As we progress steadily closer to 2062, the year in which the Jetsons take to the skies in flying cars, we are instead turning our attention to the space beneath our feet.
Tunnels present opportunities for dispelling traffic and avoiding the environmental impacts a major above-ground road can pose.
Elon Musk touts the vision of an underground transport network and The Boring Company birthed its first futuristic tunnel in California in 2018 with vehicles, like the Tesla Model X, which power themselves.
As we move underground (both figuratively and literally), another transition is occurring from petrol-fuelled cars to alternatively-fuelled vehicles (AFVs).
Brussels has already mandated the transition to AFVs by 2035, banning cars running on diesel after 2030 and all other petrol vehicles five years later. There are now seven countries in Europe that have announced measures to phase out petrol and diesel vehicles to make way for their electric successors.
With the seemingly pre-ordained marriage of tunnels and AFVs, a new array of risks expose themselves.
Electric and hydrogen vehicles present previously unexplored scenarios first responders must be trained to deal with and tunnels must be designed to cater for.
While electric vehicles are not necessarily more dangerous than their petrol-fuelled counterparts, which can also pose fire risks, the different scenarios they bring require strategy and planning.
Lithium-ion batteries, for example, are very difficult to extinguish once ignited.
In Tesla’s online Emergency Response Guide, it states: “Battery fires can take up to 24 hours to extinguish. Consider allowing the battery to burn while protecting exposures.”
Twenty-four hours is an unrealistic time frame for most roads, let alone a tunnel environment.
Tesla cites a number of other factors which are specific to electric vehicles:
- More than 11,000 litres of water may be required to extinguish a battery fire
- Responders should prevent making contact with high voltage components (how many responders would know which components are high voltage?)
- Insulated tools should be used for overhaul
- Fire can compromise airbag inflators, stored gas inflation cylinders, gas struts, and other components which can result in “an unexpected explosion”
- Due to potential re-ignition, the car should be stored with at least 50 feet clearance
- Burning batteries release to vapors which can include volatile organic compounds, hydrogen gas, hydrogen gas, carbon dioxide, carbon monoxide, soot, etc.
In research conducted around ‘Risks associated with alternative fuels in road tunnels and underground garages’, highlights elements to consider when responding to incidents involving electric vehicles:
- During an incident, the safety system of the car should disconnect the battery from the electric propulsion system and, as an extra safety measure, the ignition should be turned off and the 12-volt battery disconnected. (This prevents the car from ‘driving itself’ away).
- If the car is charging, the cable should be unplugged.
- Electric vehicles built since 1997 always have orange cables placed in the chassis, meaning that it is safe to cut the pillars. Hydraulic rescue spreaders that are propped against the rear of the back seat should, however, be avoided as batteries are sometimes placed within the rear of the back seat.
- It is safe to wade or dive down to a submerged electric vehicle in order to save passengers. Live battery parts should, however, not be opened or touched when under water.
- Electric vehicles built since 2012 are equipped solely with Li-ion batteries, the battery fluid of which is not corrosive but is combustible.
- During fires, fire gases should be ventilated to decrease the concentration of flammable and/or harmful gases. Flames should then be suppressed and the car cooled (which may require large amounts of cooling agents). If the battery is not visibly smoking and the temperature in the battery decreases, as determined by a thermal imaging camera, the vehicle can be moved from the incident site.
- If the temperature in the battery cells exceeds 190°C and continues to rise, thermal runaway can occur.
- Fog Nails and cold cutting extinguishers should not be used in scenarios involving battery packs.
- Those responsible for the car after the rescue operation has been concluded should be aware that there is a risk of re-ignition in the battery, which should be placed so that, in the event of a second fire, it can cause no harm or damage.
As we enter a new era of transportation, tunnel owners and operators must ensure tunnels are safe and compliant, while also being cost efficient and sustainable. Advancements in technology both enhance traffic flow and require new approaches to ensure safety and security remain at their highest.
International leader in the field, Kurt Vollmacher, Project Leader of ISO On Global Rescue Information, Belgium, is coming to Melbourne this March to share his insights for considerations for alternatively fuelled vehicles in tunnels. Kurt will analyse the risks associated with electric and hydrogen vehicles, share examples of AFVs that have caught fire, and explain how to adapt safety and contingency plans.
Hear from Kurt at the Future Proofing Tunnel Operations conference, being held in Melbourne from 25 – 26 March, presents strategies and solutions to the biggest challenges facing sector professionals including operational efficiency, fire safety, emergency preparedness and risk management. This event is a unique opportunity for you to learn from innovative local and international case studies on improving tunnel operations and preparing for the future.