Li-ion Tamer Off-Gas Detection

How off-gas detection works.

Off-gas detection senses the electrolyte vapour a lithium-ion cell releases when it vents — the first observable stage of the failure chain that runs cell abuse, venting and off-gassing, smoke, fire, thermal runaway. Conventional smoke and heat detection joins that chain at the third or fourth stage; off-gas sensing triggers at the second.

In effect, an off-gas sensor is the earliest practical lithium-ion fire sensor: it alarms on the vapour of a venting cell, not the smoke of one already burning. The margin between those stages is what lets a battery management system disconnect load, isolate a rack, or hold off propagation before a single cell's failure becomes a compartment fire.

Anywhere lithium-ion is dense enough to matter.

BESS containers and grid-scale storage are the headline duty — a battery energy storage system fire is exactly the scenario early off-gas warning exists to prevent, buying the response time that stops propagation. The same logic covers battery rooms and UPS installations, EV charging infrastructure, data centres, and marine and offshore battery spaces.

BESS fire safety and the regulatory picture.

Fire detection inside battery energy storage systems is not currently mandated by prescriptive UK regulation. The Battery Energy Storage Systems (Fire Safety) Bill — a private member's bill concerning fire safety at battery storage sites — was introduced in the Commons in October 2024 but lapsed at the end of the 2024–26 parliamentary session without becoming law (see the official bill page). In practice, specification is driven by project risk assessment, insurers and fire services — which is where early off-gas detection earns its place.

Last reviewed: July 2026.