management, communications or the battery management system.

Three demonstrations go to the authority having jurisdiction alongside them: that deflagration hazards are mitigated, that an indoor fire stays inside the ESS room for the full duration of its fire-resistance rating, and that smoke and combustion products leave occupant egress clear. The edition also adds reliability and survivability analyses for explosion control, detection and suppression.

Small systems carry the overhead. A modest indoor commercial installation that previously cleared on prescriptive compliance now arrives at plan review with an engineered analysis. That is engineering hours and calendar time. The smaller the system, the larger that fixed overhead sits as a share of total project cost.

The same change rewards whoever already paid for test data. The named failure cases, single-unit thermal runaway and the loss of energy management, protection and battery management systems, are the scenarios a UL 9540A installation-level test report is built to document. A vendor holding cell, module and unit-level reports brings measured behavior into the analysis. A vendor holding a product listing and a datasheet starts from modeling assumptions that an authority having jurisdiction can question.

New York held its number. Section 1207 of the New York State Fire Code, adopted by the State Fire Prevention and Building Code Council on July 25, 2025 and effective January 1, 2026, keeps 600 kWh as the capacity at which lithium-ion systems pick up a Hazard Mitigation Analysis and UL 9540A large-scale fire testing, with third-party peer review required above established capacity thresholds. NFPA 855’s 2026 edition applies the analysis at any size. NYSERDA has written compliance with the January 2026 codes into the contracts for the eight bulk storage projects it awarded in September.

The practical result for a commercial building is a documentation split by state line. A 400 kWh indoor system in New York sits below the state’s analysis trigger. The identical system in a jurisdiction on the 2026 NFPA text carries the full engineered package. That is a real cost and schedule delta, and it is one that has to be priced per jurisdiction rather than assumed uniform across a national footprint.

Which edition gets named. Code references are ordinarily dated. A state that cites NFPA 855 (2023) inherits the 600 kWh threshold; a state that cites the 2026 edition inherits its absence. Washington’s final text is what settles the question, and the council’s amended Section 1207 language is the operative pointer.

What adoption by reference changes is who holds the pen. Under prescriptive state text, a threshold moves when a state code council votes on it, through a rulemaking proceeding with a comment docket and a public record. Washington is running that process now. Under a citation, the threshold moves when NFPA’s technical committee revises the standard on its own cycle, and the state’s remaining decision narrows to which edition to name and when to renumber.

For a code council tracking a hazard that is being characterized faster than any three-year state code cycle can absorb, that is a coherent trade. It also means the substantive storage rules for Washington commercial buildings would be drafted inside NFPA’s committee process, with the state choosing a vintage.

The rulemaking’s intended adoption date is August 28, 2026. The code reaches every county and city in the state on May 3, 2027.

Sources