Most HMO landlords focus their attention on routine fire door assessments, checking gaps with gauges or ensuring escape corridors are clear of physical obstructions. Yet one of the fastest-growing and most destructive hazards in London properties is something completely overlooked: a charging e-bike battery sitting quietly in a communal hallway, which can turn into a lethal threat in moments.

A recent incident in Uxbridge highlights this rapidly growing risk. A fire broke out in a semi-detached house converted into a House in Multiple Occupation (HMO) after an e-bike battery pack failed while charging overnight. Fortunately, working alarms alerted the residents and allowed everyone to escape safely. However, the London Fire Brigade continues to draw attention to these hazards, attending fires involving e-bikes and e-scooters on average every other day across London.

To demonstrate the speed and severity of thermal runaway, CCTV footage released by the London Fire Brigade captures just how quickly a failing lithium-ion battery erupts into a violent explosion, filling an enclosed space with toxic gas and flames in under 30 seconds.

Watch London Fire Brigade CCTV E-Bike Explosion Footage

While proactive measures are vital, passive fire protection cannot prevent a faulty battery from entering thermal runaway. Its primary purpose is to contain the resulting fire and toxic smoke. Lithium-ion battery fires develop extremely fast, generating intense heat and releasing harmful gases such as carbon monoxide and hydrogen cyanide. Effective containment protects vital escape routes and gives residents crucial time to evacuate safely. This is where professional fire protection services become non-negotiable for HMO compliance.

Dedicated Fire-Resisting Storage Areas

E-bikes and e-scooters should ideally be stored and charged outdoors. When this is not possible, charging must take place in a dedicated room enclosed by fire-resisting walls, floors and ceilings. Ideally, this room should be situated at ground level with direct access outside rather than opening onto a main escape staircase or hallway.

The required period of fire protection, usually 30 or 60 minutes, is determined by the building's fire risk assessment. Higher levels of containment are essential when multiple batteries are charged, where the HMO has a single staircase or if the room is located close to sleeping areas.

Protection of the Escape Route

Scooters and e-bikes must never be stored or charged in hallways, staircases, under-stair cupboards or electrical intake rooms. A battery fire in these areas can render the main exit completely unusable within seconds. Guidance across London recommends keeping all escape routes entirely clear of combustible items. Comprehensive fire protection services ensure these vital pathways remain shielded from rapid fire spread.

Suitable Fire Doorsets

Installing high-quality fire doors helps prevent heat and toxic smoke from entering shared escape routes. Correct fire door installation ensures that doors protecting staircases, corridors, bedrooms, kitchens and designated charging rooms deliver the precise level of resistance required.

A fully compliant doorset must include:

1. An appropriate fire-resisting door leaf and frame
2. An effective self-closing device
3. Suitable intumescent seals
4. Cold-smoke seals where required
5. Controlled and tested gaps around the perimeter
6. Compatible hinges, locks and ironmongery
7. Zero unapproved holes, vents or alterations

London HMO regulations commonly require protected routes using FD30S fire doors to delay smoke spread before a fire becomes fully developed. Poor fire door installation can render a door useless during a severe battery fire.

Correct Fire Stopping Around Service Penetrations

Cables, pipes and ducts passing through walls or ceilings of a charging room create hidden pathways for fire and smoke. Professional fire stopping seals these service penetrations using tested systems matched to the specific wall type, opening size and required fire resistance period. Effective fire stopping prevents flames from bypassing fire doors and entering ceiling voids, bedrooms or adjoining properties. If your property lacks adequate fire stopping, the building's compartmentation is highly compromised.

Protecting Structural Integrity and Compartmentation

Lithium-ion fires generate intense and prolonged heat. Enhancing structural fire protection around critical steelwork, floor construction and load-bearing elements prevents structural failure during a severe incident.

Additionally, robust compartmentation separates individual bedrooms, communal spaces and storage areas. Proper compartmentation limits the spread of fire from a single failing battery to provide vital extra evacuation time and prevent total loss of the property.

Supporting Measures for Total Safety

Passive measures must always be supported by active safety controls including:

1. Automatic fire detection inside and adjacent to charging areas
2. Suitable smoke ventilation and control systems
3. Adequate fixed electrical sockets to avoid using extension leads
4. Clear rules prohibiting unattended or overnight charging
5. Regular inspections and updated fire risk assessments

Don't Get Caught Off Guard: Protect Your HMO Today

Passive measures will not stop a lithium-ion battery from failing, but properly designed compartmentation dramatically reduces the consequences. Dedicated charging areas, correct fire door installation and certified fire stopping contain flames and toxic smoke to safeguard residents and preserve vital escape routes. E-bikes and scooters should never be stored in communal hallways or staircases.

Is your property fully prepared for an e-bike fire hazard? Contact Crown Fire Systems today. Whether you need an urgent passive fire protection assessment, expert fire stopping remediations or compliant fire doors across London and the Home Counties, our team is ready to help ensure your HMO remains safe and fully compliant.

About the Author: Jurij Stekolnikov is the Ops Manager - Fire Stopping with over 15 years of industry experience, specialising in project delivery, site surveys, and compliance and QA for passive fire protection.