137 - e-mobility fires with Adam Barowy

Everybody, welcome to the fire science show. At the very beginning of this year and one of the first days, there was an interesting fire in Toronto subway where a single electric scooter device, some sort of an e-bike, has caught fire in the rolling stock. At first hand the consequences did not look very severe and I don't think it changed tremendously. I think there was a single person injured and the damage to the rolling stock was not so bad. And when I saw this fire, I kind of contemplated what if? What if this fire happened when the train was more congested? What if such a fire happened and the train stopped not at the station but in between the stations for some reason? What if there was a piece of luggage next to the e-bike? So many different scenarios, so many ways. This even could turn around in a different way. And looking through the internet, having daily discussions with all of you on LinkedIn or in the community, these kinds of fires happen more and more often. I've said it many times for that, for me, these immobility devices are some sort of a hazard that is much bigger than it looks on the first hand. Everyone's focusing on electric vehicles, cars, but for me, these scooters, the uncontrolled, uncertified devices that people take together with them, bring into different places. I think this is the real hazard of electric mobility nowadays that we, as far as safety engineering community, should focus on, and previously I had podcast episodes about this already One year ago. I've met with Adam Barovar from FSRI, who has been researching this subject for a long time, and I thought after the Toronto Fire, I should capture Adam once again and see what has changed over the last year and what more we have learned. And it seems it was a great idea because, after this talk with Adam and that you're about to listen, I've learned a lot of new things that were happening. In this episode we're discussing the explosion hazards related to batteries. We're discussing how FSRI has been studying that. We're discussing some outcomes of residential sprinklers and battery fires. We're discussing all sorts of hazards that are related to batteries, not just the fires, but also the toxicity and, as mentioned, explosion one. So I guess, a nice update to what we know on lithium ion batteries, what research directions are pursued for the near future and what to expect from upcoming research and certification efforts around. So, yeah, please join me and Adam Barovar on this discussion of the fire safety of micro mobility devices. Let's spin the intro and jump into the episode. Welcome to the fireside show. My Wojciech is and I will be your host. This podcast is brought to you in collaboration with OFR consultants. Ofr is the UK's leading fire risk consultancy. Its globally established team has developed a reputation for preeminent fire engineering expertise, with colleagues working across the world to help protect people, property and environment. Established in the UK in 2016 as a startup business of two highly experienced fire engineering consultants, the business has grown phenomenally in just seven years, with offices across the country in seven locations, from Edinburgh to Bath, and now employing more than a hundred professionals. Colleagues are on a mission to continually explore the challenges that fire creates for clients and society, applying the best research, experience and diligence for effective, tailored fire safety solutions. In 2024, ofr will grow its team once more and is always keen to hear from industry professionals who would like to collaborate on fire safety futures this year. Get in touch at OFRconsultantscom. Hello everybody, welcome to the fireside show. I am joined today once again by Adam Barowy from FSRI.

Hey, adam good to have you in the show. Great to be here. Thanks for having me here, Richard Almost exactly one year ago.

We've met here to discuss some challenges with electrical vehicles and electrical storage, and it seems that the topic has not died at all. It continues to be on everyone's mind, especially with a lot of recent incidents we have seen around. So first, before we go into the details, maybe tell me what you have been up to for the last year. What has been FSRI working on in this regard?

Well, it's a very exciting time to be working at FSRI because we're basically pursuing a program of battery fire safety research. We talked about micro-mobility last year, and so we've advanced our micro-mobility research a bit to look at the ability of residential sprinklers to control some of the fast growing hazard conditions we saw at residences. We've kicked off a three-year project in electric vehicles so your previous episodes with the other guests which have looked at electric vehicles have been really helpful in that and I think we're beginning to see some of the same things. Our testing actually begins this month in earnest and then we're going to continue to look at micro-mobility. I believe in some transportation scenarios. That's really in the works, maybe later this year, and then for energy storage, one thing that we've partnered with our friends at UL Solutions in Chicago on was trying to standardize explosion testing for energy storage a bit. So, it's more engineering than science. We ran some sort of premixed gas scenarios, looking at how to instrument explosion tests in a standardized way to get the data that people are going to be looking for when citing energy storage, say in grid scale.

Oh, now that's more than one podcast episode. This is a lot, fantastic, great to know and absolutely seems on the rise. In ITB we're also picking up on micro-mobility in terms of defining the consequences of those fires in corridor fires, hmf fires, office fires not very residential settings, because it seems you guys are doing that a lot. But we thought that people take those devices with them wherever they go into office. They would park it in a corridor or something and we are really interested in what outcome of such a fire can be. Definitely a lot of research happening, but let's focus on what we know already, because we're engineers and we have to engineer today, not to waiting for you or me to end up our most interesting research and then publish it five years later. Anyway, let's talk about design scenarios because I think that's something we have not covered last time. I now have heat release rate curve. That comes from IFAB as a laboratory in Germany who has done some electric bike fires. Their experiments. They've observed very quick fire growth of an e-bike to something like 900-ish kilowatts less than a minute. Very quick peak, but also followed by a rather quick decay of that fire and then, let's say, a 10-minute long period of low-energy fire like 100 kilowatts. So that's a reference point that I have. I don't have many more. I know that you have also put some of your devices into calorimetry devices, so perhaps you can share what you have found in your experiments.

Sure, yeah, I think the most interesting experiments we did were on overcharged e-bikes scenarios. So it's the full battery pack inside the e-bike. When I talk about e-bike, I mean I think I have to be specific that I'm talking about the things that get called e-bikes in New York City, so a lot of them are really like sit-out-cop scooters, so the terminology is kind of loose. But what it means is they have about a kilowatt-hour battery pack. Okay, so somewhere in the area of like 150, 18650 style lithium ion cells and that's within a frame which is covered in plastic parts, I think polypropylene some of them. We saw them getting melty and drippy, but calorimetry, as what we saw when we overcharged them was very quick propagation from cell to cell inside that sort of metal enclosed battery box, and that resulted in about a megawatt in about 30 seconds. Okay, so very, very fast fires. But then there's not an insignificant amount of other materials on the bike. So then that decays very quickly because there's not a lot of combustible material in a battery. It just sort of volatiles as quickly and then it transitions to the plastics of the seat and everything that's kind of covering the frame and the headlight shroud and all of that and we get about a 700 kilowatt fire that grows a bit more slowly after the fast impact and lasts a few minutes. So in terms of where the hazard is, it's really probably just that battery pack, but it's interesting that the bike is still provided a non-insignificant amount of fuel.

That's interesting. And in terms of those battery pack fires, have you had any like confirmation that it was the entire battery pack involved? Was it, I don't know, half of it? The third of it.

What we've seen we have a pretty good relationship with FDNY and what we've seen from their incident photos when they're asking us some questions about fire dynamics is almost always to me by eye. It looks like the entire battery pack goes into a thorough runaway. But there's a standard operating procedure which they have documented now and spread within their department that in some of these fires and definitely on our webpage if you watch one of our eBike fires there's enough force behind the gases venting from the cells that they can actually break their tab welded connections and be thrown across the room. Also for the fire service that means a couple new hazards. It can mean hot cells are sent across the room and providing a secondary ignition source not as big a deal to the fire services if it's been heat damaged. And now you've got this cell that you don't know it's integrity and you can't find it presenting a re-ignition some time later. So they actually make a concerted effort after a fire to look at the battery pack and determine if all the cells are there and if they're not making sure during overhaul to go find those other ejected cells. It really kind of pain the neck actually. That's the fire hazards.

I would not have thought about. And I have a name. Let's call them eFire Brands, you know, like a modern brand. Okay, and in your colorimeter, I assume, when you have burned down through the battery and you had plastics surrounding the battery going on and assuming they have not flown away from your colorimeter, I guess the entirety of it burned. I'm asking because I want to estimate like what would be the peak, peak, like what if all of them went like immediately together, but I guess it would still be in this megawatt ish range.

Yeah, it would be, and it's really governed by how big the battery pack is. I don't think you're going to see much bigger than a megawatt because we don't really see, you know, say, aftermarket batteries or replacement batteries being sold in a size much bigger than that. I think it's a limit of practicality of what shits on the eBike so they may add a second battery pack on a different location in the bike like a second module. Yeah. But there's a couple incidents. One of our own actually sort of it was a research test that just didn't go the way we expected. We built a representative residential energy storage system in the same way you'd build one of these cheap eBike batteries and but just because it was bigger, we had about seven megawatts of fire growth within about a minute. Actually that was still really within about 30 seconds now to think about and burn just as fast. But obviously that was very alarming. It didn't meet our design objectives. So we said, okay, well, we have to put some propagation resistance in. So it's representative of real products. But in Colorado there was a business that takes the gas drivetrains off commercial vehicles, like a, like a 12 foot box truck, and replaces an electric vehicle drivetrain. So where the saddle fuel tank is, they were putting sort of like the saddle battery pack and it was similar to an eBike battery. So there's this really wild dash cam video of cells being thrown sort of across the road in really dramatic fashion. It's almost kind of silly to watch and then I think that's a really very niche scenario, but it's. I think it points to the hazards of like DIY power walls and things which have become a little more popular Going back to what you've said before, that you have used overcharged batteries.

Overcharging was a prerequisite to this dramatic growth.

So overcharge certainly affects severity. So we saw the most severe fires when we had overcharge. We tried both overheating and overcharge and to be honest, I kind of prefer overheating as an experimentalist, just because it's more predictable. Overcharge is probably what's happening when people leave these on the charger unattended, and so you're getting these most severe fires out in the real world. But in a lab, especially in a commercial lab like the ones that we were testing in, time is really a commodity, and so overcharge might take four, six hours. It's very unpredictable because you've got these safety devices, even on individual cells, which are clicking on and off and preventing this from happening. We just we know it's happening in the field, so we would try to circumvent some of those protections. Still unpredictable, but overheat produced similar heat resistance, just not as severe.

I got to call back to the episode with the Lena where we discussed their tests at DBI on electric vehicles, and she also has mentioned that in one case where they hacked into the car battery and overcharged it, it was a much more violent fire they have not expected because in the previous fires they didn't had such a growth rate. So probably it's not about the. That the megawatt number is larger is about more of them going off at the same time or perhaps easier to trigger, I guess I I don't know about something tells me that this could be the case. Now to the source one megawatt. One megawatt is an interesting number Because, if I recall well, the room corner standard is approximately one megawatt ish size of a fire and that that test simulates if materials in a compartment can lead to a flash over or not, and in what time. So one megawatt is, so is a fire size that could potentially lead to a flash over fire in a compartment. So let's go into how those items can cause larger fires, because even if they start and go out within a minute or two, it's still a potential that fire spreads and becomes a manageable hazard. What's your experience with with secondary item ignitions and then what kind of materials can such a scooter ignite?

Sure, I mean. So when we did micro ability testing we did it in a ranch style home. That's probably pretty specific to North America but it's not too dissimilar from high rise style apartments. So we've used that to kind of extend our results to talking about what happens in high rise apartments in metropolitan areas. So we we did, for example, a couple different scenarios one in a closed bedroom which is about 10 feet by 12 feet, another in a sort of open concept living room which is connected to kitchen, open to a hallway, and we left one bedroom door open. So in both of those cases, when we forced thermal runaway by overcharge in these e-bikes, in both cases there was an initial offgassing before there was ignition and the ignition of that gas produced enough pressure rise. I mean we could probably nitpick about terminology, I like to call it a partial volume deflection that's how I see it as an engineer and that that produced enough pressure in both cases again to fail the windows. In the bedroom case it was a little more dramatic. We saw a glass ejected about 30 feet away from the structure and so now there's a loss of fire containment and there's a really strong ceiling jet. So in those particular battery packs of that model we're talking about. The fire was directed very strongly up I think there's probably something to that in contribution for severity and so there was flames rolling the ceiling very quickly and that really exacerbated fire growth to second items, which would include sort of the furniture in the bedroom, the bed covering, and so in the bedroom case we saw transition to flash over within one minute. But even within the more open, larger living room which I'm not remembering the dimensions off the top of my head it's at least two to three times bigger than that bedroom Even in that case we saw transition to flash over. So there was a three seat sofa that was probably about three and a half feet away. That was ignited very quickly. In between the e-bike battery fire and that sofa we saw transition to flash over within a minute. So pretty remarkable.

So it's not just the heat release in terms of a megawatt, but also the increase in ventilation through damaging the partition or the windows and a directionality component to the fire itself. Is the directionality of the fire controllable in any way? Is it an outcome of where the safety vents are, or it's just random damage to the module?

I think it's really an artifact of the way these particular battery packs are designed, which is sort of like, if you think about, like I don't know a better explanation than like an ammo can, where there's like a one piece of metal forming five sides of the box and then a cheap lid which sort of sits over the top. Well, similar to how these battery boxes are built, so that the lids, the weak spots, so all of the ejected gas and actually in some cases you can see it blew the seat out of the way and then the jets just moved straight up. I guess one of the challenges with batteries is that in fire spread and in difficulty with fire suppression in all these different cases, especially with electric vehicles. I'll avoid the topic for now, but construction is so important to fire dynamics and the ability for suppression In this shreds.

I guess you cannot focus only on fire this hazard of those partial volume defibrations or whatever the proper term is to call them. It's so obvious that any fire engineer has to take that into account. Tell me what sort of damage you have observed. You've talked about windows flying out 30 feet away of the building. Is this consistent? Is it again an outcome of the size of the battery? What scatter of consequences have you observed related to those explosions?

Well, so a couple of years ago. Now we just so we've got a paper that we're working on this winter and spring. On research, we were in a couple of years ago looking at the size of gas release versus the consequence in the space, and so we can only look at one space. We chose to look at residential garages, based on some incidents that occurred with e-bikes and, frankly, we're anticipating electric vehicles and energy storage systems. There's actually a really very severe explosion that occurred in Germany from an electric vehicle and I know I'm sort of talking about multiple products here, but I always think about this in terms of it's being fundamentally driven by propagation of some runway and some battery. The battery doesn't care it. So we kind of looked at the garage space, as in North America, where you're likely going to have hazards occurring the most due to power tools or e-bikes or EV or ESS. So, given that you might have any different number of size gas releases, we want to understand, especially as it affects the first responder when does an explosion hazard begin to occur and what does that look like? Because some homeowner might say, oh, my power tools whistling here, it's making some funny smell, or my e-bike is whenever. So we did some tests where we manufactured some plastic bags of very specific volumes and in increasing sizes and we pre-bottled some gas mixtures to represent different chemistries of lithium ion battery. So one was a NCA cathode sort of representing NCA and NMC, another was lithium ion phosphate, the functional difference being there's more hydrogen in the lithium ion phosphate mixture. And so we iterated through these series from small bags to large bags to look at each time what damage occurs to the structure. And so obviously you start with some funny bang noises, you work your way up towards the garage door, starting to bow out, and then, as the garage door starts to attach, then you start to see some damage to the exterior wall. And so it's our goal to tie back through some reference research based on this amount of damage done by this amount of gas it's this size product and so we can have this dividing line for the fire service to say hypothetically I don't know really the answer right now, we've not finished the analysis it's going to take an e-bike or more for you to be hit by a flying garage door in the driveway, and this has really happened. I mean, there was really a battalion chief in Colorado and hit by a flying garage door that was ejected during the thermal runaway of a battery pack inside a hybrid vehicle.

I think I saw videos from those experiments and what you described was literally a large balloon, like very large balloon filled with gas mixture that you would ignite and it would explode. And I assume you've used those balloons of different sizes to mimic different sizes of batteries. I think it's a very clever surrogate tool to study those experiments. Those experiments are really expensive, to be honest, like even if you test e-bikes. Those e-bikes, like you would like to burn a lot of them and you have to purchase them and they cost a lot. It's not easy and especially now that you've mentioned you want to go into electric vehicles. That's something that I'm very jealous of, because this is probably a bit of an expensive to run real tires. I think it's very smart to actually maximize our knowledge generation through using surrogate fuels. At the beginning of the episode, you've also mentioned some standardization in this regard. In terms of explosions. Is a similar way a part of this standardization? Like you can standardize an explosion.

Yeah, I mean that's really going to be a grand challenge. I don't want to say that's one of our harem lairies, but explosion protection in energy storage at the grid scale is incredibly complicated and there's endless argument in the task groups on which way is the right way to provide explosion protection. There's a lot of modeling that can be done. There's amazing modeling work being done, but one of the challenges is there's a great deal of uncertainty but whether a concept is actually going to provide adequate protections. It's partly because in NFPA 68, which is the North American standard for deflagration venting I think it's EON 144014447. Anyway, there's a North American European analog for deflagration venting and the research data that formed those standards was based around industrial process equipment and so energy storage is at a much larger scale and we're beginning to see a lot of congestion inside but also very small free volumes. So there's concern that calculations for that standard are well suited for energy storage enclosures. So we wanted to provide a standardized approach. If we split the problem in half, there's how do you create the explosion part, and then there's how do you measure it? We ran research on standardizing how you measure the effects of an explosion, and so most of it's measuring, blast pressure, standardizing where you put the probes, how many you put, how far away you put them, and then also, I think one of the more fun parts to actually have a meeting following immediately is call using photometrics to capture shrapnel, identify its size, estimate its mass and estimate its trajectory, because shrapnel is a non-trivial thing to evaluate. I think we can use high-speed footage and assess whether or not there's a shrapnel hazard or there's kind of the time-honored way and some standards, especially some old US standards, where you paint a white line three feet away and say anything past the white line is a hazard.

That's robust.

It's challenging. So when you go to a bomb range, though, and you have to go find all the parts, turns out bomb ranges are full of parts from previous tests, I can imagine.

And what did? The cold doesn't explode. Have you done any measurements on, for example, the toxicity of the amount of smoke produced, because it seems like quite a significant amount even from a single e-bike battery, of those off-gas products.

Yeah, I think you can do some meaningful back-of-the-unvillage calculations. To say, if it doesn't burn, just multiply the number of cells by some cited research. It tells you its gas composition and the amount of volume that comes out. And that gives you some sense that for an e-bike-sized battery, you're producing above immediately dangerous to life and health levels of CO. I'm not a toxicologist, but what becomes hard next is to say well, how does it affect people? I mean, really that's probably an entire episode on its own of the effects of these gases, but it's an area that we know we need to go into more. So, going back to our micro-mobility work, when we did sprinkler tests of micro-mobility, we saw that the NFPA13D and NFPA13R provided sprinkler designs were effective in both the closed bedroom and living room scenario at preventing the fire from transitioning to second items and causing flash over. So the way we saw the problem before was it doesn't matter what the toxicity is, because you won't have enough time being exposed. You die from the thermal exposure first.

As if it transitions to other items and creates a flash over and the toxicity of your battery doesn't matter, because the flash over will kill you more or less.

OK, now, in both of those scenarios we're talking about now, if you have a sprinkler, we're not really certain yet how toxicity will affect the occupants. But there was a case that we discussed at length with the FDNY Fire Marshal's office where there was a quadruple fatality above an e-bike repair store in Manhattan, and what's not clear is what type of exposure these people received so that they were on the floor above the fire. None of them were able to egress out, and so smoke may have been a part of impacting the visibility for egress, but also in terms of affecting their decision making In this building. It's kind of an old building, so there's not really fire stopping between the first floor and the second floor, and so it's clear that smoke accumulated very quickly on that floor, and the fire absolutely started in an area where batteries were being repaired and spread quickly to other batteries. But the way some of these e-bike repair shops work, especially in a place like New York City, is there's almost a free volume at night. The shops get stored with a lot of materials. If you look at incident photos that are available online, you can see dozens of e-bikes pulled out that are on the sidewalk. During firefighting, these things come out and get stacked up, and so there was obviously spread to other materials. One thing we're not sure of was the egress more impacted by the fact that this is a fast-growth fire, or is there contribution of CO in such great quantities from batteries that that affected people? That's a really important research question, tras, especially as we move towards some of the concerns that you have about micro-mobility storage in this effort to go safer with charging e-bikes.

You're segueing me to another question I had, because one scenario that I am really worried about now is the problems with growing storage of those micro-mobility devices. You just explain the case study in a workshop where those would be stored, but for me they are being stored everywhere Train stations, offices, car parks, underneath office buildings, where multi-people would come with those devices to work. They are being put against each other. And now you have said that it's approximately a megawatt-ish size of a fire. I mean, it's a nice round number that's sticked to one megawatt, easy to remember. How do you see some areas of propagation between device to device in a setting where they are orderly placed, you know, like parked? I don't think people would just throw one e-bike on another when they're parking in their office. So they would be like, let's say, stored in orderly manner.

And in a scenario where they are densely packed because they are stored for other reasons, for example, yeah, this is already something that authorities having jurisdiction in the US are beginning to send us questions on. I was already asked, in fact, this week how far apart should I require these bikes to be spaced, and I don't think that anyone has run that test yet. A bit of my concern. This actually kind of reminds me of the conversation in your podcast on carparks as it related to ceiling height, these strong jets moving so quickly up and rolling flames across the ceiling. I think that that test, when it's run, needs to be not under just open calorimetry. I think you really need that ceiling there to adequately capture that seedback mechanism of flames across the ceiling to other bikes. If we begin to look at the heat transfer to the other bikes, so I think we'll see some interesting things. They are often clad in a lot of really thin, lightweight plastic materials which would probably be the first thing to ignite on those bikes. The batteries themselves are pretty well nestled, often nestled pretty well into the frame under the seed or something like that, and so they'll be fairly well thermally protected for a while. So I think the material begins to burn around them and then you typically have an air gap, even though it's small, between the cells in the bike battery pack and closure, and so I can imagine a scenario where you have the combustibles on the bike burning away and then, somewhat unpredictably, then you get these all of a sudden battery pack propagations that are on the order of a megawatt, maybe a little less because it's not being overcharged or something, but you have very quick propagation through individual battery packs and that situation, as long as the room is not in too much an underventilated scenario, I think we tend to speed up.

Those fires can also make their own ventilation if they blow up the vapor cloud. That's an interesting twist and challenge in there. Have you tried setting them on fire from a time limited heat sources, Like I don't know? Put a blowtorch for like 30 seconds and see if it catches up for one minute? Have you found the critical amount of heat that needed to be supplied from external source to a battery to set it off consistently?

We haven't, because the easiest, most repeatable way for us to do the tests. We're typically concerned with series and trying to provide the same source fire, so we usually use a flexible, still sticky heater. Stick them directly to the pulse when we get into our electric vehicle work. Just do the practicality of modifying battery packs. We're doing exactly as you say, sort of repeating some of the work of RISE and using an external gas burner. But there's a couple of scenarios in which we had to deal with sort of disposal, in which we yeah, that's my question.

On one end, I am absolutely sure it's not just putting a battery against the fire and it's going to immediately explode. On the other hand, if I put it long enough, it's going to go. So the answer must be somewhere between never and sometimes the question is how much does it take?

Yeah, I would say it will take not less than five minutes but probably more like 10 minutes or more, and I'm basing that off of. So again, also about two years ago, in the same timeframe as when we ran the explosion research, we ran some scenarios in which we put mock-up residential energy storage systems, physically constructed similar to these unregulated e-bike batteries Cells, just sort of put in a grid inside a steel box, and we ran scenarios where we started the runaway in the battery pack first. But we ran other scenarios where we had a two-car garage and we used a group, a commodity which is very commonly used in the sprinkler industry cardboard and plastic cups and we put this exposure that was probably about I know we did caliturritory, I want to say it grew to about two megawatts, so this seven-foot-tall storage of boxes next to this battery pack. We ignited the boxes and see if this immediate exposure that took six inches away and we were not able to get the batteries to go into a runaway in the time it took for the garage to get under-ventilated and then we let it sit for like 10 minutes more and it still did not go into a runaway even with this fairly hot compartment. So in that case we actually had to force those cells to throw a runaway. So those simple steel enclosures actually provide pretty remarkable protection against an external threat. So the fires may have to burst for quite a while to get the battery pack to go.

That's very interesting because if we go back to the start of the conversation, one megawatt fire, 30 seconds and then perhaps a quick going down of the fire curve this could mean that even if there's an e-bike next to an e-bike, this initial jet fire of the off-venting gases could not be enough. But you've also mentioned that there are plastic parts in the e-bike that would catch fire. So actually the fire of the second battery would be like a tertiary fire. There would have to be something that continues burning and then probably those other batteries can go off and once they start it's going to probably be something cascading. That's on one hand, reassuring. On the other hand, I can see this be a very challenging scenario if that coincides at the time that firefighters get at the scene because they have no idea which phase of the fire. It's not a clear phase of the fire, it's not that. Oh yeah, it's flash over.

Oh, yeah, you're emphasizing a really important point for the fire service. Across these many incidents that occurred in New York, whether they're at an e-bike retail store or an e-bike repair shop, there's also been storage units, which I don't understand the backstory, but they're sort of stuffed full of e-bikes. The fire, as far as I understand, this is all. Public information is typically limited to one or maybe two e-bikes and then the other combustibles in the area. What really challenges the fire service, though, is when they say that these other battery packs and these other bikes have been heat-impact. Stability has been affected in a way that you can't assess. I don't even think experimentally. You could take it to a lab and assess the stability, put it on some shaker table or something maybe, but now they're all suspicious In a fire suppression scenario. They're very reluctant to move past e-bikes in an active room fire that have been thermally exposed, because it can mean a fast-growing fire behind them. That means now they're having to worry about pulling them out of the structure. You'll see that again in some of these post-incident photos where there's e-bikes stacked going down the sidewalk, and there's been some instances where there's been re-ignitions either when they're in the e-bike or during the salvage operation where the e-bikes are sort of deconstructed right there on the street and put into drums and brought away by some hazmat operator.

So you said that it's a possible scenario that a battery has been exposed to the heat flux. It did not ignite immediately, but it's like, let's say, put into an unstable state where it can go off like minutes, hours later as a consequence of that exposure?

Yes, and we've been struggling with a way to assess that ongoing risk for years. The way, frankly, that we deal with this I'm not doing commercial work anymore, but the way the commercial team deals with this is to remove all doubt for anything that's been thermally insulted and has integrity compromised. Those products go straight into a bride solution that they developed, which is basically baking soda in water and that provides a cooling bath that allows this safe electrical discharge, and then sometime, maybe two, three weeks later, they're brought back out and fully disassembled without the electric energy stored inside. And that's just. It's a function of if you're going to keep testing these products, you need some way to mitigate their re-ignition hazard.

Yeah, absolutely. That's prices for a fire laboratory. I'm going to follow you up on that, because we also struggle with that.

I have a research paper for you then, because we were trying to optimize preventing corrosion with enabling electrical discharge. There's details in the paper, but it simplifies the matter greatly when you're working with a contractor for disposal Fantastic fantastic.

One more thing that happened literally a few weeks ago was a fire of a micro-mobility device in an underground train in Toronto, in Subway in Toronto, and over the last year, since our last discussion, I've heard multiple instances of authorities in different cities, municipalities, that would probably be taking any sort of e-bike devices onto public transport. So I wonder what's your assessment of this, of this hazard?

As an infrequent public transportation traveler, I mean I still worry about it. I'll be taking the train to Washington DC this week and I've seen them on trains. In fact, the trains usually here provide ability to plug in your laptop, so sometimes you see e-bikes charging. I'm mostly concerned with yeah, I'm mostly concerned with enforcement. I mean, it's going to take every staff member and some members of the public to identify when the wrong device is brought to the wrong part of the train. I think they want to move towards charging spaces here as well, unlike the Amtrakts. But in the meantime they've effectively started rolling out bans on the unregulated type products. But as someone who does this for a career, unless you really know what you're looking for and get up close and personal with all aspects of some other person's personal piece of property, it's kind of hard to identify whether it's regulated or unregulated. It's not easy. So I'm concerned that maybe it reduces the rate but it's not going to stop devices from coming onto transportation altogether.

As far as I'm aware of aircraft rules, I think you can carry power banks up to like 100 amp hours or something. It's not a very big power bank, to be honest, and that's already prohibited on the aircraft and I would assume that the aircraft industry is on the top of the game in banning those things from entering their vehicles. For the set fire in Toronto, what was interesting to me was that it was actually not horrible. There seemed to be one person injured which was the owner of the device. The post fire pictures shown that the fire has not propagated into the seats next to where the device was. So for me that was a victory of fire safety engineering, because it was engineered to not spread and it did not. So that's a victory for us. But then I was contemplating but yeah, what if this train has stopped in the middle of a tunnel, not at the station, which significantly increases the difficulties in evacuation? And what if the train was crowded? If it was crowded, the consequences would be directly more dramatic. Or perhaps if there was a piece of luggage next to the vehicle. So the more I contemplated the situation, I felt that the outcome was a lucky one, not necessarily an obvious one of such scenario. So as much as I am not in favour of banning stuff, I think if our engineers should figure out how to allow things to be done safely, in this case banning the devices- Sure, yeah, and maybe segregating passengers from e-bikes is the next step.

That would be easier than separating things out entirely, separating unregulated devices from transit. Those staff are already really busy managing passengers. I just don't see that as the total solution. So I think toxicity will be a significant concern. When you look at plane incidents you tend to see people are impacted by irritant gases and there's really been remarkable success in aviation with these power banks and cell phones. But I definitely run the mass. But I believe a train car is going to be a smaller volume and an e-bike battery is going to be bigger, so those effects will be stronger. But if you see that one megawatt fire, I'm not sure the radius on how far people will have to be away from that, but a busy train car you can really definitely expect some severe injuries. That's what scares me, I think.

Also there was some horrible videos of e-bikes going in on an elevator, which would be extremely small space. It would be with such a device in one space. Really horrible scenario. And perhaps to close our discussion, the commercial part of UL is deep into certification. Any updates in certification of batteries for immobility devices? Any progress in controlling the battery space?

Sure, yes, I mean UL 2272 and UL 2849, they're relatively unchanged, but there's been some success in rolling out regulation, primarily in New York City, in saying that's no longer a voluntary standard. If you want to sell these types of devices in New York City, they have to comply. Okay, that's exciting in terms of policy and I expect to see a ripple effect and see more of that nationally At the US Fire Administrator Summit back in October we called that out directly in front of the Homeland Security Secretary, who's looking to propagate that information out to mayors across the United States. There is actually one plug that I've been waiting all show to bring up. Go on. Ul 1487 is a standard that we have in progress, and so we've got manufacturers of batteries as well as manufacturers of devices that are intended to provide safe storage of these batteries. So basically, think about it like a flammable liquid storage cabinet for batteries, and in fact it sprung. The standard was proposed out of recognition of the fact that you can't take a red or yellow cabinet and paint it blue or green and call it green for batteries because of some of these exact issues we've talked about, and so we ran some demonstrations for the need for the standard by just putting simple battery packs inside a basic cabinet and we demonstrated very quickly in our first test that we blew the door off because the battery was confined. It became an explosion hazard. But it's this step forward in being able to prevent that transition, maybe without sprinklers, the transition from battery pack fire to room fire. There are some unresolved challenges as yet in the standard for effectively kind of like whose problem is it that unburned gas might be coming from the cabinet? If it's say, mitigating battery pack to battery pack propagation, keeping the problem small, there's still this well, the gases may be kind of toxic in some scenarios of small rooms.

And there can be a lot of it. Right, it can be hundreds of liters. Yeah, there can be a lot of it.

So the ideas like internal partitions may prevent some of the propagation throughout lots of batteries. But then there's still this management of gas hazard for toxicity and explosions. Great debates ongoing. The technical committee just met a couple of weeks ago and the goal is to get the first edition published this year. Start getting that type of product certified in a way that's perhaps similar to the battery containment bags on aviation, but the idea is the batteries are storage for normal use and potentially charging inside these cabinets.

This would be for, like, residential use, public use any.

So the manufacturers, the products, make all different types. I think probably the bread and butter will be like bicycle shops for having storage inside. But they also create some products for, say, first responders who want to go up and bring some batteries down from that high rise floor safely, like, obviously, elevator is terrible idea. You already got the windows an interesting idea, but kind of hard in practice. So this is a way to maybe bring things down through like a staircase. And then I mean they're looking at residential occupancies too. I know I've got power tools at home that if I could get one of these and afford it and knew as a good solution I'd probably buy it for myself.

One thing you mentioned power tools. Power tools have disposable batteries. Like you take it off the device. Many e-bikes would have batteries that you can take out of the device and charge, not as a part of a bike but a separate item. So if you had a storage that is, let's say, fit for the particular battery, not much larger, you would quite effectively also limit the amount of air oxygen that is in that space of the air. We've talked about the ventilation factors and how quickly such a battery can eat the oxygen surrounding it. So perhaps if you really had contained space, perhaps to some extent you could also slow down this propagation. Sell to sell Right.

I think so, but you remind me of kind of the funny story with e-bikes. So there are e-bikes like power assisted e-bikes from like major mountain bike retailers that do not have separable battery packs, and so on one of our trips to New Mexico to do a battery explosion research, we actually rented some of these bikes to try them out and explore them, and then we realized we need to charge them and we're in a hotel room that's a studio style. So I'm thinking, oh my gosh, if I have an incident where I'm injured by one of these e-bikes even though it's less likely to happen I'm going to look like a complete fool, because this is what I'm supposed to know about. So I've got some great photos of my mountain bike in the shower with the door shut to the bathroom, because it was the only way I could put a door between myself and the charging e-bike.

And you had a residential sprinkler, manually operated but still in there.

I mean, I was alone laughing hysterically, and then I showed the photos to my coworkers.

That's a good story. I mean, yeah, we had that. If we cause a fire right now, we're going to look like fools. Imagine the headlines via researchers set fire by researching fire. It seems they were wrong.

Oh, we have a fantastic relationship with the fire department near the fire laboratory, but we will do anything not to call it. You can imagine.

Good, good, good, adam. An hour has passed so quickly, as expected. There was a lot to talk about these immobility devices and it's very interesting to see the research directions. Last time we finished up with showing people the I think it was from New York fire department some brochures that told people how to safely use e-bikes. Any material worth recommending to the listeners in the past year that everyone should see? Oh geez.

I will get in trouble if I don't plug it. So if you go to batteryfiresafetyorg, that is the landing page for a public safety campaign which we ran this full and that is all about. So we've got this way of remembering battery safety. We call it take charge of battery safety and CHRG. Each letter of the acronym corresponds to guidance for safely using lithium ion battery-powered products. It's kind of geared towards e-bikes, but it applies to anything that's sort of used within your home, and so we've got a great PSA like eight minute video we put together for that, as well as some guidance downloadable sheets, and that's really intended for public education. So it's kind of a lot of fun to go through. It's a nice package that we give out at like community risk reduction events to kind of start getting the public's arms around battery safety Batteryfiresafetyorg.

I'll link it. Yes, I will link it in the show notes. I'll link the videos on the pamphlets in the show notes. I always say that, as far as engineers, there's not too much water talk talk. You can do with your friends and families, but actually I had a Discussion about electric vehicle fires with my doctor last time I visited them. As far engineers are responsible for bringing this up to the society every day, and having such well-produced Materials definitely makes this outreach significantly easier. So I'll link it to that For everyone to see and spread. So thanks, thanks for plugging it in and testing. Thank you so, adam Was. It was a pleasure. I hope to see you sooner than one year from now. Now, perhaps it's gonna be a January tradition to talk about the mobility fires, but I'm more than I'm more than interested about your EV fire results. So as soon as you have some something to share, please leave me a call and we'll do a special episode on that.

Yeah, I re-listened to all your EV episodes recently and I'm especially interested in how some of our data can help with car park fires so sick. I would love to catch up with you on that. I'm very, very excited about the heat flux theater we're gonna be producing, so we could go on about that for quite a while. I think that's good, that's good news for the podcast.

That's Adam. Thank you so much for joining me here and see your all. Man, thank you, okay, yeah, thanks very much for you. You're talking to you and that's it. I hope you've enjoyed this episode. It's always a great idea to invite someone from FSRI, given the scale and amount of research days guys are Producing. I'm always jealous when they get to talk with them because of their access to facilities great scientists, fantastic place to do fire research, and I'm very happy that they are very open to share it. It's a part of their philosophy, as you perhaps remember from the episode with Steve Kerber and Craig Vasion. Anyway, enough phrase. These guys know they are doing a good job. Fantastic research, fantastic catch up. I really appreciate Adam highlighting those non-obvious hazards related to micro mobility devices explosion hazard and how that connects to the risk of fires transitioning into flash over. That's something I have not thought about before that having an explosion hazard, an explosion happening in a small compartment, can lead to establishing a new flow path in that compartment and that, in a way, has Significant effect on how the fire can grow, what science the fire can grow into and how quickly it can flash over. Actually a very, very interesting thought offline. We've also discussed, like how such an explosion can affect integrity of small fire compartments, like imagine you have a bike storage Compartment somewhere underneath your skyscraper, that's. That's a separate fire compartment and perhaps an explosion can actually destroy the fire separation, like dampers or the fire doors. Even an interesting thing that I don't think that is well Researched for now, something that perhaps we will be looking into at the ITB. Another thing the toxicological hazards related to the off-cassing. This is absolutely something that we're gonna look into. How much gas is produced in such an event, how does that spread through a compartment and to what extent this is a immediate hazard to health and life for people affected by it. Very, very interesting thing and and definitely a research direction for us. And the third thing that really captured my attention was how the fire spreads between the devices. Again, reassuring information that it is not enough to just put us a fire source next to a battery to have it immediately go off. Of course, you are never certain when and how quickly it will go off, but it seems very unlikely that it will be an immediate reaction to the heating. There is a lot of heat transfer phenomena. There is quite strong shielding by the body in which the batteries are stored in, so Perhaps lesser Hazard than I thought of. I thought that in an e-bake storage facility, the fire would be just popping off from one vehicle to another, but it seems it may not be that easy. It may not be that case. I still can see such a scenario happening where you would have a flesh over in such a compartment. However, it doesn't seem to be like a a simple, easy, quick domino, as that's very reassuring how bad it is. We will research the hell out of that and then I will tell you so a lot of interesting information. Let me know on what is the new things that you have learned from this episode. Please join me in the community of the fire science show at community dot fire science show dot com. That's a great place where we can discuss such things and exchange materials, knowledge and learn from each other. I'm gonna work in the upcoming weeks, weeks to upgrade the site with more information, more online Resources that are valuable for you working continuously on the book of fire, to make it the best research based there is in Existence in the world of fire education. Very difficult to compete with you L but at least I'm linking their web page, so I guess I'm taking over their resources in some way. Anyway, thank you very much for being here with me this week. I hope that you've enjoyed this topic. If you have ideas what Episodes you would like to listen on the fire science show, well, with the community and the access to me is easier than ever Just go to the community fire science show dot com and send your ideas there. Oh, and if you're listening this, as the episode is launched, at the end of January I will have a free webinar on wind and fire. That's happening on the 7th of February and Details how to get into that webinar are on my LinkedIn. If you follow me on LinkedIn, you will easily find them. I will be spamming that information all over the internet. If you would like to learn about the outcomes of our project on wind and fire, you are very welcome to join us. 7th of February it starts, I think, 1 30 pm Warsaw time, so hopefully easy to join if you're from Europe. Perhaps a little brutal if your West Coast USA, but yeah, there will be a replay available so you will be able to catch up. You're very welcome to join us live and I hope it will be very interesting and I'm sure I will make also a podcast episode summarizing that Information for you to listen in here. So that is it for today. Thank you very much and see you here next Wednesday. Bye, this was the fire science show. Thank you for listening and see you soon.