Angelo Zandona Shares Proven Expertise on Advancing Safer BESS Site Design

Introduction

Angelo Zandona says Lithium-ion battery cells can reach internal temperatures above 800°C during thermal runaway, with some experiments recording positive electrode temperatures as high as 1,082°C at full state of charge. Once these temperatures are reached, no traditional fire suppression method can stop the reaction. The cells must burn themselves out. The U.S. has added more than 40 gigawatts of battery storage to the grid in just five years, with cumulative capacity expected to top 50 GW by the end of 2026.

Angelo Zandona, founder of Keystone Fire Consultants and a fire and life safety expert with more than two decades of experience designing mission-critical facilities, helps clients embrace a truth the rest of the industry is only beginning to accept. Lithium-ion battery fires are fires that must be planned for. This article explains why that is, and what it means for site design.

The Science of Thermal Runaway

Thermal runaway is a chain reaction inside a battery cell. It begins when a cell is exposed to heat, mechanical damage, electrical abuse, or internal defect. Once the cell reaches a critical temperature, usually between 150°C and 220°C, the separator inside the cell begins to melt. The two electrodes touch. An internal short circuit forms. Heat builds rapidly.

The cathode then breaks down and releases oxygen. That oxygen feeds the reaction from inside the cell itself. A lithium-ion fire brings its own oxygen. Smothering it does nothing. Within seconds, the cell vents a cloud of flammable gases. These include hydrogen, carbon monoxide, methane, and traces of hydrogen fluoride. If the gas cloud finds an ignition source, the result is an explosion. If it does not, the cloud waits.

Why Water and Gas Suppression Fail

Standard fire suppression is built around three ideas. Cool the fuel. Remove the oxygen. Interrupt the chemical reaction. None of these work cleanly on a battery fire. Water can cool the outer casing of a battery enclosure. It can protect nearby structures. But it cannot reach the cells inside fast enough to stop the runaway, and it cannot stop the cathode from releasing its own oxygen. Worse, water exposed to high-voltage battery components can create an electrical hazard for responders.

Clean-agent gas systems, often used in data centers, simply do not work. They displace oxygen from the air, but the battery does not need air. It is generating oxygen inside the cell.

This is why responders at the Moss Landing fire in California in January 2025 were forced to let the fire run its course, and why the May 2024 Gateway facility in San Diego saw flare-ups for seven days after the initial event.

The “Let It Burn” Philosophy

Modern BESS fire strategy is built around containment. The goal is to keep the fire inside the unit where it started, protect adjacent units and structures from heat damage, and prevent toxic smoke from reaching populated areas.

This is the framework Angelo Zandona and the team at Keystone Fire Consultants bring to every EPC and project owner they advise. The design question is how to make the fire safe to burn. That changes everything about how a site is laid out.

How Site Design Changes

Spacing comes first. Battery containers must sit far enough apart that a fire in one unit will not cascade to its neighbors. UL 9540A testing has shown that exposed surfaces of nearby containers can rise sharply during a fire event, so setback distances are now calculated from measured heat flux data rather than rules of thumb. Deflagration venting is the second pillar. Under NFPA 68, enclosures are designed to release pressure from off-gas explosions in a controlled direction, away from people and equipment. NFPA 69 explosion prevention systems, including gas detection and ventilation, give first responders time to clear the area before any ignition.

Exposure protection matters next. Adjacent buildings, transformers, fuel tanks, and transmission lines must be far enough away, or shielded with rated walls, that radiant heat from a burning container will not cause secondary damage. Water supply planning rounds out the picture. Even though water cannot extinguish the battery fire, large volumes are needed to cool surrounding units and structures. Site water supply analysis often drives the layout of storage tanks, hydrants, and access roads.

The Numbers Behind the Risk

The risk is real but, importantly, declining. The Electric Power Research Institute (EPRI) has tracked about 90 publicly reported grid-scale BESS fire incidents since the first utility-scale system was installed in 2012. Analysis by EPRI, TWAICE, and Pacific Northwest National Laboratory found a 97% drop in failure rates per gigawatt deployed between 2018 and 2023.

Texas, California, and Arizona will account for roughly 80% of new U.S. battery storage capacity in 2026. That concentration means hundreds of new sites will be permitted in jurisdictions with active and engaged fire authorities.

What This Means for AHJs and Planners

Authorities Having Jurisdiction now expect a fire-safety case built from physics rather than from prescriptive code alone. That case begins with a Hazard Mitigation Analysis under NFPA 855, and is supported by UL 9540A test data, emergency response planning, and water supply calculations.

Architects and EPCs who treat fire safety as a late-stage permitting hurdle frequently discover that they need to expand the site, add walls, or move equipment after the design is locked in. The cost of those late changes is far higher than building fire science into the master plan from day one.

This is the daily work at Keystone Fire Consultants, where Angelo Zandona and his team translate the messy reality of battery fires into clean, defensible documentation that AHJs confidently approve and insurers comfortably underwrite.

Conclusion

Battery fires are not going away. The chemistry is the chemistry, and the only honest design response is to plan for the worst credible event and engineer the site to handle it safely.

Spacing, venting, exposure protection, and water supply are not separate checklists. They are a connected fire-safety system that begins at the site-planning stage. Projects that get this right move through permitting cleanly, satisfy insurers, and earn the trust of the communities around them.

For developers, architects, and AHJs navigating this new generation of energy storage projects, Angelo Zandona and Keystone Fire Consultants says that the right expertise applied early, these sites can be safe, permittable, and community-ready. Plan for the burn. Build for containment. And start that planning before the first container hits the ground.

FAQs

Why can’t lithium-ion battery fires be extinguished with water?

ANS: Once a cell enters thermal runaway, it generates its own oxygen internally as the cathode breaks down. Water can cool the outer enclosure but cannot reach individual cells fast enough to stop the reaction, and the oxygen problem makes traditional suppression ineffective.

What temperatures are involved in a battery fire?

ANS: Cells can reach internal temperatures above 800°C, with peak measurements over 1,000°C at full state of charge. These temperatures damage surrounding equipment and create radiant heat hazards for nearby structures.

How is “let it burn” different from doing nothing?

ANS: A let-it-burn strategy still requires active containment. Crews protect adjacent units with water, monitor air quality, manage off-gas dispersion, and prevent secondary ignition. The fire itself is allowed to consume the affected unit safely.

What is deflagration venting?

ANS: It is a designed weak point in an enclosure that releases pressure from a gas explosion in a controlled direction. NFPA 68 governs the calculation. Without venting, an off-gas ignition could damage the entire container or harm responders.

How are setback distances determined?

ANS: Setbacks are calculated using measured heat flux and flame spread data from UL 9540A large-scale fire tests. Each container design has its own data, which is why one-size-fits-all spacing rules no longer apply.