- Graeme Warnell
The Need For Environmentally Responsible EV Hub Design For Fire Suppression & Fire Water Management
Water and air quality are at the forefront of the world’s most pressing environmental issues.
Moving to alternative energy in the vehicle sector is helping the world to slowly progress to its carbon reduction goals.
Whilst we tend to focus on the upside of new technology, we have to take into consideration any negative environmental impact or risk that may increase over time.
UK EV charging infrastructure will receive over £1bn in investment over the next 10 years and it is estimated that EV numbers will reach 7.9m in the UK by 2031.
At the moment the majority of EV infrastructure is relatively new and in good condition. But what does this infrastructure look like in 10 years’ and how does it stand the test of time of intensive customer usage? Luckily EV fires are very rare, however much of this is due to the age profile of both EV’s and the associated infrastructure and a relatively low density of EV cars on the roads.
As EV car numbers increase over time, so does the risk of incidents resulting in EV fires. Given this possibility, have we designed the EV infrastructure to sufficiently protect both the public and the environment?
As time progresses, wear and tear on EV’s will increase. Minor road traffic accidents, driving over potholes and road debris impacting the underside of EV’s can all result in damage to a single cell of an EV battery which remains unseen and undetected.
In addition to the above, the consumers ongoing desire for ever faster charging means more strain is put on the EV battery with each charge, and with time, cheaper, lower quality charging cables will become more prevalent on the market.
If we look at all these factors together there is no doubt that we will see more incidents of thermal runaway from batteries resulting in EV fires in and around roads, driveways, public parking areas and on forecourts or standalone EV charging hubs.
So, what is the real difference between an EV related fire and a typical internal combustion engine fire in terms of what is consists of, how it is suppressed and what public health and environmental risks they create.
Firstly, an EV lithium-ion battery fire is far hotter than a typical ICE fire. The EV will burn at around 1200 degrees Celsius and an ICE vehicle at 600 degrees. This means the impact of the fire on the adjacent cars, canopies and charging infrastructure is more far reaching and can lead to a quicker ignition of objects in the surrounding area. An EV fire will frequently create large direction flames known as “jetting”. These can extend outwards of the fire for up to 3m in a manner that somewhat resembles a very large blow torch.
Another factor to consider is the explosive gas cloud emitted from a battery in thermal runaway which is often proceeded by a loud hissing sound.
During an EV fire there will also be significant volume of both smoke and soot emitted, both of which are highly toxic and potentially fatal. The smoke will contain both carbon monoxide and hydrogen cyanide whilst the soot will contain heavy metal particulates such as cobalt, nickel and manganese oxides. These toxic oxides can cause severe allergic skin reactions so great care needs to be undertaken in any post fire clean-up operation which may extend well outside of the EV facility itself.
As a result of all these properties of EV fires it is clear that there is a significant risk to anyone trying to tackle them who is not wearing and trained in the use of protective breathing apparatus and flame retardant clothing. Whereas member of the public may be confident enough to empty a sand bucket onto a liquid fuel spill or discharge a carbon dioxide fire extinguisher for an ICE car fire they should never attempt to deal with an EV fire themselves.
The risk to the public is significantly increased should the EV fire occur in a basement or multi storey car park. The Swiss Federal Laboratories for Materials Science and Technology recently undertook a number of studies on lithium-ion battery fires in a road tunnel environment. They discovered that the high volumes of smoke and soot density soon rendered visibility within the tunnel down to less than 0.5m. In a basement or multi storey car park the reduction in visibility will severely reduce the ability of people to locate the emergency exits safely. The confined concentrations of toxic smoke and soot make any basement or car park charging facility extremely hazardous for not only the public trapped in the area but also for firefighters trying to locate the fire.
Consideration must also be given to the location of EV chargers in relation to allocated disabled and parent child parking where people may be less able to react quickly to evacuate the area safely. This leads me to ask should we not be installing smoke extraction units specifically designed for EV fires in basements and underground car parks?
In terms of the actual fire itself, studies by the University of Newcastle demonstrated that the extreme heat intensity of lithium-ion batteries could also result in a structural weakening of concrete and other common construction materials. Are the basements and multi storey car parks where EV charging poles are now being installed, designed for these new fire risks and are the current fire suppression systems still fit for purpose?
In terms of multi storey and basement car park fire suppression systems, current sprinkler systems will have little impact on an EV fire. These were also tested by the Swiss Federal Laboratories for Materials Science and Technology who found that the typical water fed sprinkler system has no effect on extinguishing the lithium-ion battery which simply burned itself out over time.
At present there are a vast array of challenges for the emergency services in dealing with EV fires and the most common approach is based on trying to cool the battery to stop the thermal runaway and therefore stop the fire.
This is of course far easier said than done. EV batteries are difficult to access being mostly installed underneath the car and by design they are supposed to be waterproof. Depending on how quickly the fire catches hold and potentially spreads, other vehicles or infrastructure may inhibit any clear access to try and cool the battery.
It has been estimated that over 10,000 litres of water are required to sufficiently cool an EV battery fire to the point of stopping thermal runaway and suppressing the fire, although the risk or re ignition is possible for days afterwards with a badly damaged battery.
Like the toxicity issues contained within the smoke and soot, any firewater will be highly contaminated with over 100 organics chemicals and a range of toxic heavy metals. When the Swiss Federal Laboratories for Materials Science and Technology carried out an analysis of firewater used to extinguish a lithium-ion battery fore they found it contained a level of toxins and chemicals 70 -100 times greater than the levels allow in the discharge of industrial water. They stated, “under no circumstances should this water ever be allowed to enter the sewer system or natural environment”.
Whenever I go to an EV charging facility I always make a note of where the drainage is and every time, I see everything flows to rainwater storm drains and in many cases on motorway service areas into balancing ponds. When the emergency services attend their priority will be public safety in terms of evacuation and then restricting public access to the area and then extinguishing the fire. It is not the responsibility of the emergency services to ensure contaminated fire water does not lead to a contamination event, this is the site operator’s responsibility under law.
Having spent over 30 years working in the retail petroleum sector I remember the 3 golden rules we always had regarding petrol filling stations were:
1. No harm to the environment
2. No risk of fire or explosion
3. No harm to the public
When we built and maintained petrol filling stations all these factors were reduced to the lowest possible level through design risk management. In the event of an incident physical means of protecting the environment and public were always in place.
For me not much has changed in terms of the 3 biggest risks on an EV charging facility in terms of environmental contamination, fire or explosion and public safety but I see nothing included in EV infrastructure design to mitigate these risks. I find this very hard to understand as in many cases we are talking about the same industry that operates hydrocarbon sites and EV sites, why are the same principles of risk management not applied to both?
From what we know about EV fires as an industry, we must ensure that the potential risks of EV fires are included in EV infrastructure design. At present EV fires are thankfully few and far between. However, when we have an estimated 7.9m cars on the road in the UK using infrastructure reaching back over 15 years we can certainly expect for fire related issues to occur which increase the risk to public health, safety and the integrity of the environment.
For any operators or local authorities interested in understanding the risks associated with existing or planned EV charging locations please do not hesitate to reach out to Graeme Warnell at email@example.com. We are currently working with a range of like-minded industry experts across the UK and Europe to ensure the transition to EV upholds its planned legacy to deliver a clean alternative to hydrocarbons that is safe for everyone and the environment for decades to come.