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Fire Protection Engineering

Hazard Mitigation Analysis (HMA) for
Battery Energy Storage Systems (BESS)

Battery Energy Storage Systems (BESS) present distinctive fire protection challenges due to the inherent risk of thermal runaway and subsequent release of toxic and flammable substances. At Rigsbee Engineering, we have developed comprehensive strategies to manage these risks effectively. These include Hazard Mitigation Analysis (HMA), and Fire Risk Assessment (FRA). 

We have worked on installations across the country including California, New Jersey, Ohio, Texas, and Vermont.

A Hazard Mitigation Analysis (HMA) provides the owner, fire department, and other stakeholders with a living document which reviews the BESS and its components for large scale battery energy storage whether it is an outdoor or indoor installation.The goal of an HMA is to understand risks and hazards of an installation, and consequences of failures. Objectives typically include:

  • Fires or explosions will be contained within unoccupied battery storage rooms for the minimum duration of the fire-resistance-rated walls identified in Table 509.1 of the California Building Code.

  • Fires and explosions in battery cabinets in occupied work centers will be detected in time to allow occupants within the room to evacuate safely.

  • Toxic and highly toxic gases released during fires and other fault conditions shall not reach concentrations in excess of Immediately Dangerous to Life or Health (IDLH) levels in the building or adjacent means of egress routes during the time deemed necessary to evacuate from that area.

  • Flammable gases released from batteries during charging, discharging, and normal operation shall not exceed 10 percent of their lower flammability limit (LFL).

  • Flammable gases released from batteries during fire, overcharging and other abnormal conditions shall not cre ate an explosion hazard that will injure occupants or emergency responders.

The process includes a Failure Modes and Effects Analysis (FMEA) to evaluate each element of the BESS for failure modes such as thermal runaway, ventilation (HVAC), exhaust ventilation, smoke detection, fire detection, fire suppression, gas detection, etc. It is a method to break down a complicated system into elements to be individually analyzed. An evaluation of each element of the BESS system is conducted typically pertaining to failure modes such as:


  • Thermal runaway condition in a single-battery storage rack, module, or array

  • Failure of any energy storage management system 

  • Failure of a required ventilation or exhaust system

  • Voltage surges on the primary electric supply.

  • Short circuits on the load side of the stationary battery storage system.

  •  Failure of the smoke detection, fire-extinguishing or gas detection system 

  • Spill neutralization not being provided or failure of the secondary containment system

  • Failure of temperature control

  • Rigsbee Engineering looks at each project separately, evaluating the locally adopted codes while remaining mindful of the latest developments in this emerging industry and utilizing the most up to date knowledge, standards, and codes tn as part of the analysis process

  • New installations may have UL 9540 A testing completed which will be reviewed as part of the analysis

  • Existing installations where obtaining UL 9540 A testing is not possible can be a challenge met with performanced based design and fire modeling.


An HMA attempts to be an exhaustive analysis reviewing fire and explosion hazards and risks, Design Documentation, and environmental conditions to create a document capable of defining the layers of protection to mitigate identified hazards. 

Additional Services

In addition to HMAs, we provide the following services for BESS facilities:


  • Fire Tank Water Design

  • Emergency Response Plan

  • Fire Alarm Design

  • Fire Master Plan

  • Fire Modeling

  • AHJ Consulting

  • Construction Administration

With Rigsbee Engineering, we liaise between the client and fire department to help your BESS facilities get approval and remain operational. Not only code-compliant but meeting the highest standards of fire safety. We're committed to ensuring your Battery Energy Storage Systems are safe, efficient, and resilient.

Areas of Expertise

Structural Fire Protection

thermal sciences and fire dynamics

Thermal Sciences & Fire Dynamics

Fire Safety Regulation & Management



Egress Analysis & Design

water-based fire suppression

Water-Based Fire Suppression Systems

fire detection and alarm

Fire Detection, Alarm, Communication System

Smoke Management & Special Hazards

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