Why this risk is different from a normal electrical fire
A failing lithium-ion battery can enter thermal runaway — an uncontrollable, self-sustaining chemical reaction producing intense heat, flammable gas and often violent jetting flames, sometimes with little or no warning. Unlike a smouldering upholstery fire, which can take a long time to develop and gives occupants a reasonable window to notice and react, a battery in thermal runaway can go from normal operation to a fully involved fire in well under a minute, and can reignite hours later even after apparently being extinguished by the fire service. London Fire Brigade has repeatedly highlighted this as one of the fastest-growing causes of fires it attends, driven by the rapid growth in e-bike and e-scooter ownership and, particularly, second-hand and non-standard conversion kits and chargers bought online from unverified sellers. The intensity and speed of these fires, combined with the toxic smoke they generate, is why the response from fire risk assessors and managing agents has shifted quickly from treating this as a minor nuisance issue to treating it as a named, high-priority hazard in its own right.
Why communal areas are the specific concern
The risk itself exists wherever a battery is charged, but a fire that starts in a communal hallway, stairwell or bin store is far more dangerous than the same fire starting inside a single flat, because it can immediately compromise the only shared escape route for every other resident in the building. A fire inside one flat, behind a reasonably maintained fire door, is a contained problem for the neighbours; a fire in the stairwell itself is a problem for everyone above the fire.
- Corridors and stairwells are the means of escape for the entire building, not just one household.
- Communal areas often lack the compartmentation of an individual flat, allowing smoke and fire to spread faster.
- Residents charging in hallways are frequently doing so precisely because they lack safe charging space in a small flat — the underlying cause needs addressing, not just the symptom.
- Bin and cycle stores attached to or below residential accommodation can allow a battery fire to spread into the structure itself.
- Multiple bikes stored together in a single store multiply the consequence of one battery failing, since a fire can spread bike to bike.
What a workable written policy actually covers
A notice telling residents 'do not charge e-bikes in the hallway' without more is rarely effective on its own, because it does not solve the underlying problem of where residents are supposed to charge instead. A genuinely workable policy addresses both the prohibition and the alternative, and is communicated clearly rather than left as a laminated sheet by the post boxes that nobody reads twice.
- An explicit rule prohibiting charging of e-bikes, e-scooters and similar devices in communal corridors, stairwells, lobbies and other escape routes.
- Guidance on safe charging within individual flats: not left unattended overnight, not charged on a bed or soft furnishing, using only the manufacturer's original charger.
- Where possible, a designated, ventilated, fire-separated storage/charging area away from the main escape route, for buildings able to provide one.
- A clear statement on batteries and conversion kits purchased second-hand or online from unverified sellers, which have a disproportionately high failure rate.
- What residents should do if a battery is damaged, swollen, unusually hot, or was involved in a water-damage incident (which can trigger delayed failure).
- How suspected faulty batteries or non-compliance should be reported, and to whom, with a named contact rather than a vague instruction to 'tell the office'.













