Applications: Battery Energy Storage Systems (BESS)

ESS Safety - Large Scale Burn Testing a New Addition to Existing Fire Testing Standards

UL9540A This standard, developed by the private US-based accreditation agency UL Solutions, is the leading standard for fire testing and nearly every major manufacturer has performed tests using this standard. It involves measuring the results of a lab-controlled burn of various components of the system, starting with simplest and working up to the most complex:

Cell-level: Combustion of a single battery cell, measuring the gases produced

Module-level: Combustion of a collection of battery cells connected together

Unit-level: A collection of battery modules connected together and installed inside a rack and/or an enclosure

Installation-level: same setup as the unit test with additional fire suppression systems used

Large scale tests on entire BESS units: These tests involved intentionally triggering thermal runaway events within entire BESS enclosures to assess their ability to contain the fire and prevent propagation to adjacent enclosures.

The benefits of large scale fire testing:

These tests often exceed the current standard industry requirements outlined in NFPA 855 and UL 9540A

Preparations for the the upcoming CSA C800 standard, which will establish new safety benchmarks for large-scale testing of energy storage systems in 2026

The CSA C800 simulates real life incidents and provides insights into the worst-case fire performance which supports the proper risk assessment

Source: Utilitydive, BatteryStandardsTable

Extracted from the PDF; charts and images may read imperfectly.