What happens if you use a regular regulator with 100% oxygen?

[hazmat]

Subject says it all. What sorts of problems can arise?

Thanks.

 

[rhwestfall]

assuming you mean "not 02 cleaned", there is an elevated potential for a flash fire in the stage due to possible existence of contaminants/combustibles, and resulting nasty things to your lungs.....

 

[hazmat]

Oooh, that's ugly. Thanks. That's what I meant.

 

[axxel57]

Thanks for the question.

It's an issue that bothers me since I read years ago about a combustion of an Atomic Titan 1st stage.

I tried to image how that could happen,even given the fact that Titan might be more easily ignitable than brass, but didn't understand how.

I mean, how I learned it, you need for a combustion the combustion triangle.

So you need a fuel, which could be any type of contamination, means mostly carbohydrates.

You need an oxidizer, which would be the O2.

And you need heat, which comes while filling a tank for example in form of so called adiabatic heating.

In a not O2 cleaned 1st stage we might find fuel (o-rings not suitable for pure oxygen applications, dirt or whatever).

Using pure oxygen we got the oxidizer.

But where does the heat comes from?

Normally we know that our 1st stage while using it is pretty cold because of the cold expanding HP air from the tank causing adiabatic cooling.

So if my 1st stage is getting colder the more I use it, where is the heat developing so near to the tank valve releasing HP?

Especially when I'm under water diving with the water temperature even in the tropics, how can the 1st stage heat up to the point that it can complete the combustion triangle and fire up?

I mean I know that filling a tank will produce heat in the tank. It's a dead end and compressed air heats up while being compressed.

But how can a devise only a centimeter away from the source of significant cold (the tank valve when the air expands) produce enough heat to cause a combustion?

There is something I miss, but I don't know what.

Maybe somebody can help here.

 

[Brandon]

Especially when I'm under water diving with the water temperature even in the tropics, how can the 1st stage heat up to the point that it can complete the combustion triangle and fire up?

I mean I know that filling a tank will produce heat in the tank. It's a dead end and compressed air heats up while being compressed.

But how can a devise only a centimeter away from the source of significant cold (the tank valve when the air expands) produce enough heat to cause a combustion?

There is something I miss, but I don't know what.

Maybe somebody can help here.

Small piece of metallic grit gets propelled at high velocity and creates a spark. Or the gas passes a restriction in the valve/regulator and creates localized adiabatic heating to the point of ignition.

 

[Curt Bowen]

Subject says it all. What sorts of problems can arise?

Thanks.

Nothing, Ive been using standard regulators with 100% O2 for 25 plus years.

 

[ams511]

Nothing, Ive been using standard regulators with 100% O2 for 25 plus years.

I am really surprised to hear you say that. The logic behind O2 cleaning is to reduce the probability of a fire by removing contaminates. You are just one data point. My uncle used to smoke 2 packs of Lucky Strikes a day for decades, lived into his mid 90s and never had problems with his lungs. His experience doesn't mean that cigarettes are safe.

 

[KenGordon]

Thanks for the question.

It's an issue that bothers me since I read years ago about a combustion of an Atomic Titan 1st stage.

I tried to image how that could happen,even given the fact that Titan might be more easily ignitable than brass, but didn't understand how.

I mean, how I learned it, you need for a combustion the combustion triangle.

So you need a fuel, which could be any type of contamination, means mostly carbohydrates.

You need an oxidizer, which would be the O2.

And you need heat, which comes while filling a tank for example in form of so called adiabatic heating.

In a not O2 cleaned 1st stage we might find fuel (o-rings not suitable for pure oxygen applications, dirt or whatever).

Using pure oxygen we got the oxidizer.

But where does the heat comes from?

Normally we know that our 1st stage while using it is pretty cold because of the cold expanding HP air from the tank causing adiabatic cooling.

So if my 1st stage is getting colder the more I use it, where is the heat developing so near to the tank valve releasing HP?

Especially when I'm under water diving with the water temperature even in the tropics, how can the 1st stage heat up to the point that it can complete the combustion triangle and fire up?

I mean I know that filling a tank will produce heat in the tank. It's a dead end and compressed air heats up while being compressed.

But how can a devise only a centimeter away from the source of significant cold (the tank valve when the air expands) produce enough heat to cause a combustion?

There is something I miss, but I don't know what.

Maybe somebody can help here.

When you initially open the valve on the cylinder there is an inrush of O2 into the first stage, round corners and up against obstructions and then down the lp hose to the second stage. At this time there will be localised heating. That localised heating is the risk.

Mitigation include turning the gas on gently, keeping everything clean and so forth. The expectation is not that it spontaneously combusts in the water while you are breathing off it but the problem happens on the surface as you check your gas etc.

 

[Storker]

I mean, how I learned it, you need for a combustion the combustion triangle.

So you need a fuel, which could be any type of contamination, means mostly carbohydrates.

You need an oxidizer, which would be the O2.

And you need heat, which comes while filling a tank for example in form of so called adiabatic heating.

In a not O2 cleaned 1st stage we might find fuel (o-rings not suitable for pure oxygen applications, dirt or whatever).

Using pure oxygen we got the oxidizer.

But where does the heat comes from?

You don't need much of it since the auto-ignition temperature decreases with increasing pPO2. And for a hydrocarbon, that temperature isn't too high to start with. Even our O-rings are getting uncomfortably close to their auto-ignition temperature at high pPO2s: Note: Autoignition Temperature of Selected Polymers at Elevated Oxygen Pressure and Their Heat of Combustion - Hshieh - 1998 - Fire and Materials - Wiley Online Library

In that paper, you can read that nitrile rubber in 10.3 MPa (103 bar) oxygen auto-ignites at 173 °C.

Small piece of metallic grit gets propelled at high velocity and creates a spark. Or the gas passes a restriction in the valve/regulator and creates localized adiabatic heating to the point of ignition.

I'd assume that the local adiabatic heating scenario is a lot more probable than the grit-causing-a-spark scenario.

And since we're on the subject of pure oxygen and fires, I'd like to point to George H. Goble's famous experiment, for which he received the 1996 Ig Nobel Prize in chemistry:
[video=youtube;sab2Ltm1WcM]https://www.youtube.com/watch?v=sab2Ltm1WcM[/video]

 

[rhwestfall]

The expectation is not that it spontaneously combusts in the water while you are breathing off it but the problem happens on the surface as you check your gas etc.

It happened to a diver here (at a deco stop)....