California’s Storage Trade Association Says Containerized Batteries Are Safer Than Building-Based Designs

Four. That is the number of cases Scott Murtishaw, executive director of the California Energy Storage Alliance, said he could find in which fire spread from one battery container to a second, across more than 1,000 utility-scale containerized projects worldwide. In none of them, he said, did fire reach a third container.

Murtishaw made the claim in an August 24 interview with Energy-Storage.News, in which he described containerized battery energy storage designs as significantly safer than indoor, building-based configurations. He named safety concerns and local opposition as the industry’s single largest barrier. He also set out the scale California has reached: a storage fleet of roughly 21,000 MW, against under 1,000 MW before 2020, and no Flex Alerts since capacity passed 4,000 MW in 2022.

The state trade group representing storage developers has made deployment format the organizing frame of its public safety case.

The denominators. Container-to-container spread is a metric that exists only where there are containers. It counts one specific failure mode, propagation between separated outdoor enclosures, across a fleet large enough to produce a clean fraction.

There is no matching fraction on the other side of the comparison. The failure mode being measured does not have an obvious analogue inside a single fire-rated room, and the interview does not supply an indoor project count, an indoor incident count, or an indoor spread rate against which the container figure could be read.

Read as an engineering argument rather than an advocacy one, the two halves of the comparison are not measured on the same axis.

The word “indoor.” California’s front-of-the-meter fleet and a cabinet-scale or wall-mounted system in an occupied commercial building sit in different size classes, under different code sections, with different compensating measures. Collapsing both into “building-based design” is the move worth watching, because it is the version that travels. A sentence in a trade interview reaches a city council packet or an insurance underwriting file faster than a code cycle does.

The threshold that disappeared. Under prior editions of NFPA 855, a hazard mitigation analysis was triggered above 600 kWh. Code Red Consultants and Telgian both report that the 2026 edition removes that trigger, so a hazard mitigation analysis is required for any indoor or outdoor energy storage system within the standard’s scope.

The 2026 edition also adds a documented emergency response plan covering mitigation, preparedness, response and recovery, an annual review of that plan, and an annual refresher training programme for facility personnel. Those obligations attach to the facility and its staff rather than to the installer, and they recur every year for the life of the installation.

The direction of the change is away from a size test and toward a documentation test. A system does not qualify by being small, and it does not disqualify by being indoors. It qualifies by producing an analysis, a plan and a training record that an authority having jurisdiction can review.

Where the safety systems get their power. Section 4.10 of the 2026 edition covers emergency power supply systems and stored emergency power supply systems, requiring that critical safety systems be fed by reliable power in accordance with NFPA 110 or NFPA 111. Section 4.10.22 requires that the design be made available to the fire protection engineer of record and to the authority having jurisdiction for review and approval.

Detection and ventilation controls that go dark when the grid drops become a reviewable design deficiency rather than an unexamined assumption. For any installation relying on mechanical ventilation as a compensating measure, that is the operative line, and it applies to outdoor equipment drawing on building services as much as to a room inside the envelope.

Two editions inside eighteen months. The 2024 International Fire Code still references the 2023 edition of NFPA 855, so the governing edition varies by jurisdiction and has to be confirmed with the authority having jurisdiction on a per-permit basis. California is moving to pull the 2026 edition into its fire code effective July 1, 2027, with the State Fire Marshal’s SB 283 building-code proceeding open in the interim.

That produces a boundary rather than a transition. Projects permitted in a 2023-edition jurisdiction fall under a threshold-based regime, in which an installation below 600 kWh may avoid a hazard mitigation analysis entirely. Projects permitted under the 2026 edition fall under an analysis-based one. Developers underwriting California pipeline across that date are underwriting two different compliance products, and developers working across state lines are underwriting both at once.

The incidents shaping fire-marshal intuition. Falls Township Fire Marshal Rich Dippolito said a lithium-ion battery may have started a 1:37 a.m. fire on August 22 in the office area of a commercial building on Newbold Road in Bucks County, Pennsylvania. The fire was discovered by automatic alarm and drew six mutual-aid departments. No injuries were reported, and the cause remains under investigation.

No stationary storage system appears anywhere in that account. Loose cells, device packs and micromobility batteries sit outside the scope of NFPA 855, and the officials writing those reports are the same officials reviewing storage permits. The working mental model of “lithium battery in an office” is being formed by incidents in which no listed energy storage system is present.

Two arguments, one permit desk. The advocacy case and the code case point in different directions. One holds that the safe configuration is the one in the yard. The other holds that the safe configuration is the one whose hazard mitigation analysis, emergency response plan, training record and backup power for detection and suppression have been documented and submitted for review.

Only the second produces a document an authority having jurisdiction can hold a designer to, and only the second survives a change in deployment format.

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