LP tank valve removal UPDATE

Whoa.

I don't mind the argument, but lets keep the emotions down a little.

I don't think he was trying to tell you whether or not you could do anything. He was just saying that in his opinion, my ability to accept risk is greater than his. My argument is that it isn't, because I don't believe the risk is truely present.

I considered the whole "it is not safe to drive to work" issue, but I thought it was better to stick to the issue. "If what I did was risky, please explain how"

Maybe people will develop a better understanding of how risky this really was. Heck, I might even learn something.

Dave

And what kind of idiot will blow down a tank in the presence of an ignition source?

Inside a petro chem plant which are generally held together with bubble gum and bailing wire.

A PC plant is not a 100 pound cylinder.

Kent , your impressing me that your the type of person who no one else can be right or you can't be wrong, no matter what.

I never said anything about your choices anyplace. I specifically said I wasn't going to discuss the valve removal - I agree its been discussed to death. I don't know anything about the chemistry of that stuff, and I didn't discuss it. I don't see that I had a decision in that posting anyplace other than the discussion of how I use a lathe file, and why, which you can do with as you please.

What I said, as a matter of philosophy, applies regardless of circumstance. The physics of risk taking are pretty simple - if you do something that is risky enough, often enough, it will have a bad outcome. The corollary to that is that the fact that if one took a chance, committed a risky act, and didn't have a bad outcome, doesn't make the act safe. The fact that a person took a chance and it didn't have a bad outcome isn't the important lesson. The important lesson is that the lack of a bad outcome doesn't make an act safe. My intention was to make that point. I provided examples to illustrate it.

The bottom line is that taking a risk, assessing a risk, is a personal decision. The outcome depends on chance. Nothing I wrote is inconsistent with that.

Fitch

No, not the adhesive, the foam itself. Environmentalism forced a change of the foaming process from using a CFC agent to something more "environmentally friendly" (and structurally inferior). If someone is claiming otherwise, it betrays a political agenda. Environmentalism destroyed Columbia.

Ah. Now here is the man who probably knows the inside story. I read the article in the "National Review" about the failed safety culture at nasa, and the various managers (Ham, etc.) who were second-guessing the engineers.

Was that article pretty much accurate?

Jim

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Yes.

Fitch

I've seem a few that would, fortunately they didn't make their probation period.

when a 500 or 1000 gal residential tank vents it scares ten years out of you. all the folks i knew in the NM volunteer fire dept's said that if you didn't get a hose on it early, you had to just leave it alone and stand clear. but worse danger is an overfill that vents, the valve does not close until the tank is empty. you need to stay a _long_ way away from that one.

Been in a lot of petrochem plants and refineries, have you? Do you actually work in one?

A 100 pound cylinder can get you burned or dead.

Nope, I've been wrong on lots of occasions. My wife usually proves me wrong at least once a day and I admit it. . But I will never, ever change my opinion on this one. I think you need to go back and re-read all the posts. I suggested he query the chief instructor at the Texas A and M fire school as to his opinion. Does this sound like I think I am right all the time? Or his local fire chief. Again, does this sound like I think I am the only one who is right?? The response I got was:

1. Fire Chiefs don't know shit about tanks and vessels with hydrocarbons in them and he wouldn't ask a fire chief about anything.

2 Firemen don't know shit be cause they like to err on the side of caution and really don't understand because they don't have a physics or a chemical engineering degree and would do something else beside be a fireman if they had said degrees. 3 And obviously believes that only degreed people have the mental capacity to understand the fire triangle.

And you accuse ME of being block headed? I think you must have us mixed up. I' m the guy who won't take a torch to a propane tank with out it being cleared first.

That would match... The first question after "Is anybody inside?" was "Any propane bulk tanks? Where?" ("Yes, out back, big pig, about 500 gallons, maybe half full, I think")

First place the hoses went was back to the pig, about 20, maybe 25 feet from the back wall. The back wall of the house (in fact, it was the section of bathroom wall that I mentioned was the only thing left standing in the end) was the only part that wasn't actively burning at that point, although everything inside, and the entire front, was blazing away merrily. They put a man with a handline on it, and there he, or someone like him, stayed for the next 6 hours or so, until the final bits that were left of the house finally collapsed into the basement.

.Apparently:.........................

Yours is not to reason. Why?

Welcome back Fitch.

XXXXXXXXXXXXXXXXXXXXXXXXXXXX

I understand that that your reasoning was sound. It was well thought out and well calculated. It also required the courage of conviction in your reasoning. And I'm sure NASA would be eager for your talents.

I have no opinion at all about what you did. I wouldn't have done it, but only because I haven't a clue whether it is safe or not. It is a fuel container, and due diligence would have me deciding it was unsafe unless I could prove it was safe to myself.

You thought it was safe and removed the valve. Good for you.

If I needed a valveless propane tank for whatever reason, I'd probably buy a new unfilled one simply because they aren't that expensive, and spending the time doing the research to prove the risk was very small compared to the gain wouldn't be worth it to me.

It was to you. That's fine with me.

My only point was that if someone does something (anything - pick a pony) that is perceived as risky, and doesn't have a bad outcome, that is not proof that it was a safe thing to do. The definition of "Safe" being that the risk taken was small compared to the gain.

Whew! I didn't think it was that complicated. But then NASA management didn't get it either. I don't think they do yet.

Fitch

Wow, you sound pretty sure of yourself. Care to back it up? What are your qualifications?

You seem to be pretty proud of yourself for working in a petrochemical plant, but I have yet to hear what you actually do. For all I know, you are a custodian. (or maybe a fireman?)

What is your education? Do you have an associates degree? How many chemistry, math, or physics classes have you taken?

Even though you can't back up your opinions about the LP tank, you should be able to back up your statement of general knowledge.

Dave

^^^^^^^^^

Well, there you go - it's in the eye of the beholder. Dave didn't _perceive_ it as risky. You're not really talking to each other - Dave says "So me the risk" and Fitch says "It's not worth the risk for me".

And of course one doesn't just perceive risk: "yes" or "no", one perceives the _degree_ of risk. Then compares it to the "reward" involved. Which is what Fitch is saying (I hope I'm not misquoting), but it's also what everybody does naturally, all the time. Including Dave - he did perceive _some_ level of risk (there's some level of risk in _everything_), but he didn't perceive it as significant.

Bob

(Isn't it wonderful how an RCM debate like this can go on and remain (mostly) civil, polite even?

Automobile and light airplanes have fuel level senders in their tanks. These are wirewound potentiometers that vary the current flow to the fuel gauge. In many of them the float works a copper reed back and forth, with a small graphite runner on its tip that runs on the resistance wire. This takes place in a metal can with large holes in it, so that all is immersed in fuel or fuel vapours. The graphite wears out. The copper runs on the wire, chews it up, and makes sparks. IN A FUEL TANK. IN FLIGHT. I have never heard of an airplane blowing up due to this. The combustible mixture of gasoline is 8% to 18%, and the mixture in the tank is much, much richer than that. We frequently find these senders worn out in our airplanes. I'm never nervous working on the system unless we drain all the fuel to remove a tank, and then I get really careful, as the mixture in the tank drops into the combustible range. I prefer leaving a least a bit of fuel in it and keeping the cap on as much as possible. The most dangerous place is at the filler neck when the cap is off and vapours are mixing with the atmosphere, which is why we once in a while hear of fires caused by static sparks during fuelling. Airplanes can accumulate considerable static in flight, or even on the ground during a thunderstorm, or the fueller can make his own sparks in cold weather by rubbing his jacket on the wing while refuelling. So we ground everything.

Dan

I heard that, too, but was not able to find a link that didn't look like tinfoil cap folks posted it. I'm not disputing it, just can't find a good link - do you have one?

Heck that's nothing. Nearly every car on the road today has a brush type electric motor that runs the fuel pump, immersed in either liquid gasoline, or gas vapor.

I suppose from the resounding lack of booms, it probably works.

Jim

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