The 240-Minute Fire Wall: Why FRNSW's New Battery Room Rule Might Be Coming to the US

Fire and Rescue New South Wales (FRNSW) has taken a position that could change how data centers think about lithium-ion UPS battery rooms. Effective June 3, 2026, the Australian fire authority stated that battery storage rooms supporting data center uninterruptible power supplies should be separated from the rest of the building with fire-rated construction. Its preferred performance level is an FRL of 240/240/240 for load-bearing elements and -/240/240 for non-load-bearing elements.

In practical terms, that is a four-hour fire-resistance target. It applies to the room’s bounding construction: walls, floors, ceilings, and associated assemblies: not only to a single wall. FRNSW also recommends sprinkler protection for lithium-ion energy storage system groups above 50 kWh, with sprinkler design supported by representative large-scale fire testing or applicable international standards.

The position applies in New South Wales, not automatically across the United States. However, it provides an important signal for US facility managers: as lithium-ion batteries become more common in data center UPS systems, fire authorities and Authorities Having Jurisdiction (AHJs) are likely to demand more evidence that battery rooms can contain thermal runaway, toxic gases, heat release, and re-ignition risks.

What FRNSW Is Actually Requiring

The FRNSW position statement, “Lithium-ion batteries and diesel generators in data centres,” focuses on two growing risks: lithium-ion UPS batteries installed indoors and large diesel generator structures with vertically stacked generators or fuel tanks.

For lithium-ion battery rooms, the key provisions are:

• Fire-rated separation from the remainder of the data center.
• A preferred FRL 240/240/240 for load-bearing construction.
• A preferred -/240/240 for non-load-bearing construction.
• No support for reducing the fire-resistance level to lower construction costs.
• Sprinkler systems for ESS groups above 50 kWh, where the design is supported by appropriate fire testing or standards.
• Fire protection planning that considers the actual battery chemistry, capacity, cabinet configuration, room arrangement, and ventilation strategy.

An FRL rating is expressed in minutes for three performance characteristics: structural adequacy, integrity, and insulation. A 240/240/240 rating means the load-bearing assembly is expected to maintain all three characteristics for 240 minutes under the relevant fire test conditions.

That does not mean a battery fire will be harmless after four hours. It means the enclosure is designed to preserve its fire-resistance performance for that period, giving occupants and emergency responders more time to evacuate, isolate systems, establish a defensive strategy, and prevent fire spread to the data hall.

FRNSW’s concern is partly based on the limitations of existing test evidence. Its statement notes that UL 9540A cell-, module-, and unit-level tests do not, by themselves, represent every credible scenario for a battery energy storage system installed inside a room. A fire in an enclosed compartment can behave differently from a test conducted outdoors because hot gases, radiative feedback, and surrounding surfaces may accelerate fire growth.

Why This Matters to US Data Centers

The United States is not starting from zero. NFPA 855, the Standard for the Installation of Stationary Energy Storage Systems, already establishes a framework for stationary energy storage safety. The standard becomes enforceable when adopted by a local or state jurisdiction, often through the International Fire Code or NFPA 1.

Technical summaries of NFPA 855 provisions commonly point to a 2-hour fire-rated separation for lithium-ion ESS rooms in occupied buildings, along with minimum cabinet clearances, grouping limits, and fire-area energy limits. Depending on the adopted edition, system design, and AHJ interpretation, facilities may also need to address:

• Lithium-ion ESS thresholds above approximately 20 kWh.
• A dedicated battery or ESS room separated from data halls.
• Approximately 3 feet of clearance between cabinets, groupings, and adjacent walls unless testing supports an alternative.
• Energy limits per cabinet, grouping, or fire area.
• Hazard Mitigation Analysis (HMA).
• Explosion control and gas management.
• Large-scale fire testing and UL 9540A documentation.
• Detection, suppression, emergency shutdown, and firefighter access.

These requirements are not interchangeable with the FRNSW position. A US project must follow the codes adopted by its AHJ. But the direction is clear: a battery room is increasingly being treated as a distinct fire compartment, not simply another equipment area inside the electrical room.

Why Now: The Status Quo Is Failing

Thermal Management Is Becoming a Fire-Safety Issue

Lithium-ion batteries offer important operational advantages. Compared with traditional valve-regulated lead-acid batteries, lithium-ion UPS systems can provide longer service life, lower maintenance demands, higher usable energy density, and improved monitoring.

They also introduce a different hazard profile. Thermal runaway can generate intense heat, flammable gases, toxic smoke, and the possibility of re-ignition. As battery cabinets become more energy-dense, the consequences of placing multiple systems in a poorly separated room increase.

Thermal Management therefore has two meanings. Facility managers must control normal operating temperature to protect battery life, but they must also design for abnormal heat release and gas accumulation during a failure.

Redundancy Can Increase the Fire Load

Data centers are built around Redundancy. Tier III facilities are designed for concurrent maintainability, while Tier IV facilities require fault tolerance. UPS architectures commonly use N+1, 2N, or distributed redundant configurations.

That reliability model can place more batteries on site. A facility may have separate A and B power paths, independent UPS modules, and extended runtime cabinets for generators to start or for critical loads to execute an orderly transition. Electrically, that improves resilience. From a fire-protection perspective, it can increase the amount of stored energy within a building.

Redundancy must therefore be evaluated across both electrical and life-safety systems. A second UPS path does not eliminate the need for adequate room separation, fire detection, ventilation, emergency procedures, or service access.

Latency Has a Physical Cost

AI workloads and high-density computing are increasing power demand and reducing operational tolerance for interruptions. A brief power event can create application Latency, storage errors, network instability, or a cascading restart across multiple systems.

Modern data halls may support rack densities from approximately 10 to 30 kW per rack, with specialized AI deployments reaching substantially higher levels. As power density grows, UPS systems must provide clean, continuous power while cooling systems manage rising heat loads.

The result is a more tightly coupled infrastructure environment. Electrical, mechanical, fire, and controls systems cannot be planned independently. Power protection is now a facility-wide resilience discipline.

The Battery-Room Roadmap

Facility managers do not need to wait for a new local rule to begin preparing. These five steps can be taken today.

1. Build a complete battery inventory

Document every UPS battery system, including chemistry, manufacturer, model, voltage, amp-hour capacity, total kWh, installation location, age, and enclosure type. Include external battery packs and cabinets that may not appear on the primary UPS schedule.

Separate lithium-ion systems from lead-acid systems. Their maintenance requirements, monitoring capabilities, ventilation considerations, and fire-risk assessments are different.

2. Calculate energy by room, grouping, and fire area

Do not evaluate a battery installation only by UPS kVA. Calculate stored energy in kWh and map how that energy is distributed across rooms and cabinets.

Identify whether a room exceeds 50 kWh, the threshold highlighted by FRNSW for sprinkler design consideration, and whether the installation may exceed energy limits under the locally adopted NFPA 855 or IFC provisions. If the facility has multiple cabinets in one room, document spacing between cabinets and from walls.

3. Review the room envelope and penetrations

Ask a qualified fire-protection engineer to review the walls, floor, ceiling, doors, cable penetrations, ventilation openings, drains, and service bypass paths around the battery room.

A rated wall is only as effective as its weakest penetration. Cable trays, conduit, dampers, access doors, and monitoring connections must be compatible with the required fire-resistance assembly. If a new project is being designed, reserve enough space for fire-rated construction, access clearances, ventilation, and maintenance.

4. Request installation-specific test evidence

Ask the UPS and battery manufacturers for UL 9540A results, large-scale fire test data, safety data sheets, battery management system documentation, and recommended suppression criteria.

The evidence should match the actual installation. A test on a single cabinet in an open-air environment may not represent multiple cabinets inside a compartment. Confirm whether the documentation covers the same chemistry, cabinet arrangement, energy capacity, spacing, and ventilation conditions proposed for the facility.

5. Connect power monitoring with fire and facility operations

Remote monitoring should report more than UPS load percentage. Track battery temperature, state of charge, state of health, cell or module alarms, cabinet door status, smoke detection, room temperature, and ventilation status.

Integrate alerts into the facility’s incident response process. A battery alarm should identify the affected cabinet, define the required escalation, and provide safe shutdown or isolation procedures where supported. Platforms such as EcoStruxure IT and other remote monitoring solutions can help create the operational visibility needed for modern Real-Time Solutions.

Designing for Reliability Without Creating New Risk

The answer is not to abandon lithium-ion UPS technology. The technology can support higher efficiency, reduced maintenance, and improved space utilization. The answer is to design the full power-protection system around the battery’s actual risk profile.

Start with the load. Specify the required UPS capacity, runtime, power factor, bypass arrangement, and redundancy model. A 500 kW critical load with a 2N UPS design has different battery and fire-protection requirements than a 50 kW network room with a single modular UPS.

Then evaluate efficiency and heat. Modern UPS systems may achieve efficiency above 96% in high-efficiency operating modes, with some systems approaching 99% under specific conditions. Efficiency reduces operating losses, but it does not eliminate the need for thermal monitoring or emergency planning.

Finally, coordinate the electrical design with construction and fire protection. Battery rooms should be accessible for replacement, isolated from critical data hall operations, and designed with clear paths for emergency responders. The goal is not merely to keep equipment online during an outage. It is to maintain continuity while protecting personnel, adjacent systems, and the building itself.

Ace Real Time Solutions helps businesses and data center operators design, install, monitor, and maintain power protection systems using trusted manufacturers including APC by Schneider Electric, CyberPower, Vertiv, and Minuteman Technologies. Our services cover UPS systems, batteries, IT racks, power distribution, cable management, cooling considerations, remote monitoring, and lifecycle support.

Review our power protection services, explore APC products and services, or review available UPS batteries and extended battery packs. For a project-specific assessment, visit acerts.com to request a power audit, solution design, or technical specification review.

FAQ

What is the FRNSW 240-minute battery room rule?

The FRNSW position effective June 3, 2026, states that lithium-ion battery rooms supporting data center UPS systems should be separated from the remainder of the building with fire-rated construction. FRNSW’s preferred target is an FRL of 240/240/240 for load-bearing construction and -/240/240 for non-load-bearing construction.

How does the FRNSW position affect US data centers?

It does not automatically create a US legal requirement. US facilities must follow the codes adopted by their local AHJ. However, the position may influence future code interpretation and design expectations, particularly as US data centers expand lithium-ion UPS installations. Facility managers should review NFPA 855, the IFC, local amendments, and project-specific fire engineering requirements.

How does a facility manager prepare a lithium-ion UPS battery room?

Start by inventorying battery chemistry and stored energy, calculating kWh by room and fire area, reviewing fire-rated construction and penetrations, obtaining installation-specific UL 9540A or large-scale fire test evidence, and integrating battery alarms with remote monitoring and emergency response procedures. Engage the AHJ and qualified fire-protection professionals before finalizing the design.