The e-bike beside the front door turns the only exit into a wall of fire

WASHINGTON

WASHINGTON — Fire protection agencies and metropolitan fire departments are issuing increasingly specific guidance on where light electric vehicles and their batteries may be stored inside multi-family buildings, and the technical basis for the guidance is the geometry of a small apartment rather than the chemistry of a cell.

An electric bicycle or scooter parked inside a front door is parked in the one place a fire can be instantly fatal. It is beside the exit.

Why the outlet decides the outcome

Apartments are wired for convenience. The nearest outlet to the street is usually beside the entry, or in the kitchen immediately off it, because that is where a vacuum cleaner and a phone charger are used.

So the device is charged where the cable reaches, and the cable reaches the door.

When an uncertified or damaged lithium-ion pack enters thermal runaway, it does not behave like a smouldering furnishing. It vents flammable and toxic gas, and that gas ignites. A single e-bike pack can produce a flame that fills a hallway in seconds and a room in under a minute, with smoke that is lethal at concentrations far below what makes escape difficult.

Placed at the entry, that event consumes the means of egress first.

One door, and the door is the fire

Most apartments in older multi-family buildings have one way out. Even where a second exit is required, it is frequently a rear window onto a light well or a balcony without a stair.

Fire engineering has a name for this configuration when it involves storage in the exit path: an exit blocker. The building's design assumed the corridor and the door would be usable for the minutes it takes to leave. A battery failure at the door invalidates that assumption entirely, and it does so at the moment when leaving is the only action available.

The secondary problem is smoke spread. A runaway in a unit with the door open, or with a door that fails, puts hydrogen fluoride and carbon monoxide into the common corridor. That is where neighbours are, and they have no protection from it.

What building managers can actually enforce

Rules that say "no e-bikes in the hallway" fail for a predictable reason: the resident has nowhere else to charge the device, and a rule with no compliant alternative is a rule that gets broken quietly.

What works, in order of effect:

• A designated charging location away from the means of egress, ideally a detached or fire-separated space with detection, and storage that does not block the route out.
• A prohibition on charging inside dwelling units, stated in the lease, with the compliant alternative named in the same paragraph.
• Refusal of uncertified packs. Certification marks are the single most useful screening device available to a manager, and they are visible without opening anything.
• No charging overnight and never unattended, which is the period in which almost every fatal event occurs.
• Removal of any device stored in a corridor or stairwell, enforced the same day, because a corridor with a bike in it is a corridor the fire service cannot use.

What a resident should do tonight

Move the device out of the entryway. Charge it where a failure would not block your exit and where you are awake to notice it. Replace any pack that has been dropped, repaired, or bought without a certification mark. And if a neighbour is charging a scooter in a shared hallway, report it to the manager rather than assuming somebody else has.

USPA Nationwide Security posts fire watch crews in buildings whose detection or suppression systems are impaired, and patrols include the corridors and stairwells where these devices are most often stored.

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• When the building has no standpipe, the stairwell becomes the water main

Fire watch for a building with impaired protection: (800) 214-1448 or request emergency fire watch.