New FRNSW BESS Fire Safety Guidance: A Guide for Projects by Omnii

As investment in Battery Energy Storage Systems (BESS) continues to grow across Australia, lithium-ion battery energy storage fire safety is becoming an increasingly important consideration during project planning and development, particularly for large-scale BESS fire safety and the BESS fire risk assessment work that underpins development approval.

Fire and Rescue NSW (FRNSW) has revised its Technical Information Sheet for large-scale external lithium-ion battery energy storage systems (LiBESS), providing clearer expectations for projects that require a Fire Safety Study (FSS) as part of the development consent process.

The guidance addresses the specific electrical, chemical and fire risks associated with large-scale BESS and provides direction on how those risks should be assessed and managed throughout the design, installation and ongoing operation of a facility.

For developers, asset owners, engineers, BESS suppliers and project teams, the message is clear: fire safety needs to be considered early, supported by project-specific evidence and integrated into the overall site design.

Which BESS projects does the FRNSW guidance apply to?

The Technical Information Sheet applies to large-scale BESS located externally rather than within a building, typically installations supporting or augmenting grid power supply, including renewable energy developments.

It is also important to distinguish the guidance from a blanket requirement for every BESS project to undertake a Fire Safety Study.

Under the State Environmental Planning Policy (Resilience and Hazards) 2021, the consent authority can impose a condition requiring an FSS to be prepared in accordance with Hazardous Industry Planning Advisory Paper No. 2 (HIPAP No. 2) – Fire Safety Study Guidelines. Where an FSS is required for a large-scale external BESS facility, FRNSW advises that its Technical Information Sheet should be used in preparing the study.

FRNSW also identifies the Technical Information Sheet as one of the guidance materials applicable to its Fire Safety Study process. (Fire and Rescue NSW)

What does FRNSW expect a BESS Fire Safety Study to address?

Engineer reviewing fire risk assessment documentation for a BESS facility

The updated guidance goes considerably further than identifying the presence of lithium-ion batteries alone.

An FSS needs to demonstrate how credible BESS incidents have been identified, how their consequences have been assessed and how the proposed fire safety strategy will prevent an incident from escalating across the site.

1. A credible incident includes a full BESS enclosure fire

One of the most significant points in the guidance is FRNSW’s definition of a credible BESS incident.

For assessment purposes, FRNSW considers a credible incident to include fire propagating within a BESS enclosure with active fire safety systems disabled and ultimately involving the full enclosure. The ability of the enclosure and site design to contain that event is then expected to be demonstrated through large-scale fire testing.

The consequence assessment must also look beyond the BESS itself.

Potential propagation and secondary incidents need to be considered, together with chemical releases, toxic firefighting water run-off and credible incidents involving associated infrastructure such as transformers, inverters, substations, ring main units and renewable energy generation equipment. The assessment should also be based on the specific batteries proposed for the project, rather than a generic battery technology.

For project teams, this reinforces the importance of resolving equipment selection and obtaining appropriate technical data early enough to properly inform the fire strategy.

2. Large-scale fire testing becomes critical evidence

Full-scale fire test rig on a lithium-ion BESS enclosure with monitoring equipment

Large-scale fire testing (LSFT) is central to the FRNSW approach.

The Technical Information Sheet states that testing should demonstrate the effectiveness of the proposed fire safety strategy under a credible fire scenario. This includes testing involving the full BESS enclosure with active fire protection measures disabled.

Among other requirements, testing is expected to:

  • characterise the types and quantities of gases generated;
  • evaluate deflagration or explosion mitigation measures;
  • demonstrate that fire will not propagate from one BESS enclosure to another; and
  • be undertaken or witnessed and reported by an approved testing laboratory independent of the battery manufacturer or supplier.

Environmental conditions also matter. FRNSW requires effects such as wind and flame tilt to be assessed, with any supplementary modelling appropriately justified and calibrated against large-scale fire testing.

This means relying solely on nominal manufacturer separation distances or generic test information may not provide the level of evidence needed for a particular project configuration.

3. Separation distances need to be demonstrated, not assumed

Site plan showing separation distances between BESS enclosures and adjacent infrastructure

The fire safety strategy is expected to show that a credible incident can be contained to its compartment of origin without propagating to:

  • adjacent BESS enclosures;
  • transformers and inverters;
  • ring main units;
  • substations;
  • renewable energy infrastructure;
  • ancillary buildings; or
  • other fire-source features.

The assessment also needs to work in the opposite direction: a fire involving surrounding infrastructure should not be capable of propagating into the BESS.

The appropriate separation therefore depends on the proposed system, site configuration and supporting evidence rather than being treated solely as a standard layout dimension.

Managing Toxic Smoke and Firewater Risks: Guidance from Omnii

Smoke plume dispersion and firewater containment considerations near a BESS site

Thermal runaway is not only a fire propagation issue.

FRNSW requires consideration of the potential generation of a toxic smoke plume and its effect on surrounding communities, neighbours, passers-by and emergency responders under credible worst-case scenarios.

Management of contaminated firefighting water must also be considered. Where containment is connected to a reticulated stormwater system, the guidance calls for provision to automatically isolate that system when an associated fire safety measure operates.

These requirements highlight why BESS fire safety cannot be addressed solely at the individual battery enclosure level. Site drainage, environmental controls, civil design and surrounding land uses can all influence the overall fire strategy.

5. Detection and protection systems need evidence behind them

Automatic fire detection and suppression system components installed on a BESS enclosure

Where fire detection or protection measures are relied upon, FRNSW expects the Fire Safety Study to demonstrate their suitability and effectiveness.

The guidance states that systems relied upon as part of the fire safety strategy should generally operate automatically, with evidence demonstrating that individual measures and the collective system can continue performing for the required duration of an incident. Appropriate redundancy should also be provided.

Importantly, an internal fire suppression system is expected to be validated against testing involving the BESS enclosure.

FRNSW also specifically notes that gaseous or dry-powder extinguishing agents do not stop thermal runaway and may result in accumulated flammable gases within an enclosure, increasing explosion risk.

This is a key distinction for BESS projects: providing a suppression system does not, by itself, demonstrate that the fire risk has been adequately addressed.

6. Fire brigade intervention needs to be designed into the facility

Firefighters and vehicles accessing a BESS compound during an emergency response drill

Emergency response is another major component of the updated guidance.

Large-scale BESS present both electrical and chemical hazards. FRNSW notes that firefighters may be unable to enter an affected area until an appropriate electrical representative has attended the site and confirmed that power has been isolated.

The site design therefore needs to consider practical emergency response requirements including:

  • fire brigade vehicle and firefighter access;
  • electrical and chemical hazard signage;
  • hydrant positioning and coverage;
  • isolation arrangements;
  • firefighting water availability; and
  • safe access to site information and controls.

A specific change for DC-coupled BESS

One of the notable changes in the July 2026 revision relates to DC-coupled BESS installations adjacent to renewable energy generation infrastructure.

FRNSW recommends that a firefighting water supply be provided for each BESS compound or cluster of enclosures. It should be readily accessible to firefighters and capable of supporting defensive firefighting operations, including exposure protection for adjacent BESS enclosures, transformers, power conversion units and other associated infrastructure.

FRNSW specifically identified this as a new requirement when announcing the revised Technical Information Sheet on 3 July 2026. (Fire and Rescue NSW)

This requirement has the potential to influence site planning, hydraulic infrastructure and project cost, making it an important consideration during early design rather than something to resolve late in development.

7. Emergency planning extends beyond the initial fire event

Emergency plan documentation and site contact information for a BESS facility

A compliant BESS fire strategy does not end when the physical fire protection systems have been designed.

FRNSW expects an emergency plan to be developed in accordance with HIPAP No. 1 – Emergency Planning.

Among other matters, the plan should address:

  • notification of abnormal battery operation or faults;
  • automatic notification of fire services where applicable;
  • communication with remote operators;
  • attendance by appropriately qualified site representatives;
  • provision of real-time battery information to emergency services;
  • gases and other hazards associated with a fire;
  • extinguishing agents that should be used or avoided;
  • contaminated firefighting water; and
  • post-incident monitoring and management, including potential re-ignition.

An Emergency Services Information Package (ESIP) should also provide responders with information including site layouts, firefighting systems, water supplies, shutdown equipment, PPE requirements, firewater containment arrangements, site hazards and a 24/7 site contact.

What does this mean for developers and BESS project teams?

Project team reviewing BESS site layout and fire strategy planning documents

The updated FRNSW guidance reinforces the value of addressing BESS fire risk before layouts and equipment selections become difficult or costly to change.

For projects requiring a Fire Safety Study, key questions should be resolved as early as practicable:

Is suitable LSFT data available for the exact BESS configuration being proposed? Testing can directly affect separation distances, fire protection measures and the overall viability of a proposed layout.

Does the site provide sufficient separation and emergency access? BESS spacing should be informed by credible incident assessment and fire testing rather than considered only after the site arrangement has been established.

Is the firefighting water strategy adequate? Hydrant infrastructure, water supply, defensive firefighting requirements and contaminated run-off can have significant implications for site civil and hydraulic design.

Have the surrounding hazards been considered? Transformers, substations, renewable generation equipment and other infrastructure form part of the overall risk assessment.

Can the proposed emergency response actually be implemented? Isolation, remote monitoring, responder access, emergency information and appropriately qualified personnel all need to work together during an incident.

Addressing these matters early can reduce redesign and provide a stronger evidence base for consultation with the relevant authorities.

BESS modifications can also trigger further assessment

Technician replacing a battery module during a BESS maintenance upgrade

Fire safety considerations continue throughout the life of the asset.

Under the FRNSW guidance, battery modules should be replaced with modules identical to those represented by the applicable large-scale fire testing. A different battery type or chemistry should not be retrofitted without appropriate LSFT demonstrating that the existing fire safety strategy remains effective.

Where upgrades or modifications are proposed, FRNSW also calls for an updated Fire Safety Study or addendum report to be submitted for review, supported by relevant assessment and test evidence.

This makes configuration management important not just during development, but throughout the operational life of a BESS facility.

How Omnii can help with BESS Fire Safety Studies

Omnii fire engineers consulting on a large-scale BESS fire safety strategy

Large-scale BESS projects sit at the intersection of fire protection, hazardous processes, electrical infrastructure, emergency response and risk engineering.

Omnii’s Special Hazards team can support project teams in developing a Fire Safety Study and associated fire strategy that responds to the latest FRNSW expectations, including:

  • BESS fire hazard and consequence assessments;
  • review and interpretation of large-scale fire test data;
  • BESS separation and fire propagation assessments;
  • firewater and fire hydrant strategy;
  • fire detection and protection system assessment;
  • emergency response and fire brigade intervention considerations;
  • contaminated firewater and site interface considerations; and
  • coordination with the broader multidisciplinary project team.

Early involvement is particularly valuable, allowing the fire strategy to inform equipment selection, BESS layout, separation, access and firewater infrastructure before the project design becomes constrained.

Planning, designing or assessing a large-scale BESS project? Talk to Omnii’s Special Hazards team about preparing your Fire Safety Study and developing a practical fire safety strategy for your facility.

Frequently Asked Questions

Does every BESS project in NSW require a Fire Safety Study?

No. The FRNSW Technical Information Sheet applies where a Fire Safety Study is required as part of development consent for a large-scale external BESS facility. The consent authority may impose this requirement under the State Environmental Planning Policy (Resilience and Hazards) 2021.

What is large-scale fire testing for a BESS?

Large-scale fire testing assesses the behaviour of a BESS under a significant fire scenario. FRNSW expects testing relevant to the proposed fire strategy to assess matters including full-enclosure fire propagation, gas generation, explosion or deflagration risks and the potential for fire to spread to adjacent BESS enclosures.

What standards does FRNSW reference for large-scale BESS?

The Technical Information Sheet identifies several documents that may be considered, including FM Global Data Sheet 5-33, NFPA 855:2026, ANSI/CAN/UL 9540A:2026 and CSA/ANSI C800:25.

Does a BESS need a dedicated firefighting water supply?

The July 2026 guidance recommends a firefighting water supply for each BESS compound or cluster in DC-coupled installations located adjacent to renewable energy generation infrastructure. A site-specific arrangement may also be acceptable where the Fire Safety Study demonstrates adequate operational capability for fire brigade intervention.