The Desk-Charged Workplace: How Our Devices Rewrote the Office Fire Risk

There is a particular irony in the modern office fire risk. We have spent decades engineering buildings to be safer — better detection, clearer escape routes, more rigorous assessment regimes — while simultaneously filling them with energy-dense lithium-ion cells that behave unlike anything the older fire safety playbook anticipated. The risk has not crept in through the back door. We plugged it in at every desk.

A Risk Profile That Shifted Under Our Feet

Most fire risk assessments in circulation were drafted around a familiar cast of hazards: overloaded sockets, ageing wiring, waste paper near heaters. Few were written with a dozen e-bike batteries charging under standing desks, or a communal tangle of power banks and phone cables in a meeting room. Yet lithium-ion battery incidents have become a growing concern for UK insurers, who are increasingly singling out charging practices, particularly for e-bikes and e-scooters, in their underwriting questions.

The mechanism matters. When a lithium cell goes into thermal runaway, it can release intense heat, toxic flammable gases and, in confined spaces, an explosive vapour cloud. A burning laptop battery is not a Class A fire with a familiar shape; it is a self-sustaining chemical event that can reignite hours after appearing extinguished. The conventional red cylinder in the corridor was never designed with this in mind.

Where the Practice Goes Wrong

Three workplace habits deserve particular scrutiny.

Daisy-chained extension leads. The four-way block plugged into another four-way block is a fixture of under-equipped offices. Beyond the straightforward overload risk, daisy-chaining often conceals exactly how much demand a socket is actually carrying — and high-draw chargers add up faster than most people assume.

Overnight charging in unventilated corners. Charging banks of devices in a locked comms room, a windowless store or beneath a stairwell concentrates both heat and combustible material. If a cell fails at 2am, the first indication may be smoke damage discovered the following morning — or worse.

E-bike and e-scooter batteries under desks. The commuter who wheels their bike into the office and parks the battery beside their rucksack has introduced a substantial energy store into the workplace, frequently one of unknown provenance. Second-hand or aftermarket batteries with damaged casings are disproportionately represented in domestic lithium fires, and the same logic applies at work.

Rethinking the Assessment

None of this argues for banning devices — an unenforceable and counterproductive response. It argues for revisiting the risk assessment with today's reality in view. A practical starting point:

• Map where charging actually happens, not where policy assumes it happens
• Set expectations for e-micromobility batteries: designated storage away from escape routes, no charging of personal batteries on premises where practicable
• Specify quality: genuine manufacturer chargers, undamaged cables, and no stacking of extension leads
• Consider dedicated, ventilated charging areas with detection coverage for high-volume device fleets
• Brief staff — most people have no idea what thermal runaway looks like, and awareness is half the defence
• Confirm your fire detection layout still covers the rooms where charging is now concentrated

An Opinion Worth Stating

The fire safety industry, ourselves included, has been slower than it should have been to give battery-charging culture the prominence it deserves in guidance and assessment templates. That needs to change. The devices will keep multiplying; the chemistry is not going to become more forgiving. A risk assessment that treats a bank of e-bike batteries the same way it treats a kettle is not thorough — it is out of date. The offices that take this seriously now will be the ones whose insurers, and whose staff, have nothing to worry about later.