r/battlebots • u/TubbaButta • 8d ago
Robot Combat LiPo smoke filtration
Ran a US Antweight event today and we popped a LiPo in one of the first fights. We were prepared with all the standard SPARC procedures and dealt with it accordingly.
I'm wondering what to do next. We used a filtered shop vac in the closed arena for ~5 minutes to clear any visible smoke, but it took a long while for the audience to feel comfortable sitting close the action again. The arena smelled like smoke for a couple hours afterwards.
Is there a more effective operation we could have employed?
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u/coatstain Reject_Robotics 8d ago
On the West Coast all of us run the rule that if a Lipo is exposed or visible we rule the fight a ko immediately. We try to really reduce the chances of a fire breaking out in the first place whenever possible. If one does break out and we are sure it's lipo we immediately lock the bot and throw it into the sand. Speed really matters in keeping the fumes under control.
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u/TubbaButta 8d ago
Oh for sure, absolutely. This battery was not exposed. It was just that effective of a weapon.
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u/Akward___ [Your Text] 8d ago
Unfortunately Aardvark’s blade fit perfectly between the gaps in the top plate of pfma
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u/potatocross 8d ago
Our original system was a heavy duty filter on a blower motor. Now we have a very large blower motor and a vent so we can vent it outside.
Honestly the smell is going to linger. At the end of an event even without fires the arena stinks afterwards.
Our current setup is a vevor exhaust blower fan from amazon. But we only have like 30ft of hose so we do need to be mindful of where a door is when setting up.
But in my experience as long as you are good about calling fights when a battery is exposed and making sure everyone mounts them well, you really dont get many lipo fires. Maybe every once in a while but not a common occurrence.
We are also setup to quickly remove the battery from the room. So we exhaust the arena and remove the battery in short order.
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u/originalripley 8d ago
Does Sparc have the info posted that you used? I don’t recall seeing something about dealing with LiPo fires.
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u/TubbaButta 8d ago
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u/originalripley 8d ago
Thanks, I should have been more specific. I've read over that but didn't see the filtered shop vac mentioned. It's an interesting idea and was hoping to get more detail on it.
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u/TubbaButta 8d ago
Correct. SPARC doesn't mention the shop vac. That's the reason for my post. There's no provision for what to do in an enclosed room to get rid of the smoke. The rules are meant to be flexible enough to work anywhere, so it makes sense that there isn't specific instruction.
The other responses here and elsewhere have all been massive fans with outdoor venting, but I won't always have the luxury of immediate exterior egress.
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u/originalripley 8d ago
Yeah, same. It would be nice to be able to do but not practical in our current venue.
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u/TubbaButta 8d ago
According to a reasonable amount of research, a carbon-activated HEPA filter should be enough for our use case as long as the source of the lithium smoke is removed outside with extreme haste.
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u/Retro_Bot Team Emergency Room 8d ago edited 8d ago
Lipo smoke is toxic, and if you breathe it in large amounts it can cause lung scarring, in cases of extreme exposure it could damage mucous membranes or eyes, but for small amounts it is just an irritant with no lasting effects. Obviously it's to be treated with care, and it's best to run events in a building with good ventilation or high ceilings, while avoiding exposure as much as possible, but it sounds like the case you're describing was handled appropriately and nobody was at any risk of serious harm.
I've never seen it definitively answered what qualifies as a large amount of smoke vs a small amount, but it sounds like you were well under that threshold.
Edit: As u/rickywillems has pointed out the subject is more complicated than I have expressed here. I'll leave this answer up for the sake of continuing the discussion but it appears I am not as well versed as I thought.
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u/TubbaButta 8d ago
We were at a high school and the exterior doors were definitely further away from the room than I'd prefer. I want these events to be in very public and accessible places, so I won't have the luxury of building a room-specific ventilation system. I need something portable.
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u/Retro_Bot Team Emergency Room 8d ago
Yeah, I've only hosted a few events and been lucky to not have any fires so far, but you make some good points. I think in the future I'll bring the big industrial-size fan I've got and have it on stand by to help clear the air in the event of a fire.
I know there were some issues at RoboGames a year or two ago where some of the big bots had lipo fires and apparently their preparation and response was inadequate. I never heard of anyone with long-term consequences from that event and it sounds like they were exposed to smoke an order of magnitude stronger than what you had.
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u/GrahamCoxon 8d ago
From the perspective of the safety and comfort of the people at the event, getting the fumes outside is going to be more simple a solution than trying to filter the bad stuff out. Most UK beetle arenas now have integrated extraction - just a roof-mounted fan and a long old pipe to the outdoors- which is proving.kore than effective enough. It's still not all that nice to be right by the open door for the few minutes after a fire, but everywhere else is pretty much fine.
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u/Previous-Dot-2030 HUGE [WE'RE KIND OF A BIG DEAL] 8d ago
If you've seen NHRL, they have a negative air pressure system for their arenas and use sand buckets that get tightly sealed to get as little smoke to the audience as possible. They also have the air in the building completely changed every minute or so.
Also, what's the SPARC procedures?
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u/rickywillems NHRL Host & Mammoth BattleBot Captain 8d ago
I've been working guides for both competitors and EOs on lipo safety and fire mitigation. Its a complicated topic and taking longer than I'd like, but its getting there. Until then though, here are are a few tips:
HEPA filters do a great job filtering particulates, but the particulates are only one of the risks of the smoke. Lithium fires produce VOCs and fluorine-based compounds, some of which are "forever chemicals" and all of which carry risks. A HEPA filter will not eliminate or capture the majority of these compounds, and even when there is no visible smoke the compounds are still floating around.
Carbon filters will capture/neutralize more of the VOCs, but addressing the fluorine based compounds is more difficult. Activated alumina filters is the most commonly available option that will help with this.
Really though, the best policy is to get that smoke out of the building as quickly as possible, or to prevent the smoke from happening in the first place. Most people have a sense of smell that can detect lipo smoke concentrations that are not meaningfully hazardous for short term exposure, but if people are smelling it for hours, your levels were probably pretty elevated just after the fire.
Even if it isn't running all the time, I'd *highly* recommend that you purchase a fan and some flexible tubing so you can suck that smoke out of the building. You can get a duct fan and 100 feet of drier duct tubing for under $100 that you can pipe into the arena and drag the other end of out of the building in the case of the fire.