Common BESS Fire Protection Pitfalls — and How to Avoid Them

As Battery Energy Storage Systems (BESS) become a critical part of renewable energy infrastructure, designers and project teams are learning that fire protection for these systems involves challenges not typically seen in conventional electrical or industrial facilities.

While the industry continues to mature, recurring mistakes in the design, permitting, and installation process can lead to costly delays — or worse, create gaps in safety. Understanding these common pitfalls and how to avoid them is essential for achieving a code-compliant, resilient, and operationally sound BESS project.

1. Overlooking the Hazard Mitigation Analysis (HMA) Early in Design

One of the most frequent errors is delaying the Hazard Mitigation Analysis (HMA) until late in the project. The International Fire Code (IFC) Section 1206 and NFPA 855 both require an HMA to be submitted during the permitting phase, but many projects treat it as a post-design deliverable.

When the HMA is done too late, it often identifies spacing, ventilation, or suppression requirements that conflict with the existing layout—leading to redesigns and re-approvals.

How to avoid it: Begin the HMA during schematic design. Early coordination between the fire protection engineer, system integrator, and Authority Having Jurisdiction (AHJ) ensures that fire and explosion hazards are identified before equipment procurement or construction begins.

2. Treating BESS Like Traditional Electrical Rooms

BESS installations are often housed in modular, sealed containers that behave very differently from typical electrical rooms. Unlike switchgear or transformer spaces, these enclosures can trap heat and gases during a fault, creating conditions for deflagration or thermal runaway propagation.

Assuming that traditional fire sprinklers or ventilation alone will suffice is a common and dangerous misconception.

How to avoid it: Follow NFPA 855, NFPA 68, and NFPA 69 guidance for explosion control, ventilation, and deflagration venting. Use UL 9540A test data specific to the system chemistry and container design to validate performance-based fire protection solutions.

3. Inadequate Integration Between the BMS and Fire Protection Systems

The Battery Management System (BMS) is the first line of defense against electrical and thermal hazards. However, it must work in tandem with fire detection, alarm, and suppression systems to provide coordinated protection.

In some projects, the BMS operates in isolation—monitoring temperature and voltage but not communicating with fire or gas detection systems. As a result, critical delays can occur between the onset of a thermal event and system shutdown.

How to avoid it: Integrate the BMS with the fire alarm control panel so that alarms, shutdown signals, and ventilation controls function automatically and in sequence. Early integration testing should verify communication protocols and fail-safe responses.

4. Relying on Generic Fire Suppression Designs

Lithium-ion battery fires behave differently from typical electrical or Class A fires. They can reignite after suppression and produce hazardous gases such as hydrogen fluoride. Applying off-the-shelf suppression systems without understanding the specific cell chemistry, energy density, and test data can lead to underperforming protection.

How to avoid it:

• Use water-based suppression where permitted, as water is the most effective medium for cooling adjacent cells and preventing propagation.

• Validate system design against UL 9540A testing results to confirm effectiveness.

• Ensure suppression agents, detection thresholds, and discharge times are consistent with the manufacturer’s recommendations and the system’s risk profile.

5. Poor Coordination with the AHJ and Local Fire Department

Even well-designed systems can face delays if project teams fail to engage with local authorities early. AHJs may have jurisdiction-specific interpretations of NFPA 855 or IFC Chapter 12, particularly concerning separation distances, explosion venting, or fire department access.

Late engagement often leads to multiple review cycles, comment revisions, and added cost.

How to avoid it:

• Initiate early discussions with the AHJ and fire department.

• Provide draft versions of the HMA and Emergency Response Plan (ERP) for preliminary feedback.

• Incorporate their operational needs—such as staging areas, hydrant locations, and manual ventilation controls—into the site plan.

6. Insufficient Separation Distances or Fire Barriers

BESS containers are often installed close together to save space, but this increases the risk of fire spread between enclosures. NFPA 855 establishes minimum spacing and separation requirements, which may be reduced only if validated by UL 9540A test data or performance-based modeling.

Ignoring these rules can result in permit rejection or significant rework.

How to avoid it: Validate proposed spacing with the equipment manufacturer’s test data and confirm acceptance with the AHJ early in the design phase.

7. Lack of Emergency Response Planning and Training

Even with strong design measures, an emergency can still occur. Without a clear Emergency Response Plan (ERP) and proper responder training, on-site personnel may be unprepared to manage alarms, isolation procedures, or post-incident recovery.

How to avoid it: Develop the ERP in parallel with the HMA, in accordance with IFC 1206.9 and NFPA 855 Section 4.2.9. Conduct joint reviews with the local fire department to ensure familiarity with the system layout and operational protocols.

Conclusion

Battery energy storage projects operate at the intersection of electrical, mechanical, and fire protection engineering. The most common pitfalls—delayed hazard analysis, inadequate integration, and insufficient coordination—are not technical failures but procedural ones.

By addressing these issues early, aligning design and safety documentation with NFPA 855 and IFC requirements, and maintaining open communication with regulators and responders, BESS stakeholders can avoid costly delays and build systems that are both safe and reliable.

For any further inquiries regarding this topic, as well as for code consulting and fire engineering design support related to your project, please don’t hesitate to contact us via email at contact@engineeringfireprotection.com.