Pressurized fueling accident (Crickets...)

MTPyle

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A redundant PRV system would negate the need for a scatter shield. Rupture discs like OP mentioned are a great back up.
(No need to contain an explosion if an explosion can't happen)

An FMEA (Failure Modes and Effects Analysis) would be a good start.

I agree with MG on this. I am all for a rupture disc or additional blow off valve to protect against run away C02. If its in the top of the tank it will only shoot out Co2 and fuel vapors. If the seam fails with scatter shield you have all your fuel coming out.

The Red head seems to be less of an issue. As there have not been many failures and most of the issues have again been user error. same things happened with our dump cans with Red heads. if not in and out correctly they can get stuck or leak.

Mike
 

Bricoop

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Current F1 news shows that refueling may be back on for 2021. Drivers hate the added weight and tire issues from the large fuel cells. Adding fuel options allows them to get the weight back in line and is very much on the table from what I read.
They won't be refueling in 2021. It was thrown around for a while, but in all liklihood is dead at this point.

Looking at a series that does use pressurized refueling, Indycar. Everyone is in proper safety gear with extinguishers ready. They also spray the inlet on the way out of the pits.

Here's a radical idea-create a CO2 shield around the deadhead, preferably even a greater area. Basically, turn the deadhead into a mig welder. Create a hood that goes over the deadhead and the inlet. Encapsalate the area with CO2. Fuelers would need to be on O2. Is it crazy, maybe.
 

BHollander

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I work with pressurized fluid delivery vessels daily. One of my tasks is I maintain an automatic solvent delivery systems. We keep them in a bunker (literally) it is 2ft+ thick block and concrete bunker. Each vessel is made of 1/4" stainless steel and has 4 different staged pressure relief on the tank as well as rupture disc. We also have multiple pressure relief valves on the helium pressure pressure feed. The only issues we have ever had were individuals that were not properly trained and trying to do something they had no knowledge of or trying to take short cuts by not turning off flow valves. Also I will add our vessels have internal ribbing and vessels are cycled out. They have a lifespan. I am curious as to how much the PP expand and contract while traveling with no fuel same as with fuel on the desert floor in borrego or freezing night at the 1000. Aluminum does fatigue for sure. I will only fuel with Dump cans. I personally have been involved with 3 tower failures due to lack of prep and freezing cold temps causing hose to break during fuel stop. I understand pressurized systems enough to know a potential bomb when I see one. Every component on a PP should be rated for fuel and sized appropriately and serviced/ certified between uses or at least have a PM/ service/ cert schedule. I have serviced and designed many pressurized fluidic systems. Failures happen whether it be ruptured line, failed regulator, failed pressure relief due to corrosion, swollen o-rings, split seams in tanks, and many other failures. With that said a tamper resistant pressure relief should be in place. Also what is the burst pressure on a PP does anyone know? Has this been tested? Find your limits. I find it interesting the PP in question blew a weld seam out but not the barbed rubber hose. Just my .02. Racing is 90% volunteers and if your fuel system is an extra $4-$5K because it has to be properly built then so be it. Use properly rated components companies like Swagelok and Parker make great high quality components rated for whatever we will throw at it. Quit using water rated components on a fueling system. Would you plumb your vehicle with PVC?
 

MTPyle

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I would bet the sight hose with clamps can handle well over 100psi

I was told the tank was tested to 100psi. I agree OAT does matter. So it would be interesting to see what temp it was tested at.

We know for absolute certainty that the system is safe under 15psi

Mike
 

jon coleman

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just like old aircraft, ( pressurized cabins), they are cycled out, only have so many times to pressurize& de pressurize, then they are scrap metal, .
 

jon coleman

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Just for fun can someone put a tape around on of these units empty,full and then w pressure.
with No internal ribbing, its Gotta be a lot!,old trick with plastic mx tank, fill with Scalding hot water and Carfully apply psi, get s a little more volume in a rules required stock tank classes( so ive heard decades ago
 

michael.gonzalez

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Hoop Stress = P * r /t

P: pressure (psi)
r: tank radius (in)
t: tank thickness (in)

Using 10psi, 18in radius, and .125" thickness, equates to a hope stress of 1440 psi. (Yield strength of 6061 is 35,000 psi)

TL;DR: at 10psi, there will be NO noticeable change in tank diameter.
 

michael.gonzalez

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Delta_tankradius = (1-v) * P * r^2 / (E*2t)

v = .33 (6061 Aluminum Poisson's Ratio)
r = 18 in (tank radius)
P = 10 psi (pressure)
E = 10,000,000 psi (6061 Modulus of Elasticity)
t = .125 in (thickness)

Delta_tankradius = (1-.33) * 10 * 18^2 / (10,000,000 * 2 * .125)

Delta_tankradius = .0086 in
(9 thou)

(THIS IS AN ESTIMATE AS I DON"T KNOW THE ACTUAL TANK DIAMETER AND THICKNESS)
 

Bricoop

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How many teams are following this to a tee? Are you using checklists? Are you having a competent individual inspect the setup?

Watching this video gives an understanding how many opportunities there are for things to go wrong. The solution for a stuck valve is to drop it in a trash can? The vent tube is smaller than the fill tube? If the head is leaking you should wiggle it? If the fueler doesn't see the fuel in the vent line, after 5 seconds the vent line no longer function? Ever been in a racesuit, nomex, a helmet in 100+ heat? You're probably getting sweat in your eyes. (Last week we had a fueler not see an overflowing tank due to sweat in his eyes, thankfully we were using dump cans and only spilled about a liter). I could go on and on.

Even in the saftey video, the fueler doesn't have effective fire equipment on.

I went to go gather some videos of fuel stops to compare teams. Turns out most teams F*CKING SUCK when it comes to following established fueling guidelines.
The first video I came across. So many issues with this.

I struggled to find teams with a safe pit stop, but this appears to be a good one. Most guys in proper gear. Multiple extinguisher operators standing at the ready including one in a firesuit pointed at the fueler. Fueler immediately exits the area at the end of the stop. PP shutoff valve is manned with firesuit.

One of the most common issues I saw is the extinguisher on the ground next to the fueler. In a fire, that extinguisher is unusable. Never did I see the whole team in race gear. You can get every crew member the proper gear for less than the cost of a life flight. Every fueler should be in an apron. I'll never understand why someone would agree to be a stabber without 100% safety gear. The pressure pro definitely has it's flaws, when operated properly it seems similar to other fueling methods. Nothing is going to eliminate the risk entirely, but a tremendous amount can be done to reduce the risk of injury and death.
 

Bricoop

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How many teams are following this to a tee? Are you using checklists? Are you having a competent individual inspect the setup?

Watching this video gives an understanding how many opportunities there are for things to go wrong. The solution for a stuck valve is to drop it in a trash can? The vent tube is smaller than the fill tube? If the head is leaking you should wiggle it? If the fueler doesn't see the fuel in the vent line, after 5 seconds the vent line no longer function? Ever been in a racesuit, nomex, a helmet in 100+ heat? You're probably getting sweat in your eyes. (Last week we had a fueler not see an overflowing tank due to sweat in his eyes, thankfully we were using dump cans and only spilled about a liter). I could go on and on.

Even in the saftey video, the fueler doesn't have effective fire equipment on.

I went to go gather some videos of fuel stops to compare teams. Turns out most teams F*CKING SUCK when it comes to following established fueling guidelines.
The first video I came across. So many issues with this.

I struggled to find teams with a safe pit stop, but this appears to be a good one. Most guys in proper gear. Multiple extinguisher operators standing at the ready including one in a firesuit pointed at the fueler. Fueler immediately exits the area at the end of the stop. PP shutoff valve is manned with firesuit.

One of the most common issues I saw is the extinguisher on the ground next to the fueler. In a fire, that extinguisher is unusable. Never did I see the whole team in race gear. You can get every crew member the proper gear for less than the cost of a life flight. Every fueler should be in an apron. I'll never understand why someone would agree to be a stabber without 100% safety gear. The pressure pro definitely has it's flaws, when operated properly it seems similar to other fueling methods. Nothing is going to eliminate the risk entirely, but a tremendous amount can be done to reduce the risk of injury and death.


Spending $11K on a fueling system and not shelling out $2K for your volunteers to be safe is selfish.
 

MTPyle

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Bricop couple of issues with our assessment above.

We have all watched this at least 20 times and follow it to a T. We also added some of our own process's to make it even safer. All of our guys have full gear that are part of fueling the Stabber has helmet, head sock, fire suit, gloves, fire socks, and apron. We are getting all of the crew that works on the truck into fire suits for next season. But for now all that work on fuel including extinguisher guy and dead man valve guy are in full gear. We have 2 20lb fire extinguishers ready to 2 more as back up. 2 of the 4 are foam.

Our vent line is the same size as our fill line.

The trash can is there in case of a red head sticking. It would not flow much as the man on the dead man valve would have already shut the valve. We do not pull the red head until the dead man is closed. So there is no pressure on the read head.

You have a 5 gallon catch can at the end of the vent hose back at the PP tank. So you can vent at least 5 gallons before you have a problem. The hose holds a fair amount as its 2.25" and 30ft long.

We have watched all of these videos and talked to many teams that have a lot of experience with these. I would say we are 100X more safe than we were before PP.

Mike
 

Bricoop

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Bricop couple of issues with our assessment above.

We have all watched this at least 20 times and follow it to a T. We also added some of our own process's to make it even safer. All of our guys have full gear that are part of fueling the Stabber has helmet, head sock, fire suit, gloves, fire socks, and apron. We are getting all of the crew that works on the truck into fire suits for next season. But for now all that work on fuel including extinguisher guy and dead man valve guy are in full gear. We have 2 20lb fire extinguishers ready to 2 more as back up. 2 of the 4 are foam.

Our vent line is the same size as our fill line.

The trash can is there in case of a red head sticking. It would not flow much as the man on the dead man valve would have already shut the valve. We do not pull the red head until the dead man is closed. So there is no pressure on the read head.

You have a 5 gallon catch can at the end of the vent hose back at the PP tank. So you can vent at least 5 gallons before you have a problem. The hose holds a fair amount as its 2.25" and 30ft long.

We have watched all of these videos and talked to many teams that have a lot of experience with these. I would say we are 100X more safe than we were before PP.

Mike
Mike-

I've enjoyed following along as you work through the risk/benefit of each system in the other thread. Sounds like the hose holds about 7 gallons+5 gallons gives about a 5 second reaction time. Is anyone other than the filler watching the vent line/catch can? I would clarrify the goal is to have the dead man closed first, but it doesn't mean that would happen in an emergency situation. Are you guys grounding the system to the truck via a clamp? It would seem a better design could be made.

Glad to see you getting guys into the right gear. 2020 Snell helmets are coming out now, we should expect to see some sales on the 2010 and 2015 models
 

JP_JCM

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i suppose everyone wants to forget that the team wire the PRV shut and gave the tank over 200 PSI............................ Your radiator expansion tank that you made out of .063"Aluminum see upwards of 20+ psi, your water lines for your radiator on the out side of the engine see 60+PSI plus 180-260* water. I don't believe every fab guy is a certified welder and these components are not failing. The issue came from the team not training their crew on how to use the system.
 

Bricoop

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i suppose everyone wants to forget that the team wire the PRV shut and gave the tank over 200 PSI............................ Your radiator expansion tank that you made out of .063"Aluminum see upwards of 20+ psi, your water lines for your radiator on the out side of the engine see 60+PSI plus 180-260* water. I don't believe every fab guy is a certified welder and these components are not failing. The issue came from the team not training their crew on how to use the system.

Nobody is forgetting that. Multiple flaws allowed that to happen, mostly on the team's shoulders.
Do the instructions include what sealants are safe to use on the system? (We use loctite 567 on all of our fueling connections).
The reports that the system uses non-fuel safe components, doesn't have recertification schedules, doesn't use certified welders.
What does the maintenance schedule look like?
Why isn't there a litany of information online about these systems?
Systems should be designed to protect the user from their own ignorance.
Even Mike-a team brand new to the system has chosen to enhance the company issued safety protocols because they are not safe enough, in their opinion.
 

MTPyle

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Bricop, Thanks!

yes we ground the tank and the truck. We built a stake with a antenna that we put in the ground and the truck runs over it during fueling. We had our pit mat made with a hole where the stake goes. Then we ground the tank with a cable to another grind stake as well as ground it to the chassis of the trailer.

We have our PP in a trailer and made vent hose that goes outside so we never get fumes in the trailer. We also face the sight tube side away from the dead man operator.

We have the stabber nod his head when he wants the deadman valve shut. All he does it watches the vent and the second he sees fuel in the vent he nods. We practice the cadence many times to get it right. They have yet to have fuel go into the catch can. We have the same stabber and deadman guy every time.

The hardest part of being clean and not spilling is emptying the hose after use. That takes a couple guys and a process. But we only do that at the end of the day.

Not sure I would say PP safety protocol are not safe enough. We are just nervous Nellies about safety now and try to take it a step further. I am sure there is still room for improvement for us and we will never stop getting better and questioning everything we do. We are the opposite of the ego team that thinks they know everything.

Mike
 

Myshot

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A good fast pit crew is an advantage racing and can mean the difference between winning and loosing. If you have a insightful pit crew you will loose minutes at the end of the day.

Fast pit stops is a part of racing culture if its to dangerous for you than stay home and watch a bunch of entitled bitches through a ball and and slap each other ass's all the while bitching they are some how repressed.
Johnny, apparently your reading comprehension is low, this is not about
pit crew ability or speed.
But hey, there are always TOOLS in the bunch.
Here is a novel idea call and talk to Vince you seem to be an expert maybe you can help him with some ideas.
Johnny
Learn to read... But let me help you again, I DID...
They won't be refueling in 2021. It was thrown around for a while, but in all liklihood is dead at this point.

Looking at a series that does use pressurized refueling, Indycar. Everyone is in proper safety gear with extinguishers ready. They also spray the inlet on the way out of the pits.

Here's a radical idea-create a CO2 shield around the deadhead, preferably even a greater area. Basically, turn the deadhead into a mig welder. Create a hood that goes over the deadhead and the inlet. Encapsalate the area with CO2. Fuelers would need to be on O2. Is it crazy, maybe.
Bricoop,
You are mistaken, When I was a fueler at INDY many years ago, we were gravity fed.
Just looked at the 2020 rule book, they are STILL GRAVITY fed.
During a Race, all refueling must be performed by the INDYCAR-approved dry-break disconnect system. During refueling, only the fuel hose and vent hose can be attached to the fueling system. The fuel flow must be gravity-flow only and the vent hose must not have any evacuation assist devices attached.
 

Bricoop

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Johnny, apparently your reading comprehension is low, this is not about
pit crew ability or speed.
But hey, there are always TOOLS in the bunch.

Johnny
Learn to read... But let me help you again, I DID...

Bricoop,
You are mistaken, When I was a fueler at INDY many years ago, we were gravity fed.
Just looked at the 2020 rule book, they are STILL GRAVITY fed.
During a Race, all refueling must be performed by the INDYCAR-approved dry-break disconnect system. During refueling, only the fuel hose and vent hose can be attached to the fueling system. The fuel flow must be gravity-flow only and the vent hose must not have any evacuation assist devices attached.
Were you there during the Indy fueling incident? I believe it was a black Cingular car.
 

Myshot

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Hoop Stress = P * r /t

P: pressure (psi)
r: tank radius (in)
t: tank thickness (in)

Using 10psi, 18in radius, and .125" thickness, equates to a hope stress of 1440 psi. (Yield strength of 6061 is 35,000 psi)

TL;DR: at 10psi, there will be NO noticeable change in tank diameter.

The hoop strength is calculating the pressure of a "Hoop" or in this case a cylinder, what you fail to take into this calculation is the sight glass channel.interrupting the hoop and all the strength you have in that calculation. That in fact is why these tanks are dangerous. with a three sided channel, or basically a square how would that hold up to the same calculations, each pressure cycle how much movement is there in that channel at the weld points.
 

MTPyle

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One of the major differences between other motorsport and us is we are mobile. I think a fixed gravity system would be pretty safe but make them mobile and have to transfer fuel it gets risky fast.

With a PP you basically have a fixed system. You are not moving fuel around or doing any set up. it stays in the truck, box truck, or trailer and you just pull the hoses out.

I do think temp is a issue. We looked at getting a cooling blanket to wrap ours in to keep it cool. Mostly because we do not want to put hot fuel in the race truck. But then we just put it in the air conditioned trailer to solve that. We hope to get a box truck with AC soon. We keep the ac running all night to make sure the fuel is as cool as possible.

Mike
 
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