Pressurized fueling accident (Crickets...)

jon coleman

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Acme,

My FAA comment was directed towards insurance. I have a Twin engine rating and as far as the FAA is concerned I can fly any twin engine aircraft that does not require a type rating. But I can’t get insurance unless I take a make and model initial training course. My Point is that the government is pretty open with the rules but the insurance companies are not.

The rest of the points have been argued enough. Comparing NASCAR or Formula 1 to desert racing is a waste of time. The fact that we set up and tear down pits in a hurry is what adds the extra risk. I agree on a fixed pit a tower may be the best option. Or even a pumped fuel option would work.

I was mostly being a smart a$$ on the don’t use one or be next to one if you don’t want to comment. I really wanted to bring our PP to Parker so I could put up some big signs that say “stay away this thing can blow at any minute, danger” haha. So maybe now we won’t get people crowding our pits.

the reality is education is key and I think that’s up to the racing orgs to work out. BITD rules already say all PP systems have to be approved. So they are already trying to make sure each team knows what they are doing. I had to go thru a process to get our fuel cell approved by BITD when we made the change. So it’s not like everyone is just looking the other way.

Mike
pp teams should get a designated area for pitting, makes sense rDc?
 

green787

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I had no idea how big they were until I watched the video..... They are too big and have too much non re-inforced surface area to ever think about pressurizing ....... sure 15lbs..... MAYBE 25psi ..... But it's too easy to over pressurize them with C02 bottles with what??? 500psi??? IDK..., and a novice might even think they are helping it work better by over pressuring it......Isn't that how the guy got hurt was because the tank ruptured and injured him from exploding.... not a gas explosion, but a pressure explosion.... shrapnel..... I thought they were the size of maybe a 50 gallon air compressor tank..... How do you lift the PP out of the truck without a crane.... ??? I think they can be made safer with a catastrophic relief device..... Like I said with a rubber cork for a fuel cap...... Some device that blows off and renders the PP useless until it is repaired..... Dummy proof..... If I was Vince I would want it to have to be brought back to the manufacturer to be inspected and reset, and then retrain the owner......
 
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MTPyle

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Vince did get the blown up tank back. It exploded from no relief valve and regulators set too high. And yes they defeated the safety valve to run higher pressure to fuel faster

You don’t move the PP full.

Here is a pic my my new extra pressure relief valve that you found. Double safe now.

Mike
33513231-5A0C-4991-BC6E-032759A55B7C.jpeg
 

PALAPABOY

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Every type of way we fuel these cars/trucks is dangerous. The systems we all use are only as good as the people who use them. This was 100% human error that happened with Ampudia. I have seen fires start from dump cans and towers. Fueling is just dangerous, period. But hey, look on the bright side. After 2035, we’ll be racing on electricity! Haha
Pat how do we charge the battery ?
 

cynicwanderer

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Vince did get the blown up tank back. It exploded from no relief valve and regulators set too high. And yes they defeated the safety valve to run higher pressure to fuel faster

You don’t move the PP full.

Here is a pic my my new extra pressure relief valve that you found. Double safe now.

Mike View attachment 219238
I work at a shop that makes aerospace parts. we have a welding shop were we weld various parts. of course, there are various welding requirement/specs depending on the part/drawing, and I'm not personally a qualified welder, some of my co-workers are, and I have seen parts from our shop, etc... however, I thought they said they have aircraft "certified" welders doing the welding on the tanks. this is pretty sloppy welding and I have a feeling the welder who did this, would not be able to get a job here. just saying.
 

green787

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Vince did get the blown up tank back. It exploded from no relief valve and regulators set too high. And yes they defeated the safety valve to run higher pressure to fuel faster

You don’t move the PP full.

Here is a pic my my new extra pressure relief valve that you found. Double safe now.

Mike View attachment 219238

Cool.... looks good....Safety orange..... I was hoping it would screw right on..... Now set it to 25psi and test it....
By accepting my suggestion you might have got a bunch of RDC panties up in a wad......
 

Dirtman

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Having worked in oil refining all my life and worked around thousands of pressure vessels I would suggest a different relief system. We used thousands of relief valves but they have drawbacks such as opening too soon, sticking shut and not opening at set pressure, and require testing on a regular basis to insure they are working properly. In recent years there has been an understanding that they also do not like to be bounced around and we needed to start handling with care each time they were removed, tested, and reinstalled. On a fixed vessel that's not too bad but on a tank that is going to be moved around and bounced down a dirt road the relief manufacturer would tell you not a good fit.

I would have installed a rupture disc as they are more compact, don't require maintenance or testing, aren't bothered by being bounced around, are typically made of SS so clearly compatible with fuel, and when they open they go wide open and depressure the vessel immediately. The only downside is that once blown they need to be replaced but that is a fairly easy job. And it would require everyone to slow down and ask how/why that happened not just move along and try to make it work.

I'm not nearly as concerned with fuel spillage at the hose/fuel cell. Although that can certainly be bad and make a hell of a fire, so can fuel jugs and towers. If you blow up a 100 gallon PP and it ignites it will take out the entire pit and probably the pit on either side. Just go watch a youtube video of someone blowing up a 5 gallon can of gas and multiply by 20. There would be large scale fatalities.
 

9rocky

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Just go watch a youtube video of someone blowing up a 5 gallon can of gas and multiply by 20. There would be large scale fatalities.

Like this??

 

cynicwanderer

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more thoughts on welding quality... it has been said that they leak test the PP at 100Psi. do they do any NDT, like eddy current or dye testing of their weldments ? the picture of the burst tank look like it burst along a weld seem and supposedly the pressure was set at only 75Psi with the PRV disabled. if the welds were good, they should have survived that over pressure.

in any case, the weld issue is not just about pressure handling capability at the time of manufacturing. porosity and embrittlement will invite corrosion and cracking over time, especially if the tank is exposed to the elements (i.e. not painted) and transported over rough roads. those welds should be inspected periodically, just like a frame, roll cage or your fuel cell.

anyway, here are some some aircraft and pipe cert. weld samples...

Thin_Wall_Power_Plant_TIG_Pipe_Test.jpg
TIG Welding Certification.JPG
 

cynicwanderer

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here is the basic problem with pressurized fuel systems. if there is a leak (cracked weld, bad O-ring, etc), the pressurized fuel will spray out of the tank/vessel at high velocity (the smaller the hole, the higher the velocity) causing a mist. the fuel will have also absorbed some CO2 at 15Psi and when it sprays out of the tank the absorbed gas will "foam" the fuel when it hits the normal pressure of the atmosphere. just like you would have with fast decompression in diver's blood, or opening a can of pop or beer (which has less pressure than 15Psi). so, now you have a cloud of misted/vaporized fuel and if it catches on fire, e.g. when it hits a hot header or hot brakes or static will explode in the air, causing concussive injury to people and damage to equipment; meanwhile the leak that is still there will continue to spray fuel, which is now probably being continuously ignited by the remnants of the air burst, until all of the fuel has been expelled or the tank explodes because of the heat causing over pressure in the tank, assuming it didn't burst in the air burst earlier. of course, things are much worse if the pressurized tank bursts first, i.e. when it falls over or gets hit by someone and the pressurized gasoline disperses in larger volume then a small leak. but, even a small fuel air explosion is very impressive...

in general, pooling fuel on the ground from a leak is much harder to ignite.
 
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Bricoop

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how much gas do we think they used?
The atmosphere we breath doesn’t have enough Oxygen to match Gasoline’s potential energy.That’s why you can fill a tuna can fill of gas and light it. It will burn, not explode.
 

Bro_Gill

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Both can explode, the energy potential between them is vasty different though.
No it can't. A plastic can will have structural failure way below the point of a detonation. Simple physics. Detonation versus deflagration. One will throw hot shrapnel in all directions, possibly blow out ear drums, etc... The other will be a simple fuel puddle fire on the ground.
 

Frank13

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more thoughts on welding quality... it has been said that they leak test the PP at 100Psi. do they do any NDT, like eddy current or dye testing of their weldments ? the picture of the burst tank look like it burst along a weld seem and supposedly the pressure was set at only 75Psi with the PRV disabled. if the welds were good, they should have survived that over pressure.

Curious to how many times the tank was cycled to 100psi durring testing. If the Ampudia’s we’re getting away with 75psi some good information would be how many times they cycled the tank to 75 psi until failure.
 

partybarge_pilot

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No it can't. A plastic can will have structural failure way below the point of a detonation. Simple physics. Detonation versus deflagration. One will throw hot shrapnel in all directions, possibly blow out ear drums, etc... The other will be a simple fuel puddle fire on the ground.

Having built many "fireworks" from plastic housings, I beg to differ on all accounts.
 
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