BESS Glossary
This glossary defines common BESS safety, permitting, and operations terms used across codes, standards, submittals, and AHJ reviews.
A–Z terms
- AHJ (Authority Having Jurisdiction)
- The organization or official responsible for interpreting and enforcing applicable codes and permitting requirements for a specific installation.
- Alarm and action matrix
- A table that maps detection signals and thresholds to automatic actions and notifications, such as isolate, shutdown, ventilate, and notify.
- CAPA (Corrective and Preventive Action)
- A structured process to investigate an issue, define corrective actions, prevent recurrence, assign owners, and verify closure.
- CMMS (Computerized Maintenance Management System)
- Software for work orders, preventive maintenance, inspections, asset records, and maintenance evidence retention.
- Commissioning
- Verification activities that confirm installed systems perform as intended, including safety-critical controls, alarms, ventilation modes, and shutdown logic.
- Containment
- Design features that limit the spread of fire, heat, or hazardous byproducts beyond the initiating unit or enclosure.
- Deflagration
- Rapid combustion of a flammable gas-air mixture that produces a pressure wave. For BESS, it is a gas management concern in enclosed volumes.
- Derating
- Intentional reduction of allowable power or energy operation based on conditions such as temperature, state of charge, or component limitations.
- Detection
- Sensors and logic used to identify abnormal conditions such as gas, smoke, heat, or off-normal electrical behavior.
- DMS (Document Management System)
- Software used to control, version, approve, and retain safety and compliance documents and records.
- EHS (Environmental, Health, and Safety)
- Programs and software workflows used to manage incidents, audits, training, compliance tasks, and regulatory reporting.
- EMS (Energy Management System)
- Software and controls that schedule and dispatch BESS power while enforcing operating constraints and recording operational evidence.
- ERP (Emergency Response Plan)
- A site-specific plan that defines incident response actions, contacts, access routes, isolation procedures, and responder guidance.
- Exclusion zone
- An area established to protect personnel by restricting access during abnormal events, such as suspected thermal runaway or hazardous gas release.
- Exposure
- A nearby asset or structure that could be impacted by heat, fire, or vented gases from a BESS event, such as adjacent containers, buildings, transformers, or property lines.
- Fire propagation
- Spread of fire or thermal effects from the initiating unit to other units or adjacent exposures.
- HMA (Hazard Mitigation Analysis)
- A structured document that identifies hazards, defines credible scenarios, lists mitigations, and specifies verification and residual risk considerations.
- IATA
- International Air Transport Association. Publishes guidance used by air carriers for shipment of dangerous goods, including lithium batteries.
- IBC (International Building Code)
- A model building code used as a basis for many jurisdictions, often adopted with local amendments.
- IFC (International Fire Code)
- A model fire code used as a basis for many jurisdictions, often adopted with local amendments.
- IMDG Code
- International Maritime Dangerous Goods Code. Defines dangerous goods shipping requirements for sea transport, including lithium batteries.
- Interlock
- A protective control that prevents unsafe operation by requiring specific safe conditions before enabling an action.
- Isolation
- Actions that electrically or physically separate equipment to prevent escalation, such as opening breakers, disabling strings, or isolating a container.
- Local amendments
- Jurisdiction-specific modifications to model codes that can change permitting requirements, definitions, or required mitigation measures.
- Market surveillance
- Regulatory or authority activity that verifies products and installations meet applicable requirements after deployment.
- NFPA 855
- A standard addressing installation of stationary energy storage systems, often referenced in permitting and safety packages.
- Off-gas
- Gases released during abnormal battery events, including thermal runaway. Off-gas can be flammable and toxic, and drives ventilation and exhaust requirements.
- Overpressure
- Increased internal pressure in an enclosure caused by gas generation or combustion, potentially damaging structures or creating hazards.
- Preventive maintenance
- Planned maintenance and inspections intended to reduce failures and preserve safety-critical performance over time.
- Propagation
- Thermal runaway spreading from one cell or module to others, potentially leading to involvement of additional modules or units.
- RCA (Root Cause Analysis)
- A structured investigation method used to identify underlying causes of an incident or failure and define corrective actions.
- Risk register
- A structured list of risks, owners, controls, acceptance criteria, and review cadence used to manage site risk over time.
- SCADA (Supervisory Control and Data Acquisition)
- Control and monitoring systems that collect data and support operator visibility and control of site equipment.
- Separation distance
- Required spacing between BESS units and exposures to reduce the probability of escalation, often justified via code basis, test evidence, and site analysis.
- Setback
- Required distance from BESS equipment to property lines, buildings, or other protected features, typically defined by code or AHJ conditions.
- Thermal runaway
- A self-accelerating battery failure mode that generates heat and gases and can lead to fire, propagation, and hazardous conditions.
- UL 1973
- A UL standard covering safety for batteries used in stationary applications and related equipment contexts.
- UL 9540
- A UL standard for energy storage systems and equipment, often used as part of safety compliance and listing evidence.
- UL 9540A
- A test method used to evaluate thermal runaway propagation and hazard characteristics at cell, module, and unit levels for ESS.
- Ventilation and exhaust
- Design features used to control accumulation of hazardous gases and manage discharge paths during abnormal events.
Disclaimer. Informational guidance only. Not legal advice. Validate definitions and applicability against adopted codes, standards, and AHJ requirements.