Shanghai – September 07, 2026 -- APsystems' APstorage 261L liquid-cooled commercial and industrial energy storage system has passed the UL 9540A fire propagation test under the witness of TÜV Rheinland, with thermal runaway fully contained within a single cabinet and no propagation to adjacent units.
Cabinet Withstands Test at Full Charge With Fire Suppression Disabled
The test subjected the APstorage 261L to extreme conditions, operating at 100% state of charge with its fire suppression system intentionally switched off. No short circuit, fire spread, or explosion occurred, and the cabinet retained structural integrity throughout.
Heat Flux Measured at Zero, Far Below UL 9540A's 1.3 kW/m2 Limit
Heat flux near the affected cabinet registered 0 kW/m2, compared with the UL 9540A threshold of 1.3 kW/m2, removing the risk of adjacent equipment igniting through thermal radiation. Maximum module surface temperature reached 83.9°C on both the affected and neighboring modules, indicating thermal propagation between modules was prevented. The adjacent wall temperature rose to just 30.6°C, only 3.1°C above ambient.
Multi-Layer Safety System Combines Liquid Cooling With Four-Level Fire Protection
The APstorage 261L uses a single-cluster liquid-cooling architecture that keeps cell temperature variation below 3°C, paired with a four-level fire-protection system, active ventilation, and passive pressure relief mechanisms spanning the cell to installation level.
Compact 1.3 m2 Footprint Targets European C&I Deployment
With a footprint of 1.3 m2, the system offers plug-and-play connections and modular parallel expansion across multiple cabinets, aimed at industrial facilities, commercial buildings, and solar-storage-charging applications. APsystems supports the rollout through its European network and a dedicated C&I energy storage warehouse in the Netherlands, providing local product availability, training, and on-site technical support.