With such a striking title for this week’s Burning Matters newsletter, we welcome all opinions (and pitchforks) as we discuss: e-mobility devices - the boon or bane of fire safety?
Gone are the days when scooters were used to be powered solely by sheer human effort. The “kick scooters” have slowly faded into oblivion due to the rise of the electric-powered scooters or “e-scooters”.
Technology exists for the purpose of making the human experience better. As such, it does not come as a surprise that urban transportation in the form of e-scooters, e-bikes, and hoverboards has experienced a rapid proliferation in recent years. Certainly, e-mobility devices do not only contribute to faster transportation but also has the potential to play a role in the drive for sustainability and many developed countries have benefited energy-wise from a “shared e-mobility devices” scheme.
But with the rise of these devices, we also see a rapid increase in safety challenges, mainly surrounding the battery technology, lack of driving and road precautions, and essentially no harmonized standard for the manufacturing of e-mobility devices. How many videos have we watched and reposted that involved an e-mobility device catching fire for no apparent reason? Here is an example that went viral - e-device fire in India.
The London Fire Brigade (LFB) has recently released a statement to say
“So far in 2023 we've been called to, on average, an e-bike or e-scooter fire once every two days.”
This has resulted in Transport for London (TfL) banning commuters from bringing e-scooters or e-unicycles on TfL services or other premises in the public transport network. Rushed or reasonable?
Why is there no blanket ban for the use of Li Ion? Well, for years, our mobile phones and laptops have been powered by lithium-ion batteries (though with certain phones being banned on flights) and the fire statistics for these devices have been deemed acceptable. Therefore, lithium-ion batteries continue to be widely used due to their higher energy density, longer lifespan, and lower weight.
Why is the story so different when placed on e-mobility devices?
As these batteries are incorporated in transportation, they are more prone to external damage - direct, or due to the frequency of vibration and temperature variation. It is also known that transportation devices are powered by more lithium-ion cells, often as a pack, or even a module. Thus, there is a significantly higher potential for bigger fires - ones that are beyond the size that a person can and should deal with.
The reality surrounding lithium ion-related fires in e-mobility devices is that these fires are subject to ultra-fast fire growth and rapid release of toxic combustion products. A video produced by the Fire Safety Research Institute states that smoke from these fires can overpower occupants within seconds.
In 2023, the New York City Fire Department reported 18 fatalities in fires caused by lithium-ion batteries. "These fires are dangerous and fast-moving," they state. They have therefore provided a list of battery fire safety recommendations. Rather than banning, as a mitigation, the NYFD presents a quick risk assessment for e-mobility device owners:
- Check that the device never blocks exit paths.
- Check if battery is certified; if not, do not use the device.
- When charging, be present. Never charge the battery overnight.
- Check for signs of battery damage (swelling, disfiguration etc.); do not use the device if there are.
This simple yet comprehensive checklist is straightforward for anyone to apply.
In hindsight, novel technology has been essentially a common theme of the Burning Matters newsletter over the past publications. From EVs to PVs, are we truly equipped to address the challenges that arise from these novel technologies from a fire safety perspective?
The newsletter always aims to maintain a neutral stance to foster holistic discussions. However, we also maintain that banning these devices should never be our first knee-jerk reaction. In our pursuit to incorporate novel technologies in our daily lives, we call support from crucial stakeholders: E-mobility device owners, Fire Engineers, Legislators. Each must play a part, starting with the owners who need to ensure that they are applying good charging practices.
E-mobility device owners - Take Charge. This UL campaign for battery fire safety, where each letter provides a recommendation, is essential. Additionally, never play mechanic to your e-scooters! We are still understanding the intricacies of lithium-ion batteries and any personal modifications may damage the battery, leading to serious consequences.
A very important recommendation!
Fire Engineers – ensure that they design to the worst-case scenario by understanding the design fire of the technology. Some experiments on e-mobility fires based on probable heat release rate values are already available online. Research by Max Lakkonen from the Institute for Applied Fire Safety Research (IFAB), a German-based fire safety engineering, testing, and consultancy company, serves as a good starting point. This is presented in the IFAB webinar "E-bikes on trains / Fire safety".
Reasonable design fire curve for e-bikes according to IFAB experiments. Image from IFAB webinar.
The test results also include gas measurements for potential toxic products. IFAB reports that the obtained HRR curve can be applied in contexts beyond rolling stock fires.
To quote from Wojciech Węgrzyński’s post following the Metro fire in Toronto [see photo below]: “We have always requested at least a 𝟭 𝗠𝗪 design fire for any space (even empty) in any part of the subway systems we were designing. Even though other stakeholders were bashing us - why do we need useless smoke control in a space WHERE NOTHING CAN BURN? A few years later, people walk into trains with portable 1 MW fires... ”.
An e-bike fire engulfed a subway train in Toronto at the last day of 2023. (X / JOE_WARMINGTON)
Fire engineers are therefore strongly encouraged to move beyond the status quo and implement more thorough risk assessments on potential fire sources.
Legislators – ensure that the market is protected from inferior products by enforcing strict testing guidelines.
The U.K. Department for Transport has recommended buying an e-scooter from a reputable retailer. They have also warned buyers about second-hand, refurbished, or converted e-scooters. It is difficult to ascertain whether they are damaged or counterfeit products and whether they are tested to industry standards. The Department advises looking for a CE or UKCA marking.
The list could go on to include everyone in the NFPA Fire & Life Safety Ecosystem:
Referenced standards and government responsibility are falling behind when it comes to battery fire safety.
We also recommend that people use readily available resources, such as the interviews with Adam Barowy (Episodes 85 and 137) - a leading battery fire researcher - in the Fire Science Show, which has no less than 12 episodes related to this topic.
In discussing the bad, we must also take it with the good. And we cannot diminish the benefits of these e-mobility devices, especially in aiding mobility-impaired personnel. I certainly can no longer envision a world dominated by kick scooters.
Still, we want to avoid fatal fires and massive fires like this one in Germany, where 1200 e-scooters were involved in a fire that was fought by about 200 firefighters, and one firefighter injured in a fall when the roof collapsed. The electric scooters exploded one after the other in a domino effect under the effect of the heat, with materials thrown into the street.
