Data Center Battery Storage: How a Hazard Mitigation Analysis Supports Code Approval

Increasing computing demand is changing how data centers distribute power. As AI and other intensive workloads drive higher rack power, more designs place battery backup units within IT racks or adjacent power equipment. Maintaining backup power for the same duration then requires greater stored energy, bringing substantial lithium-ion battery capacity directly into the data hall.

The combined capacity can quickly exceed 600 kilowatt-hours, even when each rack contains a relatively small battery installation. Under 2021/2024 IFC Section 1207.5.2 and Table 1207.5, 600 kWh is the prescriptive lithium-ion limit per fire area, subject to exceptions. The limit applies to the fire area, rather than independently to every rack.

Without approval for increased quantities, maintaining that limit can require distributing batteries among separate fire areas with rated construction or relocating equipment. For a large, open data hall, this can be impractical. Internal subdivisions affect cooling airflow, cable routing, equipment access, and future rack expansion. Identifying the constraint after the layout is finalized can lead to expensive redesign and permitting delays.

Engineering Fire Protection, LLC (EFP) brings project experience in helping clients resolve these constraints while preserving open data hall configurations. Our work supports approval of increased battery quantities, avoiding internal fire-area subdivisions that would otherwise be needed solely to stay within the prescriptive capacity limit.

We engage the authority having jurisdiction (AHJ) early to establish the proposed battery arrangement and approval strategy. EFP then develops a project-specific hazard mitigation analysis (HMA), supported by relevant UL 9540A fire-test reports, to evaluate whether a battery failure can spread to adjacent equipment and whether the proposed protection adequately addresses the resulting hazards.

The code provides a defined approval route. Section 1207.5.2, Exception 1, permits increased quantities based on an approved HMA and large-scale fire testing. EFP connects that evidence to the actual equipment, rack layout, and protection systems, prepares the technical justification, and works through AHJ review. Where additional departures are necessary, we address them through a separate alternative-design request.

The resulting approval can preserve an open interior without capacity-driven subdivisions. Required separation from other building areas remains a separate consideration.

For developers, EFP’s early involvement helps turn a potentially disruptive code constraint into a defined approval process—before equipment procurement and construction make changes costly.

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.