Electric Scooters Fire Evacuation
Electric scooters and similar devices should not be stored or charged in living areas and escape routes! This is the main message from a recent study at RISE Fire Research.
In a recent study, we examine experimentally the consequences of a thermal runaway in electric scooters when stored in enclosed spaces such as offices and corridors. How will the spread of gas and smoke from the battery affect the potential to escape from the building?
Large-scale experiments
Six large-scale experiments with a fire in an electric scooter were carried out by RISE Fire Research in Trondheim. The scenarios examined are representative of public buildings, schools, office buildings, and other buildings that require many people to escape via large open spaces (e.g., classrooms, open-plan offices) and corridors (escape routes). Three of the experiments were carried out in a 55 m² room corresponding to a classroom, and three of the experiments were carried out in a 15 m long corridor (38 m²). The ceiling height in the building was 3 m. In addition to the experimental study, learnings from real incidents involving fires in electric scooters were collected.
A fire in an electric scooter can be very rapid and have high-temperature jet flames affecting the area around the scooter.
Rapid fire development
The study finds that a thermal runaway in a lithium-ion battery leads to rapid fire development, where the battery essentially bursts into flames, with jet fires and potential ejections of burning battery cells far away from where the fire started. This may lead to fire spread to other combustible materials in the room due to the behavior of the fire and high temperature of the jet flame. Ejection of burning battery cells poses a hazard of fire spread even to areas far away from the start location.
Fires in an electric scooter battery or similar lithium-ion batteries can also cause a rapid spread of smoke to the entire room. Due to this rapid spread of smoke, visibility in the room will be affected after a short time and make escape more difficult. Gas measurements performed in the fire experiments detected the presence of both asphyxiant and irritant gases. However, it is important to remember that the concentration of toxic gases in a room due to a fire in a lithium-ion battery depends on many factors, including battery type and size, room size, and ventilation conditions.
Burning battery cells can be ejected from an electric scooter fire, flying across the room and igniting new fires far away from the start location.
Measured temperature 4 cm underneath the battery. The battery essentially bursts into flames, with jet fires and potential ejections of burning battery cells, approximately five minutes after the pilot flame was ignited for all the tests, as seen by the rapid temperature increase.
Do’s and Don’ts
The report presents a list of recommendations for how electric scooters should be stored in a safe way. Among these recommendations are:
- Avoid storing and charging electric scooters and similar devices in living areas and escape routes.
- Building owners should facilitate safe storage of electric scooters and other equipment running on lithium-ion batteries. A good start would be to provide a dedicated storage area that is separated from escape routes, with no combustible material nearby, and equipped with functioning smoke detectors.
- The equipment can be stored outdoors, but preferably not in an area where it will be exposed to direct sunlight or freezing temperatures.
- The study was commissioned by the Norwegian Directorate for Civil Protection (DSB) and the Norwegian Building Authority (DiBK).
Janne Siren Fjærestad
janne.siren.fjarestad@risefr.no
Visit www.ri.se/en for more information.
