The car park fire is now in the clean up phase.
It does not seem good that a 3 year old car park which apparently met the requirements could burn so catastrophically. There was a similar fire in Liverpool in 2017. The official fire report raises a number of issues and questions.
To me the key point in the Liverpool fire was the spread of fuel due to the failure of plastic fuel tanks compounded by the drainage system.
Would requiring sprinklers help? Would sprinklers make an EV fire worse?
I'm no firefighting expert, but I'd be in two minds about water sprinklers in that situation - they should certainly help cool things down and so keep more surfaces below ignition temperature, but on the other hand if the problem is fuel flowing over floors, being that most fuels float on water and will often quite happily keep burning in that situation, I'd be worried about the water carrying the burning fuel further and faster than would otherwise have been the case. If the sprinklers were of the traditional glass bulb type that only opened an individual sprinkler head once the fire was reasonably close, I could almost imagine a worst case situations where the sprinklers above the burning fuel had triggered, but the ones above and somewhat ahead of the fire front (where wet cooling would be most effective in preventing subsequent vehicles catching fire) would still be closed, then opening as the fire arrives, just in time to help spread the fuel from the newly ignited cars. Maybe I'm over-thinking this - just put it down to being of the generation that had it drummed into us never ever to put water on chip-pan fires.
Thermal run-away from batteries I'm sure must be a different kettle of fish. It's not a "traditional" fire to my mind - the heating effect isn't at all dependent on a chain reaction involving fuel, heat and oxygen. Do almost what you like you're not going to make much difference to the amount of (heat) energy being produced by current and resistive heating. I guess water would be helpful in cooling neighbouring vehicles, so slowing the spread of fire. I'd almost be less worried about pouring water on an EV than on an ICE vehicle. There may be some nasty voltages in the battery, but (if the vehicle isn't on charge) they're not particularly earth referenced, and if the thing is on fire anyway no-one is likely to get close enough for any risk of a direct shock. I don't know if lithium (in whatever form it is in batteries) reacts with water (like some other metals do).
- Andy.
This is an interesting situation. Firstly there are several things that need to be considered at the design stage. Normal operation and then fault/incident operation.
Normal operation some consideration points
Is/Are as many items of the structure and install fire retardant or self extinguishing.
Fixed wiring could be AC as well as DC and probably 3 phase. It could have EVSE in operation, it may not.
What will be in the structure? ICE vehicles and EVs
Fire detection and suppression and monitoring. This almost needs to go hand in hand with an FRA (Fire Risk Assement)
Fault/incident operation some consideration points
If it is a vehicle fire what kind of vehicle is it, ICE or EV? It is difficult to deal with EV fire if you have the equipment or the mentality of dealing with an ICE fire.
Lets now say the fire was not an ICE (internal Combustion Engine) it is an EV. Lots of people bahing EV in the media for all sorts of reasons at the moment.
Further points to consider
Is it on charge or not at time of fire? What is the proximity to the next vehicle which could be ICE or EV? Can the EV on fire be moved to a safe space? Can you supress the EV fire? Fire containment? On a recent course I was shown several mobile phone Lithion battery fires and they burn vaciously and they can/could start a chain reaction by igniting the battery next to it. Most of the time the first indication is thermal runaway. There are 2 options avaialble considering the small size of the battery. Put the battery in a metal bucket full of sand or in a kind of fire safe and close door. Next stage is then to evacuate the building. It is fairly simple idea and concept as well as the safe working practice prior to the incident. All memebers of staff must have this training. However in a car park you will have a mixture of staff and the general public. so extra precautions are needed. Most people are unaware that battery fires in EV or mobile devices spread very quick, get very hot and don't realy exstinguish with water. In fact some of these fires you could put in a tank of water and they would continue to burn without atmospheric Oxygen.
'Lithium' batteries are mostly something else, only a few % lithium, and that is bound up in the plates.
Yes lithium element generates hydrogenand heat on contact with water, as the litium runs off with the oxygen,
The hydrogen takes a lot of volume or tries to, and is explosive mixed with air in the right concentration.
However, on balance, cooling a lithium battery with water is probably correct - if it is already burst and on fire any elemental lithium has probably gone, and cooling it will save adjacent cells, and an un-burst cell that is cooled is less likely to explode - gas pressure rising with temp and all that.
The problem can be that there is a lot of electric energy in a charged cell, and once shorted that comes out as heat, and in effect burning continues without air, unlike a normal fire.
The water may end up being quite unpleasant and needs to be very dilute or deliberately neutralised before it goes down the drain - some of the metal hydroxides are very caustic.
Mike.
For any kinds of Car, I believe that it is not suitable to use water-based material to eliminate fire. For ICE, fuel cannot stop burning with water, insteadly, leaked oil and fuel gas with steam may make the situation even worse(with hydrogen and oxygen), and cause burning of other material like polymer and paints; For EV, water may cause more short-circuit and hence more heat source, especially on a system that is lossing control of heat, and likely, melting its insulation material. Meanwhile, the pollution caused by corrosive solute may also increasing the damage of electronic system, like damaging the tubes and building structure, or make charging devices in the parking space( which is likely to be right close to EV car. The conductive water may also bring firefighter into danger, in case of the power system doesn't cutoff correctly when fire happens.
Water does have the advantage of being safe, and having a high heat capacity. You would need tonnes of sand to put out a single car fire .... Water based foams can be most effective on liquid fuels, or dry powders, but the water based foams are easier to get to site, and to clear up afterwards.
Mike.
Is there any update on this? It would be interesting to follow this on.
The investigation report is not expected before April 2024:
I see that Bedfordshire Fire & Rescue have pointed out quite forcefully that it was a diesel car that caught fire, not an EV.
But what we all expect is that it was a diesel hybrid car…
I didn't even know such a thing existed so looked it up. They are pretty rare beasts, but if like me you are curious then read on:-
We're about to take you to the IET registration website. Don't worry though, you'll be sent straight back to the community after completing the registration.
Continue to the IET registration site
