Thermal Lance / Oxygen Lance

Dear Doper folk

Today at work, on the basis of a half remembered grade school documentary about oxygen lances. I made the claim that steel will burn. In searching I found this wikipidiea entry about thermal lances: http://Thermal lance, Wiktionary also had an entry about Oxygen lances but I couldn’t figure out how to link to it.

These sites description lacks further information as to the fuel source or the process.

Part of the discussion at work was about the Fire triangle

The fact that fuels must be in the gaseous state Combustion (about half way down Solid fuels) and that steel doesn’t vaporize. (I can’t find a cite for that one why or another.)

So can anyone direct me to more information?

zer-coli

Of course steels can vaporize. The actual boiling point depends on the particular steel, but everything I can find suggests it’s around 3,000 C. Here, for one.

From the thermal lance wiki page:

A thermal lance or thermic lance or burning bar is a tool which burns iron in an oxygen rich environment to create very high temperatures for cutting. It consists of a long iron tube packed with iron rods, which are sometimes mixed with aluminum or magnesium rods which increase the heat output. One end of the tube is placed in a holder and oxygen is fed through the tube.

Iron burns, that’s what rusting is. Under pure oxygen it just burns a lot faster. And burning isn’t the same thing as vaporizing.

If the claim that you need to substantiate is only, “Steel will burn”, just do the steel-wool-in-a-candle-flame experiment.

Dear Doper folk

I still haven’t figured links, to paraphrase a Quaker saying “Please guide me to the Knowledge”
(For you non Quakers, the saying is: “Please hold me in the Light.” The sport Dopers will have with that one is going to be interesting to see.

zer-coli

It’s not important; we can discuss it without links. :slight_smile:

There’s stuff in the FAQ for how to make pretty links. When you get the time and inclination.

But actually, we don’t really need a prettified link, so you can just Copy and Paste the web page’s URL into the Reply window, and Vbulletin will automatically make it into a clickable link.

Viz. and to wit.

Which is perfectly acceptable.

This is how a oxy-acetylene cutting torch works. Works on iron based alloys only. You preheat with a neutral flame. When the iron gets orange hot, you hit the the cutting lever, which turns on a pure oxygen jet that cuts like a firehose through a mud fence. Once you have the cut started the iron is the main fuel so you can turn off the acetylene and keep cutting.

DDG

That probably will not convince the water cooler crowd. For some background; I work in a Northern Indiana Municipality as a Building Inspector. The Building Commissioner who is a retired fireman and I were at a Building code seminar and the subject of non-combustible building materials came up. Steel and Cement were mentioned as two materials used in the structural components of non-combustible buildings. I didn’t have the sense to keep my mouth shut, and ended up in an argeument with my Boss and the presenter.

Z

Kevbo

I don’t post much and can never tell just how much of my own personal knowledge to give as background. At various times I have been a Machinist, Carpenter, Licensed Plumber, Auto mechanic, HVACR Service tech and general maintenance person. The links I was trying to post went to the wikipidiea pages on the combustion triangle and an article on combustion. One of the Issues I was trying to figure out is: What, if anything, is the fuel? As far as I know rusting (oxidation) doesn’t require a fuel, could it be that “rapid oxidation” doesn’t require a fuel either?

O

Kevbo

On re-reading your post I realized how it was germane, See I knew all that and didn’t read with thought.
Big sigh from a little dummy.

By the way thanks to all that replied.

O

Iron is the fuel.

The difference between steel in a building and in a burning bar is that one is in air and the other in pure oxygen. In a normal in-air building fire steel wouldn’t burn, it would just weaken, sag, or melt depending on the fuel, insulation, and time in the fire.

Didn’t one of these feature prominently in the movie Thief? Was their portrayal remotely accurate?

Yes to both.

Burning lances were also featured in The Bank Job and $. In all three cases, they looked like real-world objects brought onto the set rather than a constructed prop.

Yup - check the “trivia” section for Thief on IMDB. I had heard this previously, that the actors learned how to use the actual tools and really did use them, including the thermal lance to burn through a real safe.

Well, as I see it, you’re both right, so you can salvage the discussion, with a bit of water cooler tact :smiley: .

From their point of view, as mentioned, the steel in a normal building fire doesn’t normally burn, so that’s why it’s used in non-combustible buildings, because the temperatures don’t get high enough to ignite it. So they can say, “Steel is non-combustible” and be right.

And from your point of view, technically–technically–it IS possible to get steel to burn.

So you can point that out, gracefully.

Was me, I’d start by saying cheerfully, “Hey, guys! Guess what! I found out…that we’re both right!” And then explain the bit about how technically–technically–it IS possible to get steel to burn.

Then offer to buy them a beer or something.

And practically, if there was lots of pure oxygen in a given building. Pretty unlikely though, since the presence of pure oxygen in large amounts tends to make people very attentive to matters of fire safety.

Another iron-as-fuel application is the one-time-use handwarmers. These contain fine iron powder that “burns” when exposed to air. They are supplied in a sealed plastic pouch that prevents air contact until heat is desired.

For major projects at nuclear power plants, we’ve used an oxy-gasoline lance to cut through reinforced concrete (with 3 inch diameter rebar).