Van's Air Force
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Oxygen Systems Close to Batteries!!!
- Thread starter rv7boy
- Start date
L.Adamson
Well Known Member
This is my responce from the other thread:
I'm a heating contractor. I deal with natural gas, ignitors, etc.
At the moment, I'm not yet "freaking" out in regards to this installation.
Yes, there is some potential that a spark might exist, and the fact that an oxygen rich enviroment can make things burn faster. But we're certainly not talking aluminum dust as the flammable material; and quite frankly, I don't see much difference in moving the oxygen forward of the bulkhead or behind. Afterall, it's not like these bulkheads are totally sealed from the aft fuselage section.
Personally, I'd worry much more about my engine compartment going up in flames, than this installation.
P.S. --- I just realized that my 6A has it's battery in the cabin along with my fuel lines, aux. fuel pump and tank selector valve. My oxygen system is just behind the seat in the same cockpit. What about those batteries stuck on the firewall in the engine compartment?
L.Adamson --- RV6A
f1rocket
Well Known Member
I'd be interested in the specific risks involved with this installation. I am thinking about adding an oxygen system to my airplane at some point in the future and I would like to know. My common sense tells me that the risk is not that high, and probably less than the risk in the center tunnel of most RV's where wires and connectors share the same closed space with fuel lines and fuel fittings that occasionaly leak. From my limited understanding, I don't believe the oxygen in the tank is 100% pure and the space is not sealed nor pressurized. I don't see how the comparison to Apollo 1 is pertinent, but perhaps it is because of my ignorance.
rv7boy
Forum Peruser
Hazards of Pure Oxygen
Larry, Hmmm, maybe you should relocate your battery...
I'm just trying to get folks to THINK about the possible hazards of pure Oxygen. While having gasoline lines, etc. close to a battery involves increased risk, the configuration of your 6A is not the same as what I see in Mr. Marks' photos. I think many people are not aware of the HAZARDS of PURE Oxygen. If you get the tiniest spark or even a smear of grease in 100% Oxygen, you would think a bomb went off. Granted, the O2 will disperse rather quickly in air, but I personally would not want my O2 bottle sitting right next to my batteries as he has. It would seem the locations for the batteries and the O2 system were chosen due to C.G. considerations.
Again, show me a spam can that has a certificate of airworthiness which allows the battery (ies) to be THAT CLOSE to an oxygen system, and I'll shut up.
Larry, Hmmm, maybe you should relocate your battery...
I'm just trying to get folks to THINK about the possible hazards of pure Oxygen. While having gasoline lines, etc. close to a battery involves increased risk, the configuration of your 6A is not the same as what I see in Mr. Marks' photos. I think many people are not aware of the HAZARDS of PURE Oxygen. If you get the tiniest spark or even a smear of grease in 100% Oxygen, you would think a bomb went off. Granted, the O2 will disperse rather quickly in air, but I personally would not want my O2 bottle sitting right next to my batteries as he has. It would seem the locations for the batteries and the O2 system were chosen due to C.G. considerations.
Again, show me a spam can that has a certificate of airworthiness which allows the battery (ies) to be THAT CLOSE to an oxygen system, and I'll shut up.
rv7boy
Forum Peruser
Explanation
Okay, guys, I admit that on occasion in the past, I have been over-reactive. At times, I have hurt friendships. For that I am sorry and believe I have apologized to the offended parties.
To set the scene, I am currently sitting in the Orlando airport waiting to catch a flight home.
Yesterday I sat through an hour and a half presentation on how the Columbia astronauts died. It was presented by one of the investigators. Unlike the Challenger and Apollo investigations, the investigation of the Survivability of the Columbia astronauts has been made public. I don't have the link with me, but it came out in December, so if you are interested, you can Google it.
Anytime there is loss of life in the space business, there is always the feeling or even realization that someone should have spoken up. Just because something has never happened before doesn't prevent it from happening the first time.
So the bottom line is...I have spoken up. I won't install my O2 system right next to my batteries. Each of you should do your planning, educate yourself to the hazards of ANYTHING you install in your RV, and then, hopefully, "live with your decisions."
I've said my piece.
I've got to go get on an airplane.
Have a good weekend.
Don
Okay, guys, I admit that on occasion in the past, I have been over-reactive. At times, I have hurt friendships. For that I am sorry and believe I have apologized to the offended parties.
To set the scene, I am currently sitting in the Orlando airport waiting to catch a flight home.
Yesterday I sat through an hour and a half presentation on how the Columbia astronauts died. It was presented by one of the investigators. Unlike the Challenger and Apollo investigations, the investigation of the Survivability of the Columbia astronauts has been made public. I don't have the link with me, but it came out in December, so if you are interested, you can Google it.
Anytime there is loss of life in the space business, there is always the feeling or even realization that someone should have spoken up. Just because something has never happened before doesn't prevent it from happening the first time.
So the bottom line is...I have spoken up. I won't install my O2 system right next to my batteries. Each of you should do your planning, educate yourself to the hazards of ANYTHING you install in your RV, and then, hopefully, "live with your decisions."
I've said my piece.
I've got to go get on an airplane.
Have a good weekend.
Don
f1rocket
Well Known Member
Don,
I didn't take your comments to be over-reactive, I am truly curious as to the specific danger with this installation. It looked neat, thoughful, and well done. The wiring appeared the same. I liken it to having a bottle of bleach and drain cleaner sitting next to one another under the sink. All that separates them from making nerve gas is a small, thin plastic bottle.
I'm guessing (because I don't know) that the batteries might leak or explode, or otherwise create a fire for some reason and the oxygen bottle might be ruptured in the process and spray oxygen directly on the fire?
I understand that given a choice, a different bottle location would at least reduce the impied risk of the two getting together. If that is really the point, then I get that. Thanks.
I didn't take your comments to be over-reactive, I am truly curious as to the specific danger with this installation. It looked neat, thoughful, and well done. The wiring appeared the same. I liken it to having a bottle of bleach and drain cleaner sitting next to one another under the sink. All that separates them from making nerve gas is a small, thin plastic bottle.
I'm guessing (because I don't know) that the batteries might leak or explode, or otherwise create a fire for some reason and the oxygen bottle might be ruptured in the process and spray oxygen directly on the fire?
I understand that given a choice, a different bottle location would at least reduce the impied risk of the two getting together. If that is really the point, then I get that. Thanks.
Mike S
Senior Curmudgeon
Old fireman says,
Fire requires four elements.
1. heat source.
2. oxygen
3. fuel
4. un-inhibited chemical reaction.
The battery is good for number 1, number 2 is supplied in the bottle. Number 4 is non relevant to the case in point.
However, number 3 is pretty much of a non issue in the tail cone of the 10.
I would be more concerned with the bottle, or pressure lines getting loose in turbulence, (or somehow ??) and shorting against the battery.
I am not saying it cant happen, but I just dont personally see the danger potential as being much.
YMMV
Fire requires four elements.
1. heat source.
2. oxygen
3. fuel
4. un-inhibited chemical reaction.
The battery is good for number 1, number 2 is supplied in the bottle. Number 4 is non relevant to the case in point.
However, number 3 is pretty much of a non issue in the tail cone of the 10.
I would be more concerned with the bottle, or pressure lines getting loose in turbulence, (or somehow ??) and shorting against the battery.
I am not saying it cant happen, but I just dont personally see the danger potential as being much.
YMMV
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flion
Well Known Member
True, as long as the O2 is in the bottle and the spark is outside. Mike, with O2, anything is fuel. I remember vividly about how the Apollo fire operated and read all the published reports on the incident due to a great interest in space technology at the time.
That said, the reported incidents, including the fire that took the lives of three astronauts, were all in conditions where the spark occurred in a pure O2 environment. My take is that there'd have to be a really significant O2 leak for a free spark to touch off a fire; merely sparking the bottle wouldn't do it. A small leak would diffuse rapidly in the tail cone and, being rather the opposite of air tight, rapidly from there into the atmosphere. Also, where else would you put it? There are wires throughout the airframe, especially areas that would hold an O2 system, that are perfectly capable of providing sparks. In fact, I kind of feel that wires are more notorious for spark generation than batteries. Really, it seems to me the best thing to do is make the system as leak-proof as possible. To that end, I am not really a fan of that (is it copper?) tubing to the header; I'd rather see something flexible. But other than that, the installation doesn't look too worrisome to me. Take that for what it's worth; I'm only a builder. Any A&Ps and/or DARs want to chime in?
That said, the reported incidents, including the fire that took the lives of three astronauts, were all in conditions where the spark occurred in a pure O2 environment. My take is that there'd have to be a really significant O2 leak for a free spark to touch off a fire; merely sparking the bottle wouldn't do it. A small leak would diffuse rapidly in the tail cone and, being rather the opposite of air tight, rapidly from there into the atmosphere. Also, where else would you put it? There are wires throughout the airframe, especially areas that would hold an O2 system, that are perfectly capable of providing sparks. In fact, I kind of feel that wires are more notorious for spark generation than batteries. Really, it seems to me the best thing to do is make the system as leak-proof as possible. To that end, I am not really a fan of that (is it copper?) tubing to the header; I'd rather see something flexible. But other than that, the installation doesn't look too worrisome to me. Take that for what it's worth; I'm only a builder. Any A&Ps and/or DARs want to chime in?
N395V
Well Known Member
I would be more concerned about having electric power to the landing lights, nav lights, strobes, or pitot heat. run by the fuel tanks in the wings.
Fuel, ignition source, oxygen (ambient air) , and uninhibited combustion.
How many of you pull the breakers on the electrical devices in your wings when not in use?
A good reason to use breakers (in my opinion) as opposed to fuses.
The O2 bottle next to a battery is kinda intuitively bad until you think about it. Then it becomes less bad than 28V or 14V wires running by the fuel tanks.
Fuel, ignition source, oxygen (ambient air) , and uninhibited combustion.
How many of you pull the breakers on the electrical devices in your wings when not in use?
A good reason to use breakers (in my opinion) as opposed to fuses.
The O2 bottle next to a battery is kinda intuitively bad until you think about it. Then it becomes less bad than 28V or 14V wires running by the fuel tanks.
Don,
Unlike the majority of people here (with a few notable exceptions), I have read through the entire report on the Columbia disaster. Oxygen supplies in the spacecraft played NO part in the survivability (or lack of) in the incident, apart from a post-accident indicator that at least some of the crew survived the initial breakup. There is nothing to be learned for us from this disaster with respect to the installation and operation of our oxygen systems, and mashing that "FEAR/PANIC" button in this manner does no one any good.
Should we give thought to "what if" scenarios while building our aircraft? Sure. Should we consider possible event chains that can lead to an improbable accident or failure? Sure. But we should NOT stop living because we are too afraid of dying. There is always risk in aviation and space flight. The trick is in recognizing it, minimizing what we can, and managing the rest. Fear and panic are not items to be placed on a checklist. I will steadfastly refuse to be concerned that someone thinks there is a one-in-a-bazillion chance that I'm going to die because of some ridiculously unlikely chain of events. I (and I'm sure most other builders with me) will, to the best of our ability, continue to weigh the risks and the rewards, accept the risks we choose to and manage that risk appropriately, and avoid the ones we are not comfortable with.
I'm not minimizing the risk of compressed pure oxygen - I have 15 years working with high pressure gases, including 7 years working with oxygen at pressures exceeding 7500 psi, and I've seen some pretty scary things. But I also know the risk/reward ratio and the chain of events required for it to get ugly - and my own analysis (YMMV, and obviously does) puts this in the same category as the autism/vaccine scare. The obvious rewards far exceed the minimal risk. You can always find the one case where it went bad for someone due to an improbable chain of events while ignoring the millions of other cases where it worked according to plan - but if we follow that logic no one would ever get out of bed in the morning.
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rv7boy
Forum Peruser
Greg, It's unfortunate that you missed the whole point of my post. It's NOT ABOUT Oxygen systems in the Columbia orbiter, but it's EVERYTHING about speaking up if you believe there is a problem.
I posted earlier about the Russians losing a cosmonaut in 1961 and not telling anyone about it, and then we lose three astronauts 7 years later in a very similar configuration.
The loss of Columbia might, I say might, have been avoided if people who thought we had damage on ascent had spoken louder and if they had been heard.
Just as this thread indicates, our world is filled with a lot of "I thought you said..."
Don
P.S. Based on your comment above, it appears to me you have NOT read the Columbia Crew Survival Investigation Report, NASA/SP-2008-565, which was published only two months ago. This is not the same report as the Columbia Accident Investigation Board report, published in August 2003. They didn't survive depressurization, much less breakup of the crew compartment.
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rv7boy
Forum Peruser
Good data point, Milt...but it ain't no certified spam can! And just because it hasn't...doesn't mean it won't!
From the other thread...check this out...battery fire
and the NTSB report. An airplane battery can ignite.
All I'm trying to say is THINK about where you place your high potential energy sources...and ask yourself, are they compatible...and what are the failure modes of each and how would they respond as a system if one or more failures occur.
One thing I found that hasn't been mentioned, and hopefully all of us can agree on, is this: Both the battery installation and the oxygen system must be mounted in such a way as to withstand with adequate margin such events as rough landings, turbulence, high-g forces, etc. No matter where we install our battery or our O2 system, the installation should be strong.
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RVbySDI
Well Known Member
I have to comment on this statement even though I do not have any specific details on this particular incident.
When I was a kid in the 70's our small town I grew up in lost 2 men to an exploding acetylene torch oxygen tank. I do not know all of the exact details about how this tank exploded but when it did explode there was nothing left of two buildings where they were welding, a welders truck or, sadly, two welders.
Actually, I've got the report on my desktop, theSP-2008-565 you referenced, that was recently released. And again, words do not relay the full context of the intended meaning here - what I meant to say, and worded poorly, was that the oxygen systems onboard could ONLY be used (in this case) as an indicator of crew survival of the incident to the point of activating the oxygen systems.
One for you, one for me. Touche...
I fully agree with you from the standpoint of thinking through the installation of anything and everything on the aircraft we build - I'm just springloaded against useless fearmongering. And no, I'm not accusing you of doing that...just an explanation of my mindset.
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