UL 9540A tested battery storage systems
UL 9540A tests how thermal runaway spreads through a battery system; UL 9540 is the safety standard a system is listed to. Hithium, HyperStrong and GE Vernova list both for their 5 to 6.25 MWh containers, and Valo’s GridSolv Quantum holds UL 9540 and met UL 9540A unit-level criteria.
| Flagship product | UL 9540 | UL 9540A | Data center offer | |||||
|---|---|---|---|---|---|---|---|---|
| Fluence Energy | Integrator | — | Smartstack | — | Yes | 104 | Yes | 2026-11-11 |
| Hithium | Cell maker and integrator | LFP | ∞Power 6.25 MWh 4h | Yes | Yes | 6.251 | Yes | 2026-11-11 |
| GE Vernova | Power and infrastructure major | LFP | FLEX RESERVOIR (RESTORE DC Block) | Yes | Yes | 5.0161 | — | 2026-11-11 |
| REPT BATTERO | Cell maker and integrator | LFP | Powtrix 2.0 DC Container | — | Yes | 5.0161 | — | 2026-11-11 |
| HyperStrong | Integrator | LFP | HyperBlock III | Yes | Yes | 5.0161 | — | 2026-11-11 |
| Huawei Digital Power | Integrator | LFP | LUNA2000-5015-2S | — | Yes | 5.0151 | — | 2026-11-11 |
| Tesla Energy | Integrator | LFP | Megapack 3 and Megablock | — | Yes | 51 | Yes | 2026-11-11 |
| Valo Energy (formerly Wärtsilä Energy Storage) | Integrator | LFP | GridSolv Quantum3 | Yes | Yes | 52 | — | 2026-11-11 |
| Samsung SDI | Cell maker and integrator | — | Samsung Battery Box (SBB) 2.0 | — | Yes | — | Yes | 2026-11-11 |
| Vertiv | Power and infrastructure major | — | DynaFlex BESS | — | Yes | — | Yes | 2026-11-11 |
| ZincFive | Cell and pack maker | Nickel-zinc | BC 2 AI | — | Yes | — | Yes | 2026-11-11 |
Read the test level and the model
How we read the numbersEach flag links the vendor statement or report behind it, and the spec notes name the model and test level. ZincFive’s nickel-zinc cells showed no thermal runaway in cell-level testing; Samsung SDI’s SBB 2.0 met all criteria in UL Solutions’ large-scale fire test; REPT BATTERO reports no propagation to the adjacent container.
UL’s guide to 9540A and NFPA 855 explains the editions and test levels that fire officials ask for.