In today’s era of large-scale energy storage deployment, fire safety is no longer simply a matter of “whether a fire can be extinguished.” When a lithium-ion battery goes into thermal runaway, it releases large quantities of flammable gases, including hydrogen, carbon monoxide and methane.
When these gases mix with air and accumulate within confined spaces such as BESS containers, they can reach explosive limits. Once that happens, any ignition source can trigger a violent explosion.
However, one risk that has long been overlooked is that the fire suppression product itself can become the ignition source for an explosion.
Conventional fire suppression systems can become ignition sources
Conventional fire suppression systems—such as gas systems, CO₂ extinguishers and FK-5112 systems—typically contain high-pressure vessels, solenoid actuators and electrical tubing.
In the event of flammable gas accumulation inside an energy storage enclosure, if these devices activate or malfunction, their internal electrical contacts, motor operation and high-pressure discharge can generate electrical arcs, high temperatures or mechanical sparks—potentially igniting the surrounding flammable gas atmosphere.
In other words, a fire suppression system without explosion-proof design can be more dangerous in an energy storage explosion scenario than the fire itself.
Are aerosol fire suppression systems suitable for hazardous BESS environments?
Aerosol fire suppression systems have become one of the commonly used fire protection solutions in BESS due to their non-pressurised design, simple installation and maintenance and environmental benefits. So, the question is: how do aerosol units perform in potentially explosive atmospheres?
If we look at the design standards for aerosol systems, not all aerosol products are automatically suitable for use in hazardous explosive areas:
EN 15276-2:2019—Fixed firefighting systems—Condensed aerosol extinguishing systems—Part 2: Design, installation and maintenance—Clause 4.3 explicitly states: Where aerosol generators are used in potentially explosive atmosphere, the compatibility of the generator to the atmosphere for the determined lifetime should be assessed according to ATEX directive 2014/34/EU[5].
ISO 15779:2011—Condensed aerosol fire extinguishing systems—Requirements and test methods for components and system design, installation and maintenance —General requirements—Clause 4.6 similarly states: Under certain conditions, the potential for explosive atmospheres may exist. Areas where such potential may exist are classified as hazardous. Condensed aerosols may be used in hazardous areas subject to the manufacturer obtaining the specific listings and approvals for such areas from the appropriate authorities.
Only when an aerosol unit has obtained the necessary approval for use in explosive atmospheres can it be installed in BESS. This is likely a design requirement that has been overlooked within the industry.
Explosion-proof fire suppression design is becoming critical for energy storage safety
Energy storage safety is a complete, multi-layered defense: it requires preventing thermal runaway, controlling flammable gas accumulation and—most critically—ensuring that the fire suppression equipment that activates under accident conditions is itself safe and reliable.
With their non-pressurised design, arc-free operation and modular construction, aerosol fire suppression systems—after obtaining explosion-proof certification—are a fire protection solution worth prioritising in energy storage applications.
Energy storage safety is no longer just about “whether the fire can be put out.” Under the most severe accident conditions, whether the fire suppression product itself remains safe and operational is what designers should consider most. An effective system design is one that strictly follows the fire suppression system’s design standards.