---
title: Test method for evaluating thermal runaway fire propagation in battery energy storage systems
ref_no: "UL 9540A:2026"
status: Revised
effective_on: 2026-03-13
market: United States
source_url: "https://www.shopulstandards.com/ProductDetail.aspx?productId=UL9540A"
verified_at: 2026-08-19
version: 1
canonical: "https://tsinghu.com/en/regulations/ul-9540a"
publisher: Shenzhen Tsinghu Technology Co., Ltd. (agency, not a certification body)
license: CC-BY-4.0
---

# UL 9540A:2026 Test method for evaluating thermal runaway fire propagation in battery energy storage systems

| | |
|---|---|
| Effective | 2026-03-13 |
| Scope | Cell, module, unit and installation level testing |
| Key requirements | A test method standard, not a certification scheme; data supports fire and installation approvals |
| Languages | EN |
| Market | United States |

## Change history

- 2026-03-13 — Sixth edition published (https://www.shopulstandards.com/ProductDetail.aspx?productId=UL9540A)
- 2019-11-12 — Fourth edition published (https://www.shopulstandards.com/ProductDetail.aspx?productId=UL9540A)